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NXP Semiconductors MC33291LDW
- Part No.:
- MC33291LDW
- Manufacturer:
- NXP Semiconductors
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC33291LDW.pdf
- Description:
- IC PWR SWITCH N-CHAN 1:8 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,236
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Product details
Overview
MC33291LDW from NXP Semiconductors (formerly Freescale) is an eight-output, low-side power switch IC with SPI serial interface, designed for automotive load control. It delivers 1.0 A peak per channel, features 53 V output clamping, 25 μA sleep current, and operates across 5.5–26.5 V supply range. It interfaces directly with microcontrollers to drive inductive or incandescent loads such as solenoids, relays, and lamps in body electronics modules.
For engineers reviewing the MC33291LDW datasheet, MC33291LDW pinout, MC33291LDW application, or MC33291LDW equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed automotive-grade protection features, and two rigorously cross-checked alternative parts - all grounded in the official Freescale MC33291 Rev 5 datasheet and NXP product documentation.
Technical Context
The MC33291LDW integrates SMARTMOS technology-combining CMOS logic, bipolar/MOS analog monitoring, and DMOS power MOSFETs-to deliver independent per-channel diagnostics, open-load detection, overcurrent shutdown (70–250 μs delay), and thermal foldback. Its SPI interface supports up to 3.0 MHz clocking with daisy-chain fault reporting via SO pin.
Each of its eight outputs includes a dedicated 53 V clamp, self-limiting current (1.0–3.0 A), and programmable short-fault disable via SFPD pin. The device implements overvoltage shutdown at 28–36 V and overtemperature shutdown at 155–180 °C, with hysteresis for stable recovery. All outputs are fully independent and operate without external charge pumps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output count | Eight independent low-side switches - enables compact control of multiple automotive loads without discrete drivers. |
| Peak output current | 1.0 A per channel - sufficient for driving 12 V solenoids, fuel injectors, and LED arrays without external current limiting. |
| RDS(ON) @ TJ = 150°C | Max 1.6 Ω at VPWR = 13 V - ensures <1.6 W conduction loss per channel at 1 A, supporting thermally constrained PCB layouts. |
| SPI clock frequency | Up to 3.0 MHz - allows sub-3.4 μs command latency per 8-bit write, enabling responsive real-time load sequencing. |
| Sleep supply current | 25 μA max - meets automotive "always-on" module quiescent current requirements for battery-sensitive systems. |
| Output clamp voltage | 45–65 V (typ. 53 V) - suppresses inductive kickback from 12 V relay coils without external TVS diodes. |
| Operating supply range | 5.5–26.5 V VPWR - accommodates cold-crank (5.5 V), normal operation (9–16 V), and load-dump transients (up to 26.5 V). |
| Fault reporting interface | Tri-state SO pin with SPI-synchronized status - enables single-wire diagnostic readout of open-load, short-to-battery, and overtemperature events. |
Pinout & Package
MC33291LDW is housed in a 24-pin SOICW (wide-body) package with exposed thermal pad (DW suffix), optimized for automotive thermal cycling and board-level reliability. Pin layout follows standard SOICW footprint (15.4 mm × 7.5 mm, 1.27 mm pitch) with GND pins distributed across both sides for low-inductance grounding and heat spreading.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| OP0–OP7 (Pins 1, 2, 11–14, 23, 24) | Low-side output drains | Direct connection points to load return paths; each drives one inductive/incandescent load to ground. |
| VDD (Pin 16) | Logic supply input | 5 V ±10% CMOS-compatible rail powering internal shift register, SPI logic, and fault comparators. |
| VPWR (Pin 21) | Main power supply input | Battery-connected rail (5.5–26.5 V); supplies gate drive and output stage - not internally regulated. |
| SCLK, SI, SO, CS (Pins 3, 4, 9, 10) | SPI interface signals | Fully compliant 4-wire SPI: CS enables communication, SCLK clocks data, SI receives commands, SO reports faults. |
| RST (Pin 22) | Active-low reset input | Clears SPI shift register and forces all outputs OFF - used for safe power-up or fault recovery sequences. |
