A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR Features Description The GM431 is a three terminal adjustable shunt regulator Sink Current Capability 1 mA to 100mA with thermal stability guaranteed over temperature. Output Low dynamic output impedance, 0.2W typ. voltage can be adjusted to any value between 2.5V (Vref) Low output noise and 36V by using two external resistors. The GM431 has a 0.5%, 1% or 2% reference voltage tolerance typical dynamic output impedance of 0.2W. Active output Alternate for TL431, TL431, LM431 & AS431 circuitry provides a very unique turn on characteristic, making the GM431 an excellent replacement for zener diodes in many applications such as onboard regulation and adjustable power supplies. The GM431 is an ideal voltage ref- Temperature range 0°C to+ 70 °C Available in SOT-23, TO-92, SOT-89 and SOP- 8 packages erence for 3.0 to 3.3V switching power supplies. The GM431 shunt regulator is available with 3 voltage tolerances 0.5%, 1.0% and 2.0% over TA= 0°C to + 70°C, and four package options (SOT-23, TO-92, SOT-89 and SOP-8). Whatever your application is, the GM431 offers the optimum combination of performance, reliability, and economy. Application Switching power supplies Battery-operated computers Linear regulators Computer disk drives Adjustable supplies Instrumentation LOGIC SYMBOL BLOCK DIAGRAM (POSITIVE LOGIC) CATHODE REFERENCE + GM431 V0.11 REFERENCE _ ANODE CATHODE V ref ANODE www.gammamicro.com 1 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR MARKING INFORMATION & PIN CONFIGURATIONS (TOP VIEW) TO- 92 SOP- 8 SOT-23 ANODE REF Anode GM 431G AYWW 3 1 2 Cathode 1 2 3 4 CATHODE ANODE 3 GM431G AYWW GM431G AYWW 2 1 REF ANODE NC 8 7 6 5 XXXYW 1. REF 2. Anode 3. Cathode SOT - 89 REF 1 NC ANODE 2 3 CATHODE ANODE XXX = Marking Code G** = Grade A = Assembly Location Y = Year WW, W= Weekly ORDERING INFORMATION GM431 Ordering Number 2 Precision Device code Grade Package Shipping GM431AT92B 0.5% A TO-92 1,000 Units/ ESD Bag GM431AT92RL 0.5% A TO-92 2,000 Units/ Ammo Pack(Tape) GM431AST23R 0.5% SOT-23 3,000 Units / Tape &Reel GM431AS8T 0.5% A SOP-8 100 Units / Tube GM431AS8R 0.5% A SOP-8 2,500 Units / Tape & Reel GM431AST89R 0.5% A SOT-89 1,000 Units / Tape & Reel GM431BT92B 1% B TO-92 1,000 Units/ ESD Bag GM431BT92RL 1% B TO-92 2,000 Units/ Ammo Pack(Tape) GM431BST23R 1% SOT-23 3,000 Units / Tape &Reel GM431BS8T 1% B SOP-8 100 Units / Tube GM431BS8R 1% B SOP-8 2,500 Units / Tape & Reel GM431BST89R 1% B SOT-89 1,000 Units / Tape & Reel GM431CT92B 2% C TO-92 1,000 Units/ ESD Bag GM431CT92RL 2% C TO-92 2,000 Units/ Ammo Pack(Tape) GM431CST23R 2% SOT-23 3,000 Units / Tape &Reel GM431CS8T 2% C SOP-8 100 Units / Tube GM431CS8R 2% C SOP-8 2,500 Units / Tape & Reel GM431CST89R 2% C SOT-89 1,000 Units / Tape & Reel AAA AAB AAC * For detail Ordering Number identification, please see last page. **Grade A: indicates Precision of 0.5%, B: indicates Precision of 1%, C: indicates Precision of 2% A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR EQUIVALENT SCHEMATIC CATHODE 800W 800W 20pF REF 150W 3.28KW 4KW 10kW 2.4KW 20pF 7.2KW 1kW 800W ANODE GM431 * All component values are nominal. Pin numbers shown are for the D package. 