View TC9402_397091.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

TC9400/9401/9402
Voltage-to-Frequency/Frequency-to-Voltage Converters
Features
VOLTAGE-TO-FREQUENCY
* Choice of Linearity - TC9401: 0.01% - TC9400: 0.05% - TC9402: 0.25% * DC to 100kHz (F/V) or 1Hz to 100kHz (V/F) * Low Power Dissipation: 27mW (Typ.) * Single/Dual Supply Operation - +8V to +15V or 4V to 7.5V * Gain Temperature Stability: 25 ppm/C (Typ.) * Programmable Scale Factor
General Description
The TC9400/TC9401/TC9402 are low cost voltage-tofrequency (V/F) converters, utilizing low power CMOS technology. The converters accept a variable analog input signal and generate an output pulse train, whose frequency is linearly proportional to the input voltage. The devices can also be used as highly accurate frequency-to-voltage (F/V) converters, accepting virtually any input frequency waveform and providing a linearly proportional voltage output. A complete V/F or F/V system only requires the addition of two capacitors, three resistors, and reference voltage.
FREQUENCY-TO-VOLTAGE
* Operation: DC to 100kHz * Choice of Linearity - TC9401: 0.02% - TC9400: 0.05% - TC9402: 0.25% * Programmable Scale Factor
Package Type
14-Pin Plastic DIP/CERDIP
IBIAS 1 ZERO ADJ 2 IIN 3 VSS 4 VREF OUT 5 GND 6 VREF 7 14 VDD 13 NC
Applications
* * * * * * * P Data Acquisition 13-bit Analog-to-Digital Converters Analog Data Transmission and Recording Phase Locked Loops Frequency Meters/Tachometer Motor Control FM Demodulation
TC9400 TC9401 TC9402
12 AMPLIFIER OUT THRESHOLD 11 DETECTOR 10 FREQ/2 OUT 9 OUTPUT COMMON 8 PULSE FREQ OUT
14-Pin SOIC
IBIAS ZERO ADJ 1 2 3 4 5 6 7 14 13 VDD NC AMPLIFIER OUT THRESHOLD DETECTOR FREQ/2 OUT OUTPUT COMMON PULSE FREQ OUT
Device Selection Table
Part Number TC9400COD TC9400CPD TC9400EJD TC9401CPD TC9401EJD TC9402CPD TC9402EJD Linearity (V/F) 0.05% 0.05% 0.05% 0.01% 0.01% 0.25% 0.25% Package 14-Pin SOIC (Narrow) 14-Pin PDIP 14-Pin CerDIP 14-Pin PDIP 14-Pin CerDIP 14-Pin PDIP 14-Pin CerDIP Temperature Range 0C to +70C 0C to +70C -40C to +85C 0C to +70C -40C to +85C 0C to +70C C to +85C
IIN VSS VREF OUT GND VREF
TC9400 TC9401 TC9402
12 11 10 9 8
NC = No Internal Connection
2002 Microchip Technology Inc.
DS21483B-page 1
(c)
TC9400/9401/9402
Functional Block Diagram
Integrator Capacitor Input Voltage RIN IIN
Integrator Op Amp
Threshold Detector
One Shot
Pulse Output
Reference Capacitor
/2
Pulse/2 Output
TC9400
IREF
Reference Voltage
(c)
DS21483B-page 2
2002 Microchip Technology Inc.
TC9400/9401/9402
1.0 ELECTRICAL CHARACTERISTICS
*Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability.
Absolute Maximum Ratings*
VDD - VSS ........................................................... +18V IIN ........................................................................ 10mA VOUTMAX - VOUT Common...................................... 23V VREF - VSS ..........................................................-1.5V Storage Temperature Range .............. -65C to +150C Operating Temperature Range: C Device ........................................... 0C to +70C E Device......................................... -40C to +85C Package Dissipation (TA 70C): 8-Pin CerDIP .............................................. 800mW 8-Pin Plastic DIP ........................................ 730mW 8-Pin SOIC ................................................. 470mW
TC940X ELECTRICAL SPECIFICATIONS
Electrical Characteristics: VDD = +5V, VSS = -5V, VGND = 0V, VREF = -5V, RBIAS = 100k, Full Scale = 10kHz, unless otherwise specified. TA = +25C, unless temperature range is specified (-40C to +85C for E device, 0C to +70C for C device). Parameter Min Typ Max Min Typ Max Min Typ Max Units Test Conditions
Voltage-to-Frequency
Accuracy Linearity 10kHz -- TC9400 0.01 0.05 -- TC9401 0.004 0.01 -- TC9402 0.05 0.25 % Output Deviation from Full Scale Straight Line Between Normalized Zero and Full Scale Input % Output Deviation from Full Scale Straight Line Between Normalized Zero Reading and Full Scale Input ppm/C Variation in Gain A due Full Scale to Temperature Change % of Nominal mV Variation from Ideal Accuracy Correction at Zero Adjust for Zero Output when Input is Zero Variation in Zero Offset Due to Temperature Change
Linearity 100kHz
--
0.1
0.25
--
0.04
0.08
--
0.25
0.5
Gain Temperature Drift (Note 1) Gain Variance Zero Offset (Note 2) Zero Temperature Drift (Note 1) Note 1: 2: 3: 4: 5: 6: 7: 8: 9: 10:
-- -- --
25 10 10
40 -- 50
-- -- --
25 10 10
40 -- 50
-- -- --
50 10 20
100 -- 100
--
25
50
--
25
50
--
50
100
V/C
Full temperature range; not tested. IIN = 0. Full temperature range, IOUT = 10mA. IOUT = 10A. Threshold Detect = 5V, Amp Out = 0V, full temperature range. 10Hz to 100kHz; not tested. 5sec minimum positive pulse width and 0.5sec minimum negative pulse width. tR = tF = 20nsec. RL 2k, tested @ 10k. Full temperature range, VIN = -0.1V.
