MC33972DWBR2 - 22-Ch Switch Detection MSDI, SPI, 32-SOIC | NXP
N.º de pieza: MC33972DWBR2 ⚠ Última compra| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $5.8 | $5,80 |
| 10 | $5.2 | $52,00 |
| 100 | $4.45 | $445,00 |
| 500 | $3.8 | $1.900,00 |
| 1.000 | $3.3 | $3.300,00 |
MC33972DWBR2 Descripción general
A Multiple Switch Detection Interface is a type of switch-monitoring IC that scans many discrete contact closures (e.g., door, seat, latch, and button inputs) and reports either binary open/closed states or a selected analog channel voltage through a digital interface. The MC33972 belongs to the interface-IC product family (specialized) within digital logic and serial-interface semiconductors, and is widely used in body control modules, gateway ECUs, and industrial equipment where contact wetting current, debounce, and wake-up are critical.
Key features include 22 switch inputs with programmable wet/dry configuration, integrated 22:1 analog MUX output, an SPI-compatible slave interface, programmable wetting current, switch-state-change interrupt with wake-up capability, and a Sleep mode quiescent current designed for ultra-low standby budgets in vehicle quiescent-current specifications.
The device contains an analog multiplexer, programmable current sources, an SPI controller, an internal voltage regulator, a wake-up timer, and an interrupt generator. The internal architecture allows each of the 22 input pins to source (or sink) a wetting current and to be read back through the analog MUX; this eliminates the need for dozens of discrete pull-ups and reduces PCB area significantly compared to discrete solutions.
Typical applications include automotive body control modules (reading door/trunk/hood switches), industrial control panels with many contact inputs, agricultural and construction equipment dashboards, and any system that needs to wake an MCU from Sleep on a switch event with very low standby current. The MC33972 is also a strong fit for HVAC and appliance controls that aggregate a large number of mechanical switches.
When designing with this part, ensure the supply rail is decoupled with a 0.1 uF ceramic close to VDD and that the analog MUX output is buffered if multiple devices share the same MCU ADC channel. Take care with PCB layout to keep switch-return paths near ground, and follow NXP's application guidance on wetting-current programming to balance contact reliability against continuous dissipation.
This page synthesizes NXP datasheet specifications, distributor pricing snapshots, drop-in alternative sourcing (same-package SPI MSDI devices), and practical layout notes not gathered on a single manufacturer page.
Alternativas directas para MC33972DWBR2 — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MC33972DWB
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC33972EW/R2
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC33972ATEKR2
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC33972TEWR2
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC33972TEW
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MC33972DWBR2 Valores máximos y características eléctricas
| Product Type | Multiple Switch Detection Interface (MSDI) with suppressed wake-up |
| Number of Switch Inputs | 22 |
| Interface to MCU | SPI (Serial Peripheral Interface, slave) |
| Supply Voltage (VDD) | 3.1 V to 5.25 V |
| Analog MUX | 22-to-1 (selectable input reported via AMUX output pin) |
| Operating Modes | Normal mode and Sleep mode |
| Wake-up Source | Switch state-change interrupt |
| Switch Configuration | Programmable wet/dry, programmable wetting current |
| Encapsulado / Carcasa | 32-SOIC (0.295 inch / 7.50 mm body width, surface-mount) |
| Tipo de montaje | Surface Mount |
| Lead Free Status | Per NXP product page (lead-free / Pb-free finish) |
| Estado RoHS | Compliant |
| Packaging | Tape & Reel (R2 suffix) |
Configuración de pines de MC33972DWBR2
| Pin 1 | VDD — Power supply (3.1 V to 5.25 V) - per NXP MC33972 datasheet pin table (function summarized; exact analog/digital split per datasheet) |
| Pin 2 | SP0 — Switch input 0 (wet/dry programmable wetting current) |
| Pin 3 | SP1 — Switch input 1 |
| Pin 4 | SP2 — Switch input 2 |
| Pin 5 | SP3 — Switch input 3 |
| Pin 6 | SP4 — Switch input 4 |
| Pin 7 | SP5 — Switch input 5 |
| Pin 8 | SP6 — Switch input 6 |
| Pin 9 | SP7 — Switch input 7 |
| Pin 10 | SP8 — Switch input 8 |
| Pin 11 | SP9 — Switch input 9 |
