PCA9500D - 8-Bit I/O Expander with EEPROM | NXP
MPN: PCA9500D ✓ Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
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PCA9500D Overview
An I2C I/O expander is a bus-interface peripheral that converts serial commands from a controller into parallel digital states. In the broader hierarchy, it belongs to interface ICs, digital I/O control, and general-purpose bus peripherals. The PCA9500D combines an 8-bit quasi-bidirectional port with nonvolatile storage, allowing configuration or board-identification data to be retained between power cycles.
The three address pins use internal pull-up resistors, allowing up to eight devices to share the common I2C bus. The GPIO address matches the PCF8574, while the EEPROM address matches the PCF8582C-2; consequently, one device appears as two separately addressed functions to the bus master. Its 400 kHz bus rating supports faster communication than the common 100 kHz I2C operating mode.
Because each port pin can be assigned independently as an input or output, the device can monitor board-level status and activate indicators such as LEDs. The quasi-bidirectional structure is useful for straightforward bus interfacing, although external pull-ups, electrical-level compatibility, and the intended input or output state must be considered in each design.
Typical uses include industrial control boards, removable or backplane cards, LED and switch interfaces, configuration storage, and small embedded systems where GPIO conservation is valuable. The NXP product information specifically identifies hot-insertion support as useful in removable-card and backplane systems.
A correct implementation should verify the actual device address, EEPROM map, logic thresholds, pull-up values, and pin functions against the manufacturer datasheet. Do not infer unavailable timing, voltage, temperature, or package dimensions from distributor summaries. For exact design values, consult the linked NXP documentation and validate firmware behavior across power-up, reset, bus faults, and hot-plug conditions.
Drop-in alternatives for PCA9500D — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PCA9500PW
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9500PW,118
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9500D,112
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9500D,118
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9500
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9500D Specifications
| Product Type | 8-bit I2C and SMBus I/O port expander with EEPROM |
| Number of I/O Pins | 8 |
| I/O Configuration | Independently assignable as input or output |
| I/O Electrical Type | Quasi-bidirectional |
| Serial Interface | I2C and SMBus |
| Maximum Stated Bus Frequency | 400 kHz |
| Integrated Storage | 2 kbit EEPROM |
| Address Inputs | 3 |
| Address Input Pull-Ups | Internal |
| Maximum Devices per Common Two-Wire Bus | 8 devices |
| GPIO I2C Address Compatibility | PCF8574 |
| EEPROM I2C Address Compatibility | PCF8582C-2 |
| Hot Insertion Support | Yes |
| Package | 16-pin SOIC |
| Mounting Type | Surface mount |
PCA9500D 16-pin soic Pin Configuration Guide
Pin configuration for PCA9500D (16-pin soic 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 PCA9500D.
Refer to the datasheet for full pin configuration.
Typical Applications
PCA9500D is suitable for 6 applications: Industrial Control and Status I/O, LED and Switch Expansion, Removable Card and Backplane Control, Embedded Configuration Storage, Portable and Battery-Powered Systems, Programmable Control and Test Fixture.
Industrial Control and Status I/O
The PCA9500D fits industrial control boards that need to conserve microcontroller GPIO while collecting switch states and driving indicators. Its eight quasi-bidirectional pins can each be assigned as an input or output, and the I2C interface operates up to the verified 400 kHz rate. Place the device between the host controller and field-side logic, then define pull-ups and electrical levels for the actual board. The 16-pin SOIC package keeps the interface compact, while the onboard 2-kbit EEPROM can retain board-level configuration. Validate isolation, surge exposure, and logic thresholds because the supplied snippets do not specify industrial input protection or voltage limits.
Recommended
LED and Switch Expansion
The PCA9500D provides a practical remote I/O stage for systems combining LEDs, pushbuttons, selectors, and indicators. The eight quasi-bidirectional pins can monitor switch states or activate attached devices, and the NXP description explicitly includes LEDs as an example. Connect each external circuit through the appropriate resistor or interface driver, keep the bus pull-ups within the electrical limits of the host, and write a default safe port state before enabling outputs. The verified 400 kHz capability makes repeated display or switch updates efficient. Because this is an interface expander rather than a high-current LED driver, verify external drive current and voltage requirements in the datasheet and circuit design.
