TS1431 Adjustable Precision Shunt Regulator SOT-23 Pin Definition: 1. Cathode 2. Reference 3. Anode General Description TS1431 series integrated circuits are three-terminal programmable shunt regulator diodes. These monolithic IC voltage references operate as a low temperature coefficient zener which is programmable from Vref to 36 volts with two external resistors. These devices exhibit a wide operating current range of 1.0 to 100mA with a typical dynamic impedance of 0.22Ω. The characteristics of these references make them excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op amp circuitry. The 2.5V reference makes it convenient to obtain a stable reference from 5.0V logic supplies, and since The TS1431 series operates as a shunt regulator, it can be used as either a positive or negative stage reference. Ordering Information Precision Reference Voltage TS1431 – 2.495V±2% TS1431A – 2.495V±1% TS1431B – 2.495V±0.5% Equivalent Full Range Temp. Coefficient: 50ppm/ ºC Programmable Output Voltage up to 36V Fast Turn-On Response Sink Current Capability of 1~100mA Low Dynamic Output Impedance: 0.2Ω Low Output Noise TS1431xCX RF SOT-23 3Kpcs / 7” Reel TS1431xCX RFG SOT-23 3Kpcs / 7” Reel Note: “G” denote for Green Product Where xx denotes voltage tolerance Blank: ±2%, A: ±1%, B: ±0.5% Block Diagram Voltage Monitor Delay Timmer Constant –Current Source/Sink High-Current Shunt Regulator Crow Bar Over-Voltage / Under-Voltage Protection Absolute Maximum Rating (Ta = 25oC unless otherwise noted) Parameter Cathode Voltage Continuous Cathode Current Range Reference Input Current Range Power Dissipation Junction Temperature Operating Temperature Range Storage Temperature Range

TS1431 Adjustable Precision Shunt Regulator Recommend Operating Condition Parameter Cathode Voltage (Note 1) Continuous Cathode Current Range Recommend Operating Condition Parameter TS1431 TS1431A TS1431B Deviation of reference input voltage Radio of change in Vref to change in cathode Voltage Reference voltage Reference Input current Deviation of reference input current, over temp. Off-state Cathode Current Dynamic Output Impedance Symbol VREF ∆ VREF ∆VREF /∆VKA IREF ∆IREF IKA (off) | ZKA | Test Conditions VKA =VREF, IK =10mA (Figure 1) o Ta=25 C VKA = VREF, IK =10mA (Figure 1) Ta= full range...

Test Circuits Adjustable Precision Shunt Regulator Input o-AA/V Figure 3: Off-State Current Additional Information - Stability When The TS1431/1431 A/1431 B is used as a shunt regulator, there are two options for selection of CL, are recommended for optional stability: A) No load capacitance across the device, decouple at the load. B) Large capacitance across the device, optional decoupling at the load. The reason for this is that TS1431/1431 A/1431 B exhibits instability with capacitances in the range of 10nF to 1uF (approx.) at light cathode current up to 3mA (typ). The device is less stable...

Adjustable Precision Shunt Regulator Applications Examples (Continue) Figure 6: Shunt Regulator Figure 7: High Current Shunt Regulator Figure 8: Series Pass Regulator Figure 9: Constant Current Source Figure 10: TRIAC Crowbar

Applications Examples (Continue) Figure 12: Single-Supply Comparator with Temperature-Compensated Threshold Adjustable Precision Shunt Regulator Figure 13: Constant Current Sink Delay= RxCxU^y Figure 14: Delay Timer

Typical Performance Characteristics Adjustable Precision Shunt Regulator Test Circuit for Voltage Amplification Figure 14: Small-Signal Voltage Gain and Phase Shirt vs. Frequency Test Circuit for Reference Impedance Figure 15: Reference Impedance vs. Frequency

Typical Performance Characteristics (Continue) Adjustable Precision Shunt Regulator The areas under the curves represent conditions that may cause the device to oscillate. For curves B, C, and D, R2 and V+ were adjusted to establish the initial VKA and IKA conditions with Ci_=0. VBATT and Ci_ then were adjusted to determine the ranges of stability. Test Circuit for Curve A Test Circuit for Curve B, C and D Figure 16: Stability Boundary Condition Test Circuit for Pulse Response, lk=1mA Figure 17: Pulse Response

Electrical Characteristics Adjustable Precision Shunt Regulator Figure 20: Cathode Current vs. Cathode Voltage

TS1431 Adjustable Precision Shunt Regulator Marking Diagram 1 = Device Code X = Tolerance Code (A = ±1%, B = ±0.5%, C = ±2%,) Y = Year Code M = Month Code (A=Jan, B=Feb, C=Mar, D=Apl, E=May, F=Jun, G=Jul, H=Aug, I=Sep, J=Oct, K=Nov, L=Dec) L = Lot Code

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