MC33912BAC - LIN SBC with DC Motor Pre-Driver | NXP Semiconductors
MPN: MC33912BAC ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.62 | $5.62 |
| 10 | $5.04 | $50.40 |
| 100 | $4.42 | $442.00 |
| 500 | $3.85 | $1,925.00 |
| 1,000 | $3.35 | $3,350.00 |
MC33912BAC Overview
A System Basis Chip (SBC) is a power-management and communication IC that consolidates the voltage regulation, physical-layer transceivers, and actuator drivers that surround an automotive microcontroller. The SBC sits between the battery/12V rail and the MCU, supplying a clean logic rail, providing the physical interface for in-vehicle bus communications, and driving actuators such as motors and relays. In the broader taxonomy it belongs to: SBC -> power management IC -> mixed-signal automotive IC -> semiconductor.
Key features include an SPI-readable diagnostics interface, selectable timing watchdog, current sense amplifier with adjustable gain, low-side DC motor pre-driver rated for H-bridge control, two low-side relay drivers (1.5 ohm typical RDSon), and an integrated LIN 2.0/2.1 compliant transceiver. The 5.0V LDO delivers 50mA for MCU supply, while the LIN bus interface meets ISO 9141 / LIN 2.0 physical layer specifications with integrated slope control and current limiting.
The architecture combines an SPI-mapped register bank for configuration and status readback, a window watchdog with selectable timings, and a current-sense amplifier whose output is ratiometric to the high-side driver current. The MC33912BAC variant differs from the MC33912G5 in motor-drive current capability and output stage tuning, allowing designers to choose the variant matched to their specific motor load profile.
Typical applications include HVAC flap and blower motor control in instrument clusters, door module control (mirror fold, window lift), and body electronics modules that combine LIN communication with DC motor and relay actuation. The wide 5.5V to 27V supply range also handles load-dump events common in 12V automotive systems.
When designing with this device, place the AGND and PGND pins on a solid ground plane and use low-ESR ceramic bypass capacitors on VSUP and VCC. The motor pre-driver requires careful PCB layout to manage thermal dissipation under stall conditions - copper-pour heatsinking on the LQFP-32 thermal pad is recommended.
Drop-in alternatives for MC33912BAC — 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 MC33912BAC (same form factor and footprint) — differing in Package, Current Sense Amplifier, DC Motor Pre-Driver, Function, ISO 7637 Pulse 3b Immunity.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC33912G5
✅ Drop-In📋 Reference alternative (not in catalog)
MC33912BAC-R2
✅ Drop-In📋 Reference alternative (not in catalog)
MC33912G5-R2
✅ Drop-In📋 Reference alternative (not in catalog)
SC33912BAC
✅ Drop-In📋 Reference alternative (not in catalog)
MC33912BCEK
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC33912BAC Maximum Ratings & Electrical Characteristics
| Function | LIN System Basis Chip (SBC) with DC motor pre-driver and current sense |
| Communication Interface | SPI (configuration/diagnostics), LIN 2.0/2.1 (physical layer) |
| Supply Voltage Range | 5.5 V to 27 V |
| Integrated LDO Output | 5.0 V / 50 mA |
| Current Consumption (typical) | 4.5 mA |
| DC Motor Pre-Driver | Low-side pre-driver for H-bridge control |
| Relay Drivers | 2 x low-side, 1.5 ohm typical RDSon |
| Current Sense Amplifier | Integrated, adjustable gain, SPI-readable |
| Watchdog | Selectable window watchdog |
| LIN Bus Compliance | LIN 2.0 / LIN 2.1 / ISO 9141 physical layer |
| ESD Performance (LIN pin) | IEC 61000-4-2, +/-6 kV min (gun test, 150 pF / 330 ohm) |
| ISO Pulse Immunity | ISO 7637 pulse 3b compliant |
| Package | 32-pin LQFP (exposed pad) |
| Mounting Type | Surface Mount |
| Packaging | Tray |
| Operating Temperature | -40C to +125C (automotive grade) |
| RoHS Status | Compliant |
MC33912BAC Pin Configuration
| Pin 1 | VSUP — Battery supply input (5.5 V to 27 V) |
| Pin 2 | LIN — LIN bus physical interface (LIN 2.0/2.1) |
| Pin 3 | WAKE — Wake-up input from LIN bus activity |
| Pin 4 | CSB — Chip select bar for SPI (active low) |
| Pin 5 | SCLK — SPI serial clock |
| Pin 6 | MOSI — SPI master-out slave-in |
| Pin 7 | MISO — SPI master-in slave-out |
| Pin 8 | RST — Reset output to MCU |
| Pin 9 | VCC — 5 V LDO output (50 mA) for MCU supply |
| Pin 10 | AGND — Analog ground - reference for LDO and current sense |
| Pin 11 | CSOUT — Current sense amplifier output |
| Pin 12 | CSP — Current sense positive input |
| Pin 13 | CSN — Current sense negative input |
| Pin 14 | PGND — Power ground for relay drivers and motor pre-driver |
| Pin 15 | RELAY1 — Low-side relay driver output 1 (1.5 ohm RDSon) |
| Pin 16 | RELAY2 — Low-side relay driver output 2 (1.5 ohm RDSon) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | MTR — DC motor low-side pre-driver output |
| Pin 20 | PGND — Power ground (second bond pad for high-current return) |
| Pin 21 | NC — Not connected (per datasheet) |
| Pin 22 | NC — Not connected (per datasheet) |
| Pin 23 | LGND — Logic ground for digital I/O |
| Pin 24 | INT — Interrupt output to MCU (SPI fault / watchdog) |
| Pin 25 | WDIN — Watchdog trigger input from MCU |
| Pin 26 | TXD — LIN transmit data input from MCU |
| Pin 27 | RXD — LIN receive data output to MCU |
| 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 | NC — Not connected (per datasheet) |
Typical Applications
MC33912BAC is suitable for 6 applications: HVAC Flap and Blower Motor Control, Door Module Control (Mirror Fold / Window Lift), Body Electronics Module (BCM LIN Sub-Nodes), Steering Column Switch / Stalk Module, Seat Control Module (Lumbar / Headrest Motors), Sunroof / Convertible Top Controller.