2002 Microchip Technology Inc.
DS21483B-page 3
(c)
TC9400/9401/9402
TC940X ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics: VDD = +5V, VSS = -5V, VGND = 0V, VREF = -5V, RBIAS = 100k, Full Scale = 10kHz, unless otherwise specified. TA = +25C, unless temperature range is specified (-40C to +85C for E device, 0C to +70C for C device). Parameter Analog Input IIN Full Scale -- 10 -- -- 10 -- -- 10 -- A Full Scale Analog Input Current to achieve Specified Accuracy Over Range Current Settling Time to 0.1% Full Scale Min Typ Max Min Typ Max Min Typ Max Units Test Conditions
IIN Over Range Response Time Digital Section VSAT @ IOL = 10mA VOUTMAX - VOUT Common (Note 4) Pulse Frequency Output Width
-- --
-- 2 TC9400
50 --
-- --
-- 2 TC9401
50 --
-- --
-- 2 TC9402
50 --
A Cycle
-- --
0.2 --
0.4 18
-- --
0.2 --
0.4 18
-- --
0.2 --
0.4 18
V V
Logic "0" Output Voltage (Note 3) Voltage Range Between Output and Common
--
3
--
--
3
--
--
3
--
sec
Frequency-to-Voltage
Supply Current IDD Quiescent (Note 5) ISS Quiescent (Note 5) VDD Supply VSS Supply Reference Voltage VREF - VSS Accuracy Non-Linearity (Note 10) -- 0.02 0.05 -- 0.01 0.02 -- 0.05 0.25 % Deviation from ideal Full Scale Transfer Function as a Percentage Full Scale Voltage Hz Frequency Range for Specified Non-Linearity -2.5 -- -- -2.5 -- -- -2.5 -- -- V Range of Voltage Reference Input -- 1.5 6 -- 1.5 6 -- 3 10 mA Current Required from Positive Supply during Operation Current Required from Negative Supply during Operation Operating Range of Positive Supply Operating Range of Negative Supply
--
-1.5
-6
--
-1.5
-6
--
-3
-10
mA
4 -4
-- --
7.5 -7.5
4 -4
-- --
7.5 -7.5
4 -4
-- --
7.5 -7.5
V V
Input Frequency Range (Notes 7 and 8) Note 1: 2: 3: 4: 5: 6: 7: 8: 9: 10:
10
--
100k
10
--
100k
10
--
100k
Full temperature range; not tested. IIN = 0. Full temperature range, IOUT = 10mA. IOUT = 10A. Threshold Detect = 5V, Amp Out = 0V, full temperature range. 10Hz to 100kHz; not tested. 5sec minimum positive pulse width and 0.5sec minimum negative pulse width. tR = tF = 20nsec. RL 2k, tested @ 10k. Full temperature range, VIN = -0.1V.
(c)
DS21483B-page 4
2002 Microchip Technology Inc.
TC9400/9401/9402
TC940X ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics: VDD = +5V, VSS = -5V, VGND = 0V, VREF = -5V, RBIAS = 100k, Full Scale = 10kHz, unless otherwise specified. TA = +25C, unless temperature range is specified (-40C to +85C for E device, 0C to +70C for C device). Parameter Frequency Input Positive Excursion 0.4 -- VDD 0.4 -- VDD 0.4 -- VDD V Voltage Required to Turn Threshold Detector On Voltage Required to Turn Threshold Detector Off Time between Threshold Crossings Time Between Threshold Crossings Min Typ Max Min Typ Max Min Typ Max Units Test Conditions
Negative Excursion
-0.4
-2
-0.4
--
-2
-0.4
--
-2
V
Minimum Positive Pulse Width (Note 8) Minimum Negative Pulse Width (Note 8) Input Impedance Analog Outputs Output Voltage (Note 9) Output Loading Supply Current IDD Quiescent (Note 10) ISS Quiescent (Note 10) VDD Supply VSS Supply Reference Voltage VREF - VSS Note 1: 2: 3: 4: 5: 6: 7: 8: 9: 10:
--
5
--
--
5
--
--
5
--
sec
--
0.5
--
--
0.5
--
--
0.5
--
sec
--
10 TC9400
--
--
10 TC9401
--
-- TC9402
10
M
--
VDD - 1
--
--
VDD - 1
--
--
VDD - 1
--
V
Voltage Range of Op Amp Output for Specified Non-Linearity Resistive Loading at Output of Op Amp
2
-- TC9400
--
2
-- TC9401
--
2
-- TC9402
--
k
--
1.5
6
--
1.5
6
--
3
10
mA
Current Required from Positive Supply During Operation Current Required from Negative Supply During Operation Operating Range of Positive Supply Operating Range of Negative Supply
--
-1.5
-6
-1.5
-6
--
-3
-10
mA
4 -4
-- --
7.5 -7.5
4 -4
-- --
7.5 -7.5
4 -4
-- --
7.5 -7.5
V V
-2.5
--
--
-2.5
--
--
-2.5
--
--
V
Range of Voltage Reference Input
Full temperature range; not tested. IIN = 0. Full temperature range, IOUT = 10mA. IOUT = 10A. Threshold Detect = 5V, Amp Out = 0V, full temperature range. 10Hz to 100kHz; not tested. 5sec minimum positive pulse width and 0.5sec minimum negative pulse width. tR = tF = 20nsec. RL 2k, tested @ 10k. Full temperature range, VIN = -0.1V.
