BAT43-R0 - 30V 200mA Schottky Diode DO-35 | Taiwan Semiconductor
MPN: BAT43-R0 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.09 | $0.09 |
| 10 | $0.07 | $0.70 |
| 100 | $0.04 | $4.00 |
| 500 | $0.03 | $15.00 |
| 1,000 | $0.02 | $20.00 |
BAT43-R0 Overview
A Schottky diode is a metal-to-semiconductor junction rectifier that, unlike a standard PN-junction diode, conducts at a lower forward voltage and switches with minimal reverse-recovery charge. Within the component hierarchy it belongs to discrete semiconductors -> diodes -> rectifiers -> small-signal Schottky rectifiers. This makes Schottky diodes the preferred choice for low-voltage rectification, reverse-polarity protection, and high-speed clamping where every millivolt of headroom and every nanosecond of recovery time matters.
Key features of the BAT43-R0 include the 30 V reverse standoff, a 200 mA average rectified output current, very low turn-on voltage, and an integrated fast guard ring that protects against excessive voltage events such as electrostatic discharge (ESD). The device operates up to 125 C junction temperature with a 200 mW power dissipation class, and the hermetic DO-35 glass body provides excellent long-term reliability compared with plastic SMD alternatives.
Technically, the metal-silicon junction of the BAT43 provides majority-carrier conduction, so switching speed is essentially limited only by junction capacitance rather than stored charge. This enables use in detector, clamping, and ORing circuits at frequencies far beyond what standard rectifier diodes such as the 1N4148-class silicon devices can match in forward-drop-sensitive designs.
Typical applications include low-current power-supply rectification and secondary-side rectification, reverse-battery and reverse-polarity protection on battery-powered equipment, signal detection and demodulation in RF front ends, and freewheeling or clamping functions around relays and small inductive loads.
Design consideration: keep continuous current well below the 200 mA rating when the forward drop approaches 1 V, since junction dissipation rises quickly; verify surge exposure against the 4 A non-repetitive rating in inductive circuits.
This page synthesizes distributor listings, cross-manufacturer drop-in alternatives (STMicroelectronics, Infineon, Vishay/other BAT43 sources), and practical design guidance not consolidated in any single manufacturer datasheet.
Drop-in alternatives for BAT43-R0 — 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 BAT43-R0 (same form factor and footprint) — differing in Package, ESD Protection, Average Forward Current (IF(AV)), Technology, Diode Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
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View Datasheet →BAT43-R0 Maximum Ratings & Electrical Characteristics
| Diode Type | Small Signal Schottky Barrier |
| Repetitive Peak Reverse Voltage (VRRM) | 30 V |
| Average Forward Current (IF(AV)) | 200 mA |
| Maximum Forward Voltage (VF) | 1 V |
| Non-Repetitive Peak Forward Surge Current (IFSM) | 4 A |
| Power Dissipation | 200 mW |
| Junction Operating Temperature | -65C to +125C |
| Reverse Recovery | Fast switching (Schottky, majority carrier) |
| Package | DO-35 axial glass (through hole) |
| Mounting Type | Through Hole |
| Configuration | Single diode |
| ESD Protection | Fast guard ring against excessive voltage (ESD) |
| RoHS Status | Compliant |
| Forward Voltage Turn-On | Very low turn-on voltage |
BAT43-R0 Pin Configuration
| Pin 1 | Anode — Positive terminal of Schottky junction (non-banded axial lead) |
| Pin 2 | Cathode — Banded axial lead - current flows anode to cathode |
Typical Applications
BAT43-R0 is suitable for 6 applications: Low-Current Power Supply Rectification, Reverse Polarity / Reverse Battery Protection, RF Signal Detection and Demodulation, Inductive Load Clamping and Freewheeling, Diode-OR Power Supply Merging, ESD and Overvoltage Guard in Analog I/O.
Low-Current Power Supply Rectification
The BAT43-R0's 200 mA average forward current and very low Schottky forward voltage make it ideal for secondary-side rectification in low-power AC-DC converters and auxiliary bias supplies. Its majority-carrier conduction eliminates reverse-recovery losses, improving efficiency at switching frequencies where silicon PN diodes would dissipate measurable recovery power. Placed as a half-wave or full-wave rectifier element with adequate filtering capacitance, the diode's 1 V maximum VF at full load and 4 A non-repetitive surge rating provide robust margin against capacitor inrush at startup. Designers should keep continuous current comfortably below 200 mA to limit junction dissipation within the 200 mW class.
Recommended
Reverse Polarity / Reverse Battery Protection
In battery-powered equipment, the BAT43-R0 provides series or shunt reverse-polarity protection with minimal penalty: its low Schottky turn-on voltage preserves rail headroom in series configurations, while its 30 V reverse rating withstands typical multi-cell battery stacks in the blocking direction. Compared with a standard silicon diode, the BAT43 saves several hundred millivolts of drop at operating current, which directly extends usable battery voltage range in 3.3 V and 5 V systems. The 200 mA average rating covers most handheld and IoT-class devices; above that, a P-channel MOSFET protection scheme is preferable. Verify transient surge events stay within the 4 A IFSM limit.
