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FAN1950/FAN1951
1.5A Low-Voltage Low-Dropout Regulator
Features
* 1.5A minimum guaranteed output current * 500mV maximum dropout at 1.5A Ideal for 2.5V to 1.8V or 1.65V conversion Ideal for 3.0V to 2.5V conversion * Current Limiting and Thermal shutdown * External Shut-down control (FAN1951 only) * Error flag output (FAN1951 only) * Fast transient response * Low ground current
General Description
The FAN1950 and FAN1951 are 1.5A low-dropout linear regulators that provide a low voltage, high current output with a minimum of external components. Both of these devices use a PNP output pass element achieving a maximum 500mV dropout at 1.5A load current. In addition these devices offer overcurrent limit and thermal shutdown features to ensure full protection. The FAN1951 offers a logic level enable pin and an error flag output to indicate undervoltage and over-current conditions. 1.8V and 2.5V fixed output versions are available. 3.3V, 1.65V and 1.5V options are available upon request.
Applications
* General purpose conversion for low-voltage CPUs, DSP and FPGAs * SMPS post regulator * Cable/Satellite set-top boxes * PCI Graphics adapter cards
Typical Application
FAN1950-2.5V 3.0V IN OUT GND 2.5V 10F 100K Error Output On/Off FLAG EN GND FAN1951-1.8V 2.5V IN OUT 1.8V 10F
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FAN1950/FAN1951
Pin Assignments
FAN1950Dx FRONT VIEW FAN1951Dx FRONT VIEW
1
2
3
1
2
3
4
5
GND (TAB)
GND (TAB)
OUT
EN
OUT
IN
IN
3-Lead Plastic TO-252 (DPAK)
5-Lead Plastic TO-252 (DPAK)
Pin Descriptions
Pin Number FAN1950 NA 1 2 3 NA FAN1951 1 2 3 4 5 Pin Name EN IN GND OUT FLAG Pin Function Description Enable (Input) - TTL/CMOS compatible input. Logic HIGH enables the output Input Supply Voltage Ground. This pin and TAB are ground. Output Voltage Error Flag (Output). Open-collector output. Active-low indicates an output fault condition.
2
FLAG
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FAN1950/FAN1951
Absolute Maximum Ratings
Absolute maximum ratings are the values beyond which the device may be damaged or have its useful life impaired. Functional operation under these conditions is not implied. Parameter Supply Voltage: IN Enable Voltage: EN FLAG voltage: FLAG Junction Temperature (TJ) Storage Temperature Lead Soldering Temperature, 10 seconds Power Dissipation (PD) Min. -0.2 -0.2 -0.2 -55 -65 Typ. Max. 15 15 15 150 150 300 Internally Limited Units V V V C C C W
Recommended Operating Conditions
Parameter Supply Voltage Package Thermal Resistance (JC) Junction Operating Temperature TO-252 -40 Conditions Min. 2.25 3 125 Typ. Max. 14 Units V C/W C
Electrical Specifications
(VIN = VOUT + 1V, VEN = 2.5V, Tj = +25C unless specified otherwise) The * denotes specifications which apply over the full operating temperature range. Parameter Output Voltage (VOUT) Tolerance Conditions 10mA IOUT 1.0A, 10mA IOUT 1.5A, VOUT + 1V VIN 8V IOUT = 10mA, VOUT + 1V VIN 14V VIN = VOUT + 1V, 10mA IOUT 1.5A IOUT = 1.5A, VOUT = -1% * Ground Current Minimum Load Current Current Limit EN Input Voltage (FAN1951 only) EN Input Current (FAN1951 only) FLAG Threshold Voltage (FAN1951 only) FLAG Output Leakage (FAN1951 only) Current4 IOUT = 750mA IOUT = 1.5A VOUT + 1V VIN 8V VOUT = 0V, VIN = VOUT + 1V VIH (On) VIL (Off) IIH, VEN = 2.25V IIL, VEN = 0.8V Low threshold, % VOUT High threshold, % VOUT Hysteresis VFLAG = 14V IOL = 250A * * * * * * * * * 93 99.2 1 2 400 2.25 0.8 30 4 10 20 5 2.5 * * Min. -2 -2.5 .06 0.2 350 500 20 10 mA mA mA A V V A A % % % A mV Typ. Max. 2 2.5 0.5 1 Units %
Line Regulation1,2 Load Regulation1,2 Dropout Voltage3
% % mV
FLAG Output-Low Voltage (FAN1951 only)
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FAN1950/FAN1951
Parameter Thermal Shutdown Temperature Thermal Shutdown Hysteresis Shutdown output current
Conditions
Min.
