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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

STMicroelectronics BAT42

Name: BAT42
Brand: STMicroelectronics
SKU: BAT42
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BAT42

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: BAT42.pdf

Description:: DIODE SCHOTTKY 30V 200MA DO35

Quantity:: RFQ Add To RFQ list

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Inventory:14,157

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Product details

Overview

BAT42 from STMicroelectronics is a small-signal Schottky diode in DO-35 package, designed for low-voltage, high-speed switching applications with 30 V repetitive peak reverse voltage, 200 mA forward continuous current, and 1 V typical forward voltage at 200 mA. It serves as a rectifier or clamping device in power management and signal conditioning circuits of portable electronics and DC-DC converters.

For engineers reviewing the BAT42 datasheet, BAT42 pinout, BAT42 application, or BAT42 equivalent, key selection criteria include its low VF (0.4 V @ 2 mA), fast 5 ns reverse recovery time, 7 pF junction capacitance at 1 V, low leakage (0.5 µA @ 25 V), and thermal resistance of 300 °C/W - all critical for efficiency-sensitive, space-constrained designs.

Technical Context

The BAT42 uses a metal–silicon Schottky barrier structure to achieve low forward voltage drop and minimal minority-carrier storage, enabling nanosecond-scale switching without tail current. Its junction temperature range spans –65 °C to +125 °C, and it operates reliably up to 230 °C for 10 s during soldering.

Designed for convection/conduction cooling with 4 mm lead length, the device exhibits 300 °C/W junction-to-ambient thermal resistance and supports surge currents up to 4 A (10 ms) while maintaining stable reverse blocking at 30 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	30 V - Maximum reverse voltage before breakdown; defines safe operating range in clamp/rectify roles.
I_F	200 mA - Continuous forward current at 25 °C; sets usable DC load capacity in low-power rails.
V_F	0.4 V @ 2 mA - Low turn-on threshold; reduces conduction loss in battery-fed circuits.
t_rr	5 ns - Fast reverse recovery; enables >10 MHz switching in snubberless flyback or RF detector stages.
C	7 pF @ 1 V - Low junction capacitance; minimizes signal distortion in high-frequency sampling or mixer bias networks.
R_th(j-a)	300 °C/W - Thermal resistance on infinite heatsink; informs derating above 25 °C ambient.

Pinout & Package

DO-35 glass axial package with cathode marked by ring at one end; leads are tinned copper alloy, 0.458–0.558 mm diameter; total weight 0.15 g.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward current entry point	Connected to higher potential node; must withstand 4 A surge during transient events.
Cathode	Forward current exit / reverse blocking terminal	Marked by colored ring; referenced to ground or lower-potential rail in clamp configurations.

Key Features

Feature	Design Value
Low forward voltage	0.26 V typ. @ 2 mA (BAT43), 0.4 V typ. @ 2 mA (BAT42) - directly reduces power loss in low-current bias paths.
Fast switching speed	5 ns reverse recovery time - eliminates minority-carrier delay, supporting clean edge transitions in pulse shaping.
Low junction capacitance	7 pF @ 1 V reverse bias - preserves bandwidth in RF detector and high-speed logic interface applications.
Robust thermal rating	Junction temperature range –65 °C to +125 °C - ensures operation across automotive under-hood and industrial control environments.

Applications

Portable Power Management

RF Signal Detection

Use Scenario: Reverse polarity protection and voltage clamping in USB-powered devices and coin-cell backup circuits.

IC Role / Device Role / Timing Role: Schottky rectifier providing low-loss DC path while blocking reverse current.

Use Value: 0.4 V forward drop at 2 mA limits voltage loss in 3.3 V or lower supply rails, extending battery life.

Use Scenario: Envelope detection in AM/FM receiver front-ends and RFID tag demodulators.

IC Role / Device Role / Timing Role: Signal rectifier converting RF carrier into baseband envelope.

Use Value: 7 pF capacitance and 5 ns t_rr preserve high-frequency response up to 45 MHz per manufacturer test data.

DC-DC Converter Snubbing

Logic-Level Clamping

Use Scenario: Catch diode in buck converter output stage operating at 500 kHz–1 MHz switching frequency.

IC Role / Device Role / Timing Role: Freewheeling diode conducting inductor current during high-side switch off-time.

Use Value: 5 ns recovery prevents cross-conduction loss and improves efficiency over standard PN diodes.

