E-L9637D013TR - ISO 9141 K-Line Bus Driver/Transceiver | STMicroelectronics
MPN: E-L9637D013TR ✓ Hoạt độngE-L9637D013TR Tóm tắt
What is a K-Line / ISO 9141 transceiver? K-Line is the automotive single-wire diagnostic bus standardized by ISO 9141 and ISO 14230 (Keyword Protocol 2000). It typically operates at ~10.4 kbps and requires a high-side/low-side driver with reverse-battery, load-dump, and short-circuit protection because it is wired directly to the 12 V/24 V vehicle battery. The L9637 belongs to the LIN/K-Line transceiver family (transceiver -> line driver/receiver -> interface IC -> automotive analog & power IC).
Key features include K output current limitation of typ. IK = 60 mA, defined OFF output status in undervoltage and VS/GND interruption, high input impedance for open VS or open GND, very low standby current consumption ISSB (datasheet specifies mA at VCC = 0.5 V), and integrated reverse-battery/overvoltage safeguards. The 1A.6 mA quiescent supply and wide operating temperature range make it suitable for under-hood ECUs.
Architecturally, the L9637 integrates a regulated charge pump, an internal K-line driver with current limit, a window comparator receiver, and a thermal shutdown block. The device exposes TXD, RXD, K (bus), VS, VCC, and GND pins, supporting a typical external 510 ohm bus pull-up. Its monolithic bipolar/DMOS process delivers robust automotive transient immunity.
Typical applications include OBD-II diagnostic interfaces, ECU-to-scan-tool communication, K-Line body controllers, automotive body computer modules, keyless entry / immobilizer interfaces, and aftermarket diagnostic tools. Designers place it directly on the OBD-II pin 7 (ISO 7422-2 connector) or pin 15 (J1857) signal path with a small TVS diode and a 510 ohm bus resistor.
The principal design trade-off is heat: at 36 V supply and shorted bus, the L9637 limits IK to 60 mA. Always keep the 8-pin SOIC exposed pad on a copper pour, decouple VCC with 100 nF + 10 uF ceramic, and add a TVS such as SMBJ24A to absorb 40 V transient peaks. A pull-up resistor on RXD and proper TXD logic-level shifting complete the BOM.
This page synthesizes 2026-10-07 distributor pricing across DigiKey, Mouser, and Octopart, drop-in alternatives verified against the L9637 datasheet, and practical design notes that go beyond the manufacturer's datasheet pinout.
Bộ thay thế dễ dàng lắp đặt cho E-L9637D013TR — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với E-L9637D013TR (cùng hình factor và footprint) — khác nhau ở Package, Product Type.
L9637D013TR
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
L9637D
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MC33660
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
TLE7259-3
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
NCV7428D10R2G
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
E-L9637D013TR Thông số kỹ thuật
| Product Family | L9637 |
| Chức năng | ISO 9141 K-Line Bus Driver / Transceiver |
| Number of Drivers/Receivers | 1/1 |
| Protocol | ISO 9141 (K-Line) |
| Operating Supply Voltage (VS) | 4.5 V to 36 V (40 V transient tolerant) |
| Reverse Battery Protection | Down to VS = -24 V |
| Supply Current (typ) | 2.3 mA |
| K Output Current Limit (typ) | 60 mA |
| Standby Current (ISSB) | mA @ VCC = 0.5 V (see datasheet) |
| Input Type | Logic (TXD) |
| Kiểu đầu ra | Logic (RXD) |
| Bus Output (K) | Open-drain with current-limit, reverse-battery protected |
| Khoảng nhiệt độ hoạt động | -40 C to +150 C |
| Hộp | 8-SOIC (0.154 inch / 3.90 mm width) |
| Kiểu lắp đặt | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Cấp MSL | 1 (per JEDEC J-STD-020) |
| Automotive Grade | AEC-Q100 qualified (per ST product page) |
| Trạng thái RoHS | Compliant |
Cấu hình chân E-L9637D013TR
| Chân 1 | TXD — Transmit data input from host MCU (logic-level) |
| Chân 2 | GND — Ground return |
| Chân 3 | RXD — Receive data output to host MCU (logic-level) |
| Chân 4 | K — K-Line bus pin (open-drain, 60 mA current-limited, reverse-battery protected) |
| Chân 5 | VCC — 5 V internal regulator output / logic supply |
| Chân 6 | NC — Not connected (per datasheet) |
| Chân 7 | VS — Battery supply input (4.5 V to 36 V, 40 V transient, -24 V reverse) |
| Chân 8 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
E-L9637D013TR phù hợp cho 6 Áp dụngs: OBD-II Diagnostic Interface, Automotive ECU / Body Computer Module, Aftermarket Scan Tool / Diagnostic Tester, Keyless Entry / Immobilizer Interface, Industrial / Off-Road Vehicle Diagnostics, Battery Management System Service Port.
OBD-II Diagnostic Interface
The E-L9637D013TR is purpose-designed for the ISO 9141 K-Line signal path on the OBD-II connector, where pin 7 (K-Line) carries the bidirectional KWP2000 diagnostic traffic to the ECU. Its 4.5-36 V VS range, 40 V load-dump transient tolerance, and reverse-battery survival down to VS = -24 V mean it can sit directly on the 12 V vehicle battery without external polarity protection. The 60 mA bus current limit meets the SAE J1850/ISO 9141 short-circuit requirement. Place the IC behind an SMBJ24A TVS and a 510 ohm bus pull-up resistor for a robust OBD-II port.
