TL432LIBQDBZR - Adjustable 2.495V Shunt Reference, ±0.5% | TI
MPN: TL432LIBQDBZR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.4428 | $0.44 |
| 10 | $0.38 | $3.80 |
| 100 | $0.28 | $28.00 |
| 500 | $0.22 | $110.00 |
| 1,000 | $0.18 | $180.00 |
| 3,000 | $0.15 | $450.00 |
TL432LIBQDBZR Overview
A shunt voltage reference is a two-terminal (or three-terminal with adjust) device that behaves like a non-inverting precision Zener diode. When biased with a resistor from a higher supply, it holds its cathode-to-anode voltage fixed at the programmed VREF, allowing any desired reference voltage to be set with external resistors. The TL432LI sits within the hierarchical group: shunt reference -> voltage reference -> power management IC -> analog semiconductor. It is functionally equivalent to the TL431 family but offers a different pinout in the SOT-23-3 package and improved IREF/Idev characteristics.
Key features include adjustable cathode voltage from 2.495V up to 36V, a typical output impedance of 0.2 ohm, low cathode current of 400 nA min and 15 mA max, and operation across the automotive -40°C to +125°C range. The SOT-23-3 (DBZ) outline is footprint-compatible with the standard TL431/TL432 family, easing second-source sourcing. The TL432LI is also offered in 1% (A) tolerance grades for tighter designs.
Technologically, the TL432LI uses a buried-Zener bandgap core with trimmed thin-film resistors to achieve tight initial tolerance and low temperature drift. The optimized IREF/Idev values minimize the error terms introduced by the feedback divider at low cathode currents, enabling high-accuracy closed-loop designs without the bias-induced errors seen in classic TL431 circuits.
Typical applications include adjustable linear regulator feedback, switching-mode power supply (SMPS) error-amplifier reference, isolated point-of-load rails, automotive voltage monitors, and ADC/DAC precision references. The wide cathode operating range also makes it useful in high-voltage rails up to 36V.
When designing with this part, remember the TL432LI pinout in the SOT-23-3 differs from the TL431 in the same package - pin 1 is REF, pin 2 is ANODE, and pin 3 is CATHODE. Verify orientation against the datasheet footprint before PCB reuse.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not offered as a single view on the manufacturer datasheet, helping engineers compare sourcing options and pinout compatibility at a glance.
Drop-in alternatives for TL432LIBQDBZR — 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 TL432LIBQDBZR (same form factor and footprint) — differing in Package, Operating Temperature Range, Reference Type, Output Voltage Range, Reference Voltage (Vref).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TL432BCDBZR
✅ Drop-In📋 Reference alternative (not in catalog)
TL432ACLPR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
TL432ACDBZR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
TL431BQDBZR
✅ Drop-In✓ In Stock
$0.07 / Unit
View Datasheet →ATL432LIBIDBZR
✅ Drop-In✓ In Stock
$0.26 / Unit
View Datasheet →LM4040BIM3-2.5/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
TL432LIBQDBZR Specifications
| Reference Type | Shunt Voltage Reference (adjustable) |
| Nominal Reference Voltage (VREF) | 2.495 V |
| Cathode Voltage Range | 2.495 V to 36 V |
| Initial Cathode Tolerance | ±0.5% (B grade, 25 °C) |
| Min Cathode Current (IKA min) | 400 nA |
| Max Cathode Current (IKA max) | 15 mA |
| Typical Output Impedance | 0.2 ohm |
| Operating Temperature Range | -40 °C to +125 °C (automotive) |
| Reference Current (IREF) | Optimized low-Iref design |
| Deviation Current (Idev) | Optimized low-Idev design |
| Package | SOT-23-3 (DBZ) - 3-pin |
| Mounting Type | Surface Mount |
| Pinout (SOT-23-3) | Pin1=REF, Pin2=ANODE, Pin3=CATHODE (differs from TL431 in same pkg) |
| RoHS Status | Compliant |
TL432LIBQDBZR Pin Configuration
| Pin 1 | REF — Reference (program the output via external resistor divider) |
| Pin 2 | ANODE — Anode (typically tied to ground) |
| Pin 3 | CATHODE — Cathode (regulated output, sinks current) |
Typical Applications
TL432LIBQDBZR is suitable for 6 applications: Adjustable Linear Regulator Feedback, SMPS Error-Amplifier Reference, Automotive Voltage Monitor, Precision ADC/DAC Reference Buffer, Isolated Point-of-Load Rail, Battery Charger Termination Sensor.
Adjustable Linear Regulator Feedback
The TL432LIBQDBZR's 2.495V nominal VREF, ±0.5% B-grade initial tolerance, and 400 nA-15 mA cathode range make it ideal as the error-amplifier reference inside an adjustable linear regulator such as a discrete LM317-style design. Its 36V cathode rating supports input rails up to 36V including 24V industrial supplies and 12V-15V automotive feeds. Placed with a resistor divider on the REF pin, the low IREF/Idev of the LI variant keeps error from the divider below the part's own tolerance, yielding output accuracy within ±1% across load and temperature. Unlike a Zener diode, it also has a stable temperature coefficient curve for production-line consistency.
Recommended
SMPS Error-Amplifier Reference
In switch-mode power supplies the TL432LIBQDBZR serves as the precision reference at the inverting input of the primary-side opto-isolator feedback loop. With 2.495V-36V cathode capability and 0.2 ohm output impedance, it drives opto-coupler LED currents up to 10 mA with tight loop accuracy across line and load variations. The ±0.5% B-grade tolerance translates directly to ±0.5% output set-point accuracy when used with 1% feedback resistors, while the optimized IREF (sub-µA) means the resistor-divider error term is negligible. This reference is appropriate for isolated DC-DC converters, telecom bricks, and USB-PD secondary-side regulation loops.
Recommended
Automotive Voltage Monitor
The TL432LIBQDBZR suits automotive battery monitoring where the 12V-36V cathode range covers 12V cranking and 24V truck supplies. Its -40°C to +125°C operating range matches automotive under-hood environments, and the low 400 nA minimum cathode current enables continuous low-power monitor circuits that draw negligible quiescent current. Combined with a comparator and MOSFET, it forms a precision over-voltage or under-voltage cutoff for module protection. The 36V rating also tolerates load-dump transients when paired with a TVS clamp, making it a robust choice for ECU and sensor-supply supervision.
Recommended
Precision ADC/DAC Reference Buffer
When configured as a fixed 2.5V reference by shorting REF to CATHODE, the TL432LIBQDBZR delivers a low-impedance 2.495V rail suitable for ADC/DAC external reference inputs. The 0.2 ohm typical output impedance holds the reference voltage stable against transient ADC reference-pin currents during conversions, and the ±0.5% initial tolerance sets a predictable gain-error budget for 12-14-bit converters. The low Idev characteristic ensures that even at microamp loading levels the reference error contributed by the part itself remains well inside the ADC's calibration envelope, supporting data-acquisition and instrumentation designs.
Recommended
Isolated Point-of-Load Rail
On isolated secondary sides, the TL432LIBQDBZR provides local regulation feedback to a primary-side PWM controller through an optocoupler or digital isolator. Its 400 nA minimum cathode current draws little power from the post-transformer rail, while the 36V cathode ceiling tolerates wide rectified-DC input voltage excursions before the converter stabilizes its output. Designers often pair it with a TL431-type opto error amplifier for cost-sensitive industrial converters, but the TL432LI's optimized low-IREF design gives tighter load-regulation accuracy without changing the external component count.
Recommended
Battery Charger Termination Sensor
Inside a battery charger, the TL432LIBQDBZR detects the end-of-charge voltage and signals a microcontroller or charge-FET driver. With its 2.495V internal reference and external resistor divider, the trip point can be programmed to anything from a single Li-ion cell to a 12V SLA battery, while the 15 mA cathode current can directly drive indicator LEDs or small relays. The 36V cathode maximum covers even high-voltage battery stacks, and the low IREF/Idev ensures the threshold accuracy is not undermined by leakage in the divider network, giving reliable state-of-charge transitions in charging cycles.
Recommended
Recommended Products Summary
Engineering reference data for TL432LIBQDBZR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TL432BCDBZR | TL432ACLPR | TL431BQDBZR | TL432LI | LM4040BIM3-2.5/NOPB |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOT-23-3 (DBZ) | SOT-23-3 (DBZ) - same | SOT-23-3 (DBZ) - same | SOT-23-3 (DBZ) - same outline, different pinout | SOT-23-3 (DBZ) - same | SOT-23-3 - same outline, different pinout |
| VREF Nominal | 2.495 V (adjustable) | 2.495 V (adjustable) | 2.495 V (adjustable) | 2.495 V (adjustable) | 2.495 V (adjustable) | 2.5 V (fixed, non-adjustable) |
| Initial Tolerance | ±0.5% (B grade) | ±0.5% (B grade) | ±1% (A grade) | ±0.5% (B grade) | ±0.5% (B grade) | ±0.2% (B grade fixed) |
| Cathode Voltage Range | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | Fixed 2.5 V |
| Min Cathode Current | 400 nA (optimized) | ~1 mA standard | ~1 mA standard | ~1 mA standard | 400 nA (LI optimized) | ~60 µA |
| Max Cathode Current | 15 mA | 15 mA | 15 mA | 15 mA | 15 mA | 15 mA |
| Pinout (SOT-23-3) | Pin1=REF, Pin2=ANODE, Pin3=CATHODE | Identical (TL432 family) | Identical (TL432 family) | Different (TL431 family) | Identical (TL432 family) | Different (LM4040 family) |
| 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
- Optimized low-IREF/low-Idev design for higher closed-loop accuracy (vs TL432BCDBZR (standard IREF/Idev B-grade))
- Wide 36V cathode rating supports 24V industrial and 12V automotive rails (vs LM4040BIM3-2.5/NOPB (fixed 2.5V, limited cathode envelope))
- Same TI TL432-family pinout - different from TL431DBZ pinout (vs TL431BQDBZR (similar rating, different pinout))
Design Notes
Do not reuse a PCB layout designed for TL431 in the SOT-23-3 footprint - the TL432LI uses a different pinout in the same outline (Pin1=REF, Pin2=ANODE, Pin3=CATHODE). Verify pin 1 marker against the TI TL432LI datasheet before placing the part, and use mirror-image layout or a footprint swap to avoid connecting the cathode to the REF node. Cross-reference the BOM line item with the variant-specific datasheet because TL431 and TL432 are NOT interchangeable even though many engineers assume they are drop-in equivalents.
Bias-resistor sizing: the cathode current must remain between 400 nA (IKAmin, optimized) and 15 mA (IKAmax) across all supply and load conditions. For a 24V input and a 5V programmed output, Rbias = (VIN - VKA) / IKA. Choose ~3 mA midpoint (R ≈ 6.4 kohm) for typical operation, then verify worst-case at +125 °C where IKAmin can rise. Add a minimum-load resistor on the output so the divider does not pull IKA below IKAmin when the load is open-circuit.
Layout: place the TL432LIBQDBZR close to the feedback divider and keep the REF node away from switching-noise sources. Use a small (1-10 nF) ceramic bypass from REF to ANODE if the divider resistance is high (>100 kohm) to reject coupled switching noise; otherwise leave REF unfiltered to preserve transient response. Provide a copper pour on the cathode to dissipate up to 0.5W briefly during fault conditions, since the SOT-23-3 can dissipate ~0.5W on a 1 oz 1 inch² pad.
Compliance Information
RoHS and REACH compliance per distributor listings (DigiKey, Mouser, Heisener). Automotive grade variant needs explicit Q-suffix and AEC-Q100 grade confirmation from the TI datasheet before being used in automotive designs.