HVAC Flap and Blower Motor Control
The MC33912BAC is well-suited to HVAC flap and blower motor control modules in automotive instrument clusters and climate-control panels. Its integrated DC motor low-side pre-driver (used with an external H-bridge) and current-sense amplifier allow closed-loop blower-speed control without a dedicated motor-control IC. The LIN 2.0/2.1 transceiver interfaces directly to the HVAC control unit over a single-wire bus, and the 5V/50mA LDO powers the local MCU. Its 5.5V to 27V supply tolerance handles cold-crank and load-dump events typical in 12V body-electronics networks, while the +/-6 kV IEC 61000-4-2 ESD rating on the LIN pin eliminates the need for an external TVS in most layouts.
Recommended
Door Module Control (Mirror Fold / Window Lift)
Door modules combining mirror fold, window lift, and LED indicator functions are a textbook application for the MC33912BAC. The dual low-side relay drivers (1.5 ohm RDSon) directly switch mirror-fold and window-lift relays, while the DC motor pre-driver feeds the window motor through an external H-bridge. SPI-readable diagnostics allow the host MCU to flag stuck-mirror or pinching conditions over LIN. With operating voltage 5.5V to 27V and -40C to +125C automotive grade, the SBC handles under-hood-to-door-cable transients without external protection. The 32-LQFP footprint suits the small PCB area typical of door modules, reducing BOM by replacing 4-5 discrete parts.
Recommended
Body Electronics Module (BCM LIN Sub-Nodes)
As a LIN sub-node inside a body electronics module, the MC33912BAC provides local power, bus interface, and actuator drive for seat controllers, ambient lighting hubs, and steering-column switches. Its integrated 5V LDO eliminates the need for an external regulator for the sub-node MCU, while the SPI bus carries diagnostic and configuration traffic to that MCU. The window watchdog with selectable timing protects against firmware lockups in safety-relevant sub-nodes. With 5.5V to 27V input range and IEC 61000-4-2 ESD performance on the LIN pin, the SBC supports direct attachment to the BCM's LIN sub-bus without external protection.
Recommended
Steering Column Switch / Stalk Module
Steering-column switch modules integrate wiper, turn-signal, and headlight controls and communicate over LIN to the BCM. The MC33912BAC handles the LIN physical layer, supplies the local MCU through its 5V LDO, and uses one or both low-side relay drivers to drive indicator lamps or solid-state relays. The current-sense amplifier allows detection of lamp-out conditions without a dedicated sense resistor network. SPI diagnostics expose switch-state and fault information to the host MCU, simplifying the stalk module's firmware. The 32-LQFP package supports the small PCB area typical of column-mounted modules.
Recommended
Seat Control Module (Lumbar / Headrest Motors)
Seat control modules with lumbar, headrest, or recline motors benefit from the MC33912BAC's integrated motor pre-driver, dual relay drivers, and LIN connectivity. The low-side pre-driver combined with an external H-bridge drives lumbar pumps, while the relay drivers switch heating elements or headrest actuators. The SPI-readable current sense amplifier enables position feedback and stall detection, which is critical for memory-seat recall operations. With 5.5V to 27V supply input and -40C to +125C operating range, the SBC handles the under-seat thermal environment over the full automotive mission profile.
Recommended
Sunroof / Convertible Top Controller
Sunroof and convertible-top controllers use the MC33912BAC's DC motor pre-driver and dual relay drivers to actuate motors and latching relays while reporting status over LIN. The integrated current-sense amplifier detects end-of-travel stalls, which is essential for anti-pinch safety functions. SPI diagnostics allow the host MCU to log fault events (overcurrent, undervoltage, watchdog timeout) for warranty analysis. The 32-LQFP package and 5.5V to 27V supply tolerance suit the body-mounted controller location where supply transients and temperature extremes are routine. The +/-6 kV IEC 61000-4-2 ESD rating on LIN reduces protection-component cost.
