BAT43-TR - 30V 200mA Schottky Diode DO-35 | Vishay
MPN: BAT43-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.0519 | $0.05 |
| 10 | $0.049 | $0.49 |
| 100 | $0.043 | $4.30 |
| 500 | $0.036 | $18.00 |
| 1,000 | $0.03 | $30.00 |
BAT43-TR Overview
A Schottky diode is a metal-to-silicon rectifier in which a metal-semiconductor junction replaces the P-N junction of a conventional diode. This construction yields a lower forward turn-on voltage and dramatically faster switching with essentially no reverse-recovery charge, placing the BAT43 within the hierarchy: Schottky diode -> small-signal rectifier -> discrete semiconductor. Small-signal Schottky diodes are workhorse components in signal detection, reverse-polarity protection, and low-power rectification stages.
Key features of the BAT43-TR, per the Vishay datasheet, include very low turn-on voltage for minimal conduction loss at low signal levels, fast switching speed for high-frequency operation, and an integrated guard ring that protects against excessive voltage events such as electrostatic discharge (ESD). The 4 A IFSM surge rating provides robust margin against inrush and transient events far beyond the 200 mA continuous rating.
The device is targeted at general purpose applications: RF signal detection where low forward voltage preserves signal headroom, ORing and reverse-polarity protection in battery-powered circuits where every 100 mV of drop matters, freewheeling and clamp functions in low-power switch-mode circuits, and precision rectification in measurement front-ends. The DO-35 glass body is hermetically sealed, giving stable leakage behavior over temperature compared to plastic packages and easy manual handling for prototyping.
Vishay also offers the same BAT43 die in the SOD-123 surface-mount case, allowing migration from through-hole prototypes to SMD production without changing electrical behavior.
Design consideration: Schottky diodes exhibit higher reverse leakage than silicon P-N diodes, which roughly doubles for every 10 C of temperature rise; verify that leakage at the highest ambient temperature remains acceptable, especially in peak-detector or sample-hold circuits.
This page synthesizes verified distributor pricing, drop-in alternatives, pinout data, and practical design notes not consolidated in the manufacturer datasheet, providing information gain for sourcing and design engineers.
Drop-in alternatives for BAT43-TR — 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-TR (same form factor and footprint) — differing in Device Type, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
BAT42-TR
✅ Drop-In✓ In Stock
$0.04 / Unit
View Datasheet →BAT43
✅ Drop-In✓ In Stock
$0.08 / Unit
View Datasheet →BAT43
✅ Drop-In✓ In Stock
$0.08 / Unit
View Datasheet →BAT43-TR Maximum Ratings & Electrical Characteristics
| Device Type | Schottky Barrier Diode (small signal) |
| Repetitive Peak Reverse Voltage (VRRM) | 30 V |
| Average Forward Current (IF(AV)) | 200 mA |
| Non-Repetitive Peak Surge Current (IFSM) | 4 A |
| Forward Turn-On Voltage | Very low (Schottky junction, per datasheet) |
| Switching Speed | Fast (Schottky, no reverse recovery) |
| ESD Protection | Integrated guard ring against excessive voltage |
| Package | DO-204AH (DO-35) axial glass, through-hole |
| Mounting Type | Through Hole |
| Packaging | Tape & Reel (-TR suffix) |
| SMD Variant | Available in SOD-123 case |
| Application Class | General purpose |
BAT43-TR Pin Configuration
| Pin 1 | Anode — Positive terminal; current flows in (body end without cathode band) |
| Pin 2 | Cathode — Negative terminal; marked by the band/cathode mark on the DO-35 glass body |
Typical Applications
BAT43-TR is suitable for 6 applications: RF and Signal Detection, Battery-Powered Reverse Polarity Protection, Diode ORing of Low-Voltage Rails, Freewheeling and Clamping in Low-Power Switching Circuits, Precision and Half-Wave Rectification in Measurement Front-Ends, Through-Hole Prototyping and Hobby / Repair Electronics.
RF and Signal Detection
The BAT43-TR excels as a detector diode because its metal-to-silicon Schottky barrier turns on at a far lower voltage than a silicon P-N diode, allowing rectification of small RF or audio signal envelopes that would be lost across a 0.6 V silicon junction. Per the Vishay datasheet, the device features very low turn-on voltage and an integrated guard ring that protects the sensitive detector node against electrostatic discharge. In a typical envelope-detector circuit, the BAT43 rectifies the input into an RC hold network; the design trade-off is Schottky reverse leakage, which roughly doubles every 10 C and can discharge the hold capacitor at elevated ambient temperatures. The DO-35 glass body also gives stable, low-leakage behavior compared to plastic packages.
Recommended
Battery-Powered Reverse Polarity Protection
In battery-operated products, a series diode for reverse-polarity protection costs voltage headroom, and the BAT43-TR minimizes that cost: its low Schottky forward voltage wastes far less of a 1.5 V or 3 V cell budget than a standard silicon diode. Rated 200 mA average forward current and 30 V reverse voltage, it comfortably covers portable electronics supply rails, and the 4 A IFSM surge rating absorbs capacitive inrush at power-up. The trade-off is that Schottky leakage, though small at room temperature, grows with temperature and can matter in very low-power sleep modes. For loads above 200 mA or where even the Schottky drop is unacceptable, replace the diode with a P-channel MOSFET ideal-diode circuit instead.
