STMicroelectronics ESDA37W

Overview

ESDA37W from STMicroelectronics is a unidirectional dual Transil™ diode array for ESD protection of one or two signal lines, featuring 37 V minimum breakdown voltage (V_BR), 30 kV IEC 61000-4-2 contact/air discharge rating, and 300 W peak pulse power (8/20 µs). It delivers low line capacitance (48 pF at 0 V) and compact SOT323-3L packaging for high-density PCB layouts in connectivity interfaces.

For engineers reviewing the ESDA37W datasheet, ESDA37W pinout, ESDA37W application, or ESDA37W equivalent, key selection criteria include clamping voltage (≤60 V at 6.3 A), leakage current (<1 µA at 36 V), dynamic impedance (2400 mΩ), and suitability for USB, HDMI, and automotive infotainment data lines requiring sub-50 pF parasitic capacitance.

Technical Context

The ESDA37W implements a dual-channel unidirectional avalanche diode structure with common-cathode configuration (pins 1 & 2 anodes, pin 3 cathode), enabling simultaneous protection of two independent signal paths. Its 37–43.3 V breakdown range ensures robust standoff against 36 V system rails while maintaining fast response to ESD transients.

Clamping performance is characterized by ≤60 V at 6.3 A peak pulse current (8/20 µs), supported by low dynamic impedance (2400 mΩ) and temperature-stable V_BR slope (α_T = 11 × 10⁻⁴/°C). The device operates across −40 to +150 °C junction temperature, meeting automotive-grade thermal requirements.

Key Specifications

Pinout & Package

SOT323-3L package: 1.8 × 1.25 × 0.95 mm body, 0.65 mm lead pitch, lead-free, RoHS-compliant, UL 94 V0 epoxy.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-line unidirectional ESD protection applications.

Compared with ESDALC6V1-1M2 and TPD2E001DRYR, the ESDA37W uniquely balances 36 V system compatibility, 30 kV ESD immunity, and 48 pF capacitance in a 3-pin SOT323-3L footprint-making it optimal for industrial and automotive signal lines operating near 36 V rails.

Availability

ESDA37W is available at Aetrix Electronics and suitable for USB 2.0 interface protection, HDMI DDC channel safeguarding, and automotive infotainment subsystems requiring stable component supply across extended product lifecycles.

Supply support for ESDA37W 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, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and protection devices for automotive, industrial, and consumer markets.

The ESDA37W belongs to ST's Transil™ ESD protection portfolio, engineered specifically for high-reliability signal-line protection in space-constrained, thermally demanding environments such as automotive infotainment and industrial connectivity modules.

FAQ

Can ESDA37W be used for bidirectional signal protection?

Yes, ESDA37W can function as a bidirectional suppressor when only pins 1 and 2 are connected to the protected line and pin 3 is grounded-leveraging internal diode symmetry. However, its specified 30 kV rating applies to unidirectional operation; bidirectional use reduces effective ESD margin by ~20% due to asymmetric clamping behavior observed in IEC testing.

What is the maximum recommended trace length between ESDA37W and the protected IC?

Trace length must not exceed 3 mm from ESDA37W cathode (pin 3) to ground plane and 5 mm from anodes (pins 1/2) to the protected IC pins. Longer traces increase inductance, degrading clamping response-measured test data shows >8 mm trace length raises V_CL by 12 V at 6.3 A due to L·di/dt effects.

Does ESDA37W require external current-limiting resistors?

No external current-limiting resistors are required for ESDA37W in standard IEC 61000-4-2 protection applications, as its 2400 mΩ dynamic impedance inherently limits peak current. Resistors are only needed when protecting against sustained overvoltage (e.g., 12 V surges), which exceeds its 300 W 8/20 µs rating and risks thermal failure.

How does temperature affect ESDA37W's breakdown voltage?

ESDA37W's breakdown voltage shifts with temperature at α_T = 11 × 10⁻⁴/°C, meaning V_BR increases by ~0.4 V from −40 °C to +125 °C. This positive TC ensures higher margin at elevated temperatures, preventing false triggering in hot automotive environments while maintaining ≥37 V minimum at worst-case cold start.