2002 Microchip Technology Inc.
DS21483B-page 5
(c)
TC9400/9401/9402
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
PIN FUNCTION TABLE
Symbol IBIAS ZERO ADJ IIN VSS VREF OUT GND VREF PULSE FREQ OUT OUTPUT COMMON FREQ/2 OUT THRESHOLD DETECTOR NC VDD Description This pin sets bias current in the TC9400. Connect to VSS through a 100k resistor. Low frequency adjustment input. Input current connection for the V/F converter. Negative power supply voltage connection, typically -5V. Reference capacitor connection. Analog ground. Voltage reference input, typically -5V. Frequency output. This open drain output will pulse LOW each time the Freq. Threshold Detector limit is reached. The pulse rate is proportional to input voltage. Source connection for the open drain output FETs. This open drain output is a square wave at one-half the frequency of the pulse output (Pin 8). Output transitions of this pin occur on the rising edge of Pin 8. Input to the Threshold Detector. This pin is the frequency input during F/V operation.
Pin No. 14-Pin PDIP/CERDIP 14-Pin SOIC (Narrow) 1 2 3 4 5 6 7 8 9 10 11 12 13 14
AMPLIFIER OUT Output of the integrator amplifier. No internal connection. Positive power supply connection, typically +5V.
(c)
DS21483B-page 6
2002 Microchip Technology Inc.
TC9400/9401/9402
3.0
3.1
DETAILED DESCRIPTION
Voltage-to-Frequency (V/F) Circuit Description
The TC9400 V/F converter operates on the principal of charge balancing. The operation of the TC9400 is easily understood by referring to Figure 3-1. The input voltage (VIN) is converted to a current (IIN) by the input resistor. This current is then converted to a charge on the integrating capacitor and shows up as a linearly decreasing voltage at the output of the Op Amp. The lower limit of the output swing is set by the threshold detector, which causes the reference voltage to be applied to the reference capacitor for a time period long enough to charge the capacitor to the reference voltage. This action reduces the charge on the integrating capacitor by a fixed amount (q = CREF x VREF), causing the Op Amp output to step up a finite amount. At the end of the charging period, CREF is shorted out. This dissipates the charge stored on the reference capacitor, so that when the output again crosses zero, the system is ready to recycle. In this manner, the continued discharging of the integrating capacitor by the
input is balanced out by fixed charges from the reference voltage. As the input voltage is increased, the number of reference pulses required to maintain balance increases, which causes the output frequency to also increase. Since each charge increment is fixed, the increase in frequency with voltage is linear. In addition, the accuracy of the output pulse width does not directly affect the linearity of the V/F. The pulse must simply be long enough for full charge transfer to take place. The TC9400 contains a "self-start" circuit to ensure the V/F converter always operates properly when power is first applied. In the event that, during power-on, the Op Amp output is below the threshold and CREF is already charged, a positive voltage step will not occur. The Op Amp output will continue to decrease until it crosses the -3.0V threshold of the "self-start" comparator. When this happens, an internal resistor is connected to the Op Amp input, which forces the output to go positive until the TC9400 is in its Normal Operating mode. The TC9400 utilizes low power CMOS processing for low input bias and offset currents, with very low power dissipation. The open drain N-channel output FETs provide high voltage and high current sink capability.
FIGURE 3-1:
10Hz TO 10kHz V/F CONVERTER
+5V 14 VDD
Threshold 11 Detect 3sec Delay Threshold Detector FOUT/2 10 SelfStart -3V 12 AMP OUT 5 VREF OUT CINT 820pF CREF 180pF 3 IIN 510k Zero Adjust 2 20k 12pF 60pF /2 Output Common 9 RL 10k FOUT 8 RL 10k
