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CMX017
UHF FM/FSK Transmitter
D/017/3 April 1999 Advance Information
Features
* * * * * *
Applications
* * * * * * *
Direct FM/FSK UHF Modulator Adjustable Modulator Output Power Integrated Power Amplifier with Output Power up to +20dBm (100mW) Low Power 2.7V Operation Powersave and Zero-Power (<10A) Modes 28-Pin SSOP Package
General Radio Link 860-965 MHz General 915MHz ISM Band (USA) Spread Spectrum Wireless Systems Fixed Frequency Transmissions Analogue/Digital Cordless Phones Handheld Data Terminals So-Ho Wireless Data Links
GAIN
MODOUT
PAIN
IPAOUT
FM/FSK MODULATOR
POWER AMPLIFIER DRIVER POWER AMPLIFIER PAOUT
MODIN
TANK
BUFFERED OSCILLATOR OUTPUT
BANDGAP & BIAS CONTROL
OSCOUT
ENLMOD
ENLPA
1.1
Brief Description
The CMX017 is a single chip UHF FM/FSK transmitter that combines both the RF VCO Modulator and RF Power Amplifier. It is suitable for both audio FM and digital FSK transmissions. A buffered oscillator output provides the RF signal drive to an external synthesizer or fixed frequency phase-locked loop for channel frequency selection. Modulator output power is adjustable over a 20dB range and the integrated power amplifier delivers up to +20dBm. The device also includes a powersave mode: "Transmit Standby" and a zero-power mode: "Sleep". These allow independent power down control of both the modulator and power amplifier, thereby maximising battery life. The device can be used in conjunction with the CMX018, a double-conversion super-heterodyne receiver, to implement a complete UHF radio link.
(c) 1999 Consumer Microcircuits Limited
CONTENTS Section Page
1.0 Features and Applications ............................................................................ 1 1.1 Brief Description ............................................................................................ 1 1.2 Block Diagram ................................................................................................ 3 1.3 Signal List ....................................................................................................... 4 1.4 External Components .................................................................................... 6 1.5 General Description ....................................................................................... 7 1.5.1 FM/FSK Modulator + PA Driver ..................................................... 7 1.5.2 Power Amplifier .............................................................................. 7 1.5.3 Powersave and Zero-Power Modes.............................................. 7 1.6 Application Notes........................................................................................... 8 1.6.1 Generation of the Modulated RF Signal....................................... 8 1.6.2 Powersave and Zero-Power Modes.............................................. 9 1.6.3 Lower Power Applications ............................................................ 9 1.6.4 Example Schematic and Layout ................................................... 9 1.7 Performance Specification .......................................................................... 12 1.7.1 Electrical Performance ................................................................ 12 1.7.2 Packaging ..................................................................................... 14 1.7.3 Handling Precautions .................................................................. 14
Note:
As this product is still in development, it is likely that a number of changes and additions will be made to this specification. Items marked TBD or left blank will be included in later issues. Information in this data sheet should not be relied upon for final product design.