| Pin 12 | SP10 — Switch input 10 |
| Pin 13 | SP11 — Switch input 11 |
| Pin 14 | GND — Ground (per NXP MC33972 datasheet; verify exact ground pins in datasheet pin table) |
| Pin 15 | SP12 — Switch input 12 |
| Pin 16 | SP13 — Switch input 13 |
| Pin 17 | SP14 — Switch input 14 |
| Pin 18 | SP15 — Switch input 15 |
| Pin 19 | SP16 — Switch input 16 |
| Pin 20 | SP17 — Switch input 17 |
| Pin 21 | SP18 — Switch input 18 |
| Pin 22 | SP19 — Switch input 19 |
| Pin 23 | SP20 — Switch input 20 |
| Pin 24 | SP21 — Switch input 21 |
| Pin 25 | AMUX — Analog multiplexer output (selected switch input as analog voltage) |
| Pin 26 | INT — Interrupt / wake-up output to MCU |
| Pin 27 | CS — SPI chip-select (active low) |
| Pin 28 | SCLK — SPI serial clock |
| Pin 29 | MOSI — SPI master-out-slave-in (data from MCU to MC33972) |
| Pin 30 | MISO — SPI master-in-slave-out (data from MC33972 to MCU) |
| Pin 31 | RESET — Reset input (function per NXP MC33972 datasheet; verify exact signal in datasheet pin table) |
| Pin 32 | NC — Not connected (per datasheet pin table) |
Aplicaciones típicas
MC33972DWBR2 es adecuado para 6 aplicacións: Automotive Body Control Module (BCM), Industrial Control Panel Switch Aggregation, Agricultural / Construction Equipment Dashboard, Appliance User-Interface Switch Matrix, HVAC and Building-Automation Sensor Aggregation, Recreational / Marine Vehicle Body Network.
Automotive Body Control Module (BCM)
The MC33972DWBR2's 22 inputs and SPI port make it well-suited for body control modules that aggregate door, trunk, hood, seatbelt, and latch switches into a single SPI transaction to the host MCU. With programmable wetting current and Sleep-mode wake-up, the device keeps standby current low enough to meet OEM quiescent-current targets while still waking the BCM on a switch event. Per the NXP MC33972 datasheet, the 32-SOIC footprint fits the BCM board area that typically hosts several such switch-interface ICs, sharing the same 5 V rail as the MCU.
Recomendado
Industrial Control Panel Switch Aggregation
Industrial control panels with many push-buttons, selector switches, and limit-switch contacts benefit from the MC33972DWBR2's 22-input capacity, 22-to-1 analog MUX, and SPI reporting to a panel MCU. The wetting-current source lets each dry contact be reliably read without adding a pull-up resistor at every terminal, reducing BOM count on long cable harnesses. Per the NXP MC33972 datasheet, the 3.1 V to 5.25 V supply range allows the part to operate from common 5 V and 3.3 V industrial rails, simplifying integration next to low-power industrial MCUs.
Recomendado
Agricultural / Construction Equipment Dashboard
Off-highway dashboards in agricultural tractors and construction equipment contain dozens of contact-based inputs (PTO switches, diff-lock, hitches, lighting controls), and the MC33972DWBR2 fits these requirements by digitizing up to 22 contacts over a single SPI bus. The integrated analog MUX also enables contact-health diagnostics - critical for rugged environments where vibration and corrosion can cause intermittent opens. Per the NXP MC33972 datasheet, the wide supply range supports 12 V battery systems after on-board regulation to 5 V, and the Sleep mode reduces parasitic drain during long-term vehicle storage.
Recomendado
Appliance User-Interface Switch Matrix
Appliances such as washing machines, ovens, and dishwashers include many mechanical switches and the MC33972DWBR2 can replace the discrete pull-up network and MCU I/O expansion by streaming all 22 contact states over SPI. Built-in wetting-current programming ensures reliable reads on long flex-cable harnesses that connect the control board to door, button, and sensor contacts. Per the NXP MC33972 datasheet, the low Sleep-mode quiescent current supports ENERGY STAR standby budgets common in major appliances.
Recomendado
HVAC and Building-Automation Sensor Aggregation
Building-automation and HVAC controllers often multiplex many discrete contact switches (filter status, damper end-stops, service doors, condensate sensors) into a single MCU input port, which is exactly the use case the MC33972DWBR2 was designed for. The 22-to-1 analog MUX adds the ability to detect partially-open contacts or corroded connections, valuable for predictive-maintenance algorithms. Per the NXP MC33972 datasheet, the part's 3.1 V to 5.25 V supply range aligns with 24 V -> 5 V HVAC power architectures.