Recommended
Removable Card and Backplane Control
The PCA9500D is a sensible candidate for removable-card and backplane management because NXP explicitly identifies hot-insertion support. The three address inputs allow up to eight devices to share the common two-wire bus, while the onboard EEPROM can retain card or board configuration data. Use the address pins and bus pull-ups carefully in a multi-card system, and design the connector and power rails to tolerate the insertion sequence. The I2C protocol remains the central control path, but hot-plug correctness also depends on the host firmware, bus fault handling, and external protection. Those system-level conditions should be tested with the target card populated and disconnected.
Recommended
Embedded Configuration Storage
The PCA9500D combines eight I/O lines with a 2-kbit EEPROM, making it useful when a compact embedded system needs local configuration retention in addition to bus-controlled digital I/O. NXP states that port configuration data is kept in the device, while the EEPROM address is compatible with the PCF8582C-2 and the GPIO address is compatible with the PCF8574. Firmware can therefore address the port and storage as separate functions. Confirm the exact EEPROM organization, write sequence, endurance, and retention limits in the manufacturer datasheet rather than assuming a generic memory map. Treat stored values as configuration data and validate them before applying them to safety-relevant outputs.
Recommended
Portable and Battery-Powered Systems
The PCA9500D can extend a microcontroller's available I/O in a compact embedded product where pin count and board area are constrained. Its eight quasi-bidirectional pins handle low-voltage digital status or indicator functions, while the EEPROM preserves configuration without requiring a separate memory package in the base design. The verified material does not provide supply-voltage or quiescent-current figures, so battery life cannot be calculated from the snippets alone. Confirm operating voltage, input thresholds, leakage, and sleep behavior in the datasheet, and account for the continuous current required by the I2C pull-ups. Use the device for low-current signal expansion rather than assuming it can power loads directly.
Recommended
Programmable Control and Test Fixture
The PCA9500D is useful in a compact test fixture or programmable controller where a host computer or microcontroller must monitor inputs and operate remote digital lines over a two-wire bus. The eight independent I/O assignments allow fixture sensing and control functions to be combined in one package, while the EEPROM can store fixture identification or configuration. The 400 kHz bus rating can reduce command latency when the full bus network and pull-up design are suitable. Keep the fixture I/O within verified logic levels and protect external connector pins from ESD or test-fixture transients. Firmware should initialize the port to a known safe state before driving actuators, and production tests should include bus disconnect and reconnection cases.
Recommended
Recommended Products Summary
Engineering reference data for PCA9500D — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9500PW | PCA9500PW,118 | PCA9500D,112 | PCA9500D,118 | PCA9500 |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| I/O Port Width | 8 bits | 8 bits | 8 bits | 8 bits | 8 bits | 8 bits |
| Serial Interface | I2C and SMBus | I2C and SMBus | I2C and SMBus | I2C and SMBus | I2C | I2C and SMBus |
Key Differentiators
- Integrated configuration storage alongside GPIO expansion (vs PCA9500PW)
- Two-wire bus expansion without consuming eight dedicated MCU pins (vs PCA9500PW,118)
- Address and EEPROM-function compatibility (vs PCA9500)
Design Notes
Route the I2C SDA and SCL traces as a compact bus and place the pull-up network close to the bus master or according to the system’s current-sharing strategy. The PCA9500D address inputs have internal pull-ups, but external SDA/SCL pull-ups are still required for normal open-drain operation. Check rise time against the 400 kHz target, total bus capacitance, and the controller’s sink-current limit before reducing resistance.
Do not treat the GPIO address and EEPROM address as one register space. The verified datasheet material states that the GPIO address is compatible with the PCF8574 and the EEPROM address with the PCF8582C-2, allowing one device to appear as two separate bus targets. Implement separate transactions and verify read, write, and retained-data behavior with the exact ordering code before production firmware release.
The eight quasi-bidirectional pins are interface signals, not power outputs. Use suitable resistors, buffers, or transistor drivers when driving LEDs, relays, or other loads. In portable systems, include the continuous I2C pull-up current and any external-driver current in the battery budget. The supplied snippets do not provide supply-voltage or quiescent-current values, so obtain those figures from the manufacturer datasheet before sizing the power source.
For removable cards and backplanes, test the bus with the target card connected, disconnected, reset, and power-ramped. Account for connector capacitance, reflected SDA/SCL edges, and any peripheral holding SCL low. The verified hot-insertion feature makes the PCA9500D relevant to this use case, but it does not by itself specify the external protection or isolation needed for a particular connector.
Compliance Information
The supplied verified results do not state PCA9500D compliance status. Confirm RoHS, REACH, lead-free, halogen-free, and conflict-minerals declarations for the exact NXP ordering code.