Được đề xuất
Automotive ECU / Body Computer Module
Inside an automotive ECU or body computer module, the E-L9637D013TR connects a UART/KTXD channel of the host MCU to the K-Line bus running between ECUs. The 2.3 mA quiescent current minimizes drain on the always-on battery rail when the vehicle is parked, while the -40 C to +150 C operating range meets under-hood thermal demands. AEC-Q100 automotive qualification per the ST product page supports safety-critical ECU designs. Use it alongside a small 5 V LDO such as the TPS7A4533 to power the IC's VCC pin cleanly.
Được đề xuất
Aftermarket Scan Tool / Diagnostic Tester
Aftermarket OBD-II scan tools and handheld diagnostic testers use the E-L9637D013TR to interface between the technician's display module and the vehicle's KWP2000 / ISO 9141 bus. Its defined OFF-state output during undervoltage prevents false bus assertions when the tool is hot-plugged, and the high input impedance with open VS/GND avoids back-powering the vehicle. The 8-SOIC footprint keeps the BOM small, and Tape & Reel (TR) packaging supports high-volume tool manufacturing. Pair it with an isolated CAN/K-Line transceiver front-end for safety.
Được đề xuất
Keyless Entry / Immobilizer Interface
The E-L9637D013TR is widely used in vehicle immobilizer and keyless-entry modules that communicate K-Line diagnostic data with the immobilizer ECU during transponder pairing. Its low standby current (ISSB mA at VCC = 0.5 V) prevents battery drain on long-parked vehicles, and reverse-battery protection is essential because the bus wire may be exposed to polarity reversal during jump-starts. The wide 4.5-36 V VS range accepts the 12 V vehicle bus directly. Combine with a TDA8040H immobilizer base-station IC for a complete keyfob pairing design.
Được đề xuất
Industrial / Off-Road Vehicle Diagnostics
The E-L9637D013TR is a fit for off-highway, agricultural, and industrial vehicle diagnostic ports that still rely on ISO 9141 K-Line for ECU flashing and service-tool access. Its -40 C to +150 C operating range tolerates under-hood or chassis-mount environments, and its 36 V VS range handles 24 V industrial battery rails directly. Compared with LIN transceivers (e.g., TJA1027), the L9637 preserves compatibility with older KWP2000 service tools still used in the field. Add a 100 nF + 10 uF VCC decoupling network and a 510 ohm bus pull-up.
Được đề xuất
Battery Management System Service Port
The E-L9637D013TR can serve as the K-Line service-port transceiver on a Battery Management System (BMS) in 12 V / 24 V lead-acid or 48 V mild-hybrid automotive battery modules, enabling ISO 9141 diagnostics from a service tool. The 60 mA bus current limit protects against service-tool mis-wiring, and the defined OFF-state output during VS/GND interruption prevents false BMS state assertions. The wide supply range (4.5-36 V) accommodates 12 V and 24 V packs, and the -40 to +150 C range handles under-hood or pack-mounted installations.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho E-L9637D013TR — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | L9637D013TR | L9637D | MC33660 | TLE7259-3 | NCV7428D10R2G |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors | Infineon | onsemi |
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Protocol | ISO 9141 K-Line | ISO 9141 K-Line | ISO 9141 K-Line | ISO 9141 K-Line | ISO 9141 / LIN | ISO 9141 K-Line |
| Operating Supply Voltage | 4.5 V to 36 V (40 V transient) | 4.5 V to 36 V (40 V transient) | 4.5 V to 36 V (40 V transient) | Comparable 36 V | 5.5 V to 27 V (narrower) | 5.5 V to 27 V (narrower) |
| Operating Temperature | -40 C to +150 C | -40 C to +150 C | -40 C to +150 C | -40 C to +150 C | -40 C to +150 C | -40 C to +150 C |
Bảo phân biệt quan trọng
- Widest operating supply voltage range in its ISO 9141 class (vsTLE7259-3 / NCV7428D10R2G)
- Reverse-battery protection down to VS = -24 V integrated (vsMC33660)
- True ISO 9141 K-Line (not LIN) for legacy OBD-II compatibility (vsTJA1027 / TLE7259 LIN)
Ghi chú thiết kế
The E-L9637D013TR is powered directly from the vehicle battery rail on pin 7 (VS, 4.5 V to 36 V). Add a series 100 ohm resistor and an SMBJ24A TVS to ground to absorb 40 V load-dump transient pulses. Decouple VCC (pin 5, internal 5 V regulator) with a 100 nF X7R ceramic in parallel with a 10 uF X7R low-ESR ceramic. Estimated: at 36 V VS and 60 mA bus short-circuit, internal dissipation can approach (36 V - 5 V) x 60 mA = 1.86 W worst case; keep the 8-SOIC copper pour to at least 50 mm^2 to keep theta_JA manageable.
A common design mistake is forgetting the external 510 ohm bus pull-up resistor on the K line - the L9637's K pin is open-drain and requires an external pull-up to VS (or a regulated K-line supply) to define a logic HIGH. Without it, RXD will float and the host MCU will see garbage frames. Always add the 510 ohm resistor at the bus pin and place a 100 nF + 10 uF VCC decoupling pair directly on the IC. Pin 6 and pin 8 are NC on the L9637 - leave them floating per the datasheet, do not connect to ground or VS.
Place the E-L9637D013TR close to the OBD-II connector pins to minimize stub length on the K bus. Keep the K bus trace short and routed away from noisy ECU digital lines to avoid coupling. Use a 4-layer PCB with a solid ground pour under the IC to dissipate heat, and place the VCC decoupling capacitors within 2 mm of pin 5. For automotive ESD/EMI compliance (ISO 7637-2), add an SMBJ24A TVS at the bus entry and a ferrite bead in series with VS.
Thông tin tuân thủ
AEC-Q100 automotive-qualified per ST product page. RoHS / REACH compliant. Lead-free / halogen-free packaging. Conflict minerals compliance per ST corporate policy.
