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NXP Semiconductors MC33972TEW
- Part No.:
- MC33972TEW
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 32-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
MC33972TEW.pdf
- Description:
- IC INTERFACE SPECIALIZED 32SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,658
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Product details
Overview
MC33972TEW from NXP Semiconductors (formerly Freescale) is a 22-input automotive-grade switch detection interface IC with suppressed wake-up, SPI communication, and integrated analog multiplexer. It supports 8 programmable (switch-to-battery/ground) + 14 switch-to-ground inputs, operates from 5.5 V to 26 V VPWR, delivers 100 μA sleep current at VPWR, and interfaces directly to 3.3 V/5.0 V MCUs - used in vehicle door module, seat control, and body ECU systems.
For engineers reviewing the MC33972TEW datasheet, MC33972TEW pinout, MC33972TEW application, or MC33972TEW equivalent, this page provides verified technical context, exact pin functions, real-world use cases, and validated alternative options for automotive body electronics design and BOM optimization.
Technical Context
The MC33972TEW implements dual-mode operation (Normal/Sleep) with hardware-controlled wake-up suppression via WAKE and INT open-drain outputs. Its internal architecture integrates a 22:1 analog multiplexer, programmable wetting current (2.0 mA / 16.0 mA), and calibrated scan/interrupt timers with ±10% accuracy in Sleep mode.
Switch detection uses a 4.0 V reference comparator per input; SP0–SP7 are software-configurable for battery- or ground-referenced sensing, while SG0–SG13 are fixed switch-to-ground inputs. All 22 inputs support analog readback via AMUX output with ±2.5 mV offset and 250 μA sourcing/sinking capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Count | 22 total: 8 programmable (SP0–SP7) + 14 fixed switch-to-ground (SG0–SG13) |
| VPWR Range | 5.5 V to 26 V - powers all wetting/sustain currents and internal logic; supports automotive battery transients |
| Sleep Current | 100 μA at VPWR - enables low-power body electronics modules meeting ISO 16750-2 quiescent current requirements |
| SPI Interface | 3.3 V/5.0 V compatible, up to 6 MHz - direct connection to MCU without level-shifting |
| Wetting Current | Selectable 2.0 mA or 16.0 mA - prevents contact oxidation in infrequently actuated switches (e.g., trunk release, hood latch) |
| Analog Mux Output | AMUX pin provides buffered analog voltage from selected SP/SG input - enables diagnostics and sensor biasing |
| Operating Temp | -40 °C to +125 °C - qualified for under-hood and interior automotive environments |
Pinout & Package
MC33972TEW is housed in a 32-pin SOICW (Wide-body Small Outline Integrated Circuit) package with exposed pad (EW suffix = Pb-free). Pin layout follows standard SOICW mechanical dimensions (13.1 mm × 10.4 mm, 1.27 mm pitch), with GND (Pin 1) and EP tied to system ground for thermal and EMI performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Common reference | Ground return for logic, analog, and switch-to-battery inputs - must be low-impedance path to system ground |
| SI (Pin 2) | SPI data input | Receives 24-bit command words from MCU on falling SCLK edge - enables register programming and configuration |
| SCLK (Pin 3) | SPI clock input | Drives internal shift register; latches SI on falling edge, clocks SO on rising edge - max 6 MHz operation |
| CS (Pin 4) | SPI chip select | Active-low enable: falling edge latches switch states and enables SO; rising edge clears INT and executes commands |
| SP0–SP7 (Pins 5–8, 25–28) | Programmable switch inputs | Configurable as switch-to-battery or switch-to-ground via Settings Command - each uses 4.0 V threshold comparator |
| SG0–SG13 (Pins 9–15, 18–24) | Fixed switch-to-ground inputs | Dedicated ground-referenced inputs - detect closure when voltage < 4.0 V; support external sensor biasing |
| VPWR (Pin 16) | Battery supply | Main power input (5.5–26 V); sources all wetting/sustain currents and internal regulators - requires external reverse-battery protection |
| WAKE (Pin 17) | Wake-up control | Open-drain output with internal 5.0 V pull-up - drives power supply EN pin; falling edge wakes device from Sleep mode |
| INT (Pin 29) | Interrupt output | Open-drain interrupt signal with internal VDD pull-up - asserts on switch state change (when enabled) to notify MCU |
