Answer: The TL432ACDBZR is electrically the 1 % TL431A (same §6.8 table: 2470 / 2495 / 2520 mV, Imin 0.6 mA max, VKA up to 36 V, 0–70 °C), but its pinout differs from TL431: in SOT-23 (DBZ) it is 1 = REF, 2 = cathode, 3 = anode, where the TL431 is cathode, REF, anode. Marking: T4B3, T4BG, T4BS or T4BU; 3000-piece reels. (TI SLVS543S p.4, §6.8 p.9, Addendum p.44.)
Key specifications
| Parameter | Value | Condition | Source |
|---|---|---|---|
| Reference voltage Vref (min / typ / max) | 2470 / 2495 / 2520 mV (±1 %) | VKA = Vref, IKA = 10 mA, TA = 25 °C | §6.8 p.9 |
| Vref deviation over 0–70 °C, VI(dev) | 6 typ / 16 max mV | SOT-23-3 and TL432 devices; max − min over the rated range | §6.8 p.9, note 1 |
| ΔVref / ΔVKA | −1.4 typ / −2.7 max mV/V (ΔVKA = 10 V − Vref); −1 / −2 mV/V (36 V − 10 V) | IKA = 10 mA | §6.8 p.9 |
| Reference input current Iref | 2 typ / 4 max µA | IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ | §6.8 p.9 |
| Iref deviation over temperature, II(dev) | 0.8 typ / 1.2 max µA | IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ | §6.8 p.9 |
| Minimum cathode current for regulation Imin | 0.4 typ / 0.6 max mA | VKA = Vref | §6.8 p.9 |
| Off-state cathode current Ioff | 0.1 typ / 0.5 max µA | VKA = 36 V, Vref = 0 | §6.8 p.9 |
| Dynamic impedance | ZKA | 0.2 typ / 0.5 max Ω | |
| Cathode voltage VKA (recommended) | Vref to 36 V | Absolute maximum 37 V | §6.4 p.5; §6.1 p.5 |
| Cathode current IKA (recommended) | 1 – 100 mA | Absolute maximum −100 to 150 mA | §6.4 p.5; §6.1 p.5 |
| Operating free-air temperature (C grade) | 0 – 70 °C | TL43xxC; junction absolute maximum 150 °C | §6.4 p.5; §6.1 p.5 |
| RθJA / RθJC(top), DBZ (SOT-23-3) | 206 / 76 °C/W | JEDEC metrics, SPRA953 | §6.3 p.5 |
| Orderable / packing | TL432ACDBZR: Active, SOT-23 (DBZ) 3-pin, 3000 / large T&R, MSL 1 260 °C | Device marking T4B3, T4BG, T4BS, T4BU | Package Option Addendum, PDF p.44 |
Pinout (SOT-23-3, DBZ): the reason this part exists
| Pin (DBZ, SOT-23-3) | TL432 | TL431 (for comparison) |
|---|---|---|
| 1 | REF | CATHODE |
| 2 | CATHODE | REF |
| 3 | ANODE | ANODE |
Source: Table 5-1 and the DBZ top views, p.4.
TI describes TL431 and TL432 as functionally the same with separate pinout options (§8.1 p.21). The swap also applies to other packages: in SOT-23-5 (DBV) the TL432 has cathode on pin 4 and REF on pin 5, while the TL431 has cathode on pin 3 and REF on pin 4; in SOT-89 (PK) the TL432 puts cathode on pin 1 (Table 5-1, p.4).
When to choose TL432 over TL431
- Layout. If REF sits next to the divider and the cathode faces the series resistor or opto-coupler, the R/K/A order can shorten traces. This is the only reason to pick it; there is no electrical advantage.
- Second-sourcing a board. If an existing board was laid out for the TL432 pinout, a TL431 in the same footprint will not work. Pin 1 becomes the cathode, so the divider tap is shorted to the output.
Design notes
Setting the voltage. With a divider R1 (cathode to REF) and R2 (REF to anode), VKA = Vref × (1 + R1/R2) + Iref × R1 (Figure 7-2, p.19). The equation holds only while the cathode current is above Imin, so the part has enough loop gain (§9.2.2.2.1 p.26). Use the TL431 calculator to pick E24/E96 pairs and the series resistor. The formula is the same; only the pin numbers on your schematic symbol change.
