TL432BSA-7 - Adjustable Shunt Reference, 36V, ±0.5%, SOT-23-3 | Diodes Incorporated
MPN: TL432BSA-7 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.36 | $3.60 |
| 100 | $0.24 | $24.00 |
| 500 | $0.18 | $90.00 |
| 1,000 | $0.14 | $140.00 |
| 3,000 | $0.11 | $330.00 |
TL432BSA-7 Overview
A shunt voltage reference is a two-terminal device that maintains a fixed voltage across its cathode-anode terminals by sinking current to ground, analogous to a Zener diode but with much tighter tolerance, lower dynamic impedance, and better temperature stability. The TL432 family (and the related TL431 family) belongs to the broader category of programmable shunt regulators, which are key analog building blocks in power management, signal conditioning, and feedback loops. They occupy the same hierarchical role as bandgap voltage references, Zener references, and series voltage regulators, but differ by being driven by current rather than input voltage.
Key features of the TL432BSA-7 include an adjustable reference voltage set by an external resistor divider, low dynamic output impedance across the operating current range, and a wide cathode operating current window from 1 mA to 100 mA. The TL432 pinout reverses the reference (REF) and anode (A) positions relative to the TL431, so it is NOT a drop-in pin replacement for TL431 footprints. The reference tolerance is graded by suffix: 'B' designates ±0.5%, 'A' designates ±1.0%, and standard is ±2.0%.
The TL432BSA-7 uses a bandgap core stabilized by on-chip temperature-compensation circuitry to deliver a flat temperature coefficient across the full industrial -40 °C to +125 °C range. The low dynamic impedance (~0.5 ohm typical) and 100 mA cathode capability allow it to serve as both a precision reference and a feedback error amplifier in isolated and non-isolated switching power supply topologies.
Typical applications include switching power supply feedback loops, precision constant-current sinks, adjustable voltage references in industrial control, ADC/DAC reference rails, battery chargers, and comparator-style overvoltage monitors. Its SOT-23-3 footprint also suits high-density analog boards where a TL431 TO-92 part would be too large.
When designing with the TL432BSA-7, verify the pinout against the TL431 footprint on existing PCBs, since the REF and ANODE pins swap positions. Provide at least 1 mA of cathode bias current to keep the device in regulation, and bypass the reference pin with a 0.1 µF capacitor when noise-sensitive ADCs are tied to the reference ladder.
This page synthesizes distributor pricing, drop-in alternatives sourced from the TL432 and TL431 pin-compatible families, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for TL432BSA-7 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with TL432BSA-7 (same form factor and footprint) — differing in Package, MSL Level, Operating Temperature Range, Output Voltage Range, Reference Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TL432ASA-7
✅ Drop-In📋 Reference alternative (not in catalog)
TL432BQDBZR
✅ Drop-In📋 Reference alternative (not in catalog)
TL432BS3T1G
✅ Drop-In📋 Reference alternative (not in catalog)
TL432AIL3T
✅ Drop-In✓ In Stock
$0.14 / Unit
View Datasheet →TL432AQDBZR
✅ Drop-In📋 Reference alternative (not in catalog)
TL432BSA-7 Maximum Ratings & Electrical Characteristics
| Reference Type | Shunt - Adjustable |
| Output Voltage (Min/Fixed) | 2.495 V |
| Output Voltage - Max | 36 V |
| Cathode Current (Max) | 100 mA |
| Tolerance | ±0.5% (B grade) |
| Cathode Voltage (Max) | 40 V |
| Operating Temperature | -40 °C to +125 °C |
| Package | SOT-23-3 |
| Mounting Type | Surface Mount |
| Tolerance Grade Suffix | B = ±0.5%, A = ±1%, blank = ±2% |
| Pinout Family | TL432 (REF and ANODE swapped vs TL431) |
| Tape and Reel Qty | 3000 |
| RoHS Status | Compliant |
| MSL Level | 1 |
| Topology | Shunt References |
| Dynamic Impedance (Typ) | 0.5 ohm |
TL432BSA-7 Pin Configuration
| Pin 1 | K (Cathode) — Regulated output / cathode terminal - typically tied to Vout and R1 of divider |
| Pin 2 | REF — Reference input - tied to R1/R2 divider junction; bypass with 0.1 µF for noise-sensitive loads |
| Pin 3 | A (Anode) — Ground / anode terminal - reference for cathode and REF pins |
Typical Applications
TL432BSA-7 is suitable for 6 applications: Switching Power Supply Feedback, Precision Adjustable Voltage Reference, Constant-Current LED Driver Sink, ADC / DAC Reference Rail, Battery Charger Voltage Monitor, Industrial Control Card Power Rail.
Switching Power Supply Feedback
The TL432BSA-7 serves as the secondary-side error amplifier in isolated flyback and forward converters, replacing a TL431 in boards that follow the TL432 K-R-A pinout. With 100 mA cathode drive and 0.5 ohm typical dynamic impedance, it sinks the opto-coupler LED bias current directly to set loop gain, while the adjustable V_KA = 2.495 V × (1+R1/R2) reference precisely defines the regulated output rail. The B-grade ±0.5% tolerance tightens load and line regulation without external trim, and the wide 36 V tolerance voltage handles 24 V industrial bus rails plus margin.
Recommended
Precision Adjustable Voltage Reference
The TL432BSA-7 operates as a two-terminal adjustable Zener-like reference for instrumentation and test equipment rails. Setting V_KA with two 1% resistors gives a stable 2.495 V to 36 V reference rail with sub-mV load regulation across 1 mA to 100 mA cathode bias. The wide operating temperature range (-40 °C to +125 °C) and tight B-grade ±0.5% tolerance suit bench multimeters and lab-grade analog signal chains where the reference directly feeds an ADC or DAC reference pin.
Recommended
Constant-Current LED Driver Sink
Used as a constant-current sink, the TL432BSA-7 regulates LED current by fixing the voltage across a sense resistor at V_REF = 2.495 V. With cathode drive up to 100 mA, it directly biases indicator LEDs, optocouplers, or small display segments from a higher rail. The shunt topology means the TL432 simply sinks excess current - no series-pass transistor is required for currents within its 100 mA rating - simplifying isolated LED biasing in industrial HMIs.
Recommended
ADC / DAC Reference Rail
The TL432BSA-7 provides a low-cost adjustable reference for low- to mid-resolution ADCs and DACs, with the option to bypass the REF pin with a 0.1 µF capacitor for noise reduction. The 0.5 ohm typical dynamic impedance keeps reference voltage flat across the dynamic load of successive-approximation ADCs, while the SOT-23-3 footprint fits inside dense mixed-signal layouts. The B-grade ±0.5% tolerance translates directly into ADC gain error budget without external calibration.
Recommended
Battery Charger Voltage Monitor
In single- and multi-cell lithium-ion or lead-acid chargers, the TL432BSA-7 functions as a comparator-style overvoltage monitor. The REF pin senses the cell voltage divider; when V_REF exceeds 2.495 V, the cathode pulls low and disables the charger FET. The 100 mA cathode capability lets it directly drive small logic-level MOSFETs or optocouplers without an additional driver stage. Wide 36 V tolerance voltage covers stacked 12 V lead-acid battery packs.
Recommended
Industrial Control Card Power Rail
Industrial PLC I/O cards use the TL432BSA-7 as a stable auxiliary reference for 24 V loop-powered transducers and 4-20 mA current loops. The shunt topology tolerates input supply variation typical of 24 V industrial bus rails, while the wide operating temperature range and SOT-23-3 footprint survive dense control-card PCB layouts. The B-grade ±0.5% tolerance maintains loop accuracy without periodic field recalibration.
Recommended
Recommended Products Summary
Engineering reference data for TL432BSA-7 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TL432ASA-7 | TL432BQDBZR | TL432BS3T1G | TL432AIL3T | TL432AQDBZR |
|---|---|---|---|---|---|---|
| Brand | Diodes Incorporated | Diodes Incorporated | Texas Instruments | onsemi | STMicroelectronics | Texas Instruments |
| Package | SOT-23-3 | SOT-23-3 - same | SOT-23-3 - same | SOT-23-3 - same | SOT-23-3 - same | SOT-23-3 - same |
| Pinout | K-R-A (TL432 family) | K-R-A (TL432 family) - same | K-R-A (TL432 family) - same | K-R-A (TL432 family) - same | K-R-A (TL432 family) - same | K-R-A (TL432 family) - same |
| Reference Voltage (Min) | 2.495 V | 2.495 V | 2.495 V | 2.495 V | 2.495 V | 2.495 V |
| Output Voltage (Max) | 36 V | 36 V | 36 V | 36 V | 36 V | 36 V |
| Cathode Current (Max) | 100 mA | 100 mA | 100 mA | 100 mA | 100 mA | 100 mA |
| Initial Tolerance | ±0.5% (B grade) | ±1.0% (A grade) - looser | ±0.5% (B grade) - same | ±0.5% (B grade) - same | ±1.0% (A grade) - looser | ±1.0% (A grade) - looser |
| Operating Temperature | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
Key Differentiators
- Tighter ±0.5% initial accuracy than A-grade TL432 variants (vs TL432ASA-7 / TL432AIL3T / TL432AQDBZR)
- K-R-A TL432-family pinout for boards laid out for TL432 footprint (vs TL431BSA-7 (K-A-R pinout))
- Wide 36 V cathode tolerance supports 24 V industrial rails (vs Lower-voltage Zener references)
Design Notes
Do NOT assume TL432BSA-7 is pin-compatible with TL431 footprints. The TL432 family reverses REF and ANODE pin assignments (SOT-23-3 pinout is K-R-A, while TL431 is K-A-R). Dropping a TL432 onto a TL431 pad will mis-wire the divider and either short Vout to ground or leave the device unable to regulate. Always verify the package marking against the datasheet pinout diagram before PCB assembly.
Bias the TL432BSA-7 with at least 1 mA of cathode current to stay in regulation. In typical feedback designs a pull-up of 10 k to 4.7 k on the opto-coupler LED cathode gives ~3 mA at minimum VIN and well under the 100 mA absolute maximum. At 100 mA continuous cathode current into a SOT-23-3 (θJA ~357 °C/W on a minimal pad) the junction rises ~85 °C above ambient - derate in enclosed industrial enclosures.
When the TL432BSA-7 directly drives an ADC or DAC reference pin, bypass the REF pin with a 0.1 µF ceramic capacitor to suppress broadband noise from the bandgap core. For switching power supply feedback loops driving high-impedance opto-coupler LEDs, a small RC network (10 kΩ + 100 pF) on the cathode compensates the loop and prevents optocoupler CTR-induced oscillation.
Estimated: at V_KA = 5 V and I_K = 100 mA the TL432BSA-7 dissipates 500 mW. With θJA = 357 °C/W on a 1 oz 1 square inch copper pad, junction temperature climbs 178 °C above ambient - above the 150 °C absolute maximum. For continuous currents above 50 mA, expand the cathode copper pour to at least 1 square inch or add a small series resistor to drop V_KA × I_K dissipation below 250 mW.
Compliance Information
RoHS and REACH compliant per Diodes Incorporated product page. MSL-1 rated. Pb-free / halogen-free per Diodes environmental data. Not AEC-Q100 qualified - use automotive-graded TL432-Q1 variants for automotive applications.
