L9638D - LIN Bus Transceiver, 20 kbaud, 26 V | STMicroelectronics
料号： L9638D ✓ 量产中L9638D 概述
A LIN transceiver is a dedicated interface IC that connects a microcontroller's protocol handler to the physical bus wiring of a vehicle. In the hierarchy of electronics, a LIN transceiver belongs to the interface IC family, alongside CAN, RS-232 and RS-485 transceivers, and is a physical-layer building block for in-vehicle distributed power and control networks. LIN is a single-wire, low-cost, low-bitrate serial bus standardized for body electronics and comfort systems.
Key features of the L9638D include conformance to the LIN specification revision 2.0, compatibility with standard ISO 9141 systems, operation down to 6 V for battery-connected 12 V systems, a very low typ. 10 microamp sleep quiescent current, wake-up through the LIN bus line, and an enable input driven directly from a microcontroller CMOS output.
Technically the device is a monolithic integrated circuit that combines a bus driver and receiver with control logic for power-saving modes and external wake-up handling. Because the LIN bus is a single wire referenced to ground, the transceiver provides the dominant/ recessive level conversion, bus biasing and bus-recessive detection that the protocol handler requires, while the host microcontroller handles framing, checksums and timing.
Typical applications include body control modules, door and tailgate modules, climate control units, ambient light and seat-occupancy sensor nodes, window lift controllers, and other LIN-attached automotive sub-systems where a low-cost single-wire network replaces point-to-point wiring.
When designing with the L9638D, place the bus line connection and its pull-up resistor close to the device, keep the LIN trace away from switching nodes, and verify supply decoupling for the 6 V to 26 V operating range, including the 40 V transient condition present on automotive battery lines. The sleep current of 10 microamp typ. supports dark-current-sensitive parked vehicles.
This page consolidates verified distributor pricing, an explicit drop-in alternative shortlist, parameter-by-parameter comparison and practical layout guidance that are not gathered together in the original manufacturer datasheet.
直接替换替代料： L9638D ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： L9638D （相同外形与封装尺寸） ——差异在于 Package.
E-L9637D013TR
✅ 直接替换联系询价
查看数据手册 →L9639D
✅ 直接替换📋 参考替代料（不在目录中）
L9638D013TR
✅ 直接替换📋 参考替代料（不在目录中）
E-L9637D013TR
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →L9638D 规格参数
| Product Type | LIN bus transceiver (1/1, half duplex) |
| LIN Specification | LIN specification revision 2.0 |
| Maximum Transmission Rate | 20 kbaud |
| Operating Supply Voltage Range | 6 V to 26 V |
| Transient Supply Voltage | 40 V |
| Sleep Mode Quiescent Current | 10 uA typical |
| Wake-Up | Through LIN bus line |
| Enable Input | CMOS input from microcontroller |
| Bus Compatibility | ISO 9141 compatible |
| Bus Lines | 1 single-wire bidirectional LIN line |
| Number of Transceivers | 1 |
| 封装 | SO-8 (8SO), 4.9 mm x 3.9 mm body |
| 安装类型 | Surface Mount |
L9638D 引脚配置
| 引脚 1 | RXD — Receive data output to the host microcontroller |
| 引脚 2 | GND — Ground |
| 引脚 3 | TXD — Transmit data input from the host microcontroller |
| 引脚 4 | EN — Enable / sleep control input driven from microcontroller CMOS |
| 引脚 5 | NC — Not connected |
| 引脚 6 | LIN — Single-wire bidirectional LIN bus line |
| 引脚 7 | VS — Positive supply voltage, 6 V to 26 V |
| 引脚 8 | GND — Ground |
典型应用
L9638D 适用于 6 应用s: Body Control Module LIN Interface, Door and Tailgate Module, Climate Control Unit, Seat and Occupancy Sensor Node, Window Lift and Tailgate Actuator, Automotive LIN Gateway and Diagnostics.
Body Control Module LIN Interface
The L9638D fits a body control module that aggregates door, window, lighting and climate nodes onto a single LIN sub-network. With a 6 V to 26 V operating supply range the transceiver tolerates 12 V battery transients up to 40 V without a separate suppressor, and its typ. 10 uA sleep quiescent current keeps parked-vehicle dark current negligible across dozens of installed modules. The host microcontroller drives TXD and EN from CMOS outputs and reads the bus state on RXD, while the transceiver handles dominant/recessive level conversion and bus wake-up detection so the ECU can stay asleep until the bus becomes active.
推荐
Door and Tailgate Module
A door or tailgate module in a LIN sub-network typically has very little space, power and processing budget, which is exactly where the 8-pin SOIC L9638D is efficient. Only one external bus line plus the supply and a single transceiver is needed to join the node to the vehicle LIN bus, and the bus wake-up path allows the module to wake when a neighbouring node activates the line. Pairing the L9638D with a small Cortex-M class microcontroller such as the STM32F072 family gives a compact, low-cost slave node with a 20 kbaud physical layer that comfortably exceeds the throughput needed for switch-position and motor-status reporting.
推荐
Climate Control Unit
In a climate control head unit, a LIN bus typically carries panel button events, temperature set points and blower feedback, and the bus wiring replaces many point-to-point cables. The L9638D supports this with a 20 kbaud LIN 2.0 physical layer, ISO 9141 compatibility, and a hardware enable input so the panel firmware can de-assert the transceiver when the module is idle. Because the climate unit is permanently powered in a parked car, the typ. 10 uA sleep quiescent current materially reduces parasitic drain over long parking periods, and the single-wire bus keeps the harness weight and cost down.
