STMicroelectronics DA112S1RL

Overview

DA112S1RL from STMicroelectronics is a 12-diode ESD protection array in SO-8 package, configured as six dual-diode cells for bidirectional transient clamping. It delivers 15 kV air/8 kV contact IEC 61000-4-2 Level 4 ESD immunity, 18 V repetitive peak reverse voltage per diode, and 12 A 8/20 µs surge current handling-used to protect microcontroller I/O lines and ISDN S-interface logic-side signal paths.

For engineers reviewing the DA112S1RL datasheet, DA112S1RL pinout, DA112S1RL application, or DA112S1RL equivalent, key selection criteria include its dual-reference voltage configuration (REF1/REF2), low 2 µA reverse leakage at 15 V, 1.2 V forward voltage at 50 mA, input capacitance under 36 pF at 5 V DC bias, and SO-8 thermal resistance of 170 °C/W.

Technical Context

The DA112S1RL implements six independent dual-diode clamping cells, each connecting between an I/O line and one of two common reference rails (REF1 and REF2). Its clamping action activates when transient voltage exceeds ±18 V relative to the reference pair, limiting peak excursion to ≤9 V (at 12 A, 8/20 µs) while maintaining low DC forward drop (1.2 V @ 50 mA).

It operates across –55 °C to +150 °C junction temperature, with thermal resistance of 170 °C/W (junction-to-ambient), and requires external DC bias on REF1/REF2 to define the protected voltage window-either 0 V to +18 V or –9 V to +9 V-enabling flexible interface-level protection without series impedance.

Key Specifications

Pinout & Package

DA112S1RL uses the standard SO-8 surface-mount package (JEDEC MS-012AC), with 1.27 mm pitch, 4.9 mm body width, and lead-free ECOPACK® construction compliant with RoHS and UL94 V0.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SM1212-08HTG and TPD2E001DRYR, DA112S1RL uniquely supports 6-line protection with programmable ±9 V or 0–18 V clamping windows, higher 18 V standoff, and SO-8 thermal performance-making it optimal for ISDN, industrial I/O, and mixed-signal telecom interfaces.

Availability

DA112S1RL is available at Aetrix Electronics and suitable for ISDN interface protection, microcontroller I/O port hardening, and industrial serial communication systems requiring stable component supply and long-lifecycle support.

Supply support for DA112S1RL 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 silicon solutions for automotive, industrial, and consumer markets with emphasis on reliability and system-level integration.

DA112S1RL belongs to ST's legacy ESD protection array product line, engineered specifically for robust, low-capacitance transient suppression in telecommunication and embedded control interfaces where dual-reference clamping and multi-line integration are critical.

FAQ

What is the correct biasing scheme for REF1 and REF2 pins?

REF1 and REF2 must be externally biased to define the clamping window: either REF1 = 0 V and REF2 = +18 V for 0–18 V operation, or REF1 = –9 V and REF2 = +9 V for ±9 V symmetric protection. No internal biasing is provided-the rails must be driven by stable external sources or resistor dividers.

Can DA112S1RL protect AC-coupled signals?

Yes, but only if the AC coupling capacitor is sized to maintain DC bias on the I/O line within the clamping window during idle periods. For example, with REF1 = 0 V and REF2 = +18 V, the signal's DC common-mode must remain between 0 V and 18 V; otherwise, forward conduction may occur during normal operation.

Does DA112S1RL require series current-limiting resistors?

No-DA112S1RL is designed for direct connection to I/O pins without series resistors. Its 1.2 V forward voltage at 50 mA and low dynamic impedance ensure minimal impact on signal levels during normal operation, though external resistors may be added for additional current limiting in extreme surge scenarios.

How does DA112S1RL compare to single-diode TVS arrays like PESD5V0S1BA?

Unlike single-diode arrays, DA112S1RL provides dual-diode cells referenced to two independent rails (REF1/REF2), enabling programmable clamping windows and true bidirectional protection per line. PESD5V0S1BA offers only unidirectional clamping to V_CC/GND and lacks configurable voltage ranges or multi-line integration in SO-8.