Typ. 150 10
Max.
Units C C
VEN 0.8V, VIN 8V, VOUT = 0V
*
20
A
Notes: 1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant junction temperature by low duty cycle pulse testing. 2. Line and load regulation are guaranteed up to the maximum power dissipation. Power dissipation is determined by input/ output differential and the output current. Guaranteed maximum output power will not be available over the full input/output voltage range. 3. Dropout voltage = VIN - VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 2.25V, dropout voltage is the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V. 4. Flag output cannot be pulled to a voltage higher than VIN.
4
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FAN1950/FAN1951
Typical Performance Characteristics
Dropout Voltage vs. Output Current 0.6 0.5 Dropout (V) 0.4
-40C +125C
0.6 0.5 Dropout (V)
+75C
Dropout Voltage vs. Temperature
IL = 1.5A
0.4
IL = 1A
0.3
-10C
0.3 0.2 0.1
0.2
+25C
0.1 0 0.5 0.7 0.9 1.1 1.3 1.5
0 -50
Load Current (A)
50 100 Tj Vout = 2.5V, 1.8V, Iout = 1A, 1.5A
0
150
Ground Current vs. Load Current Vin = Vout + 1V, 25C 25.00 20.00 15.00
I gnd (mA)
10.00 5.00 0.00 0 500 1000 1500 2000 Load Current (mA)
0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 0
Ground Current vs. Supply Voltage Vin = Vout + 1V, 25C
Ground Current (mA) (V)
Ground Current (mA)
5
10 Vin (V) Iout = 10mA
15
20
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FAN1950/FAN1951
Typical Performance Characteristics (continued)
Ground Current vs. Temperature Vin = 3V 30.00 Ground Current (mA) 25.00
IGND_ @ 1.5A
20.00 15.00 10.00 5.00
IGND_@10mA IGND @ 750mA
0.00 -50
0
50 Temperature (C)
100
150
FAN1950D18 Short-Circuit Recovery Response
FAN1950D18 Short-Circuit Transient Response
Vin = 3V, Vout = 1.8V Ch.1 - Vout (1V/div) Ch.2 - Load Current (2A/div)
Vin = 3V, Vout = 1.8V Ch.1 - Vout (1V/div) Ch.2 - Load Current (2A/div)
FAN1950D25 Short-Circuit Recovery Response
FAN1950D25 Short-Circuit Transient Response
Vin = 3V, Vout = 2.5V Ch.1 - Vout (1V/div) Ch.2 - Load Current (2A/div)
Vin = 3V, Vout = 2.5V Ch.1 - Vout (1V/div) Ch.2 - Load Current (2A/div)
6
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FAN1950/FAN1951
Typical Performance Characteristics (continued)
Load Transient Response Vin=2.5V, Vout=1.8V, Cin=10F Ceramic Load Transient Response Vin=2.5V, Vout=1.8V, Cin=10F Ceramic
Cout = 10F Tantalum (ESR~700m) Ch1 - Vout (AC, 0.5V/div) Ch2 - Load Current (1A/div.)
Cout = 10F Ceramic Ch1 - Vout (AC, 0.5V/div.) Ch2 - Load Current (1A/div.)