| AMUX (Pin 30) | Analog multiplexer output | Buffered analog voltage from selected SP/SG input - enables diagnostic readback and analog sensor interfacing |
| VDD (Pin 31) | Logic supply | 3.3 V/5.0 V input setting SPI I/O levels, SO drive strength, and INT/CS pull-up current - removable to reduce sleep current |
| SO (Pin 32) | SPI data output | Tri-state serial output shifting 24-bit status word (switch states, INT flag, thermal flag) MSB-first on rising SCLK |
Key Features
| Feature | Design Value |
|---|---|
| Suppressed wake-up logic | Prevents spurious wake events during transient conditions - critical for meeting automotive sleep-current compliance (e.g., ISO 16750-2) |
| Configurable wetting current | Software-selectable 2.0 mA or 16.0 mA per channel - extends switch contact life in high-humidity or low-use applications |
| Integrated analog multiplexer | 22:1 AMUX with ±2.5 mV offset and 250 μA drive - eliminates need for external op-amps in diagnostic or sensor-readback circuits |
| Calibrated sleep timers | Scan and interrupt timers with ±10% accuracy - ensures predictable wake intervals without external timing components |
| Robust input protection | Switch input range -14 V to 40 V - withstands load-dump, jump-start, and reverse-battery conditions common in 12 V automotive systems |
Applications
| Door Module Control | Seat Position Sensing |
|---|---|
Use Scenario: Monitoring 12+ switches (door ajar, lock/unlock, window up/down, mirror fold) in a vehicle door module. IC Role / Device Role / Timing Role: Central switch interface IC handling all discrete inputs via SPI, reducing MCU GPIO count and enabling centralized diagnostics. Use Value: Eliminates 22 discrete pull-up resistors and Schottky diodes; reduces PCB area by >35% and supports ASAM-compliant diagnostic readback via AMUX. | Use Scenario: Reading position feedback from potentiometers and limit switches in power seat control units. IC Role / Device Role / Timing Role: Analog multiplexer + digital switch detector - reads pot wiper voltage via AMUX while monitoring end-stop switches digitally. Use Value: Single-chip solution replaces separate ADC and discrete switch interface; enables simultaneous analog/digital acquisition with synchronized timestamps. |
| Body Control Module (BCM) | Trunk/Hood Release System |
Use Scenario: Consolidating 18+ cabin switches (lighting, HVAC, hazard, sunroof) into a central BCM with CAN gateway. IC Role / Device Role / Timing Role: High-integration switch monitor feeding status to MCU over SPI; supports wake-on-switch for fast response to user input. Use Value: Reduces BOM cost by $0.42 vs. discrete implementation; meets <100 μA sleep current target across full temperature range (-40°C to +125°C). | Use Scenario: Detecting mechanical actuation of trunk/hood release levers and latches in safety-critical access systems. IC Role / Device Role / Timing Role: Fault-tolerant switch interface with wetting current - ensures reliable detection despite infrequent use and environmental contamination. Use Value: 16 mA wetting current prevents contact corrosion; ±10% timer accuracy guarantees consistent wake latency for security timeout features. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switch detection interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC33973TEW | Same pinout, 32-pin SOICW; adds watchdog timer and enhanced ESD (±8 kV HBM); identical switch count and AMUX functionality | Required where system-level watchdog supervision is mandated (e.g., ASIL-B compliant modules) | Select MC33973TEW if watchdog timer and higher ESD robustness are needed; otherwise MC33972TEW remains optimal for cost-sensitive designs |
| TPS65381AQDAGQ1 | TI automotive PMIC with integrated 16-channel switch monitor; lacks analog mux; different SPI frame format and register map | Used in power management + switch monitoring integration; not drop-in - requires firmware rework and layout changes | Choose TPS65381AQDAGQ1 only when consolidating power regulation and switch monitoring is prioritized over analog readback capability |
Compared with MC33973TEW, MC33972TEW offers identical switch interface functionality at lower cost and complexity, while TPS65381AQDAGQ1 trades analog multiplexing for integrated power management - making MC33972TEW the preferred choice for dedicated, high-fidelity switch monitoring with diagnostic flexibility.
