GM431S 2.5V ADJUSTABLE SHUNT REGULATOR Description Features The GM431S is a three terminal adjustable shunt regulator with a specified thermal stability guaranteed over temperature. The output voltage can be adjusted to any value between 2.5V (VREF) and 36V by using two external resistors. Active output circuitry provides a very sharp turn on characteristic, making the GM431S an excellent replacement for zener diodes in many applications such as on board regulation and adjustable power supplies. The Sink Current Capability 1mA to 100mA Fast Turn On Response Low output noise 0.5%, or 1% reference voltage tolerance Temperature range -40°C to + 125°C Available in most advanced Small SOT23, SOT23, TO92, SOT89 and SO8 packages The GM431S shunt regulator is available with two voltage tolerances 0.5%, and 1.0% over full temperature range and four package options SOT-23, TO-92, SOT-89 and SO-8. Application Switching power supplies Battery-orperated computers Linear regulator Computer disk drives Adjustable supplies Instrumentation Logic Symbol Block Diagram Cathode Reference Cathode Reference VREF Anode www.gammamicro.com.tw GM431SV2.01 Anode 1 GM431S 2.5V ADJUSTABLE SHUNT REGULATORS Marking Information and Pin Configurations (Top View) Small SOT23 and SOT23 TO92 Anode 2 SOT89 431Sg AYWW 431Sg AYWW ASxYW 1 Ref Ref 1 3 Cathode Ref 1 2 3 Cathode 3 Cathode 2 Anode Anode (GM431S) Anode 2 ASx: Marking Code (see table below) RSxYW 1 Cathode RSx: Marking Code (see table below) 3 Ref g: Grade Code (A: 0.5%, B: 1.0%) (GM431SR) A: Assembly/Test Site Code Y: Year W: Week code WW: Week Ordering Information GM431SV2.01 Ordering Number 2 Precision Device Code Grade Package Shipping GM431SAT92BG 0.5% A TO-92 1,000 Units/ESD Bag GM431SAT92RLG 0.5% A TO-92 2,000 Units/Ammo Pack (Tape) GM431SAST23RG 0.5% ASA A SOT-23 3,000 Units/Tape & Reel GM431SAST23MRG 0.5% ASA A Small SOT-23 3,000 Units/Tape & Reel GM431SRAST23RG 0.5% RSA A SOT-23 3,000 Units/Tape & Reel GM431SAST89RG 0.5% A SOT-89 1,000 Units/Tape & Reel GM431SBT92BG 1.0% B TO-92 1,000 Units/ESD Bag GM431SBT92RLG 1.0% B TO-92 2,000 Units/Ammo Pack (Tape) GM431SBST23RG 1.0% ASB B SOT-23 3,000 Units/Tape & Reel GM431SBST23MRG 1.0% ASB B Small SOT-23 3,000 Units/Tape & Reel GM431SRBST23RG 1.0% RSB B SOT-23 3,000 Units/Tape & Reel GM431BST89RG 1.0% B SOT-89 1,000 Units/Tape & Reel GM431S 2.5V ADJUSTABLE SHUNT REGULATOR Absolute Maximum Ratings PARAMETER Cathode Voltage Continuous Cathode Current Range Reference Input Current Range Power Dissipation at TA = 25°C SOT-23 TO-92 SOT-89 Package Thermal Resistance SOT-23 TO-92 SOT-89 Operating Ambient Temperature Range Storage Temperature Lead Temperature (soldering 10 sec.) SYMBOL RATINGS UNITS VKA IK IREF 37 -100 to 150 -50μA to 10mA V mA PD 0.23 0.78 0.8 W 336 132 132 -40 - 125 - 65 to 150 260 JA TA °C/W °C °C °C Recommended Operating Conditions PARAMETER Cathode Voltage Cathode Current SYMBOL Min Max UNITS VKA IK VREF 1 36 100 V mA Equivalent Schematics Cathode 800 800 20pF Reference 3.28K 4K 10k 20pF 1K Anode GM431SV2.01 2.4K 7.2K 3 GM431S 2.5V ADJUSTABLE SHUNT REGULATORS Electrical Characteristics (TA = 25°C unless otherwise specified) Parameter Reference Voltage Symbol GM431SA VREF GM431SB VREF Deviation over Temperature VREF(DEV) Condition VKA = VREF, IK = 10mA, Test circuit 1 Min Typ Max 2487 2500 2513 2475 2500 2525 8 17 Unit mV VKA = VREF, IK = 10mA, TA = 0 to 70°C VKA = 10V to VREF -2.7 -1.0 VKA = 36V to 10V -2 -0.4 mV Ratio of change in VREF to change in VKA VREF/VKA Reference Input Current IREF IK = 10mA, R1 = 10K, R2 = ∞ Test circuit 2 0.5 1.2 µA IREF Deviation over Temperature VREF(DEV) IK = 10mA, R1 = 10K, R2 = ∞ TA =Full range, Test circuit 2 0.4 1.2 µA Minimum Cathode Current IK(MIN) VKA = VREF Test circuit 1 0.4 1.0 mA Off-state cathode Current IK(OFF) VKA = 36V, VREF = 0V Test circuit 3 0.1 1 µA Dynamic Impedance |ZKA| VKA = VREF, IK = 1mA to 10mA, f ≤1kHz, Test circuit 1 0.25 0.5 Ω IK = 10mA mV/V Test Circuits VIN VKA IK VIN VKA IK R1 VIN VKA IK(OFF) IREF VREF GM431SV2.01 VREF 4 Test Circuit 1 VKA = VREF R2 VREF Test Circuit 2 VKA VREF Test Circuit 3 Off-State GM431S 2.5V ADJUSTABLE SHUNT REGULATOR Typical Characteristics 150 Cathode current (mA) 200 800 Cathode current (µA) 1000 600 400 200 0 -200 100 50 0 -50 -100 -400 -0.5 0 0.5 1.0 1.5 2.0 2.5 Cathode Voltage (V) -150 -2 3.0 3 2.5 0.6 2 0.5 0.4 0.3 0.2 1.5 1 0.5 0.1 0 -40 -20 0 20 40 60 80 100 120 TA Ambient Temperature (˚C) Figure 6. Reference Input Current vs. Ambient Temperature 0 0 100K 200K 300K 400K 500K 600K Frequency (Hz) Figure 7. Dynamic Impedance 2.500 2.498 2.496 2.494 2.492 2.490 2.488 2.486 -40 -20 0 20 40 60 80 100 120 TA Ambient Temperature (˚C) Figure 8. Reference Input Voltage vs. Ambient Temperature GM431SV2.01 VREF, Reference Input Voltage (V) 1 0 2 Cathode Voltage (V) Figure 5. Cathode Current vs. Cathode Voltage Impedance IREF, Reference Input Current (mA)) Figure 4. Cathode Current vs. Cathode Voltage -1 5 GM431S 2.5V ADJUSTABLE SHUNT REGULATORS Design Guide for AC-DC SMPS (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 photo-coupler. Transformer R1 SBD R3 GM384X series (+) IF VF Phototransistor IB Output VO R2 C1 Light Emitting Diode R5 GM431S (-) VREF R4 Figure 9. Typical Shunt Regulator/ Error Amplifier Determination of external constants for the Shunt Regulator DC Characteristic determination: In the application circuit above, R1 and R2 are protection resistors for the light emitting diode in the photo-coupler, and R2 is a bypass resistor to feed IK Minimum, and these are determined as shown below. The photo-coupler specification should be obtained separately from the manufacturer. Using the parameters in this circuit, the following formulas are obtained: VO – VF - VK R1 = IF + IB VF R2 = IB VK is the GM431S operating voltage, and is set at around 3V, taking into account a margin for fluctuation. R2 is the current shunt resistance for the 1ight emitting diode, in which a bias current IB of around 1/5 IF f1ows. Next, the output voltage can be determined by R3 and R4, and the following formula is obtained: GM431SV2.01 VO = VREF ( 6 R3 + R4 ) R4 VREF = 2.5V Typical The abSo1ute va1ueS of R3 and R4 are determined by the GM431S reference input current IREF and the AC characteristics described in the next Section. The IREF va1ue is around 0.7µA Typ. GM431S 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 amp1ifier. Taking the configuration in Figure 10, the error amp1ifier characteristic is as Shown in Figure 10. G1 Gain G (dB) * fOSC: PWM Switching frequency G2 When R5= 0 F1 FAC F2 When R5= 0 fOSC Frequency f (Hz) Figure 10. GM431S Error Amplification Characteristic In Figure 17, the following formulas are obtained: Gain G1 = G0 50 dB to 60 dB (determined