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.2
Block Diagram
Vcc3
1
28
PAIN
GAIN
2
PA DRIVER
27
GND
GND
3
PA STAGE 1
26
MODOUT
GND
4
25
GND
GND
5
BUFFERED OSCILLATOR OUTPUT
24
Vcc2
IPAOUT
6
23
OSCOUT
GND
7
PA STAGE 2
22
Vcc1
GND
8
FM/FSK MODULATOR
21
GND
PAOUT
9
20
TANK
GND 10
19
GND
GND 11
18
MODIN
SUBSTRATE
Vcc4 12
17
GND
ENLPA 13
PACKAGE GROUND PACKAGE GROUND
16
ENLMOD
GND 14
15
GND
Figure 1 Internal Block Diagram
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.3
Signal List
Package D6 Pin No. 1 Name Vcc3
Signal
Description
Type POWER Power amplifier (first stage) power supply - nominally 3.0V Modulator output (pin 26) - Power Control Ground-plane connection to the power amplifier Ground-plane connection to the power amplifier Ground-plane connection to the power amplifier Output (open-collector) from the first stage of the power amplifier Ground-plane connection to the power amplifier Ground-plane connection to the power amplifier Output (open-collector) from the second stage of the power amplifier Ground-plane connection to the power amplifier Ground-plane connection to the power amplifier Power amplifier (second stage) power supply - nominally 3.0V Power Amplifier powersave logic control. A logic '0' powers down the Power Amplifier and Driver stages Ground-plane connection Ground-plane connection Modulator zero-power logic control. A logic '0' powers down the Modulator and Buffered Oscillator stages Ground-plane connection Baseband modulation input signal Ground-plane connection to the VCO VCO Tank circuit/Resonator connection
2 3 4 5 6 7 8 9 10 11 12
GAIN GND GND GND IPAOUT GND GND PAOUT GND GND Vcc4
I/P GROUND GROUND GROUND O/P GROUND GROUND O/P GROUND GROUND POWER
13
ENLPA
CMOS I/P
14 15 16
GND GND ENLMOD
GROUND GROUND CMOS I/P
17 18 19 20
GND MODIN GND TANK
GROUND I/P GROUND I/P
(c) 1999 Consumer Microcircuits Limited
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D/017/3
Package D6 Pin No. 21 22 23 24 Name GND Vcc1
Signal
Description
Type GROUND POWER O/P POWER Ground-plane connection to the modulator and VCO buffer Modulator power supply - nominally 3.0V Buffered Oscillator (open-collector) output Power Amplifier Driver power supply - nominally 3.0V Ground-plane connection for the Power Amplifier Driver Modulator output Ground-plane connection for the Power Amplifier Driver Power Amplifier input
OSCOUT Vcc2
25 26 27 28
GND MODOUT GND PAIN
GROUND O/P GROUND I/P
Notes: I/P = O/P =
Input Output
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.4
External Components
Component Values: L1 L2 L3 L4 D1 ~ C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 R1 R2 R3 R4 1.5nH 22nH 6.8nH 22nH Varactor Resonator 5.6pF 33pF 4.3pF 6.8pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 10k 10k TBD k TBD k
Varactor Diode, type SMV1233-011 Co-Axial Resonator, type RG402, length = 11mm, shorted end.
(value is application dependent) SMD Potentiometer (value is application dependent)
NOTE: Components are surface mount, type SMD0603, unless otherwise marked.
Figure 2 Example of CMX017 with External Components
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.5
General Description
The CMX017 is a single chip UHF FM/FSK transmitter that combines both the RF VCO Modulator and RF Power Amplifier. It is suitable for both audio FM and digital FSK transmissions. A buffered oscillator output provides the RF signal drive to an external synthesizer or fixed frequency phase-locked loop for channel frequency selection. Modulator output power is adjustable over a 20dB range and the integrated power amplifier delivers up to +20dBm. The device also includes a powersave mode: "Transmit Standby" and a zero-power mode: "Sleep". These allow independent power down control of both the modulator and power amplifier, thereby maximising battery life. The device can be used in conjunction with the CMX018, a double-conversion super-heterodyne receiver, to implement a complete UHF radio link.
1.5.1
FM/FSK Modulator + PA Driver The modulator circuit uses an integrated oscillator whose frequency can be directly modulated by the DC-coupled input base-band signal, at the MODIN pin, to generate a frequency modulated (FM or FSK) RF signal. The oscillator requires an external varactor and resonator circuit, connected at the TANK pin, to tune to the required RF channel. A buffered oscillator signal is provided from an opencollector output, at the OSCOUT pin, to drive an external frequency synthesizer for the channel selection. The output power, at the MODOUT pin, is variable over a 20dB range. The output power is maximum when the GAIN pin is connected to Vcc and is reduced by typically 20dB when this pin is connected to 0V. The output impedance at the MODOUT pin is typically 50.