3 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR ABSOLUTE MAXIMUM RATINGS (over free-air temperature range except as noted) SYMBOL Value UNIT VKA 37 V Continuous cathode current range IK -100 to 150 mA Reference input current range Iref -50µA to 10mA mA Power dissipation at TA = 25°C SOT-23 SOP-8 TO-92 SOT-89 PD PARAMETER Cathode Voltage (1) Package thermal impedance SOT-23 TO-92 SOP-8 SOT-89 0.23 0.60 0.78 0.80 W (2, 3) Operating ambient temperature range Lead temperature (soldering) 10 seconds qJA 336 132 163 132 TA 0 to + 70 °C TLEAD 260 °C °C/W These are stress ratings only. Functional operation of the device at these or any conditions beyond the "recommended operating conditions" is not implied. Exposure to absolute maximum rated conditions may affect device reliability. NOTES: 1. Voltage values are with respect to the anode except as noted. 2. Maximum power dissipation is a function of TJ(max), qJA and TA. Maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) - TA)/ qJA. 3. Package thermal impedance is calculated per JESD 51. RECOMMENDED OPERATING CONDITIONS SYMBOL MINIMUM MAXIMUM UNIT Cathode Voltage VKA Vref 36 V Cathode Current IK 1.0 100 mA GM431 PARAMETER 4 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted) GM431A (0.5%) PARAMETER Reference Voltage Vref temp deviation CONDITION Vref Vdev DVref Ratio of change in Vref to change in VKA DVKA Reference input current Iref VKA = Vref, IK = 10 mA, TA = 25°C (1) VKA=Vref,IK=10 mA,TA= 0 to 70°C (1) MIN TYP MAX UNIT 2.487 2.500 2.512 V 4 17 mV VKA = Vref, IK = 10 mA (1), TA = full range IK = 10mA DVKA = 10V to Vref -2.7 -2.0 DVKA = 36V to 10V IK = 10mA, R1 = 10KW, R2 = (2) Deviation of reference input current over full temperature range I = 10mA, R1 = 10KW, R2 = Iref(dev) K TA = full range (2) Minimum operating current IK(min) VKA = Vref (1) Off-state cathode current IK(off) Dynamic impedance | ZKA | f 1kHz,VKA=Vref, IK=1mA to 100mA (1) -1.0 -0.4 mV/V 0.7 4.0 mA 0.4 1.2 mA 0.4 1.0 mA 0.1 1 mA 0.2 0.50 W MIN TYP MAX UNIT 2.475 2.500 2.525 V 4 17 mV VKA = 36V, Vref = 0V (3) VKA = 16V, Vref = 0V (3) GM431B (1.0%) PARAMETER CONDITION Reference Voltage Vref Vref temp deviation Vdev Ratio of change in Vref to change in VKA DVref DVKA Reference input current Iref VKA = Vref, IK = 10 mA, TA = 25°C (1) VKA=Vref,IK=10 mA,TA= 0 to 70°C(1) VKA = Vref, IK = 10 mA (1), TA = full range IK = 10mA DVKA = 10V to Vref DVKA = 36V to 10V IK = 10mA, R1 = 10KW, R2 = (2) Deviation of reference input current over full temperature range I = 10mA, R1 = 10KW, R2 = Iref(dev) K TA = full range (2) Minimum operating current IK(min) VKA = Vref (1) Off-state cathode current IK(off) Dynamic impedance | ZKA | f 1kHz,VKA=Vref, IK=1mA to 100mA (1) VKA = 36V, Vref = 0V (3) VKA = 16V, Vref = 0V (3) -2.7 -2.0 -1.0 -0.4 mV/V 0.7 4.0 mA 0.4 1.2 mA 0.4 1.0 mA 0.1 1 mA 0.2 0.50 W GM431 NOTES: (1) See test circuit 1 on page 5. (2) See test circuit 2 on page 5. (3) See test circuit 3 on page 5. 5 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted) GM431C (2.0%) PARAMETER CONDITION Reference Voltage Vref temp deviation Vref Vdev DVref Ratio of change in Vref to change in VKA DVKA Reference input current Iref VKA = Vref, IK = 10 mA, TA = 25°C (1) VKA=Vref,IK=10 mA,TA= 0 to 70°C (1) MIN TYP MAX UNIT 2.45 2.500 2.55 V 4 17 mV VKA = Vref, IK = 10 mA (1), TA = full range IK = 10mA DVKA = 10V to Vref -2.7 -2.0 DVKA = 36V to 10V IK = 10mA, R1 = 10KW, R2 = (2) Deviation of reference input current over full temperature range I = 10mA, R1 = 10KW, R2 = Iref(dev) K TA = full range (2) Minimum operating current IK(min) VKA = Vref (1) Off-state cathode current IK(off) Dynamic impedance | ZKA | f 1kHz,VKA=Vref, IK=1mA