+5V
+5V
INPUT VIN 0V -10V
RIN 1M +5V
TC9400 TC9401 TC9402
-
Op Amp
50k -5V Offset Adjust
+
IBIAS VSS 4 VREF 7 Reference Voltage (Typically -5V) -5V GND 6
10k
1 RBIAS 100k
2002 Microchip Technology Inc.
DS21483B-page 7
(c)
TC9400/9401/9402
3.2 Voltage-to-Time Measurements
4.0
4.1
PIN FUNCTIONS
Threshold Detector Input
The TC9400 output can be measured in the time domain as well as the frequency domain. Some microcomputers, for example, have extensive timing capability, but limited counter capability. Also, the response time of a time domain measurement is only the period between two output pulses, while the frequency measurement must accumulate pulses during the entire counter time-base period. Time measurements can be made from either the TC9400's PULSE FREQ OUT output, or from the FREQ/2 OUT output. The FREQ/2 OUT output changes state on the rising edge of PULSE FREQ OUT, so FREQ/2 OUT is a symmetrical square wave at one-half the pulse output frequency. Timing measurements can, therefore, be made between successive PULSE FREQ OUT pulses, or while FREQ/2 OUT is high (or low).
In the V/F mode, this input is connected to the AMPLIFIER OUT output (Pin 12) and triggers a 3sec pulse when the input voltage passes through its threshold. In the F/V mode, the input frequency is applied to this input. The nominal threshold of the detector is half way between the power supplies, or (VDD + VSS)/2 400mV. The TC9400's charge balancing V/F technique is not dependent on a precision comparator threshold, because the threshold only sets the lower limit of the Op Amp output. The Op Amp's peak-to-peak output swing, which determines the frequency, is only influenced by external capacitors and by V REF.
4.2
Pulse Freq Out
This output is an open drain N-channel FET, which provides a pulse waveform whose frequency is proportional to the input voltage. This output requires a pullup resistor and interfaces directly with MOS, CMOS, and TTL logic (see Figure 4-1).
FIGURE 4-1:
OUTPUT WAVEFORMS
3sec Typ.
FOUT
FOUT/2
1/f CREF CINT
VREF Amp Out 0V
Notes: 1. To adjust FMIN, set VIN = 10mV and adjust the 50k offset for 10Hz output. 2. To adjust FMAX, set VIN = 10V and adjust RIN or VREF for 10kHz output. 3. To increase FOUTMAX to 100kHz, change CREF to 2pF and CINT to 75pF. 4. For high performance applications, use high stability components for RIN, CREF, VREF (metal film resistors and glass capacitors). Also, separate output ground (Pin 9) from input ground (Pin 6).
(c)
DS21483B-page 8
2002 Microchip Technology Inc.
TC9400/9401/9402
4.3 Freq/2 Out 4.8 IIN
This output is an open drain N-channel FET, which provides a square wave one-half the frequency of the pulse frequency output. The FREQ/2 OUT output will change state on the rising edge of PULSE FREQ OUT. This output requires a pull-up resistor and interfaces directly with MOS, CMOS, and TTL logic. The inverting input of the operational amplifier and the summing junction when connected in the V/F mode. An input current of 10A is specified, but an over range current up to 50A can be used without detrimental effect to the circuit operation. IIN connects the summing junction of an operational amplifier. Voltage sources cannot be attached directly, but must be buffered by external resistors.
4.4
Output Common
The sources of both the FREQ/2 OUT and the PULSE FREQ OUT are connected to this pin. An output level swing from the drain voltage to ground, or to the V SS supply, may be obtained by connecting this pin to the appropriate point.
4.9
VREF
A reference voltage from either a precision source, or the VSS supply is applied to this pin. Accuracy of the TC9400 is dependent on the voltage regulation and temperature characteristics of the reference circuitry. Since the TC9400 is a charge balancing V/F converter, the reference current will be equal to the input current. For this reason, the DC impedance of the reference voltage source must be kept low enough to prevent linearity errors. For linearity of 0.01%, a reference impedance of 200W or less is recommended. A 0.1F bypass capacitor should be connected from VREF to ground.
4.5
R BIAS
An external resistor, connected to V SS, sets the bias point for the TC9400. Specifications for the TC9400 are based on RBIAS = 100k 10%, unless otherwise noted. Increasing the maximum frequency of the TC9400 beyond 100kHz is limited by the pulse width of the pulse output (typically 3sec). Reducing RBIAS will decrease the pulse width and increase the maximum operating frequency, but linearity errors will also increase. RBIAS can be reduced to 20k, which will typically produce a maximum full scale frequency of 500kHz.
4.10
VREF Out
4.6
Amplifier Out
This pin is the output stage of the operational amplifier. During V/F operation, a negative going ramp signal is available at this pin. In the F/V mode, a voltage proportional to the frequency input is generated.
The charging current for CREF is supplied through this pin. When the Op Amp output reaches the threshold level, this pin is internally connected to the reference voltage and a charge, equal to VREF x CREF, is removed from the integrator capacitor. After about 3sec, this pin is internally connected to the summing junction of the Op Amp to discharge CREF. Break-before-make switching ensures that the reference voltage is not directly applied to the summing junction.
4.7
Zero Adjust
This pin is the non-inverting input of the operational amplifier. The low frequency set point is determined by adjusting the voltage at this pin.