Recommended
RF Signal Detection and Demodulation
The BAT43-R0 functions as an envelope detector in RF front ends because the metal-silicon Schottky junction begins conducting at very low forward voltage, rectifying small amplitude signals that a 0.7 V-threshold silicon diode would miss entirely. Its fast, majority-carrier switching has no reverse-recovery limitation, so it tracks modulation envelopes cleanly up to the frequency range where junction capacitance dominates. Typical use is AM/envelope detection and signal-strength measurement after an LNA or IF stage. Designers should consult the junction capacitance specification in the datasheet to confirm performance at their target frequency band.
Recommended
Inductive Load Clamping and Freewheeling
Across relay coils, small solenoids, and low-current inductive loads, the BAT43-R0 serves as a freewheeling (flyback) clamp that safely recirculates inductive current when the drive transistor turns off. Its fast Schottky switching responds essentially instantly to the collapsing field, and the 4 A non-repetitive surge rating absorbs the initial clamp current peak at nominal load currents up to 200 mA. The very low forward drop also reduces coil current decay time less aggressively than a Zener-plus-diode arrangement, trading release speed for component simplicity. Select the clamp position and series resistance according to the relay release-time requirement.
Recommended
Diode-OR Power Supply Merging
For ORing two low-current supply rails - for example a battery backup feeding a mains-derived 5 V rail - the BAT43-R0's low forward drop minimizes the voltage penalty of the ORing element, and its 30 V rating comfortably covers rail differentials. Schottky operation avoids reverse-recovery shoot-through when rails switch. The 200 mA rating suits standby and microcontroller rails but not main power paths; above roughly 150 mA continuous, thermal dissipation (IF x VF approaching the 200 mW class) and a Schottky rectifier in a larger package should be evaluated. Polarity orientation of the axial DO-35 body is the key assembly check.
Recommended
ESD and Overvoltage Guard in Analog I/O
The BAT43-R0 features an integrated fast guard-ring structure that protects against excessive voltage events such as electrostatic discharge, per manufacturer datasheets. Arranged as upper and lower clamps between an analog input node and the supply rails, the pair confines transient excursions to one diode drop beyond the rails, protecting downstream amplifier or ADC inputs. The very low Schottky turn-on voltage means clamping engages earlier than with silicon PN diodes, reducing stress on protected circuitry. Designers must confirm leakage current suitability for high-impedance nodes, since Schottky reverse leakage is higher than silicon diode leakage and rises with temperature.
Recommended
Recommended Products Summary
Engineering reference data for BAT43-R0 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BAT43 (ST) | BAT43 (Infineon) | BAT42 | BAT41 | BAT48 |
|---|---|---|---|---|---|---|
| Package | DO-35 axial glass | DO-35 axial - same | DO-35 axial - same | DO-35 axial - same | DO-35 axial - same | DO-35 axial - same |
| Brand | Taiwan Semiconductor | STMicroelectronics | Infineon | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Reverse Voltage (VRRM) | 30 V | 30 V | 30 V | ~40 V | ~100 V | ~40 V |
| Forward Current | 200 mA | 200 mA | 200 mA | 200 mA | 200 mA | 200 mA |
| Drop-in Compatibility | Reference part | Yes - identical | Yes - identical | Yes - same footprint, higher VRRM | Yes - same footprint, higher VRRM | Yes - same footprint, higher VRRM |
Key Differentiators
- Lower forward voltage margin at same ratings (vs BAT41)
- Direct multi-source availability (vs BAT43 (STMicroelectronics / Infineon))
- Higher reverse voltage than BAT42/BAT48 alternatives in reverse (vs BAT42)
Design Notes
Estimated: at the full 200 mA rating with VF approaching 1 V, junction dissipation is about 200 mW, exactly at the device's dissipation class - leaving no thermal margin. Keep continuous forward current to roughly 100-150 mA in warm environments so dissipation stays well under the 200 mW limit, and check that repetitive surge events in rectifier duty remain far below the 4 A non-repetitive IFSM rating. Compute worst-case dissipation as IF(avg) x VF at your actual load, referencing the datasheet VF-vs-IF curve.
Schottky diodes exhibit higher reverse leakage than silicon PN diodes, and leakage roughly doubles every 10 C. For high-impedance nodes (sample-and-hold, precision clamp, peak detector above 1 M-ohm source impedance), verify the datasheet IR value at your operating temperature - leakage current through the BAT43 can corrupt a high-Z measurement. In such circuits, consider a 1N4148-class silicon diode despite its higher forward drop, or reserve the BAT43 for low-impedance paths.
The 30 V reverse rating is a hard limit: automotive load-dump transients, inductive kickback above the clamp, and mains-derived spikes can exceed it instantly and destroy the junction. In flyback-clamp duty, the BAT43 must see only the coil clamp voltage, not the switching node plus supply. Also note polarity: the cathode band marks the banded DO-35 lead - reversed insertion blocks or shorts the supply path. Avoid substituting SOD-123 (BAT43W) parts on DO-35 footprints; the footprints are not interchangeable.
Compliance Information
RoHS-compliant construction offered on DigiKey/Mouser for the Taiwan Semiconductor BAT43-R0. REACH, halogen-free and conflict-minerals declarations not stated in provided data - consult manufacturer compliance documentation.
