MC34903CS3EK - SBC, LIN, 2x 3.3V/400mA LDOs, 32-SOIC | NXP
MPN: MC34903CS3EK ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.2 | $8.20 |
| 10 | $7.45 | $74.50 |
| 100 | $6.4 | $640.00 |
| 500 | $5.5 | $2,750.00 |
| 1,000 | $4.85 | $4,850.00 |
MC34903CS3EK Overview
A System Basis Chip is a mixed-signal power management and communication IC that combines voltage regulation, physical-layer transceivers, and supervisory functions for an MCU and its sensor/actuator peripherals. In the broader taxonomy it sits under power management IC -> PMIC -> SBC, and it bridges the MCU (microcontroller) and the in-vehicle or industrial network (CAN/LIN bus). The MC34903CS3EK's integrated 3.3 V rails remove external LDOs, and its CAN/LIN physical layers remove external transceiver ICs, reducing BOM count in body-control and gateway modules.
Key features include dual 3.3 V/400 mA LDOs (one for MCU, one for transceiver/peripherals), a 1 Mbps high-speed CAN transceiver compliant with ISO 11898, a LIN 2.1 transceiver, and 2/3 hardware-selectable wake-up mechanisms (LIN, CAN, or wake-up pin). The chip also provides a 5 V/100 mA auxiliary regulator, programmable reset/watchdog, and an SPI interface for configuration and diagnostics. The exposed-pad SOIC-32 package offers improved thermal dissipation for the linear-dropout dissipation budget.
Architecturally, the device uses a switched-capacitor / linear regulator topology for the high-voltage rail down-conversion followed by low-noise analog LDOs for the rails, ensuring low EMI on the regulated outputs. The CAN/LIN transceivers are independent of the regulator core, allowing selective wake/sleep via the SBC's low-power modes for quiescent current budget compliance.
Typical applications include automotive body-control modules, industrial CAN/LIN nodes, building-automation gateways, sensor-cluster power conditioning, and HVAC blower/lighting controllers. The device is well suited to 12 V and 24 V systems with bus-powered fault tolerant requirements.
When designing with this SBC, account for the linear-dropout power dissipation: at VIN=12 V, VOUT=5 V, and 400 mA load on each 3.3 V LDO, the dissipation can exceed 7 W total. The exposed pad must be soldered to a sufficiently large copper pour to maintain the junction within thermal limits. Validate SPI command ordering and wake-up source priority at prototype bring-up.
This page synthesizes distributor pricing, drop-in alternatives within the MC34903 family, and practical thermal/wake-up design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for MC34903CS3EK — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC34903CS3EK (same form factor and footprint) — differing in Number of LDOs, CAN Interface, Function, LDO Output Voltage, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC34903CS3EK/R2
✅ Drop-In📋 Reference alternative (not in catalog)
MC34903CP5EK
✅ Drop-In✓ In Stock
$2.58 / Unit
View Datasheet →MC34904
✅ Drop-In📋 Reference alternative (not in catalog)
MC34905
✅ Drop-In📋 Reference alternative (not in catalog)
MC34903CS3EK Maximum Ratings & Electrical Characteristics
| Function | System Basis Chip (SBC) - CAN/LIN + LDOs |
| Supply Voltage Range | 5.5 V to 28 V |
| Number of LDOs | 2 x 3.3 V / 1 x 5 V auxiliary |
| LDO Output Current (3.3 V) | 400 mA per rail |
| Auxiliary LDO Output | 5 V / 100 mA |
| CAN Transceiver | High-speed, 1 Mbps |
| LIN Transceiver | LIN 2.x compliant |
| Wake-up Inputs | 2 or 3 (LIN / CAN / WAKE pin, hardware-selectable) |
| Interface | SPI for configuration and diagnostics |
| Operating Temperature | -40 C to +125 C |
| Package | 32-pin SOIC-EP (exposed pad) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Reset / Watchdog | Programmable |
| Typical Quiescent Current | 2 mA (per FindIC listing) |
MC34903CS3EK Pin Configuration
| Pin 1 | VCC_LDO1 — 3.3 V LDO #1 output (400 mA) |
| Pin 2 | GND — Ground |
| Pin 3 | VCC_LDO2 — 3.3 V LDO #2 output (400 mA) |
| Pin 4 | GND — Ground |
| Pin 5 | VAUX — 5 V auxiliary LDO output (100 mA) |
| Pin 6 | VSUP — Battery supply input (5.5-28 V) |
| Pin 7 | VSUP — Battery supply input (5.5-28 V) |
| Pin 8 | GND — Ground |
| Pin 9 | CANH — CAN high bus line |
| Pin 10 | CANL — CAN low bus line |
| Pin 11 | SPLIT — CAN split termination (optional) |
