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TL431 TL431A CJ431 SOT-23 Shunt Voltage Reference IC SMD (25-Pack)
TL431 TL431A CJ431 SOT-23 Shunt Voltage Reference IC SMD (25-Pack)
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TL431 / TL431A / CJ431 — SOT-23 Adjustable Shunt Voltage Reference
The TL431 is a precision programmable shunt voltage reference widely used in SMPS feedback loops, voltage regulators, and ADC reference circuits. This listing provides 25 pieces in compact SOT-23 SMD package — new and original parts.
Key Specifications
| Parameter | Value |
|---|---|
| Part Numbers | TL431 / TL431A / CJ431 |
| Package | SOT-23 (3-pin SMD) |
| Output Voltage Range | 2.5V – 36V (adjustable) |
| Reference Voltage (Vref) | 2.495V (typ.) |
| Cathode Current | 1mA – 100mA |
| Temperature Coefficient | ≤50 ppm/°C (TL431A) |
| Operating Temperature | 0°C to +70°C |
| Quantity | 25 PCS |
Why Choose TL431 SOT-23?
- ✅ Industry-standard reference — used in virtually every SMPS feedback circuit
- ✅ Compact SOT-23 package — ideal for space-constrained PCB designs
- ✅ Adjustable output — set any voltage from 2.5V to 36V with two resistors
- ✅ New & original — genuine TL431A grade, not remarked
- ✅ 25-pack value — cost-effective for prototyping and production
Compatible With / Works With
- SMPS optocoupler feedback (PC817 + TL431 classic topology)
- LM358, LM324 op-amp comparator circuits
- Arduino ADC external reference (2.5V fixed)
- Raspberry Pi voltage monitoring circuits
- Battery charger termination circuits
Typical Applications
- SMPS Feedback Loop — flyback/forward converter output regulation via optocoupler
- Precision Voltage Reference — ADC reference for STM32, ATmega, ESP32
- Overvoltage Protection — crowbar circuit with SCR or thyristor
- LED Driver Constant Current — simple 2-resistor current sink
- Battery Charger — charge termination voltage detection
FAQ
Q: What is the difference between TL431 and TL431A?
A: TL431A has tighter tolerance on Vref (±0.5% vs ±2%), making it preferred for precision applications. Both are electrically interchangeable in most circuits.
Q: Is CJ431 a direct replacement for TL431?
A: Yes. CJ431 is a Chinese-manufactured equivalent with identical pinout and electrical characteristics, fully interchangeable in standard circuits.
Q: Can TL431 be used as a 5V regulator?
A: Yes, with two resistors (R1 and R2) to set the output: Vout = Vref × (1 + R1/R2). For 5V: use R1=100kΩ, R2=40.2kΩ.
Package Contents
- 25× TL431 / TL431A / CJ431 SOT-23 Shunt Voltage Reference IC
