STMicroelectronics L9637D013TR

Overview

L9637D013TR from STMicroelectronics is an ISO 9141-compliant monolithic bus driver for automotive diagnostic K-line communication, featuring bidirectional K-I/O with supply-dependent thresholds, integrated pull-up resistors on TX/RX/LO, and thermal shutdown at 160–200 °C. It operates from 4.5 V to 36 V (40 V transient), draws ≤120 µA quiescent current in OFF mode, and delivers typ. 60 mA K-output current - deployed in ECU diagnostic interfaces.

For engineers reviewing the L9637D013TR datasheet, L9637D013TR pinout, L9637D013TR application, or L9637D013TR equivalent, key selection criteria include K-line voltage range (−24 V to V_S), defined output states during undervoltage/GND interruption, controlled output slew for EMI compliance, and reverse-battery protection down to −24 V.

Technical Context

The L9637D013TR implements a dedicated ISO 9141 physical layer interface with dual comparator-based input stages (K and L) referenced to V_S, where K supports bidirectional data exchange and L provides unidirectional line monitoring. Its internal V_CC regulator supplies TTL-compatible logic and pull-ups, enabling operation across automotive battery voltages without external regulation.

Functional safety features include overtemperature shutdown selective to the K-I/O path, defined high-impedance outputs during V_S/GND loss, and hysteresis (≥0.025·V_S) on K and LI inputs to reject transients. Output slope control limits dV/dt to reduce radiated emissions, and all bus pins tolerate ±0.2 mJ Schaffner-class pulses.

Key Specifications

Pinout & Package

Package: SO8 (ECOPACK®), 5.0 mm × 6.2 mm body, 1.27 mm pitch, gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ISO 9141 bus driver applications.

Compared with MC33290DTBR2G, the L9637D013TR eliminates external regulators and pull-ups while delivering tighter ISO 9141 timing control; versus TLE6250G, it provides dedicated K/L-line functionality absent in CAN transceivers - making it the only validated choice for legacy automotive diagnostics.

Availability

L9637D013TR is available at Aetrix Electronics and suitable for OBD-II diagnostic interfaces, ECU flash programming ports, and body control module diagnostics requiring stable component supply across automotive production lifecycles.

Supply support for L9637D013TR 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 broad manufacturing and quality certifications.

The L9637 belongs to ST's automotive interface product line, engineered specifically for ISO 9141-2 and KWP2000 diagnostic bus systems - prioritizing robustness, low-power sleep modes, and fail-safe behavior in vehicle ECUs.

FAQ

What is the maximum allowable external pull-up resistance on the K-line?

The maximum external pull-up resistance on K must not exceed 5 kΩ to ensure reliable ON-state definition under all operating conditions. This value is specified in the functional description section to maintain proper voltage thresholds and avoid marginal logic transitions during low-V_S or high-temperature operation.

Does the L9637D013TR support K-line wake-up from standby mode?

Yes - the device supports wake-up via K-line activity while in standby (ISSB ≤ 1 µA). Upon detecting a valid K-line pulse, it exits standby within ≤5 µs delay (t_d), restoring full functionality without requiring external reset or V_CC reassertion.

How does the L9637D013TR handle K-line short-to-battery or short-to-ground faults?

It tolerates shorts to battery (V_S) or ground on K and LI pins due to internal protection circuitry. Short-to-battery is clamped by internal diodes; short-to-ground triggers current limiting (IKSC = 30–100 mA) and thermal shutdown if sustained - preventing damage while maintaining bus integrity elsewhere.

Is the internal V_CC regulator sufficient to power an external microcontroller's I/O?

No - the internal V_CC (3–7 V, 1.4–2.3 mA typical) is designed solely to power the device's own logic and pull-up resistors. It lacks current capacity and regulation stability for external MCU I/O; a dedicated 5 V or 3.3 V regulator remains required for host controller interfacing.