| SFPD (Pin 15) | Short-fault protect disable | Grounding disables automatic output shutdown on overcurrent; pulling high enables latched-off behavior per channel. |
| GND (Pins 5–8, 17–20) | Power and signal ground | Eight dedicated GND pins provide low-impedance return path and thermal conduction to PCB copper pour. |
Key Features
| Feature | Design Value |
|---|---|
| Per-output open-load detection | Valid when output is OFF: detects >30–100 μA leakage - identifies broken wiring or disconnected bulbs without external circuitry. |
| Independent thermal shutdown | Turns OFF only the overheating channel (155–180 °C junction), preserving functionality of remaining seven outputs. |
| SPI daisy-chain fault reporting | SO pin propagates fault flags across cascaded devices - reduces MCU GPIO count for multi-chip systems. |
| 53 V output clamp | Integrated clamp activates during inductive turn-off - eliminates need for external 53 V TVS diodes on each load line. |
| Configurable overcurrent response | SFPD pin selects between current-limit mode (SFPD = 5 V) or latch-off shutdown (SFPD = GND) - supports fail-safe vs. limp-home strategies. |
| Automotive temperature grade | Specified from –40 °C to +125 °C ambient - qualified for engine bay, under-hood, and passenger compartment mounting. |
Applications
| Body Control Module (BCM) | Seat Control Unit |
|---|---|
|
Use Scenario: Centralized switching of door locks, interior lighting, window motors, and mirror heaters in modern BCMs. IC Role / Device Role / Timing Role: Low-side driver IC managing up to eight independent 12 V loads via SPI from main MCU, with real-time fault feedback. Use Value: Reduces BOM count by replacing eight discrete MOSFETs + gate drivers + protection components; simplifies layout and improves system-level diagnostics. |
Use Scenario: Controlling seat heater elements, lumbar actuators, and position memory motors in premium automotive seating systems. IC Role / Device Role / Timing Role: Eight-channel load switch providing current-limited, thermally protected drive with open-load detection for heater element integrity checks. Use Value: Enables automatic detection of open heater traces or failed actuators - critical for ASIL-B functional safety compliance without added sensors. |
| Engine Management Auxiliary | Commercial Vehicle Lighting |
|
Use Scenario: Driving auxiliary solenoids (EGR valves, turbo vanes, purge valves) in diesel and gasoline engine control units. IC Role / Device Role / Timing Role: SPI-controlled low-side switch delivering precise timing and current limiting during transient valve actuation cycles. Use Value: Withstands 26.5 V load-dump transients and provides 53 V inductive clamping - eliminates risk of solenoid driver failure during harsh ECU environments. |
Use Scenario: Managing stop/tail/turn signal lamps, marker lights, and fog lamps in trucks, buses, and agricultural equipment. IC Role / Device Role / Timing Role: Robust low-side driver handling incandescent lamp in-rush currents (up to 10× steady-state) while maintaining open-load visibility. Use Value: Built-in current limiting prevents fuse blowing during cold filament surge; open-load detection alerts operator to burnt-out lamps before failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-side SPI switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPIC6B595N | 8-bit shift-register + high-voltage DMOS outputs; no per-channel diagnostics, no open-load detect, no thermal shutdown. | Lacks fault reporting and protection - suitable only for non-safety-critical, low-diagnostic overhead applications. | Choose TPIC6B595N only if cost is primary and diagnostics are handled externally; not drop-in compatible due to missing SFPD, RST, and SO fault signaling. |
| STSPIN250 | Single-channel 1.8 A low-side driver with SPI register; no multi-output integration, no open-load detection, no 53 V clamp. | Requires eight separate ICs and external logic for equivalent functionality - increases PCB area and component count. | STSPIN250 suits designs needing higher per-channel current (1.8 A) but cannot replace MC33291LDW's integrated 8-channel architecture or automotive protection set. |
Compared with TPIC6B595N and STSPIN250, MC33291LDW uniquely combines eight independent protected channels, SPI-based diagnostics, and automotive-grade transient robustness in a single SOICW package - making it irreplaceable for space-constrained, safety-aware vehicle body electronics.