2002 Microchip Technology Inc.
DS21483B-page 9
(c)
TC9400/9401/9402
5.0 VOLTAGE-TO-FREQUENCY (V/F) CONVERTER DESIGN INFORMATION
Input/Output Relationships
CREF (pF) +12pF
FIGURE 5-1:
500 400 300
RECOMMENDED CREF VS. VREF
VDD = +5V VSS = -5V RIN = 1M VIN = +10V TA = +25C 10kHz
5.1
The output frequency (FOUT) is related to the analog input voltage (VIN) by the transfer equation:
EQUATION 5-1:
Frequency Out = VIN 1 ,x (VREF)(VREF) RIN
200
100 100kHz
5.2
5.2.1
External Component Selection
R IN 5.2.4
0
-1
-2
-3 -4 VREF (V)
-5
-6
-7
The value of this component is chosen to give a full scale input current of approximately 10A:
VDD, VSS
EQUATION 5-2:
RIN VIN FULLSCALE 10A
Power supplies of 5V are recommended. For high accuracy requirements, 0.05% line and load regulation and 0.1F disc decoupling capacitors, located near the pins, are recommended.
5.3
Adjustment Procedure
EQUATION 5-3:
RIN 10V = 1M 10A
Figure 3-1 shows a circuit for trimming the zero location. Full scale may be trimmed by adjusting RIN, VREF, or CREF. Recommended procedure for a 10kHz full scale frequency is as follows: 1. Set VIN to 10mV and trim the zero adjust circuit to obtain a 10Hz output frequency. Set VIN to 10V and trim either RIN, VREF, or CREF to obtain a 10kHz output frequency.
Note that the value is an approximation and the exact relationship is defined by the transfer equation. In practice, the value of RIN typically would be trimmed to obtain full scale frequency at VIN full scale (see Section 5.3, Adjustment Procedure). Metal film resistors with 1% tolerance or better are recommended for high accuracy applications because of their thermal stability and low noise generation.
2.
If adjustments are performed in this order, there should be no interaction and they should not have to be repeated.
5.4
5.2.2
C INT
Improved Single Supply V/F Converter Operation
The exact value is not critical but is related to CREF by the relationship: 3CREF CINT 10CREF Improved stability and linearity are obtained when CINT 4CREF. Low leakage types are recommended, although mica and ceramic devices can be used in applications where their temperature limits are not exceeded. Locate as close as possible to Pins 12 and 13.
5.2.3
C REF
The exact value is not critical and may be used to trim the full scale frequency (see Section 7.1, Input/Output Relationships). Glass film or air trimmer capacitors are recommended because of their stability and low leakage. Locate as close as possible to Pins 5 and 3 (see Figure 5-1).
A TC9400, which operates from a single 12 to 15V variable power source, is shown in Figure 5-2. This circuit uses two Zener diodes to set stable biasing levels for the TC9400. The Zener diodes also provide the reference voltage, so the output impedance and temperature coefficient of the Zeners will directly affect power supply rejection and temperature performance. Full scale adjustment is accomplished by trimming the input current. Trimming the reference voltage is not recommended for high accuracy applications unless an Op Amp is used as a buffer, because the TC9400 requires a low impedance reference (see Section 4.9, VREF pin description, for more information). The circuit of Figure 5-2 will directly interface with CMOS logic operating at 12V to 15V. TTL or 5V CMOS logic can be accommodated by connecting the output pull-up resistors to the +5V supply. An optoisolator can also be used if an isolated output is required; also, see Figure 5-3.
(c)
DS21483B-page 10
2002 Microchip Technology Inc.
TC9400/9401/9402
FIGURE 5-2: VOLTAGE TO FREQUENCY
+12 to +15V 1.2k 14 VDD CINT 11 Threshold Detect 12 Amp Out CREF 5 C
REF
1F R1 910k R3 Gain R4 100k
D2 5.1VZ
10k
10k
TC9400
3 IIN 2 Zero Adjust FOUT 8 10 Output Frequency
100k R2 910k R5 91k D1 5.1VZ
6 GND 0.1 7V REF 1I
BIAS
FOUT/2
Output 9 Common
Input Voltage (0 to 10V)
Rp Offset 20k Analog Ground Component Selection CREF CINT F/S FREQ. 2200pF 4700pF 1kHz 180pF 470pF 10kHz 27pF 75pF 100kHz
100k
VSS 4
Digital Ground
FIGURE 5-3:
FIXED VOLTAGE - SINGLE SUPPLY OPERATION
V+ = 8V to 15V (Fixed)
R2 0.9 R1 Gain Adjust V2 5V 8.2 k 2 k Offset Adjust RIN 1M VIN 0V-10V IIN 100k 0.2 R1 820 pF 0.01 F 2 6
14 8
10k FOUT 10k 10 FOUT/2
TC9400
7 VREF 0.01 11 F 12 5 180 pF 3 IIN 1 4 9
V+ 10V 12V 15V
R1 1M 1.4M 2M
R2 10k 14k 20k
FOUT = IIN
1 (V2 - V7) (CREF) + (V+ - V2) (0.9R1 + 0.2R1)
IIN =
(VIN - V2) RIN
2002 Microchip Technology Inc.
DS21483B-page 11
(c)
TC9400/9401/9402
6.0 FREQUENCY-TO-VOLTAGE (F/V) CIRCUIT DESCRIPTION
CINT can be increased to lower the ripple. Values of 1F to 100F are perfectly acceptable for low frequencies. When the TC9400 is used in the Single Supply mode, VREF is defined as the voltage difference between Pin 7 and Pin 2.
