PCA9703PW/Q900 - 16-bit SPI GPI, 18V Tolerant | NXP
MPN: PCA9703PW/Q900 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.49 | $3.49 |
| 10 | $3.14 | $31.40 |
| 100 | $2.91 | $291.00 |
| 500 | $2.62 | $1,310.00 |
| 1,000 | $2.41 | $2,410.00 |
PCA9703PW/Q900 Overview
A GPI (General Purpose Input) shift register is a type of input-only I/O expander within the broader hierarchy of interface ICs -> I/O expanders -> parallel-in serial-out shift registers. Unlike I2C GPIO expanders, SPI GPI shift registers stream input states to a microcontroller as a serial bit field, which minimizes pin count on the host MCU and gives deterministic, fast read-back of many switch contacts.
Key features include 16 input-only channels tolerant to 18 V regardless of the device supply, a maskable INT output that flags any change of input state, a 3 V input switching threshold for robust noise immunity, and SPI compatibility up to 5 MHz. The Q900 suffix and /Q900,118 ordering code identify the automotive AEC-Q100 compliant variant with extended -40 C to +125 C operation; NXP states that PCA9703PW/Q900 is AEC-Q100 compliant and PPAP documentation is available via i2c.support@nxp.com.
Technically, the PCA9703 samples its 16 GPI inputs into an internal shift register and shifts data out on MISO under host control of CS and SPI clock. Any input change (open, closed, or 12 V/24 V level via divider) triggers the interrupt output, which can be masked to prevent nuisance CPU wake-ups. The low-power CMOS process keeps static consumption minimal, which is critical for always-on battery-backed switch monitoring.
Typical applications include automotive switch monitoring (door, window, seat, and steering-column switches), industrial control panels and limit-switch monitoring, and 12 V/24 V system status sensing where contacts ride on battery-level rails the chip inputs directly tolerate.
A key design consideration is input threshold scaling: although inputs tolerate 18 V, the 3 V threshold means designers must confirm logic levels and switch pull-up arrangements so that a valid LOW is below threshold and a valid HIGH is safely above it across temperature.
This page synthesizes distributor pricing, lifecycle status, drop-in alternative analysis, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PCA9703PW/Q900 — 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 PCA9703PW/Q900 (same form factor and footprint) — differing in Function, Interrupt Output, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PCA9703PW,118
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PCA9675PW,118
✅ Drop-In✓ In Stock
$1.49 / Unit
View Datasheet →PCA9703PW/Q900 Specifications
| Function | 16-bit SPI GPI shift register with maskable interrupt |
| Number of Input Channels | 16 (input only) |
| Interface Type | SPI serial |
| Maximum SPI Clock Frequency | 5 MHz |
| Input Voltage Tolerance | 18 V |
| Input Switching Threshold | 3 V |
| Operating Temperature Range | -40 C to +125 C |
| Package | 24-TSSOP (PW) |
| Mounting Type | Surface Mount |
| Interrupt Output | Yes (maskable INT) |
| AEC-Q100 Status | Compliant (Q900 variant, PPAP available via NXP i2c.support) |
| Power Consumption | Low power (CMOS) |
| Application Focus | Switch status monitoring |
PCA9703PW/Q900 24-tssop (pw) Pin Configuration Guide
Pin configuration for PCA9703PW/Q900 (24-tssop (pw) package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for PCA9703PW/Q900.
Refer to the datasheet for full pin configuration.
Typical Applications
PCA9703PW/Q900 is suitable for 6 applications: Automotive Switch Monitoring, Industrial Control Panels, 12 V / 24 V System Status Sensing, Building Access and Security Panels, Appliance and White-Goods Control, Test and Measurement Fixtures.
Automotive Switch Monitoring
The PCA9703PW/Q900 is purpose-built for automotive switch status monitoring, where door, window, seat, and steering-column switches ride on 12 V battery rails. Its 18 V tolerant inputs connect directly to these switch networks without external level shifting, while the 3 V threshold guarantees clean state detection against automotive transients. The Q900 variant is AEC-Q100 compliant with PPAP support available from NXP, satisfying OEM qualification requirements for -40 C to +125 C cabin and under-hood environments. The maskable INT output lets the body controller wake only on an actual switch change, cutting quiescent power in always-on systems. A single 5 MHz SPI read returns all 16 switch states in microseconds, replacing dozens of MCU GPIO lines.
Recommended
Industrial Control Panels
In industrial control panels and machine interfaces, the PCA9703 consolidates 16 limit-switch, selector-switch, and pushbutton inputs into one SPI-readable register. Its 18 V input tolerance allows direct monitoring of 24 V-adjacent control circuits via simple dividers or of 12 V panel rails directly, and the 3 V threshold provides noise margin in electrically noisy factory environments. Because the part is input-only with low CMOS power draw, it suits always-on monitoring in panels where thermal budget is limited. The maskable interrupt enables event-driven polling so the PLC or panel controller is interrupted only when an operator actuates a switch, improving scan latency and reducing bus traffic on shared SPI backplanes.