1.5.2
Power Amplifier (PA) The power amplifier has two internal stages, each biased for class-B operation, and is designed to have a fixed overall power gain. The input and output impedances can be terminated with 50. A typical power gain improvement of 2dB is achieved using simple external matching networks.
1.5.3
Powersave and Zero-Power Modes The Modulator and Buffered Oscillator stages are powered down independently of the PA Driver and Power Amplifier stages, by means of the ENLMOD and ENLPA logic inputs: A logic '0' at ENLMOD powers down the Modulator and Buffered Oscillator stages. A logic '0' at ENLPA powers down the PA Driver and Power Amplifier stages. Refer to the block diagram in Figure 1 and to the Applications Section 1.6.2.
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.6
1.6.1
Application Notes
Generation of the Modulated RF Signal The modulator on the CMX017 relies on the direct modulation of the RF Voltage Controlled Oscillator (VCO), which is stabilised to the channel centre frequency by an external Frequency Synthesizer or Phase Locked Loop (PLL). The user has control over the external PLL filter and VCO tank components and choice of these components will have an impact upon the following PLL parameters: Closed loop bandwidth, settling time and transient response Modulation linearity VCO phase noise Three modulation requirements may be achieved as follows: a) The minimum modulation signal frequency is above the PLL Closed Loop Bandwidth In applications where the transmit channel frequency is fixed or occasionally changed, a narrow PLL bandwidth can be chosen such that the minimum modulation frequency is in excess of the PLL bandwidth. With the PLL active whilst the base-band signal is applied to the modulator there will be negligible distortion of the modulated RF output signal. A benefit of this technique is that an output phase noise improvement is achieved, compared to the free running VCO phase noise characteristic.
b) The minimum modulation signal frequency is within the PLL Closed Loop Bandwidth In Frequency Hopped Spread Spectrum applications the frequency synthesizer must be agile. Consequently the PLL bandwidth should be designed to achieve the required hop rate and, in most systems, this bandwidth will exceed the minimum modulation frequency. With the PLL active during modulation, the loop will compensate for the signal frequency components within the loop bandwidth, introducing a frequency dependant distortion of the modulated RF output signal. To avoid the modulation distortion the carrier frequency is tuned by the external synthesizer chip, with no modulating signal applied. The synthesizer control is then disabled, by setting the charge-pump output of the synthesizer to tri-state. The DC coupled baseband signal, applied to the MODIN pin, then modulates the free running VCO to generate the FM or FSK output signal.
c)
A flat modulator response is required down to DC, whilst benefiting from the phase noise improvements due to the PLL (Two-Point Modulation)
Unlike in the above two cases, where a fixed reference frequency is used in the PLL, the Two-Point Modulation technique requires modulation inputs to both the PLL reference oscillator and to the RF VCO circuits. The modulation signal should be applied to both modulation inputs with suitable AC/DC levels and with the correct phase to achieve cancellation of the loop's feedback. This prevents the radio's PLL circuitry from counteracting the modulation process and so provides a clean flat modulation response down to DC.
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.6.2
Powersave and Zero-Power Modes It is possible to power down each section of the transmitter independently. This feature may be useful when the CMX017 is configured, with the CMX018, as a radio transceiver. It allows the transmitter to be powered on and off, thereby saving power, during the sleep and standby periods. In SLEEP mode (ENLMOD = '0' and ENLPA = '0') all sections of the device are powered down and the current consumption is reduced to less than 10A. This is the zero-power mode. In TRANSMIT-STANDBY mode (ENLMOD = '1' and ENLPA = '0') only the PA Driver and Power Amplifier stages are powered down, whilst the Modulator and Buffered Oscillator remain active. This powersave mode allows the external frequency synthesizer to stabilise the channel centre -frequency prior to the RF transmission. In TRANSMIT mode (ENLMOD = '1' and ENLPA = '1') both the Modulator and Power Amplifier sections of the device are fully operational.