Vout vs. Temperature 1.834 1.824 1.814 Vout (V) 1.804 1.794 1.784 1.774 1.764 -100 -50 0 50 100 Junction Temperature (C) Iout = 10 mA; Vout = 1.8V 150 2.450 -50 -25 Vout (V) 2.525 2.500 2.475 2.550
Vout vs. Temperature (C) (10 mA Load)
0 25 50 75 100 125 Junction Temperature (C) Iout = 10 mA; Vout = 2.5V
150
FAN1950D18 Ripple Rejection (PSRR)
FAN1950D25 Ripple Rejection (PSRR)
Vin = 5V Vin = 3V
Vin = 3V and 5V Vout = 1.8V Iload = 1A Cin = Cout = 10F/ 6.3V Tantalum PSRR - 10dB/div
Vin = 5V Vout = 2.5V Iload = 1A Cin = Cout = 10F/ 6.3V Tantalum PSRR - 10dB/div
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FAN1950/FAN1951
Input and Output Capacitor Requirements
A 4.7F or greater Input Capacitor (Ceramic or Tantalum), installed closely between VIN and GND leads of the part, is required for stability, better transient response, noise and ripple rejection. A higher value of electrolytic input capacitor can be recommended if the bulk capacitor of the power supply is located more than 3- 4 inches from the device or a large and fast-risetime load is a requirement. FAN1950 and FAN1951, as most of LDO regulators, require an Output Capacitor. The recommended value of this capacitor is 10F. The larger capacitor will
additionally improve the Transient Response, Ripple Rejection and output noise. The low-ESR Tantalum capacitors are the best for this application: they provide stable work and good transient response over the temperature range. Using the Ceramic capacitors as the Output capacitor can provoke instability (oscillation in the Output Voltage). Aluminum electrolytic capacitors also can be used if their ESR is below 3.
8
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FAN1950/FAN1951
Mechanical Dimensions
5-Lead TO-252 DPAK Package
A 6.80 6.35 5.64 5.04 6.00 MIN
1.27 0.50
6.56 MIN
6.30 5.90 1.02 0.60
6.25
3.00 MIN C 1 (0.44) 0.570.07 0.25 M A M C 1.27 LAND PATTERN RECOMMENDATION 5.08 B 2.40 2.18 (5.09) 0.60 0.40 2 3 4 5 1.27 0.690.15 1 1.27 1.00 3.81
(4.05) 10.42 9.20
SEE DETAIL A
3 5 4 2
1 0.10 B
GAGE PLANE
0.60 0.40
0.51 (1.54) NOTES: UNLESS OTHERWISE SPECIFIED A) ALL DIMENSIONS ARE IN MILLIMETERS. B) THIS PACKAGE CONFORMS TO JEDEC, TO-252, ISSUE C, VARIATION AA, DATED NOV. 1999. 0.13 MAX SEATING PLANE
10 0
1.78 1.40 (2.90)
DETAIL A
(ROTATED 90) SCALE: 2X
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FAN1950/FAN1951
Mechanical Dimensions
3-Lead TO-252 DPAK Package
6.73 6.35 5.46 5.21 A 6.00 MIN
L3
4 6.50 MIN
D 1.02 0.64 C 1 2 3 1 1.14 0.76 2.29 4.57 3 6.25
3.00 MIN
(0.59) 0.89 0.64 0.25 M A M C
1.40 MIN 4.60
2.30
LAND PATTERN RECOMMENDATION
B 2.39 2.18
SEE NOTE D
E1
4
0.58 0.46
D1 10.41 9.40
SEE DETAIL A
2 3
1
0.10 B
GAGE PLANE 0.61 0.46 10 0
0.51
NOTES: UNLESS OTHERWISE SPECIFIED A) B) (1.54) C) D) ALL DIMENSIONS ARE IN MILLIMETERS. THIS PACKAGE CONFORMS TO JEDEC, TO-252, ISSUE C. VARIATION AA & AB, DATED NOV. 1999. DIMENSIONING AND TOLERANCING PER ASME Y14.5-1994. HEAT SINK TOP EDGE COULD BE IN CHAMFERED CORNERS OR EDGE PROTRUSION. DIMENSIONS L3, D, E1 & D1 TABLE: OPTION AA OPTION AB L3 0.89 - 1.27 1.52 - 2.03 D 5.97 - 6.22 5.33 - 5.59 E1 4.32 MIN 3.81 MIN D1 5.21 MIN 4.57 MIN
1.78 1.40 (2.90)
0.127 MAX SEATING PLANE
E)
DETAIL A
(ROTATED -90) SCALE 12X
10
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FAN1950/FAN1951
Ordering Information
Part Number FAN1951D18X FAN1951D25X FAN1950D25X Output Voltage 1.8V 2.5V 2.5V Package 5 Lead TO-252 DPAK in Tape and Reel 5 Lead TO-252 DPAK in Tape and Reel 3 Lead TO-252 DPAK in Tape and Reel
Note: Please contact sales for other voltage and package options.
DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.
www.fairchildsemi.com 8/30/04 0.0m 005 Stock#DS30001950 2003 Fairchild Semiconductor Corporation
2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.

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