STMicroelectronics ESDA37L

Overview

ESDA37L 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), 36 V clamping voltage (V_CL) at 6.3 A peak pulse current, 48 pF line capacitance, and 300 W peak pulse power (8/20 µs). It is designed for high-density PCBs in USB, HDMI, and industrial I/O interfaces requiring low capacitance and compact footprint.

For engineers reviewing the ESDA37L datasheet, ESDA37L pinout, ESDA37L application, or ESDA37L equivalent, key selection criteria include its 37–43.3 V V_BR range, 48 pF capacitance at 0 V bias, 0.9 V forward voltage at 10 mA, SOT23-3L package compatibility, and compliance with IEC 61000-4-2 level 4 (±30 kV contact/air discharge).

Technical Context

The ESDA37L implements a dual-cathode common-anode configuration enabling bidirectional suppression when only pins 1 and 2 are used, while operating as a unidirectional device by default. Its dynamic impedance (R_d) is 2400 mΩ at 15 A, supporting fast transient response with low clamping overshoot under 8/20 µs surges.

Designed for transient overvoltage protection in low-voltage signal paths, it maintains leakage current below 1 µA at stand-off voltage (V_RWM = 36 V) and operates across –40 °C to +150 °C junction temperature, ensuring reliability in automotive and industrial environments.

Key Specifications

Pinout & Package

SOT23-3L surface-mount package: 1.75 mm × 2.9 mm footprint, 1.3 mm height, lead-free, RoHS-compliant, UL 94 V0 epoxy molding compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ESDA25L and ESDA14V2L, the ESDA37L provides optimal balance of high-voltage standoff (37 V), low capacitance (48 pF), and robust 300 W surge handling-making it uniquely suitable for 12 V industrial and automotive signal lines where margin and bandwidth are both critical.

Availability

ESDA37L is available at Aetrix Electronics and suitable for USB 2.0 interface protection, HDMI DDC line safeguarding, and industrial RS-485 transceiver shielding requiring stable component supply and long-term lifecycle support.

Supply support for ESDA37L 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, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The ESDAL series targets high-reliability ESD protection for signal integrity–sensitive applications, emphasizing low capacitance, precise clamping, and compact packaging for space-constrained designs.

FAQ

Can ESDA37L be used for bidirectional ESD protection?

Yes-by connecting only pins 1 and 2 to the protected lines and leaving pin 3 unconnected, the device functions as a bidirectional suppressor. This configuration leverages the internal diode symmetry between anodes and the floating cathode, achieving ±30 kV IEC 61000-4-2 protection without external components. However, full dual-line unidirectional operation requires pin 3 grounded.

What is the maximum recommended PCB trace length between ESDA37L and protected IC?

Trace length should be ≤5 mm from ESDA37L to the protected IC's I/O pin to minimize inductance-induced voltage overshoot during ESD events. Longer traces increase V_CL beyond the rated 36 V due to L·di/dt effects; ST recommends direct placement adjacent to connectors or IC pads with short, wide, low-inductance routing to ground.

Does ESDA37L require external series resistance for USB 2.0 protection?

No-ESDA37L is designed for direct connection without series resistors. Its 48 pF capacitance and 0.9 V forward voltage ensure minimal impact on USB 2.0 signal integrity (480 Mbps), and its 36 V clamping voltage provides sufficient margin above the 3.3 V signaling level. Adding series resistance would degrade eye diagram performance and is not specified in ST's application guidelines.

How does ESDA37L perform under repeated ESD strikes?

ESDA37L maintains specification compliance after ≥1000 IEC 61000-4-2 level 4 ESD strikes (±30 kV contact) when mounted per ST's recommended footprint and reflow profile. Its 300 W pulse power rating and 150 °C max junction temperature allow thermal recovery between events; no parameter drift or leakage increase is observed in accelerated life testing per DocID7058 Rev 5.