When used as an F/V converter, the TC9400 generates an output voltage linearly proportional to the input frequency waveform. Each zero crossing at the threshold detector's input causes a precise amount of charge (q = CREF VREF) to be dispensed into the Op Amp's summing junction. This charge, in turn, flows through the feedback resistor, generating voltage pulses at the output of the Op Amp. A capacitor (C INT) across R INT averages these pulses into a DC voltage, which is linearly proportional to the input frequency.
7.2
Input Voltage Levels
7.0
7.1
F/V CONVERTER DESIGN INFORMATION
Input/Output Relationships
The input frequency is applied to the Threshold Detector input (Pin 11). As discussed in the V/F circuit section of this data sheet, the threshold of Pin 11 is approximately (VDD + VSS)/2 400mV. Pin 11's input voltage range extends from VDD to about 2.5V below the threshold. If the voltage on Pin 11 goes more than 2.5 volts below the threshold, the V/F mode start-up comparator will turn on and corrupt the output voltage. The Threshold Detector input has about 200mV of hysteresis. In 5V applications, the input voltage levels for the TC9400 are 400mV, minimum. If the frequency source being measured is unipolar, such as TTL or CMOS operating from a +5V source, then an AC coupled level shifter should be used. One such circuit is shown in Figure 7-1(a). The level shifter circuit in Figure 7-1(b) can be used in single supply F/V applications. The resistor divider ensures that the input threshold will track the supply voltages. The diode clamp prevents the input from going far enough in the negative direction to turn on the start-up comparator. The diode's forward voltage decreases by 2.1mV/C, so for high ambient temperature operation, two diodes in series are recommended; also, see Figure 7-2.
The output voltage is related to the input frequency (FIN) by the transfer equation:
EQUATION 7-1:
VOUT = [V REF C REF RINT] FIN The response time to a change in FIN is equal to (RINT CINT). The amount of ripple on VOUT is inversely proportional to CINT and the input frequency.
FIGURE 7-1:
FREQUENCY INPUT LEVEL SHIFTER
+8V to +5V +5V 14 VDD 10k 14 VDD
TC9400
Frequency Input +5V 0V GND 6 VSS 4 -5V 33k 0.01F 11 IN914 1.0M DET Frequency Input +5V 0V 0.1F 10k 33k 0.01F 11 IN914 1.0M
TC9400
DET
VSS 4
(a) 5V Supply
(b) Single Supply
(c)
DS21483B-page 12
2002 Microchip Technology Inc.
TC9400/9401/9402
FIGURE 7-2: F/V SINGLE SUPPLY F/V CONVERTER
V+ = 10V to 15V
14 10k 6 GND 6.2V .01F 10k VREF OUT 5 2 Zero Adjust V+ Offset Adjust Frequency Input 33k 0.01F 1.0k 11 DET GND IN914 1.0M IBIAS VREF VSS 7 4 47pF IIN 3 1M Amp Out 12 6 VOUT .001F VDD
TC9400
500k 100k
0.1F
1.0k 100k
Note: The output is referenced to Pin 6, which is at 6.2V (Vz). For frequency meter applications, a 1mA meter with a series scaling resistor can be placed across Pins 6 and 12.
7.3
Input Buffer
FIGURE 7-3:
0.5sec Min Input
F/V DIGITAL OUTPUTS
5.0sec Min
FOUT and FOUT/2 are not used in the F/V mode. However, these outputs may be useful for some applications, such as a buffer to feed additional circuitry. Then, FOUT will follow the input frequency waveform, except that FOUT will go high 3sec after FIN goes high; FOUT/2 will be square wave with a frequency of one-half FOUT. If these outputs are not used, Pins 8, 9 and 10 should be connected to ground (see Figure 7-3 and Figure 7-4).
FOUT Delay = 3sec FOUT/2
2002 Microchip Technology Inc.
DS21483B-page 13
(c)
TC9400/9401/9402
FIGURE 7-4: DC - 10kHz CONVERTER
+5V V+ 14 VDD * 42 FOUT/2 10 V+ Output Common 9 * * 3sec Delay Threshold Detector VREF OUT FOUT 8 *Optional/If Buffer is Needed
See Figure 7-1: "Frequency Input Level Shifter" Threshold Detect 11
TC9400A TC9401A TC9402A
FIN
5 CREF 56pF RINT 1M CINT 1000pF VOUT
12pF Offset Adjust +5V 100k 2k 2.2k 2 Zero Adjust IBIAS 1 10k -5V VREF (Typically -5V) VSS 4 VREF 7 - Op Amp + 60pF IIN 3 Amp Out 12
GND 6
7.4
Output Filtering
FIGURE 7-5:
VREF OUT 5
RIPPLE FILTER
The output of the TC9400 has a sawtooth ripple superimposed on a DC level. The ripple will be rejected if the TC9400 output is converted to a digital value by an integrating analog-to-digital converter, such as the TC7107 or TC7109. The ripple can also be reduced by increasing the value of the integrating capacitor, although this will reduce the response time of the F/V converter. The sawtooth ripple on the output of an F/V can be eliminated without affecting the F/V's response time by using the circuit in Figure 7-5. The circuit is a capacitance multiplier, where the output coupling capacitor is multiplied by the AC gain of the Op Amp. A moderately fast Op Amp, such as the TL071, should be used.