Recommended
12 V / 24 V System Status Sensing
System status sensing - battery-present flags, fuse-blown indicators, contactor aux contacts, door-interlock switches - benefits from the PCA9703's direct 18 V tolerant inputs. Status contacts that sit at vehicle or cabinet battery potential can be wired to the GPI pins through pull-ups without discrete translation stages, reducing component count and failure points. The 3 V switching threshold, per the NXP datasheet, gives a defined logic boundary when sensing switch-closed-to-ground topologies. In 24 V systems, inputs still tolerate transients up to 18 V on lower-rail sensing points; designers should verify the divider arrangement against the absolute maximum ratings. The INT pin chains naturally into multi-chip daisy schemes for more than 16 monitored points.
Recommended
Building Access and Security Panels
Access-control and alarm panels must monitor many reed switches, tamper loops, and keypad contacts simultaneously and reliably. The PCA9703 provides 16 input channels with interrupt-driven change notification, so the panel processor can sleep between events while the GPI device watches the loops. The 18 V input tolerance accommodates supervised loop circuits powered from 12 V standby batteries, and the 3 V threshold supports classic end-of-line resistor supervision schemes where the sensed voltage distinguishes normal, alarm, and tamper states. AEC-Q100 temperature rating (-40 C to +125 C) ensures outdoor reader and gate hardware survives harsh environments, while the SPI port at 5 MHz keeps loop-scan time negligible even with cascaded devices.
Recommended
Appliance and White-Goods Control
Modern appliances monitor door switches, water-level floats, lid interlocks, and mode selectors across many channels. The PCA9703 gathers up to 16 such contacts into a single SPI port read, freeing scarce MCU GPIO on cost-optimized appliance controllers. Its 18 V tolerance matches mains-derived low-voltage sensing rails, and the input-only architecture avoids contention when switches toggle unpredictably. The maskable INT output lets the main controller ignore switch activity during sensitive operations (for example, during a wash cycle) and then unmask for user-input handling, a pattern documented in the datasheet's application section. Low CMOS quiescent consumption supports always-plugged appliances where standby power regulations are strict.
Recommended
Test and Measurement Fixtures
Production test fixtures and automated test equipment frequently need to read dozens of limit switches, probe-present flags, and fixture interlocks. The PCA9703 converts 16 such discrete signals into one SPI-accessible word, and multiple devices can share an SPI bus with individual CS lines or be chained for wider input words. Its 18 V tolerant inputs interface directly with fixture wiring that may carry 12 V sensing levels, and the 3 V threshold delivers repeatable digital transitions needed for reliable pass/fail decisions. The AEC-Q100 -40 C to +125 C range provides comfortable margin against fixture thermal cycling, and the maskable interrupt supports event-driven logging of fixture faults between test cycles without continuous polling of the SPI bus.
Recommended
Recommended Products Summary
Engineering reference data for PCA9703PW/Q900 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9703PW,118 | PCA9675PW |
|---|---|---|---|
| Package | 24-TSSOP (PW) | 24-TSSOP (PW) - same | 24-TSSOP (PW) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Number of I/O Bits | 16 (input only) | 16 (input only) | 16 (quasi-bidirectional) |
| Interface | SPI up to 5 MHz | SPI up to 5 MHz | I2C (Fast-mode Plus) |
| Interrupt Output | Yes (maskable INT) | Yes (maskable INT) | Yes (INT) |
Key Differentiators
- 18 V tolerant inputs eliminate level-shifting circuitry (vs PCA9675PW)
- SPI interface enables fast, deterministic 16-bit reads (vs PCA9675PW)
- Automotive AEC-Q100 qualification with PPAP support (vs PCA9703PW,118)
Design Notes
Keep SPI traces (SCLK, MISO, CS) short and route them away from the high-voltage switch wiring feeding the GPI pins. Because the part is intended to sit near switch harnesses that carry 12 V rails and inductive kick transients, series resistors on GPI inputs (typically a few kOhms, per the datasheet's input structure) plus local TVS protection on the harness side help clamp ringing. The 3 V threshold gives about 1.5 V of noise margin over a solid ground-closed level at 3.3 V logic, but long unshielded switch runs can couple more than that, so verify thresholds on real harnesses.
Do not confuse the PCA9703 (SPI, input-only, 18 V tolerant) with same-package NXP parts such as the PCA9675 (I2C bidirectional I/O) or PCA9548A (I2C switch); all share TSSOP-24 footprints but are electrically incompatible. Also confirm that you are ordering the correct grade: the /Q900,118 code is the AEC-Q100 automotive variant (PPAP via i2c.support@nxp.com), while standard-grade suffixes are not PPAP-qualified. Switch bounce will toggle INT repeatedly - either mask INT during debouncing windows or debounce in firmware after each SPI read.
Estimated: with a low-power CMOS GPI shift register, system standby current is dominated by the input pull-up network, not the IC. For 16 inputs pulled up to 12 V through, for example, 10 kOhm resistors, closed-switch current is 1.2 mA per channel (12 mA worst case all-closed) - significant for battery-backed nodes. Use higher-value pull-ups (with attention to leakage and threshold margin against the 3 V limit) or duty-cycle the pull-up rail if the platform requires sub-milliamp standby. Verify actual ICC from the datasheet table for your exact VDD.
Compliance Information
NXP datasheet states: 'PCA9703PW/Q900 is AEC-Q100 compliant. Contact i2c.support@nxp.com for PPAP.' RoHS/REACH/lead-free status should be confirmed on the NXP product page environmental section.