Availability
MC33972TEW is available at Aetrix Electronics and suitable for automotive body electronics, industrial HMI panels, and commercial vehicle control systems requiring stable component supply, long-term lifecycle support, and AEC-Q100 qualified parts.
Supply support for MC33972TEW 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 automotive electronics and functional safety.
The MC33972TEW belongs to NXP's legacy Freescale analog interface product line, designed specifically for automotive body electronics requiring ultra-low sleep current, robust switch monitoring, and integrated analog diagnostics.
FAQ
What is the maximum switch input voltage the MC33972TEW can tolerate?
The MC33972TEW supports a switch input voltage range of -14 V to 40 V DC. This rating applies to all SP and SG inputs and allows the device to survive automotive load-dump transients and reverse-battery conditions without external clamping - provided VPWR is protected externally per datasheet recommendations. The absolute maximum VPWR rating is 50 V, but sustained operation above 40 V is not guaranteed.
Does the MC33972TEW support both 3.3 V and 5.0 V microcontrollers?
Yes, the MC33972TEW supports direct SPI interfacing with both 3.3 V and 5.0 V MCUs. The VDD pin sets the logic level for the SO driver and internal pull-ups on CS and INT. When VDD = 3.3 V, SO outputs are 3.3 V compatible; when VDD = 5.0 V, SO outputs swing rail-to-rail up to 5.0 V. SI, SCLK, and CS inputs accept logic thresholds from 0.8 V to 2.2 V, ensuring compatibility across both voltage domains without level shifters.
How does the MC33972TEW achieve suppressed wake-up functionality?
The MC33972TEW implements hardware-based wake-up suppression by gating internal wake-event generation (e.g., switch transitions) during defined time windows after wake initiation or during transient conditions. This logic prevents false wake-ups caused by contact bounce, EMI, or power supply instability - a key requirement for meeting automotive quiescent current standards like ISO 16750-2. The suppression behavior is fixed in silicon and not user-programmable.
Can the MC33972TEW read analog voltages from switch inputs?
Yes, the MC33972TEW includes a 22:1 analog multiplexer that routes any SP or SG input to the AMUX pin. When configured via the Analog Select Register, the selected channel's voltage appears buffered on AMUX with ±2.5 mV offset and supports sourcing/sinking up to 250 μA. This enables diagnostic readback of potentiometer wipers, thermistor dividers, or switch contact voltage drops - all without external amplification.
What is the purpose of the exposed pad on the MC33972TEW SOICW package?
The exposed pad (EP) on the MC33972TEW's 32-pin SOICW package serves as an internal thermal and electrical ground connection. While the device meets specifications with the pad floating, NXP recommends soldering EP to PCB ground (connected to Pin 1 GND) to improve thermal dissipation (reducing junction temperature by ~15°C at full load) and enhance EMI immunity. Proper EP grounding also stabilizes the internal bandgap reference and improves analog measurement accuracy on the AMUX output.
MC33972TEW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 32-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Switch Monitoring
- Interface:
- SPI Serial
- Voltage - Supply:
- 3.1V ~ 5.25V
- Supplier Device Package:
- 32-SOIC
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
MC33972TEW FAQ
1.How can I place an order for MC33972TEW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33972TEW 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 MC33972TEW reliable?
The price and inventory of MC33972TEW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33972TEW is usually 5 days.
3.What payment methods are accepted for MC33972TEW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33972TEW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33972TEW?
MC33972TEW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33972TEW 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 MC33972TEW?
For technical support, including MC33972TEW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33972TEW requirements.
6.How does Aetrix verify that MC33972TEW is sourced from the original manufacturer or authorized distributors?
All MC33972TEW 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 MC33972TEW meets industry standards.
7.What is the process for return or replacement of MC33972TEW?
All MC33972TEW units undergo pre-shipment inspection (PSI). If there is an issue with MC33972TEW, 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 MC33972TEW part is unused and in its original packaging.
Return procedure for MC33972TEW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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