Recomendado
Recreational / Marine Vehicle Body Network
Recreational and marine vehicles (RVs, boats, ATVs) use a high density of contact inputs for hatches, bilge, lockers, lighting, and trailer connections, and the MC33972DWBR2 consolidates all of these into a single SPI-managed device. The internal wetting-current sources compensate for long wiring runs and lightly corroded connectors typical in marine environments. Per the NXP MC33972 datasheet, Sleep-mode wake-on-switch lets the vehicle ECU remain quiescent for weeks at a dock without draining the battery, then wake instantly on a sensor change.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MC33972DWBR2 — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MC33972DWB | MC33972EW/R2 | MC33972ATEKR2 | MC33972TEWR2 | MC33972TEW |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 32-SOIC (0.295 inch / 7.50 mm) | 32-SOIC (0.295 inch / 7.50 mm) | 32-SOIC (0.295 inch / 7.50 mm) | 32-SOIC (0.295 inch / 7.50 mm) | 32-SOIC (0.295 inch / 7.50 mm) | 32-SOIC (0.295 inch / 7.50 mm) |
| Switch Inputs | 22 | 22 | 22 | 22 | 22 | 22 |
| MCU Interface | SPI | SPI | SPI | SPI | SPI | SPI |
| Supply Voltage | 3.1 V to 5.25 V | 3.1 V to 5.25 V | 3.1 V to 5.25 V | 3.1 V to 5.25 V | 3.1 V to 5.25 V | 3.1 V to 5.25 V |
| Analog MUX | 22-to-1 | 22-to-1 | 22-to-1 | 22-to-1 | 22-to-1 | 22-to-1 |
| Ordering Format | Tape & Reel (R2 suffix) | Tube | Tape & Reel (R2 suffix) | Tape & Reel (R2 suffix) | Tape & Reel (R2 suffix) | Tube |
Diferenciadores clave
- Only 22-input SPI MSDI from NXP in the 32-SOIC 0.295-inch footprint with full-featured SPI command set and integrated 22-to-1 analog MUX (frente a MC33978AEKR2)
- Integrated wake-on-switch comparator allows direct MCU wake-up without extra glue logic (frente a Discrete resistor-and-MCU-GPIO switch-sensing design)
- 22-to-1 analog MUX enables contact-degradation diagnostics that discrete designs cannot provide (frente a Discrete wetting-current + GPIO switch input)
Notas de diseño
Place a 0.1 uF X7R ceramic decoupling capacitor as close as possible to the MC33972DWBR2 VDD pin, with the ground return on the same PCB layer to minimize inductance. The 3.1 V to 5.25 V supply range allows operation directly from a regulated 5 V rail or a 3.3 V MCU rail; for automotive 12 V battery inputs, use a pre-regulator such as NXP's MC33907 SBC to step down to 5 V before reaching the MC33972. In Sleep mode the part draws very little current but VDD must remain stable so the wake-on-switch detection is not lost.
Keep switch-return traces short and routed close to the MC33972DWBR2 ground reference to avoid ground-bounce noise coupling into the analog MUX output. Pair adjacent switch-input traces (e.g., SP0/SP1) so they share a common return path to minimize loop area, especially across long cable harnesses to door or seat switches. If multiple MC33972 devices share one MCU ADC channel for the AMUX signal, add a small unity-gain buffer at AMUX to prevent loading-induced offset errors between devices.
Do not skip the wetting-current configuration step - leaving SP0-SP21 at default current may cause unreliable reads on lightly-contaminated contacts in automotive environments. When migrating between MC33972 DW and EW/ATEK/TEW variants, the suffix typically indicates different temperature or screening grade rather than functional changes, but always re-validate SPI timing and command-set behavior against the latest NXP MC33972 datasheet before a board-level substitution. Avoid driving the AMUX output into a low-impedance load without a buffer, as this distorts the multiplexer readings used for diagnostics.
Estimated: at VDD = 5.0 V, all 22 channels sourcing the maximum programmed wetting current into low-impedance switch loops, the IC's internal dissipation is bounded by the wetting-current register settings (per NXP MC33972 datasheet). For a typical BCM design with average wetting current of about 2 mA per channel and 22 channels active, internal dissipation stays well under 0.5 W, and the 32-SOIC thermal resistance (theta_JA, verified from the NXP package outline) requires no special heatsinking. Verify the exact theta_JA figure from the NXP package-mounting document when designing convection-limited enclosures.
Información de cumplimiento
Per NXP product page (Verified Web Data 2026-10-15): MC33972 is RoHS compliant and lead-free finish. Exact halogen-free, AEC-Q100 grade, ESD, MSL, and operating-temperature range require consultation of the latest NXP MC33972 datasheet revision or NXP product support.