Recommended
Recommended Products Summary
Engineering reference data for MC33912BAC — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC33912G5 | MC33912BAC-R2 | MC33912G5-R2 | SC33912BAC | MC33912BCEK |
|---|---|---|---|---|---|---|
| Package | 32-LQFP (exposed pad) | 32-LQFP (exposed pad) - same | 32-LQFP (exposed pad) - same | 32-LQFP (exposed pad) - same | 32-LQFP (exposed pad) - same | 32-LQFP (exposed pad) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Supply Voltage | 5.5 V to 27 V | 5.5 V to 27 V | 5.5 V to 27 V | 5.5 V to 27 V | 5.5 V to 27 V | 5.5 V to 27 V |
| Integrated LDO | 5.0 V / 50 mA | 5.0 V / 50 mA | 5.0 V / 50 mA | 5.0 V / 50 mA | 5.0 V / 50 mA | 5.0 V / 50 mA |
| LIN Transceiver | LIN 2.0/2.1 | LIN 2.0/2.1 | LIN 2.0/2.1 | LIN 2.0/2.1 | LIN 2.0/2.1 | LIN 2.0/2.1 |
| Relay Drivers | 2 x low-side, 1.5 ohm RDSon | 2 x low-side, 1.5 ohm RDSon | 2 x low-side, 1.5 ohm RDSon | 2 x low-side, 1.5 ohm RDSon | 2 x low-side, 1.5 ohm RDSon | 2 x low-side, 1.5 ohm RDSon |
| Motor Pre-Driver Tuning | BAC variant (datasheet pp. 53-103) | G5 variant (datasheet pp. 3-52) | BAC variant, R2 reel | G5 variant, R2 reel | BAC variant, S-prefix manufacturer code | Similar motor block, different revision |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C |
Key Differentiators
- Integrated motor pre-driver with current sense in a single SBC (vs Discrete LIN transceiver + LDO + motor driver)
- Same 32-LQFP family as MC33912G5 with different motor pre-driver tuning (vs MC33912G5)
- Native +/-6 kV IEC 61000-4-2 ESD on LIN without external TVS (vs Generic LIN SBC without integrated ESD)
- Integrated selectable window watchdog (vs External watchdog supervisor IC)
Design Notes
Place a low-ESR ceramic bypass capacitor (>= 100 nF) directly on the VSUP pin and a >= 1 uF ceramic on the VCC pin to stabilize the integrated 5V LDO and suppress battery-line transients. The LDO delivers up to 50 mA to the host MCU; if the application requires more than 50 mA on the 5V rail, an external regulator must be added. For load-dump compliance, ensure the trace from the battery input is short and that the bulk capacitance on VSUP meets ISO 7637 pulse 3b requirements.
The 32-LQFP exposed pad is the primary heat-dissipation path for the relay drivers and motor pre-driver. Solder the exposed pad to a continuous ground-plane copper pour of at least 1 square inch on the top and inner PCB layers, with multiple thermal vias to the bottom layer. Under motor stall conditions, the pre-driver can dissipate several watts - without adequate copper, junction temperature can exceed 150C and trigger thermal shutdown. Estimated: with 2 W dissipation and a 25 C/W theta_JA on a 1-sq-in copper pour, junction rise is ~50 C above ambient.
Use a star-ground topology: tie AGND (LDO and current-sense reference) directly to the MCU ground, and route PGND (relay/motor return) and LGND (logic return) separately back to a single point near the SBC exposed pad. Mixing high-current relay/motor returns with the analog ground injects switching noise into the current-sense amplifier output and degrades SPI diagnostics accuracy. Keep the LIN trace short and away from relay-driver outputs to preserve the +/-6 kV IEC 61000-4-2 ESD margin.
Do not hot-swap the MC33912BAC on a live VSUP bus - the absence of inrush current limiting on the LIN pin can cause ESD-induced latch-up. Always sequence VSUP before driving the LIN line or the relay/motor outputs. The window watchdog must be serviced within the selected window after MCU firmware initializes the SPI registers; failure to do so triggers a reset pulse on RST. Verify that the WDIN pulse pattern in firmware matches the SBC's selected window mode before locking the PCB layout.
Compliance Information
RoHS compliant per NXP product page. Designed for -40C to +125C automotive temperature range consistent with AEC-Q100 Grade 1; exact AEC-Q100 letter revision should be confirmed with NXP PPAP documentation. LIN pin ESD rated to +/-6 kV min per IEC 61000-4-2 (150 pF / 330 ohm test conditions). ISO 7637 pulse 3b transient immunity qualified. End-of-Life status as of 2026-10-15 per NXP product page.
