STMicroelectronics L9826

Overview

L9826 from STMicroelectronics is an octal protected low-side driver IC for automotive body control modules, featuring 8 independent 450 mA output channels with dual-control architecture (SPI + parallel inputs NON1/NON2 for outputs 1–2), intrinsic 50 V flyback clamping, and integrated diagnostics via 8-bit SPI register readout. It operates from 4.5–5.5 V supply and supports inductive load switching in engine bay and lighting systems.

For engineers reviewing the L9826 datasheet, L9826 pinout, L9826 application, or L9826 equivalent, this page delivers verified electrical specs (R_DS(on) = 1.5 Ω @ 25 °C, t_don ≤ 5 µs for outputs 1–2), diagnostic behavior (open-load/short-to-V_BAT/short-to-GND detection), protection thresholds (I_LIM = 0.5–1.1 A, T_JSC = 150 °C), and SO20 package layout - all confirmed against ST's Doc ID 7214 Rev 10.

Technical Context

The L9826 integrates two distinct control paths: parallel active-low inputs (NON1/NON2) exclusively for outputs 1 and 2, enabling direct PWM or power-on sequencing without SPI overhead; and a full 8-bit SPI interface (NCS, CLK, SDI, SDO) for synchronized channel enable/disable and real-time fault status readback. The shift register latches data on NCS rising edge after ≥8 CLK cycles, ensuring noise-immune command transfer.

Diagnostics operate via voltage comparison against V_DG = 0.32–0.4·V_CC, with dedicated fault latches cleared only on NCS low. Outputs 1–2 support current regulation mode under overload (I_OUT > I_LIM), while outputs 3–8 trigger immediate shutdown on I_OUT > I_SBC. Thermal shutdown (T_JSC = 150 °C) and 50 V output clamp protect against inductive kickback during turn-off.

Key Specifications

Pinout & Package

Package: SO20 (Small Outline, 20-pin, 0.65 mm pitch), ECOPACK®-compliant, with exposed thermal pad (not electrically connected). Pin 1 marked by notch or dot; top-view pin numbering follows standard SOIC convention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal low-side driver applications.

Compared with L9826, TLE6232GP offers higher current but no parallel control, while BD8960AEFJ-M adds watchdog functionality but lacks integrated flyback protection - making L9826 uniquely suited for cost-sensitive, inductive-load-dominant automotive body control where dual-control and clamp integration reduce system-level component count.

Availability

L9826 is available at Aetrix Electronics and suitable for automotive lighting control, engine bay solenoid actuation, and body control module designs requiring stable component supply across extended temperature ranges (-40 °C to +150 °C).

Supply support for L9826 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 analog, power, microcontroller, and automotive ICs with over 40 years of automotive qualification expertise.

The L9826 belongs to ST's Automotive Power Switch family, engineered specifically for robust, diagnostic-capable low-side driving in harsh vehicle environments - emphasizing functional safety, EMC resilience, and long-term supply stability.

FAQ

What is the maximum continuous output current per channel for L9826?

The L9826 specifies 450 mA continuous DC output current per channel under normal operating conditions (T_J ≤ 150 °C, V_CC = 4.5–5.5 V). Absolute maximum pulsed current is 1.0 A (per Table 3), but sustained operation above 450 mA triggers thermal shutdown due to R_DS(on) power dissipation. Derating is required above 60 °C ambient.

How does the diagnostic function distinguish between open-load and short-to-V_BAT faults?

Diagnostic logic compares output voltage against V_DG = 0.32–0.4·V_CC. For outputs 1–2 in parallel mode: open-load or short-to-GND yields V_OUT < V_DG (status bit low); short-to-V_BAT yields V_OUT > V_DG (status bit low). In SPI mode, the same voltage comparison applies but status bits are inverted: short-to-V_BAT sets bit high, while open-load/short-to-GND sets bit low.

Can outputs 1 and 2 be paralleled with outputs 3–8 for higher current drive?

No - outputs cannot be externally paralleled across channels. Outputs 1 and 2 are internally optimized for current regulation and thermal management; outputs 3–8 use faster short-circuit shutdown. Paralleling would unbalance current sharing, disable individual diagnostics, and risk thermal runaway. ST recommends using a single channel per load or selecting a higher-current device like L9825.

What is the purpose of the nRes pin, and how does it interact with undervoltage detection?

The nRes pin provides asynchronous hardware reset (active low) that clears all internal registers and forces all outputs OFF. It is logically OR'd with the internal undervoltage reset circuit, which asserts when V_CC drops below 3–4 V (V_DDRES). This dual-reset architecture ensures fail-safe shutdown during brown-out or battery disconnect events, preventing undefined output states in automotive power systems.