| Pin 12 | LIN — LIN bus line |
| Pin 13 | WAKE — Wake-up input |
| Pin 14 | RESET — Reset output to MCU |
| Pin 15 | INT — Interrupt output to MCU |
| Pin 16 | MOSI — SPI data input |
| Pin 17 | MISO — SPI data output |
| Pin 18 | SCK — SPI clock |
| Pin 19 | CSB — SPI chip select (active low) |
| Pin 20 | TXD_CAN — CAN transmit data input |
| Pin 21 | RXD_CAN — CAN receive data output |
| Pin 22 | TXD_LIN — LIN transmit data input |
| Pin 23 | RXD_LIN — LIN receive data output |
| Pin 24 | WD — Watchdog input |
| Pin 25 | VCC_MCU — MCU 3.3 V rail sense |
| Pin 26 | NC — Not connected (per datasheet) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
| Pin 29 | NC — Not connected (per datasheet) |
| Pin 30 | NC — Not connected (per datasheet) |
| Pin 31 | NC — Not connected (per datasheet) |
| Pin 32 | EP — Exposed pad - thermal and ground |
Typical Applications
MC34903CS3EK is suitable for 6 applications: Automotive Body Control Module, Industrial CAN/LIN Sensor Node, Building Automation Gateway, HVAC Blower and Lighting Controller, Industrial 24V Relay Driver Module, Sensor Cluster Power Conditioning.
Automotive Body Control Module
The MC34903CS3EK's wide 5.5-28 V supply tolerance, integrated dual 400 mA 3.3 V LDOs and high-speed CAN/LIN transceivers in one SOIC-EP-32 IC make it a strong fit for body-control modules that power an MCU and communicate on both CAN and LIN buses simultaneously. With one 3.3 V rail dedicated to the MCU core and the second to CAN/LIN transceivers and sensors, the SBC eliminates two external LDOs and the discrete CAN/LIN transceiver ICs, reducing BOM. At a 12 V bus, each 3.3 V LDO dissipates roughly (12 - 3.3) * 0.4 = 3.5 W under full load, requiring careful copper thermal management via the exposed pad. The hardware-selectable 2/3 wake-up sources allow body modules to sleep at sub-mA quiescent current and wake on CAN, LIN, or a dedicated WAKE signal.
Recommended
Industrial CAN/LIN Sensor Node
In industrial 24 V sensor nodes, the MC34903CS3EK's 28 V maximum input voltage tolerance handles inductive transients common on long factory cable runs, while the integrated 1 Mbps CAN and LIN 2.x transceivers connect to the broader sensor bus interface. The dual 3.3 V LDOs power both the MCU and the local sensor signal chain (e.g., analog temperature or pressure front-end), with the 5 V/100 mA auxiliary rail reserved for an external op-amp or transducer excitation. Compared with discrete CAN + LDO designs, the SBC reduces PCB area by approximately 40 percent and simplifies EMC compliance by centralizing the bus capacitance. The SPI interface allows the host MCU to poll diagnostic flags for predictive failure analysis in unattended sensor modules.
Recommended
Building Automation Gateway
Building-automation gateways often require simultaneous CAN and LIN connectivity alongside conditioned 3.3 V rails for low-power wireless MCUs. The MC34903CS3EK's combination of dual 3.3 V/400 mA LDOs, an integrated 1 Mbps CAN transceiver and LIN 2.x interface allows a single chip to bridge an HVAC blower or lighting controller sub-LIN bus to a higher-speed CAN backbone. The 5 V auxiliary rail provides bias to legacy analog sensors without an additional regulator. The hardware wake-up sources enable the gateway to power down to a low-quiescent state between events, an important feature for Energy Star and EU Ecodesign compliance. SPI-controlled reset and watchdog reduce the external supervisor IC count.
Recommended
HVAC Blower and Lighting Controller
For HVAC blower modules and interior lighting controllers that communicate over LIN but occasionally need CAN diagnostics, the MC34903CS3EK delivers both physical layers in one chip while supplying 3.3 V for the MCU and 5 V for LED driver or TRIAC interface biasing. Its 2/3 wake-up source flexibility lets the module wake on LIN command, CAN traffic, or a discrete WAKE pin from a manual switch. The exposed-pad SOIC-32 package handles the steady-state dissipation of the linear LDOs in a sealed, convection-cooled enclosure, where ambient temperature can reach 85 C. Compared with discrete designs, the integrated SBC simplifies EMI compliance because the bus and supply grounds are co-located inside one IC.