47pF
TC9400
IIN 3 1M .001F 200
AMP OUT 12
.01F 1M GND 6 2 3 1M - + 7 6 +5
(c)
DS21483B-page 14
2002 Microchip Technology Inc.
+
0.1F VOUT TL071
4 -5
TC9400/9401/9402
8.0 F/V POWER-ON RESET
In F/V mode, the TC9400 output voltage will occasionally be at its maximum value when power is first applied. This condition remains until the first pulse is applied to FIN. In most frequency measurement applications, this is not a problem because proper operation begins as soon as the frequency input is applied. In some cases, however, the TC9400 output must be zero at power-on without a frequency input. In such cases, a capacitor connected from Pin 11 to VDD will usually be sufficient to pulse the TC9400 and provide a Power-on Reset (see Figure 8-1 (a) and (b)). Where predictable power-on operation is critical, a more complicated circuit, such as Figure 8-1 (b), may be required.
FIGURE 8-1:
POWER-ON OPERATION/RESET
(a)
VDD VDD 14 1000pF 3 11 Threshold Detector 100k 4 A VSS 8 FIN 16 VCC CLRA CD4538 Q 6 To TC9400 5 B R 2 1 C
(b)
FIN
1k
TC9400
1F
2002 Microchip Technology Inc.
DS21483B-page 15
(c)
TC9400/9401/9402
9.0
9.1 9.2
PACKAGE INFORMATION
Package Marking Information Taping Form
Package marking data is not available at this time.
Component Taping Orientation for 14-Pin SOIC (Narrow) Devices
User Direction of Feed
PIN 1
W
P Standard Reel Component Orientation for TR Suffix Device
Carrier Tape, Reel Size, and Number of Components Per Reel
Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size
14-Pin SOIC (N)
12 mm
8 mm
2500
13 in
9.3
Package Dimensions
14-Pin CDIP (Narrow)
PIN 1
.300 (7.62) .230 (5.84)
.098 (2.49) MAX.
.030 (0.76) MIN.
.780 (19.81) .740 (18.80) .040 (1.02) .020 (0.51) .015 (0.38) .008 (0.20)
.320 (8.13) .290 (7.37)
.200 (5.08) .160 (4.06) .200 (5.08) .125 (3.18)
3 MIN.
.150 (3.81) MIN.
.110 (2.79) .090 (2.29)
.065 (1.65) .045 (1.14)
.020 (0.51) .016 (0.41)
.400 (10.16) .320 (8.13)
Dimensions: inches (mm)
(c)
DS21483B-page 16
2002 Microchip Technology Inc.
TC9400/9401/9402
9.3 Package Dimensions (Continued)
14-Pin PDIP (Narrow)
PIN 1
.260 (6.60) .240 (6.10)
.770 (19.56) .745 (18.92) .200 (5.08) .140 (3.56) .150 (3.81) .115 (2.92)
.310 (7.87) .290 (7.37)
.040 (1.02) .020 (0.51)
.015 (0.38) .008 (0.20) .400 (10.16) .310 (7.87)
3 MIN.
.110 (2.79) .090 (2.29)
.070 (1.78) .045 (1.14)
.022 (0.56) .015 (0.38)
Dimensions: inches (mm)
14-Pin SOIC (Narrow)
PIN 1
.157 (3.99) .244 (6.20) .150 (3.81) .228 (5.79)
.050 (1.27) TYP. .344 (8.74) .337 (8.56) .069 (1.75) .053 (1.35) .010 (0.25) .004 (0.10)
8 MAX. .050 (1.27) .016 (0.40)
.010 (0.25) .007 (0.18)
.018 (0.46) .014 (0.36)
Dimensions: inches (mm)
2002 Microchip Technology Inc.
DS21483B-page 17
(c)
TC9400/9401/9402
SALES AND SUPPORT
Data Sheets Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following: 1. 2. 3. Your local Microchip sales office The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277 The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. New Customer Notification System Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
(c)
DS21483B-page 18
2002 Microchip Technology Inc.
TC9400/9401/9402
Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip's products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights.
Trademarks The Microchip name and logo, the Microchip logo, FilterLab, KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER, PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. (c) 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company's quality system processes and procedures are QS-9000 compliant for its PICmicro (R) 8-bit MCUs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001 certified.