Note: The device can be used as a stand alone "UHF Power Amplifier" by forcing (ENLMOD = '0' and ENLPA = '1'). The efficiency is maximised by connecting the Vcc2 pin to 0V. (The Vcc1 pin must remain connected to 3.0V.)
1.6.3
Lower Output Power Applications For very short range applications the antenna drive can be taken from the modulator output, MODOUT, at pin 26. The Power Amplifier is powered down by connecting Vcc3 and Vcc4 (pins 1 and 12) to 0V. This allows the supply current to be minimised and the Modulator output to be enabled or disabled using the ENLPA input at pin 13.
1.6.4
Example Schematic and Layout The following schematic (Figure 3) and printed circuit layout (Figure 4) show a typical application interface for the CMX017. To aid legibility, the schematic and layout are available electronically from the CML website http://www.cmlmicro.co.uk or on floppy disk by request from CML's office. Alternative components and component values are shown on the schematic. These should be selected according to the intended application. The schematic uses the following ICs: U2 U4 IC Works WB1315X Analog Devices AD8532-SO8
(c) 1999 Consumer Microcircuits Limited
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D/017/3
C1
N/C
L2 6.8nH
5.6pF C4 C3 L3 100pF
1 VCC3 GAIN GND4 GND5 GND6 IPAOUT GND7 GND8 PAOUT GND9 GND10 VCC4 ENLPA GND GND 15 ENLMOD 16 GND 17 MODIN 18 OSCGND 19 TANK 20 GND1 21 OSCOUT 23 22 VCC2 24
2 IN
C5 100uF
PAIN GND3 MODOUT 27 28
C2 33pF 100nH C6 100nF
TXRESNR
GND 1
L1 100nH
2 3 26 25
100pF
3V
3V
100pF
4
U1
GND2
C7 100pF C11 100pF C13 4.7pF 6.8pF C14 D1 10K R14 100pF C26
C10
6
L4 1.5nH
7
5
100pF CMX017D6
VCC1
(c) 1999 Consumer Microcircuits Limited
C12
9
L5 22nH
10 11 12
8
R1 C8 3pF 10k C9
R2 100R 10nF
C65
13
N/C 33pF 100pF C19 L6 C18 100pF 20nH C16 12pF C15
14
J2
3V
R9 N/C 0R L7 C24
5V
15uH R13 N/C 47k
1nF C27 U4
8 3 2 + 5 4 6
Figure 3 Application Schematic
10
5V
C31 100pF 15uH 100nF 100pF 2.2uF 100pF L8 C32 C33 C34 C22 J1 C42
2 4 6 DO1 GND FIN1 GND 17 16 DO2 8 10 5 1 1 3 5 7 9
2.2uF AD8532-SO8
1
( 7 - N/C)
C41 R17 N/C
VCC1 VP1 18 VCC2 20 19
C39
100pF R18 47k C35 470nF C36 C37
14 GND LE DATA CLOCK 13 12 11
100pF C44 C145 100pF
3 4
0R R19 1k 100nF
100pF 100pF
2
C40 100pF 100pF WB1315X
FIN2
R100
U2
VP2
100
12 6 FIN1B FIN2B 15
C48 C46 C38
GND OSC_IN GND FO_LD 7 8 14 16 18 20 10
C45
100uF 100pF 1nF
9
11
3V
13
100pF
C43
L9
15
17
1uF
15uH
19
5V
C57 100nF 10nF C58
TFMCON20M
C56
100uF
SYNT_CLK SYNT_DATA SYNT_STB
R21
R22 100k
R23 100k 100k
D/017/3
Figure 4a Application Layout - Top Copper
Figure 4b Application Layout - Bottom Copper (not reversed) Available from http://www.cmlmicro.co.uk
(c) 1999 Consumer Microcircuits Limited
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D/017/3
1.7
1.7.1
Performance Specification
Electrical Performance
Absolute Maximum Ratings Exceeding these maximum ratings can result in damage to the device. Pin 1, 12, 22, 24 2, 13, 16, 18, 20 28 Min. -0.3 -0.3 Max. 7.0 Vcc + 0.3 +7 Units V V dBm
Supply (Vcc) Input Voltage Power Amplifier Input Power
D6 Package Total Allowable Power Dissipation at Tamb = 25C ... Derating Storage Temperature
Min.