to 100mA (1) VKA = 36V, Vref = 0V (3) VKA = 16V, Vref = 0V (3) -1.0 -0.4 mV/V 0.7 4.0 mA 0.4 1.2 mA 0.4 1.0 mA 0.1 1 mA 0.2 0.50 W NOTES: (1) See test circuit 1. (2) See test circuit 2. (3) See test circuit 3. TEST CIRCUITS VIN VKA VIN VKA lref lk VIN VKA lk(off) R1 V ref R2 lref Vref GM431 Vref 6 Test Circuit 1 V KA = V ref Test Circuit 2 V KA > V ref Test Circuit 3 Off-State A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR TYPICAL APPLICATIONS GM431A, GM431B Vin Vout Vout Vin R1 R1 R2 R2 R1 Vout=( 1+ R2 ) Vref Vout=( 1+ Figure 1. Shunt Regulator Vin R1 ) Vref R2 Figure 2. High Current Shunt Regulator Vout Vin GM 7805 In Out Common Vout R1 R1 R2 R2 Vout=(1+ R1 )Vref R2 Vout=(1+ Vout(min) = Vref+ 5.0V Vout(min) = Vref+ Vbe Figure 3. Output Control for a Three Terminal Fixed Regulator RCL Vin Iout R1 ) Vref R2 2.0V Figure 4. Series Pass Regulator Vin Isink Vout V Isink= ref RS Iout= Vref RS RCL Figure 6. Constant Current Sink Figure 5. Constant Current Source Vout Vin Vout Vin R1 R1 R2 Vout(trip)=(1 + R1 ) Vref R2 Figure 7. TRIAC Crowbar Vout(trip)=(1 + R1 ) Vref R2 Figure 8. SCR Crowbar GM431 R2 7 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR 1000 200 800 150 Cathode current (mA) Cathode current (mA) Typical Performance Characteristics 600 400 200 0 -200 50 0 -50 -100 -400 -1 -0.5 0 0.5 1 1.5 2 2.5 -150 -2 3 -1 0 1 2 3 Cathode Voltage (V) Cathode Voltage (V) Figure 9. Cathode Current vs. Cathode Voltage Figure 10. Cathode Current vs. Cathode Voltage 0.6 2.5 0.5 2 Impedance (W) Iref, REFERENCE INPUT CURRENT (mA) 100 0.4 0.3 0.2 1.5 1 0.5 0.1 0 0 0 20 40 60 80 0 100K 200K 300K 400K 500K 600K Frequency (Hz) T A , AMBIENT TEMPERATURE (°C) Avol, OPEN LOOP VOLTAGE GAIN (dB) Vref, REFERENCE INPUT VOLTAGE (V) 2.5 2.498 2.496 2.494 2.492 2.49 2.488 2.486 0 20 40 60 GM431 50 40 30 20 10 0 -10 10 100 1k 10k 100k 1M T A , AMBIENT TEMPERATURE (°C) f, FREQUENCY (HZ) Figure 13. Reference Input Voltage versus Figure 14. Open-Loop Voltage Gain vs. Frequency Ambient Temperature 8 80 0° I KA =10mA 36° T A =25°C 72° 108° 144° 180° 60 Phase Shift Figure 12. Dynamic Impedance Frequency Figure 11. Reference Input Current versus Ambient Temperature A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR Design Guide for AC-DCSMPS (Switching Mode Power Supply) Use of Shunt Regulator in Transformer Secondary side Control This example is applicable to both forward transformers and flyback transformers. A shunt regulator is used on the secondary side as an error amplifier, and feedback to the primary side is provided via a photocoupler. Transformer R1 SBD R3 GM384X GM38C4X (+) Output IF VF Phototransistor Photocoupler Light emitting diode VO R2 IB (-) Vref VK R5 C1 R4 REF GM431 GND Figure 16. Typical Shunt Regulator/ Error Amplifier Determination of External Costants for the Shunt Regulator Dc characteristic determination: In figure 16, R1 and R2 are protection resistor for the light emitting diode in the photocoupler, and R2 is a bypass resistor to feed IK Minimum, and these are determined as shown below. The photocoupler specification should be obtained separately from the manufacturer. Using the parameters in figure 16, the following formulas are obtained: R1 = VO - VF - VK I F +I B , R2 = VF IB Next, the output voltage can be determined by R3 and R4, and the following formula is obtained: VO = R3 +R4 X V ref , V erf =2 .5 V Typ R4 The absolute values of R3 and R4 are determined by the GM431 reference input current Iref and the AC characteristics described in the next section. The Iref value is around 0.7µA Typ. GM431 VK Is the GM431 operating voltage, and is set at around 3V, taking into account a margin for fluctuation. R2 is the current shunt resistance for the light emitting diode, in which a bias current IB of around 1/5 IF flows. 