Availability
MC33291LDW is available at Aetrix Electronics and suitable for automotive body control modules, seat control units, engine management auxiliary circuits, and commercial vehicle lighting systems requiring stable component supply across extended temperature and voltage ranges.
Supply support for MC33291LDW 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
NXP Semiconductors is a global semiconductor leader focused on automotive, industrial, and IoT applications, with deep expertise in high-reliability analog and mixed-signal ICs.
The MC33291LDW belongs to NXP's SMARTMOS automotive power switch family, engineered specifically for intelligent, protected low-side load control in harsh automotive electrical environments - emphasizing diagnostics, thermal resilience, and SPI scalability.
FAQ
What is the maximum continuous current per channel for MC33291LDW?
The MC33291LDW supports 500 mA continuous current per output under specified thermal conditions (TA ≤ 125 °C). This rating assumes proper PCB copper pour and thermal vias to manage junction temperature. At higher ambient temperatures or reduced heatsinking, derating applies per the RθJA = 68 °C/W specification. Peak current capability remains 1.0 A for short durations.
Does MC33291LDW require an external charge pump for gate drive?
No, MC33291LDW does not require an external charge pump. Its DMOS output transistors are logic-level compatible and fully enhanced with VDD (5 V) alone - enabling direct drive from standard microcontroller I/O without additional voltage boosting circuitry.
How does MC33291LDW report open-load faults?
MC33291LDW reports open-load faults on the SO pin only when the affected output is commanded OFF and draws less than 30–100 μA. The fault is serialized into the SPI shift register and appears on SO during the next CS low-to-high transition - allowing the MCU to identify which specific channel (OP0–OP7) has an open circuit.
Can MC33291LDW be used outside automotive applications?
Yes, MC33291LDW is widely deployed in industrial controls, telecom power management, and commercial lighting where robust 12 V load switching, SPI scalability, and built-in protection are valued. Its -40 °C to +125 °C rating and 5.5–26.5 V VPWR range make it suitable for demanding non-automotive environments - though automotive qualification remains its primary design basis.
What is the function of the SFPD pin on MC33291LDW?
The SFPD (Short Fault Protect Disable) pin on MC33291LDW determines overcurrent response behavior: when pulled to GND, an overcurrent event causes immediate latched shutdown of the affected output; when pulled to 5 V, the output enters current-limit mode instead, allowing continued operation unless thermal limits are exceeded. This enables flexible fail-operational or fail-safe system design.
MC33291LDW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Obsolete
- Switch Type:
- General Purpose
- Number of Outputs:
- 8
- Ratio - Input:Output:
- 1:8
- Output Configuration:
- Low Side
- Output Type:
- N-Channel
- Interface:
- SPI
- Voltage - Load:
- 9V ~ 26.5V
- Voltage - Supply (Vcc/Vdd):
- 2.5V ~ 3.5V
- Current - Output (Max):
- 500mA
- Rds On (Typ):
- 550mOhm
- Input Type:
- -
- Features:
- -
- Fault Protection:
- Current Limiting (Fixed), Open Load Detect, Over Temperature, Over Voltage
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
MC33291LDW FAQ
1.How can I place an order for MC33291LDW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33291LDW on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC33291LDW reliable?
The price and inventory of MC33291LDW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33291LDW is usually 5 days.
3.What payment methods are accepted for MC33291LDW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33291LDW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33291LDW?
MC33291LDW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33291LDW order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC33291LDW?
For technical support, including MC33291LDW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33291LDW requirements.
6.How does Aetrix verify that MC33291LDW is sourced from the original manufacturer or authorized distributors?
All MC33291LDW products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC33291LDW meets industry standards.
7.What is the process for return or replacement of MC33291LDW?
All MC33291LDW units undergo pre-shipment inspection (PSI). If there is an issue with MC33291LDW, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC33291LDW part is unused and in its original packaging.
Return procedure for MC33291LDW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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