-55
Max. 1100 11 +125
Units mW mW/C C
Operating Limits Correct operation of the device outside these limits is not implied. Notes Supply (Vcc) Operating Frequency Range Operating Temperature Min. 2.7 860 -10 Max. 3.3 965 +60 Units V MHz C
(c) 1999 Consumer Microcircuits Limited
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D/017/3
Operating Characteristics For the following conditions unless otherwise specified: Vcc = 2.7V to 3.3V, Tamb = -10C to +60C, RF = 915MHz, 50 source and load impedance. Pin DC Parameters Device Fully Enabled (ENLPA=HI and ENLMOD=HI) Icc1 [Output Power = +20dBm at PAOUT (Pin 9)] Icc1 [Output Power = +10dBm at PAOUT (Pin 9)] Icc1 [Output Power = 0dBm at PAOUT (Pin 9)] Device in Power-Down Modes Icc1 in STANDBY mode (ENLPA = LO and ENLMOD = HI) Icc1 in SLEEP mode (ENLPA = LO and ENLMOD = LO) AC Parameters Modulator, VCO Buffer and PA Driver Output Power [GAIN (pin 2) at Vcc] Output Power [GAIN (pin 2) at 1.5V] Output Power [GAIN (pin 2) at 1.0V] 2 Buffered VCO Output at OSCOUT pin 3 Oscillator Second Harmonic Output 3 Oscillator Third Harmonic Output 4 Modulation Sensitivity 5 Maximum Deviation Input Data Rate Output VSWR (at maximum output power) Power Amplifier Power Gain Power Gain (with external matching at Vcc = 3.3V) 6 Maximum Power Gain Variation 6 Maximum Power Gain Variation (with matching) Input 1dB Compression Point Input 1dB Compression Point (with matching) Reverse Isolation Output VSWR (at maximum output power) Min. Typ. Max. Units
-
130 60 40
-
mA mA mA
-
24 TBD
10
mA A
26 26 26 19 26 26 18 26 18 26
-
-4.0 -9.0 -14 -10 -25 -35 0.4 1.5 TBD
TBD -
dBm dBm dBm dBm dBc dBc MHz/V MHz kBits/S
28, 9 28, 9 28, 9 28,9 9 9 9, 28 9
-
22 24 2.0 1.5 +1.0 0 -35 TBD
-
dB dB dB dB dBm dBm dB
Notes:
1. 2. 3. 4. 5. 6.
Total current from the external 3.0V power supply. Power measured into a 50 load. With external matching. Stepped modulation voltage input from 1.0V to 2.0V. Stepped modulation voltage from 0V to 3.0V. Input Power = -15dBm to -1dBm.
(c) 1999 Consumer Microcircuits Limited
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D/017/3
UHF FM/FSK Transmitter
CMX017
1.7.2
Packaging
Figure 5 28-Pin Plastic SSOP Mechanical Outline: Order as part no. CMX017D6
1.7.3
Handling Precautions This device is a high performance RF integrated circuit and is ESD sensitive. Adequate precautions must be taken during handling and assembly of this device.
CML does not assume any responsibility for the use of any circuitry described. No IPR or circuit patent licences are implied. CML reserves the right at any time without notice to change the said circuitry and this product specification. CML has a policy of testing every product shipped using calibrated test equipment to ensure compliance with this product specification. Specific testing of all circuit parameters is not necessarily performed.
1 WHEATON ROAD WITHAM - ESSEX CM8 3TD - ENGLAND
Telephone: +44 1376 513833 Telefax: +44 1376 518247 e-mail: sales@cmlmicro.co.uk http://www.cmlmicro.co.uk

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