Analog Devices Inc./Maxim Integrated DS9502P/T&R

Overview

DS9502P/T&R from Dallas Semiconductor (now part of Maxim Integrated) is a symmetric dual-port bidirectional ESD protection diode in a 6-lead TSOC surface-mount package, featuring 7.5V Zener clamping, 9.5V trigger voltage, 5.5V holding voltage, 2.0A peak pulse current, and 55pF junction capacitance at 5V. It is designed for SRAM-based battery-buffered portable memory modules requiring >27 kV IEC 801-2 ESD immunity.

For engineers reviewing the DS9502P/T&R datasheet, DS9502P/T&R pinout, DS9502P/T&R application, or DS9502P/T&R equivalent, key selection criteria include snapback-triggered clamping behavior, low-leakage (<100 nA), industrial temperature range (–40°C to +85°C), symmetric dual-port bondout for balanced energy dissipation, and compatibility with all 5V logic families.

Technical Context

The DS9502P/T&R operates as a bidirectional Zener-based transient voltage suppressor with snapback I/V characteristics: it transitions from high-impedance standby (≤100 nA leakage at 7.0V) to low-voltage conduction (5.5V holding voltage) upon exceeding 9.0–9.5V trigger voltage, sustaining ≥30 mA holding current. Its symmetric dual-port structure ties pins 1&6 and 2&5 internally to distribute ESD energy evenly across both protection paths.

Designed specifically for memory module I/O line augmentation, the device complements on-die ESD structures without signal attenuation-enabled by low 55pF capacitance at 5V bias and <75 K/W junction-to-case thermal resistance. It fails short-circuit under catastrophic ESD events (>27 kV), preserving downstream SRAM integrity.

Key Specifications

Pinout & Package

DS9502P/T&R is housed in a 3.7 × 4.0 × 1.5 mm TSOC (Thin Small Outline Carrier) surface-mount package with gull-wing leads and symmetric dual-port internal bonding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NUP4105MR6T1G and ESDE05C24, the DS9502P/T&R uniquely delivers snapback-triggered 5.5V clamping with symmetric dual-port architecture-critical for balanced energy handling in memory module I/O pairs-while maintaining compatibility with legacy 5V logic families and industrial temperature operation.

Availability

DS9502P/T&R is available at Aetrix Electronics and suitable for SRAM-based portable memory modules, 5V logic interface protection, memory card adapters, and embedded data acquisition systems requiring stable component supply and long-term lifecycle support.

Supply support for DS9502P/T&R 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

Dallas Semiconductor, acquired by Maxim Integrated in 2001, specialized in precision analog, mixed-signal, and secure memory solutions for industrial and embedded applications.

The DS9502P/T&R belongs to Dallas' ESD protection diode product line, engineered specifically to augment on-chip protection in battery-buffered SRAM modules and meet stringent IEC 801-2 Level 4 requirements.

FAQ

What is the clamping behavior of the DS9502P/T&R during an ESD event?

The DS9502P/T&R exhibits Zener snapback clamping: above 9.0–9.5 V trigger voltage, it transitions to a low-impedance state with 5.5 V holding voltage, sustaining ≥30 mA current. This foldback behavior reduces voltage stress on protected circuits versus standard TVS diodes. The DS9502P/T&R maintains this state until current falls below 30 mA, then reverts to high-impedance mode with ≤100 nA leakage.

How does the symmetric dual-port structure of the DS9502P/T&R improve ESD protection?

The DS9502P/T&R's symmetric dual-port bondout ties pins 1&6 and 2&5 as separate anode pairs sharing a common cathode (pins 3&4), enabling balanced current division during bidirectional transients. This design maximizes energy dissipation across both ports, reduces localized heating, and avoids single-point failure-critical for protecting paired I/O lines in SRAM modules. The DS9502P/T&R achieves >27 kV IEC 801-2 immunity using this architecture.

What is the maximum operating temperature range for the DS9502P/T&R?

The DS9502P/T&R is rated for continuous operation from –40°C to +85°C, meeting industrial temperature requirements. Its leakage current remains ≤100 nA at 7.0 V across this full range, and its 5.5 V holding voltage and 2.0 A peak pulse capability are guaranteed within these limits. The DS9502P/T&R's thermal resistance (R_ΘJC = 75 K/W) ensures reliable performance in compact, thermally constrained memory module designs.

Can the DS9502P/T&R be used to protect high-speed digital interfaces?

Yes-the DS9502P/T&R's 55 pF junction capacitance at 5 V bias minimizes signal rise-time degradation on 5V memory buses up to ~100 MHz. Its TSOC package's low inductance supports fast transient response (t_r < 1 ns), and symmetric dual-port layout avoids skew between protected lines. However, for >200 MHz interfaces like DDR or USB 3.0, lower-capacitance alternatives (e.g., <15 pF) are recommended. The DS9502P/T&R is optimized for SRAM I/O, not RF or GHz serial links.

What happens to the DS9502P/T&R after an ESD event exceeding its absolute maximum ratings?

When subjected to ESD energy beyond its 2.0 A peak pulse rating or 27 kV IEC 801-2 limit, the DS9502P/T&R is designed to fail short-circuit-maintaining a low-resistance path between anode and cathode. This "fail-short" behavior prevents open-circuit failure, ensuring downstream components (e.g., SRAM chips) remain isolated from further overvoltage. The DS9502P/T&R's short-fail mode is intentional and documented in its datasheet as a safety mechanism for system-level protection.