9 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR AC Characteristic Determination: This refers to the determination of the gain frequency characteristic of the shunt regulator as an error amplifier. Taking the configuration in figure 16, the error amplifier characteristic is as shown in figure 17. G1 Gain G (dB) * fosc: PWM switching frequency G2 When R5= 0 When R5= 0 F1 FAC F2 Fosc Frequency f (Hz) Figure 17. GM431 Error Amplification Characteristic In Figure 17, the following formulas are obtained: Gain G1 = G0 50 dB to 60 dB (determined by shunt regulator) G2 = R5 R3 Corner frequencies f1 = 1/(2p C1 G0 R3) f2 = 1/(2p C1 R5) G0 is the shunt regulator open-loop gain; this is given by the reciprocal of the reference voltage fluctuation DVref/DVKA, and is approximately 50 dB. Practical Example Consider the example of a photocoupler, with an internal light emitting diode VF = 1.05 V and IF = 2.5 mA, power supply output voltage V2 = 5 V, and bias resistance R2 current of approximately 1/5 IF at 0.5 mA. If the shunt regulator VK = 3 V, the following values are found. R1= 5V - 1.05V - 3V =316W 2.5mA + 0.5mA R2= 1.05V =2.1 kW 0.5mA Next, assume that R3 = R4 = 10 kW. This gives a 5 V output. If R5 = 3.3 kW and C1 = 0.022 µF, the following values are found. GM431 G2 = 3.3 kW / 10 kW = 0.33 times (–10 dB) f1 = 1 / (2 x p x 0.022 µF x 316 x 10 kW) = 2.3 (Hz) f2 = 1 / (2 x p x 0.022 µF x 3.3 kW) = 2.2 (kHz) 10 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR SOT-89 PACKAGE OUTLINE DIMENSIONS 4.50 ± 0.05 1.650 REF Units: mm Pad Layout 1.50 ± 0.05 1.400 REF 2 R 0.13~4X NO DRAFT~2 R 0.13~3X 3 4.20 ± 0.05 2.5 ± 0.05 45° 6° R 0.1 MAX 1.00 ± 0.07 0.7 0.46 ± 0.025 1.50 1.5 1.50 0.38 ± 0.01 3.00 ± 0.025 1.5 6°~2X 1 R 0.13~2X R 0.13~2X Unit: mm 6°~2X SOT-23 PACKAGE OUTLINE DIMENSIONS 2.90 ± 0.1 0.13 0.4 ± 0.1 Pad Layout 0~0.1 0.031 1.5 ± 0.05 2.8 ± 0.1 0.8 0.035 0.9 0.65 ± 0.05 0.079 2.0 0.95 ± 0.038 0.8 ± 0.05 1.9 ± 0.05 5° Unit: mm 0.037 0.95 0.95 Inches ( mm ) GM431 1.10 ± 0.1 0.037 11 A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR SOP-8 PACKAGE OUTLINE DIMENSIONS 0.008 +0.0018 -0.0005 0.200 +0.05 -0.01 0 ° ~ 8° 0.028 0.710 +0.013 -0.022 Pad Layout 0.060 +0.33 -0.56 1.52 0.236 ± 0.008 5.990 +0.21 -0.20 0.154 +0.003 -0.004 0.275 0.155 7.0 4.0 PIN INDENT 3.91 ± 0.1 0.024 0.050 0.6 1.270 Inches ( mm ) 0.191 +0.002 -0.004 4.850 +0.05 -0.10 0.057 NOM 1.450 NOM 0.063 ± 0.005 1.600 ± 0.130 ( Inches ) mm 0.007 ± 0.003 0.175 ± 0.075 0.050 NOM 1.270 NOM 0.016 +0.004 -0.003 0.410 +0.10 -0.08 TO-92 PACKAGE OUTLINE DIMENSIONS 4.6 ± 0.1 3.6 ± 0.15 2° 2° 4.6 ± 0.1 2.3 2° 1.45 ± 0.1 2° 3 - 0.46 14.5 ± 0.5 0.38 ± 0.015 GM431 1.27 1.27 12 Unit: mm 3.6 ± 0.15 1.3 ± 0.1 5° 5° A Power Management GM431 A MICROELECTRONICS 2.5V ADJUSTABLE SHUNT REGULATOR ORDERING NUMBER GM 431 A T92 B Shipping B : EDS Bag RL: Ammo Pack R: Tape & Reel T: Tube Circuit Type Voltage Tolerance A: 0.5% B: 1.0% C: 2.0% (Tape) Package T92: TO-92 ST23: SOT-23 S8: SOP-8 ST89: SOT-89 GM431 Gamma Micro. 13 A A MICROELECTRONICS Power Management GM431 GM431 2.5V ADJUSTABLE SHUNT REGULATOR 14