Recommended
Diode ORing of Low-Voltage Rails
When two supplies, such as a battery and a USB input, feed a common low-voltage rail, BAT43-TR diodes in series with each source prevent back-feeding between them. The very low turn-on voltage of this Vishay Schottky keeps the ORing loss small, which matters at 3.3 V and below where a silicon diode's 0.6-0.7 V drop would consume an unacceptable fraction of the budget. With a 200 mA rating per diode, this suits low-power logic and sensor rails rather than main power paths. Designers should account for the forward-voltage difference between sources, which determines which supply dominates, and verify the leakage of the off-state diode does not partially back-feed at high ambient temperature.
Recommended
Freewheeling and Clamping in Low-Power Switching Circuits
The BAT43-TR serves as a freewheel or clamp diode across relays, small inductors, and flyback windings in low-power switch-mode and switching-transistor circuits. Schottky diodes have essentially no reverse-recovery charge, so the BAT43 begins conducting immediately when the switch opens, and its fast Schottky switching avoids the recovery losses a P-N diode would add at each cycle. The 4 A non-repetitive surge rating provides margin against the initial inductor current spike during clamping events. It is appropriate for currents up to 200 mA continuous; for higher-energy inductive loads, step up to a higher-current Schottky. Place the diode directly across the inductor terminals to keep the clamp loop area, and hence radiated EMI, minimal.
Recommended
Precision and Half-Wave Rectification in Measurement Front-Ends
In precision half-wave rectifiers and AC-coupled measurement front-ends, the BAT43-TR's low forward voltage lets the circuit rectify signal amplitudes well below the 0.6 V threshold of a silicon diode, extending usable dynamic range at the low end. The guard-ring ESD protection noted in the Vishay datasheet also safeguards front-end inputs exposed to connectors and field wiring. The important design constraint is reverse leakage: in peak-hold or sample-hold configurations, leakage current discharges the storage capacitor and produces droop, and this droop worsens exponentially with temperature. Pair the BAT43 with a low-input-bias op-amp and size the hold capacitor against the leakage spec at the maximum expected ambient temperature.
Recommended
Through-Hole Prototyping and Hobby / Repair Electronics
The axial DO-204AH (DO-35) glass package makes the BAT43-TR exceptionally convenient for breadboarding, hand soldering, and board-level repair: the leads accept standard 0.1 inch and 2.54 mm pitch layouts, and the hermetically sealed glass body tolerates repeated rework without the moisture sensitivity of SMD parts. The very low turn-on voltage and fast Schottky switching give prototyped circuits essentially final-production rectification behavior, so a design proven with the DO-35 part can migrate to the SOD-123 surface-mount BAT43 variant without electrical change. When repairing vintage or battery-powered equipment, always confirm the original diode's reverse-voltage requirement does not exceed the BAT43's 30 V rating.
Recommended
Recommended Products Summary
Engineering reference data for BAT43-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BAT42-TR | BAT43 (ST) | BAT43 (Infineon) |
|---|---|---|---|---|
| Package | DO-204AH (DO-35) axial | DO-204AH (DO-35) axial - same | DO-204AH (DO-35) axial - same | DO-35 axial - same |
| Brand | Vishay General Semiconductor - Diodes Division | Vishay Intertechnology | STMicroelectronics | Infineon |
Key Differentiators
- Identical ratings to cross-brand equivalent with dual sourcing (vs BAT43 (STMicroelectronics))
- Integrated ESD guard ring (vs Generic small-signal Schottky diodes)
- SMD migration path on the same die (vs BAT42-TR)
Design Notes
Respect the 30 V reverse-voltage limit with margin. Schottky diodes have soft, high-leakage breakdown, and the internal guard ring protects against ESD events, not sustained overvoltage. In inductive environments, add a snubber or clamp if voltage spikes could approach the rating. Also verify polarity on insertion: the band on the DO-35 body marks the cathode, and reversed installation in a protection role leaves the rail unprotected.
Estimated: at 200 mA forward current and a typical Schottky VF near 0.3-0.4 V, conduction loss is roughly 60-80 mW, which the axial DO-35 dissipates easily with minimal temperature rise in free air. However, reverse leakage approximately doubles every 10 C; in enclosed or hot assemblies, re-check IR at the real ambient temperature, especially in peak-detector or battery-drain-sensitive circuits where leakage becomes the limiting parameter rather than power dissipation.
For through-hole assembly, keep axial leads short in RF detector and clamp layouts - each centimeter of lead adds inductance that degrades high-frequency clamping. Bend leads with a support tool at least 2 mm from the glass body to avoid sealing cracks. When migrating to production, the same BAT43 die is offered in the SOD-123 SMD case per the Vishay datasheet, allowing footprint change without re-characterizing electrical behavior.
Compliance Information
Compliance status not stated in the retrieved web data; verify on the Vishay product page or distributor compliance certificate before releasing into a RoHS-controlled BOM.