推荐
Seat and Occupancy Sensor Node
Seat-occupancy and ambient-light sensor nodes are simple, low-cost slaves that sit on the vehicle LIN bus and report a few bytes of data. The L9638D is well matched because it needs only a single bus line, draws typ. 10 uA in sleep, and can be woken by bus activity so that the sensor node does not have to hold its transceiver active continuously. With a 20 kbaud physical layer and LIN 2.0 conformance, the transceiver comfortably supports the periodic polling frames used by seat controllers, while the SO-8 footprint keeps the PCB area minimal in space-constrained seat electronics.
推荐
Window Lift and Tailgate Actuator
Window lift, sunroof and tailgate actuators are motor-driven loads that in modern vehicles are often placed on a LIN sub-network behind a body controller. The L9638D provides the LIN physical layer to the actuator ECU, and its ability to operate down to 6 V means the node keeps communicating during battery sag on engine cranking, while the 40 V transient rating protects against load-dump events at the module input. The enable input allows the actuator firmware to keep the transceiver in sleep when the motor is idle, cutting quiescent current on the parked vehicle, and the bus wake-up lets the body controller wake the node on demand.
推荐
Automotive LIN Gateway and Diagnostics
A gateway or diagnostic interface bridging a LIN sub-network to the vehicle CAN backbone needs a LIN physical layer that can sit on the bus while other domains remain asleep. The L9638D supports this role with bus wake-up, allowing the gateway to be brought online by activity from any LIN node, and with the enable input giving the host MCU explicit control of transceiver state during diagnostics sessions. Its 6 V to 26 V supply window and 40 V transient tolerance suit raw battery-connected wiring, and the LIN 2.0 / ISO 9141 conformance keeps it compatible with legacy body-network test equipment used in plant diagnostics.
推荐
推荐产品汇总
工程参考数据： L9638D ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | L9637D | L9639D | L9638D013TR | L9637D013TR |
|---|---|---|---|---|---|
| Package | SO-8 (8SO) | SO-8 (8SO) - same footprint | SO-8 (8SO) - same footprint | SO-8 (8SO) - same footprint | SO-8 (8SO) - same footprint |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Function | LIN 2.0 bus transceiver, ISO 9141 compatible | Same-family single-wire bus transceiver | Single-wire bus transceiver for ISO 9141 style systems | Same LIN transceiver, grade suffix | Same-family transceiver, grade suffix |
| Maximum Transmission Rate | 20 kbaud | 20 kbaud class LIN physical layer | 20 kbaud class bus physical layer | 20 kbaud | 20 kbaud class LIN physical layer |
| Operating Supply Voltage | 6 V to 26 V | 6 V to 26 V class automotive range | 6 V to 26 V class automotive range | 6 V to 26 V | 6 V to 26 V class automotive range |
| Transient Supply Voltage | 40 V | 40 V class transient rating | 40 V class transient rating | 40 V | 40 V class transient rating |
| Sleep Quiescent Current | 10 uA typical | 10 uA class sleep current | 10 uA class sleep current | 10 uA typical | 10 uA class sleep current |
| Wake-Up | LIN bus wake-up plus CMOS enable input | Bus wake-up and enable control | Enable control, bus wake-up behaviour differs | LIN bus wake-up plus CMOS enable input | Bus wake-up and enable control |
关键差异点
- Automotive-specific supply tolerance （对比 L9639D)
- Ultra-low sleep current for parked-vehicle drain （对比 L9637D)
- Compact 8-pin SOIC footprint with one bus line （对比 L9638D013TR)
设计说明
Place the L9638D close to the LIN bus connector entry point so the external bus line trace stays short and is not routed parallel to switching or motor-drive traces. Keep the LIN line away from the motor and relay power paths of the module, since the single-wire bus is sensitive to injected noise. Provide a local supply decoupling capacitor at the VS pin and route the ground pins directly to the ground plane, because the transceiver detects bus recessive levels referenced to the local ground.
Estimated: with the transceiver in sleep the dominant board-level quiescent load is the 10 uA typ. sleep current of the L9638D itself; in a 12 V vehicle parked for 30 days this corresponds to roughly 0.09 Ah, before other board loads are counted. Estimated: at an average operating supply of 12 V and an operating supply current of 1 mA the device contributes about 12 mW of dissipation, so no special heat sinking is required in the SO-8 package.
Do not treat any SO-8 LIN transceiver as automatically interchangeable: the L9638, L9637 and L9639 differ in bus wake-up behaviour and enable logic, and swapping them without re-reading the pin configuration can leave the module unable to wake. Also confirm the 40 V transient capability is handled at the module level; if the LIN harness is exposed to unclamped load dump, external protection may still be required on the supply input.
Keep the enable (EN) and TXD traces away from the LIN line and the supply return path to avoid coupling the host microcontroller's digital edges into the bus receiver. Because the LIN bus is single-wire and referenced to ground, a solid, uninterrupted ground plane under the transceiver and connector is more important than on differential buses. Firmware should also keep the transceiver in sleep through the EN pin whenever the ECU is idle so the 10 uA typ. sleep current benefit is actually realised.
合规信息
The verified distributor listing for L9638D requested inventory verification for lead-free and RoHS status, so no compliance claim could be extracted. Confirm RoHS, REACH, AEC-Q100 grade and lead-free termination with STMicroelectronics for the specific ordering code before release.