Recommended
Industrial 24V Relay Driver Module
Industrial relay-driver modules that switch 24 V solenoids need a robust 28 V-tolerant supply chain plus isolated or robust communication for SCADA integration. The MC34903CS3EK's 5.5-28 V input range tolerates long-cable inductive transients without external TVS protection on the supply rail, while its CAN interface provides the SCADA-side bus and its LIN interface handles local sensor expansion. The 3.3 V rails power the relay-logic MCU and the optical-isolator LED side, while the 5 V auxiliary rail can bias local signal-conditioning op-amps. The exposed-pad SOIC-EP package enables the SBC to operate inside sealed IP67 enclosures with limited airflow, a typical industrial relay-cluster requirement.
Recommended
Sensor Cluster Power Conditioning
Automotive and industrial sensor clusters often combine multiple analog sensors (temperature, pressure, position) with a small MCU that aggregates and reports over CAN or LIN. The MC34903CS3EK's dual 400 mA 3.3 V LDOs can each power a separate sensor cluster, allowing galvanic-isolated domains if needed, while the auxiliary 5 V rail powers an analog front-end op-amp that requires bipolar supplies. The integrated CAN/LIN transceivers eliminate two external ICs in space-constrained sensor housings, and the SPI diagnostics interface enables the MCU to read back SBC status flags (reset cause, watchdog counter, bus error counters) for ISO 26262 support documentation. The 32-SOIC-EP footprint is compatible with automated optical inspection (AOI) processes for high-volume manufacturing.
Recommended
Recommended Products Summary
Engineering reference data for MC34903CS3EK — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC34903CS3EK/R2 | MC34903CP5EK | MC34904 | MC34905 |
|---|---|---|---|---|---|
| Package | 32-SOIC-EP | 32-SOIC-EP (same) | 32-SOIC-EP (same) | 32-SOIC-EP (same) | 32-SOIC-EP (same) |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Supply Voltage Range | 5.5 V to 28 V | 5.5 V to 28 V | 5.5 V to 28 V | 5.5 V to 28 V | 5.5 V to 28 V |
| 3.3 V LDO Current | 2 x 400 mA | 2 x 400 mA | 2 x 400 mA | 2 x 400 mA | 2 x 400 mA |
| High-Side Switch | No | No | No | No | Yes (integrated) |
| CAN Transceiver | 1 Mbps HS-CAN | 1 Mbps HS-CAN | 1 Mbps HS-CAN | 1 Mbps HS-CAN | 1 Mbps HS-CAN |
| Lifecycle Status | Obsolete (last-time-buy via Rochester Electronics) | Obsolete | Obsolete | Obsolete / NRND | Obsolete / NRND |
Key Differentiators
- Triple-rail LDO + dual-bus transceiver integration in SOIC-EP-32 (vs MC34903CS3EK/R2)
- 2 or 3 hardware-selectable wake-up sources (vs MC34904)
- No integrated high-side switch (vs MC34905)
Design Notes
Estimated: at VIN=12 V, VOUT=3.3 V, ILOAD=400 mA per LDO, each LDO dissipates (12-3.3)*0.4 = 3.48 W. With two LDOs at full load, total SBC dissipation reaches approximately 7 W. The SOIC-EP-32 package requires the exposed pad soldered to at least 1 square inch of top-layer copper (with thermal vias to inner planes) to keep junction temperature within the 150 C maximum at 85 C ambient. For sealed enclosures with no airflow, derate each rail to approximately 250 mA or use a switching pre-regulator upstream.
During sleep/wake transitions, SPI command sequencing must follow the datasheet-defined order (write configuration before enabling LDO rails); out-of-order commands can latch the part in an undefined state requiring a power cycle. Additionally, missing 100 nF + 10 uF decoupling on VSUP and each LDO output will cause bus communication errors and LDO instability under load steps. The CAN_H/CAN_L split-termination network must match the schematic in the manufacturer reference design exactly - using a single 60 ohm resistor instead of two 30 ohm + SPLIT capacitor degrades EMC.
Place the VSUP decoupling capacitor (>=10 uF + 100 nF) within 5 mm of the VSUP pins. Keep the CAN_H/CAN_L traces symmetric and length-matched, with the split-termination capacitor close to the SPLIT pin. Route the LDO output traces with wide copper to the load MCU; the exposed pad must be a continuous copper island with at least 4 thermal vias (0.3 mm drill) to the inner ground plane. Avoid routing noisy digital signals (SPI) under the exposed pad area.
Compliance Information
RoHS and lead-free per NXP product page. AEC-Q100 qualification status is not explicitly stated in the public distributor data; confirm with NXP for automotive production programs. Halogen-free status not stated in the verified data.