by shunt regulator) R5 G2 = R3 Corner frequencies f1 = 1/ f2 = 1/ pC1G0R3) pC1R5) G0 iS the Shunt regulator open-loop gain; this is given by the reciprocal of the reference voltage fluctuation: VREF/VKA, and is approximately 50 dB. R1 = 5V – 1.05V – 3V = 316Ω 2.5mA + 0.54mA R2 = 1.05V 0.54mA = 2.1kΩ Next, assume that R3 = R4 = 10k. This gives a 5V output. If R5 = 3.3 k, and C1 = 0.022 pF, the following values are found. G2 = 3.3kΩ / 10kΩ = 0.33 times (-10 dB) f1 = 1 / (2 0.022µF 316 10 k) = 2.3 (Hz) f1 = 1 / (2 0.022µF 3.3k) = 2.2 (kHz) 2 GM431SV2.01 Practical Example Consider the example of a photocoupler, with an internal light emitting diode VF = 1.05 V and IF = 2.5mA, power supply output vo1tage V2 = 5V, and bias resistance R2 current of approximately 1/5 IF at 0.5mA. If the Shunt regulator VK = 3V, the following values are found. 7 GM431S 2.5V ADJUSTABLE SHUNT REGULATORS Package Outline Dimensions – Small SOT 23 0.012 – 0.020 (0.300 – 0.500) 0.089 – 0.100 (2.250 – 2.550) 0.110 – 0.118 (2.800 – 3.000) 0.012 – 0.020 (0.300 – 0.500) 8° 0.010 (0.250) 0.047 – 0.055 (1.200 – 1.400) 0.022 (0.550) Ref 0.037 (0.095) Typ . 0.071 – 0.079 (1.800 – 2.000) 0.003 – 0.006 (0.080 – 0.150) 0.000 – 0.004 (0.000 – 0.100) 0.035 – 0.045 (0.900 – 1.150) 0.035 – 0.041 (0.900 – 1.105) GM431SV2.01 Inch (mm) 8 GM431S 2.5V ADJUSTABLE SHUNT REGULATOR Package Outline Dimensions – SOT 23 0.110 – 0.120 (2.80 – 3.04) 0.003 – 0.007 (0.08 – 0.18) 0.013 – 0.017 (0.34 – 0.44) 0.063 – 0.104 (2.11 – 2.62) 0.047 – 0.055 (1.20 – 1.40) 0 - 8° typ 0.075 (1.91) Typ. 0.037 (0.93) Typ. 0.0150 – 0.0200 (0.382 – 0.508) 0.0005 – 0.0040 (0.025 – 0.102) Package Outline Dimensions – SOT 89 0.173 – 0.181 (4.39 – 4.59) 0.061 REF 1.550 REF 0.084 – 0.090 (2.13 – 2.28) 0.155 – 0.167 (3.94 – 4.24) 0.055 – 0.063 (1.39 – 1.60) 0.014 – 0.017 (0.35 – 0.43) 0.090 – 0.102 (2.28 – 2.59) 8° 0.035 – 0.047 (0.89 – 1.19) 0.016 – 0.023 (0.400 – 0.580) 0.013 – 0.021 (0.320 – 0.520) 0.059 BSC (1.49) BSC GM431SV2.01 0.118 BSC (2.99) BSC 9 GM431S 2.5V ADJUSTABLE SHUNT REGULATORS Package Outline Dimensions – TO 92 3.85 – 4.19 4.7 – 5.2 4.9 – 5.2 12.7 – 14..2 0.4 – 0.55 typ. 1.22 – 1.32 Package Outline Dimensions – SO 8 0.189 – 0.197 (4.800 – 5.004) 0.228 – 0.244 (5.791 – 6.198) 0.016 – 0.050 (0.406 – 0.270) GM431SV2.01 0.014 – 0.020 (0.356 – 0.508) 10 0.050 (1.270) Typ . 0.150 – 0.157 (3.810 – 3.988) 8.0° Max 0.053 – 0.059 (1.346 – 1.753) Seating Plan 0.004 – 0.010 (0.102 – 0.254) 0.008 – 0.010 (0.203 – 0.254) GM431S 2.5V ADJUSTABLE SHUNT REGULATOR Ordering Number GM 431S A APM Gamma Micro Circuit Type Output Accuracy A: 0.5% B: 1.0% GM 431SR A APM Gamma Micro Circuit Type Output Accuracy A: 0.5% B: 1.0% ST23 R G Package Type Shipping Type G:Green T92: TO92 ST23:SOT23 ST23M: Small SOT23 ST89: SOT89 S8: SO8 B: Bag RL: Ammo Pack (Tape) T: Tube R: Tape & Reel ST23 R G Package Type Shipping Type T92: TO92 ST23:SOT23 ST23M: Small SOT23 ST89: SOT89 S8: SO8 B: Bag RL: Ammo Pack (Tape) T: Tube R: Tape & Reel G:Green Note: Pb-free products: RoHS compliant and compatible with the current require-ments of IPC/JEDEC J-STD-020. Suitable for use in Pb-free soldering processes with 100% matte tin (Sn) plating. Lead-free (RoHS compliant) Halogen free(Br or Cl does not exceed 900ppm by weight in homogeneous material and total of Br and Cl does not exceed 1500ppm by weight) GM431SV2.01 Green products: 11