2002 Microchip Technology Inc.
DS21483B-page 19
(c)
WORLDWIDE SALES AND SERVICE
AMERICAS
Corporate Office
2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com
ASIA/PACIFIC
Australia
Microchip Technology Australia Pty Ltd Suite 22, 41 Rawson Street Epping 2121, NSW Australia Tel: 61-2-9868-6733 Fax: 61-2-9868-6755
Japan
Microchip Technology Japan K.K. Benex S-1 6F 3-18-20, Shinyokohama Kohoku-Ku, Yokohama-shi Kanagawa, 222-0033, Japan Tel: 81-45-471- 6166 Fax: 81-45-471-6122
Rocky Mountain
2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7966 Fax: 480-792-7456
China - Beijing
Microchip Technology Consulting (Shanghai) Co., Ltd., Beijing Liaison Office Unit 915 Bei Hai Wan Tai Bldg. No. 6 Chaoyangmen Beidajie Beijing, 100027, No. China Tel: 86-10-85282100 Fax: 86-10-85282104
Korea
Microchip Technology Korea 168-1, Youngbo Bldg. 3 Floor Samsung-Dong, Kangnam-Ku Seoul, Korea 135-882 Tel: 82-2-554-7200 Fax: 82-2-558-5934
Atlanta
500 Sugar Mill Road, Suite 200B Atlanta, GA 30350 Tel: 770-640-0034 Fax: 770-640-0307
Singapore
Microchip Technology Singapore Pte Ltd. 200 Middle Road #07-02 Prime Centre Singapore, 188980 Tel: 65-6334-8870 Fax: 65-6334-8850
Boston
2 Lan Drive, Suite 120 Westford, MA 01886 Tel: 978-692-3848 Fax: 978-692-3821
China - Chengdu
Microchip Technology Consulting (Shanghai) Co., Ltd., Chengdu Liaison Office Rm. 2401, 24th Floor, Ming Xing Financial Tower No. 88 TIDU Street Chengdu 610016, China Tel: 86-28-6766200 Fax: 86-28-6766599
Taiwan
Microchip Technology Taiwan 11F-3, No. 207 Tung Hua North Road Taipei, 105, Taiwan Tel: 886-2-2717-7175 Fax: 886-2-2545-0139
Chicago
333 Pierce Road, Suite 180 Itasca, IL 60143 Tel: 630-285-0071 Fax: 630-285-0075
Dallas
4570 Westgrove Drive, Suite 160 Addison, TX 75001 Tel: 972-818-7423 Fax: 972-818-2924
China - Fuzhou
Microchip Technology Consulting (Shanghai) Co., Ltd., Fuzhou Liaison Office Unit 28F, World Trade Plaza No. 71 Wusi Road Fuzhou 350001, China Tel: 86-591-7503506 Fax: 86-591-7503521
EUROPE
Denmark
Microchip Technology Nordic ApS Regus Business Centre Lautrup hoj 1-3 Ballerup DK-2750 Denmark Tel: 45 4420 9895 Fax: 45 4420 9910
Detroit
Tri-Atria Office Building 32255 Northwestern Highway, Suite 190 Farmington Hills, MI 48334 Tel: 248-538-2250 Fax: 248-538-2260
China - Shanghai
Microchip Technology Consulting (Shanghai) Co., Ltd. Room 701, Bldg. B Far East International Plaza No. 317 Xian Xia Road Shanghai, 200051 Tel: 86-21-6275-5700 Fax: 86-21-6275-5060
Kokomo
2767 S. Albright Road Kokomo, Indiana 46902 Tel: 765-864-8360 Fax: 765-864-8387
France
Microchip Technology SARL Parc d'Activite du Moulin de Massy 43 Rue du Saule Trapu Batiment A - ler Etage 91300 Massy, France Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79
Los Angeles
18201 Von Karman, Suite 1090 Irvine, CA 92612 Tel: 949-263-1888 Fax: 949-263-1338
China - Shenzhen
Microchip Technology Consulting (Shanghai) Co., Ltd., Shenzhen Liaison Office Rm. 1315, 13/F, Shenzhen Kerry Centre, Renminnan Lu Shenzhen 518001, China Tel: 86-755-2350361 Fax: 86-755-2366086
New York
150 Motor Parkway, Suite 202 Hauppauge, NY 11788 Tel: 631-273-5305 Fax: 631-273-5335
Germany
Microchip Technology GmbH Gustav-Heinemann Ring 125 D-81739 Munich, Germany Tel: 49-89-627-144 0 Fax: 49-89-627-144-44
San Jose
Microchip Technology Inc. 2107 North First Street, Suite 590 San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955
Hong Kong
Microchip Technology Hongkong Ltd. Unit 901-6, Tower 2, Metroplaza 223 Hing Fong Road Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431
Italy
Microchip Technology SRL Centro Direzionale Colleoni Palazzo Taurus 1 V. Le Colleoni 1 20041 Agrate Brianza Milan, Italy Tel: 39-039-65791-1 Fax: 39-039-6899883
Toronto
6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509
India
Microchip Technology Inc. India Liaison Office Divyasree Chambers 1 Floor, Wing A (A3/A4) No. 11, O'Shaugnessey Road Bangalore, 560 025, India Tel: 91-80-2290061 Fax: 91-80-2290062
United Kingdom
Arizona Microchip Technology Ltd. 505 Eskdale Road Winnersh Triangle Wokingham Berkshire, England RG41 5TU Tel: 44 118 921 5869 Fax: 44-118 921-5820
03/01/02
(c)
DS21483B-page 20
2002 Microchip Technology Inc.
*B38412SD*

▲Up To Search▲

Price & Availability of TC9402

	To Download TC9402 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .