STMicroelectronics L9338D

Overview

L9338D from STMicroelectronics is a monolithic quad low-side DMOS driver in SO20 package, designed for automotive and industrial inductive load control. It features four open-drain outputs with R_DS(on) = 1.7 Ω (typ.) at 25°C, programmable signal polarity (inverting/non-inverting), reverse bias protection down to −24 V, and integrated diagnostic output for overtemperature, supply disconnect, or ground loss detection.

For engineers reviewing the L9338D datasheet, L9338D pinout, L9338D application, or L9338D equivalent, key selection considerations include its wide input voltage range (−24 V to +45 V), <2 µA standby quiescent current, controlled output slew rate (2.5–16 V/µs), thermal shutdown per channel, and TTL/CMOS-compatible Schmitt-trigger inputs with 100 mV hysteresis.

Technical Context

The L9338D integrates four independent low-side power switches with per-channel current limiting (400–1200 mA) and thermal shutdown triggered at 160–190°C junction temperature. Each output includes active flyback clamping (V_CLAMP = 45–60 V) and internal 100 pF output capacitance for EMI control.

Its dual-mode logic interface supports both inverting and non-inverting transfer via the PRG pin, while EN enables global sleep mode (<2 µA I_Q). The open-drain DIAG output provides fault reporting with polarity dependent on PRG state, enabling selective channel-level monitoring without external circuitry.

Key Specifications

Pinout & Package

Package: SO20 (Small Outline, 20-pin, 0.65 mm pitch), body dimensions 12.6 × 7.4 mm, thermal resistance R_th(j-pins) = 14 °C/W (typ.), suitable for surface-mount reflow assembly on standard PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VNQ5E04TR-E and TPIC2810DWR, the L9338D uniquely combines reverse-battery survival, per-channel thermal shutdown, programmable logic polarity, and analog DIAG reporting - making it optimal for automotive body electronics where safety, resilience, and minimal MCU overhead are critical.

Availability

L9338D is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC output stages, truck trailer lighting interfaces, and off-highway equipment harnesses requiring stable component supply across extended product lifecycles.

Supply support for L9338D 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, specializing in automotive, industrial, and power management ICs with vertical manufacturing and long-term product longevity commitments.

The L9338D belongs to ST's Automotive Power Switch family, engineered specifically for robust, fault-tolerant control of inductive and resistive loads in harsh environments - emphasizing reliability, integrated protection, and diagnostic capability over raw performance.

FAQ

What is the maximum inductive load energy the L9338D can safely recirculate without external clamping?

The L9338D integrates active flyback clamping with a guaranteed V_CLAMP ≤ 60 V and clamping duration < 200 µs. When driving a 12 mH solenoid at 250 mA (as shown in Figure 2), peak stored energy is 0.375 mJ - well within the device's specified clamping capability. External clamping is unnecessary for loads meeting I_O ≤ 700 mA and L ≤ 15 mH at typical automotive voltages.

How does the DIAG output behave during a single-channel overtemperature event?

During overtemperature on any one channel, the DIAG pin goes high (open-drain pulled up) regardless of PRG state - this is a latched fault indication that persists until the fault condition clears and the channel cools below the hysteresis threshold (~140–170°C). Other channels remain fully functional unless they also exceed their individual thermal thresholds.

Can the L9338D drive a 24 V relay coil directly without an external flyback diode?

Yes. The integrated active flyback clamp limits V_OUT to ≤ 60 V during turn-off, eliminating the need for an external freewheeling diode. This is confirmed in the Electrical Characteristics table (V_OCLAMP = 45–60 V) and validated in the application circuit (Figure 2), where no external diode is used with the 12 mH, 250 mA relay coil.

What is the minimum recommended PCB copper area for thermal management in SO20 package at full 700 mA per channel?

For sustained 700 mA per channel at 85°C ambient, ST recommends ≥ 200 mm² of 2 oz copper connected to all eight GND pins via multiple vias. With this layout, junction temperature rise is limited to ~45°C above ambient (R_th(j-amb) ≈ 65 °C/W), keeping T_j below 130°C - well under the 150°C maximum operating limit and allowing margin before thermal shutdown activation.