Worked shunt example (12 V ±10 % in, 5 V out, 0–10 mA load). R1 = R2 = 10 kΩ gives 2.495 V × 2 + 2 µA × 10 kΩ = 5.010 V typical, and the divider draws 0.25 mA. The series resistor must still deliver 0.6 mA (A-grade Imin max) into the cathode at 10.8 V and full load. Using TI’s “>1 mA (Imin(max))” figure (§8.1 p.21): Rs ≤ (10.8 − 5.01) / (10 + 1 + 0.25 mA) = 515 Ω, so choose 510 Ω. At 13.2 V and no load, Rs passes 16.1 mA, of which 15.8 mA flows into the TL432ACDBZR: P = 5.01 V × 15.8 mA ≈ 79 mW, a rise of about 16 °C with RθJA = 206 °C/W. Rs itself dissipates about 0.13 W, so size its power rating for that, not for the 79 mW in the TL431.
What the grade does not cover. The tolerance printed on the grade is Vref at 25 °C with VKA = Vref. TI lists the other error terms separately (§9.2.2.2.2 p.27): resistor tolerance, VI(dev) over temperature, ΔVref/ΔVKA, and |ZKA| × ΔIKA. At a 5 V output each term is scaled by (1 + R1/R2) = 2:
- VI(dev) of 16 mV max becomes up to 32 mV at the output over 0–70 °C (0.64 %).
- Raising VKA from 2.495 V to 5.01 V (ΔVKA = 2.5 V) moves Vref by −1.4 mV/V typ to −2.7 mV/V max, i.e. −3.5 to −6.8 mV, or −7 to −13.5 mV at the output.
- A 10 mA swing in cathode current through |ZKA| = 0.5 Ω max adds 5 mV at VKA = Vref.
Capacitors on the cathode. TI states the TL43xx is internally compensated and stable with no capacitor between cathode and anode (§8.3 p.22). If you add one, or if the load itself is capacitive, check the value against the stability boundary charts, Figure 6-16 (p.17) and Figure 6-18 (p.18). Some combinations of capacitance and cathode current fall outside the stable region, so “adding a bigger cap” is not automatically safer.
Footprint check before release. TI’s DBZ layout example (Figure 9-16, §9.5 p.31) is drawn for the TL432: REF on pin 1 via Rref, cathode on pin 2 via Rsup with CL to ground. It is the right starting point for this part, and the wrong one for a TL431.
Pitfalls specific to TL432ACDBZR
- Pinout differs from TL431. In SOT-23, pin 1 is REF and pin 2 is cathode (p.4). Using a TL431 symbol or footprint for this part, or the reverse, swaps cathode and REF. Check the pinout against the ordering code every time, since other makers also sell both orders under similar names.
- “TL432” in a cross-reference list. Some substitution tables treat TL432 as a TL431 equivalent. It is only one if the footprint is changed.
- Marking T4B read as TL431. T4B_ is the TL432A in DBZ; TAC_ is TL431A (Addendum pp.34, 44). See the TL431 SOT-23 marking codes.
- Expecting an industrial temperature range. TL432ACDBZR is 0–70 °C (Addendum p.44).
- Starving the cathode. Imin max is 0.6 mA for this grade (p.9); TI’s general rule is more than 1 mA (§8.1 p.21).
Part numbers (information only)
| Ordering code | Status | Packing | Marking | Source |
|---|---|---|---|---|
| TL432ACDBZR | Active | 3000, large T&R | T4B3, T4BG, T4BS, T4BU | Addendum p.44 |
| TL432ACDBZT | Active | 250, small T&R | T4BG, T4BS, T4BU | Addendum p.44 |
G4 and ”.A” variants are also listed.
FAQ
- What is the difference between TL431 and TL432? Only the pinout. In SOT-23, TL431 is cathode/REF/anode and TL432 is REF/cathode/anode (TI SLVS543S p.4). The electrical tables are shared.
- Can I replace a TL431 with a TL432? Not in the same footprint. Pins 1 and 2 are swapped, so the board must be laid out for the part you fit.
- What is the TL432ACDBZR marking code? T4B3, T4BG, T4BS or T4BU (TI Package Option Addendum p.44).
- What accuracy is the TL432ACDBZR? 1 % at 25 °C: 2470–2520 mV, the same as the TL431ACDBZR.
- Does the TL432 need a different resistor formula? No. VKA = Vref × (1 + R1/R2) + Iref × R1, with R1 from cathode to REF.
Related (internal links)
- TL431 calculator
- TL431 SOT-23 marking codes
- TI TL431ACDBZR (same specs, K/R/A)
- TI TL431CDBZR (2 %)
- TL431 alternatives
Sources (retrieved 2026-10-26)
- Texas Instruments, TL431, TL432 Precision Programmable Reference, SLVS543S (revised May 2024), including the Package Option Addendum: https://www.ti.com/lit/ds/symlink/tl431.pdf
Disclaimer
Values are copied from TI SLVS543S (revised May 2024) and its Package Option Addendum, read on 26 Oct 2026. Ordering data and markings can change; check the current TI addendum before you release a BOM, and validate the circuit on your own hardware.
Reviewed by: Jasper · Updated: 2026-10-26