Use Scenario: Input protection clamp on microcontroller GPIO pins exposed to external analog sensors.

IC Role / Device Role / Timing Role: Voltage limiter shunting ESD transients above 3.3 V or 5 V logic thresholds.

Use Value: 0.5 µA leakage at 25 V ensures negligible quiescent current draw in always-on monitoring circuits.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky diode applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N5711	Higher V_RRM (70 V), higher V_F (0.45 V @ 10 mA), same DO-35 package	Better suited for higher reverse voltage margin; less optimal for ultra-low-V_F demand	Choose when system reverse stress exceeds 30 V but low-leakage priority remains.
SB120	Higher I_F (1 A), TO-277 package, V_F = 0.5 V @ 1 A	Targeted at higher-current power rectification, not signal-level switching	Select only if forward current >200 mA is required and board space allows SMD footprint.

Compared with 1N5711 and SB120, BAT42 offers the lowest forward voltage at microamp/milliamp bias levels and best capacitance-recovery trade-off for signal integrity-critical roles - making it preferred in battery-constrained, high-frequency, or low-noise analog front-ends.

Availability

BAT42 is available at Aetrix Electronics and suitable for portable power management, RF signal detection, DC-DC converter snubbing, and logic-level clamping requiring stable component supply and consistent parametric performance across production batches.

Supply support for BAT42 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The BAT series belongs to ST's general-purpose discrete portfolio, engineered specifically for cost-sensitive, high-volume applications demanding reliable low-V_F Schottky performance in through-hole packages.

FAQ

What is the maximum junction temperature for continuous operation of BAT42?

The BAT42 has a maximum continuous junction temperature of +125 °C, as specified in its absolute maximum ratings. Operation beyond this limit risks irreversible degradation of the Schottky barrier. Derating is required above 25 °C ambient, based on its 300 °C/W thermal resistance and actual power dissipation.

Can BAT42 be used as a replacement for BAT43 in a circuit?

Yes, BAT42 and BAT43 share identical package, absolute ratings, and thermal specs, but differ in forward voltage: BAT42 is rated 0.4 V typ. @ 2 mA, while BAT43 is 0.26 V typ. @ 2 mA. Substitution is acceptable where slightly higher V_F is tolerable; verify voltage headroom in low-bias applications.

Is BAT42 suitable for high-frequency RF applications above 100 MHz?

No - BAT42's 7 pF junction capacitance and 5 ns reverse recovery are validated up to 45 MHz per ST's test conditions (Fig. 5, f = 1 MHz C measurement; Fig. 3, h = 80% at 45 MHz). Above 100 MHz, parasitic effects dominate; dedicated RF Schottky diodes like HSMS-285x are recommended.

Does BAT42 have built-in ESD protection?

No - BAT42 is a passive Schottky diode without integrated ESD structures. Its 0.5 µA reverse leakage at 25 V reflects inherent junction behavior, not protection capability. For ESD-prone interfaces, external TVS or dedicated ESD diodes (e.g., PUSB3FR) must be added in parallel.

BAT42 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Tape & Reel (TR)

Product Status:: Active

Technology:: Schottky

Voltage - DC Reverse (Vr) (Max):: 30 V

Current - Average Rectified (Io):: 200mA

Voltage - Forward (Vf) (Max) @ If:: 1 V @ 200 mA

Speed:: Small Signal =< 200mA (Io), Any Speed

Reverse Recovery Time (trr):: 5 ns

Current - Reverse Leakage @ Vr:: 500 nA @ 25 V

Capacitance @ Vr, F:: 7pF @ 1V, 1MHz

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

Operating Temperature - Junction:: -65°C ~ 125°C

BAT42 FAQ

1.How can I place an order for BAT42 through Aetrix?

Please submit a Request for Quotation (RFQ) for BAT42 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BAT42 reliable?

The price and inventory of BAT42 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAT42 is usually 5 days.

3.What payment methods are accepted for BAT42?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAT42 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BAT42?

BAT42 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BAT42 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BAT42?

For technical support, including BAT42 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAT42 requirements.

6.How does Aetrix verify that BAT42 is sourced from the original manufacturer or authorized distributors?

All BAT42 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BAT42 meets industry standards.

7.What is the process for return or replacement of BAT42?

All BAT42 units undergo pre-shipment inspection (PSI). If there is an issue with BAT42, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BAT42 part is unused and in its original packaging.

Return procedure for BAT42:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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