TCA9536-Q1 - 4-Bit I2C/SMBus I/O Expander AEC-Q100 | TI
MPN: TCA9536-Q1 ✓ Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
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| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
TCA9536-Q1 Overview
An I/O expander is an interface IC that extends the number of general-purpose input/output (GPIO) pins of a microcontroller or system controller through a serial bus such as I2C or SMBus. In the hierarchy of embedded system components, the I/O expander sits within the interface IC family, alongside level translators, bus buffers, and serial transceivers, and functions as a remote GPIO peripheral for system masters that need additional discrete control or monitoring lines without adding a larger microcontroller.
Key features of the TCA9536-Q1 include 4 configurable I/O pins that can be individually programmed as inputs or outputs through a 4-bit Configuration register, an Input Port register for reading pin states, an Output Port register for driving pins, and a Polarity Inversion register for active-HIGH or active-LOW operation. The device supports fast-mode I2C bus operation up to 1 MHz, uses only two bus lines (SDA and SCL), and operates across the wide 1.65V to 5.5V VCC range for compatibility with 1.8V, 2.5V, 3.3V, and 5V logic systems.
The architecture implements four 4-bit registers (Configuration, Input Port, Output Port, and Polarity Inversion) accessible over the serial bus, with power-on reset defaulting all pins to inputs. Because the TCA9536-Q1 register map follows the widely deployed PCA9536 register convention, the same software drivers used for PCA9536-class expanders generally work unchanged, simplifying migration and second-sourcing within an existing firmware stack.
Typical applications include automotive body-control modules, GPIO expansion in space-constrained sensor nodes, keypad or switch monitoring, LED and relay control through external drivers, and power-rail sequencing enables in infotainment and cluster displays. Its tiny X2SON footprint makes it especially attractive where board area is the limiting factor.
Design consideration: because the X2SON package places multiple pins on very fine pitch beneath the die, follow TI's recommended PCB land pattern exactly, including via-in-pad thermal relief, and verify solderability with the correct reflow profile for the Q1 automotive grade.
This page synthesizes verified distributor data, drop-in alternative analysis, and practical design guidance that goes beyond the raw datasheet parameters.
Drop-in alternatives for TCA9536-Q1 — 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:
TCA9536ADTMR
✅ Drop-In📋 Reference alternative (not in catalog)
TCA9536-Q1 Specifications
| Function | 4-bit I/O expander for I2C bus / SMBus |
| Number of I/O Pins | 4 |
| Supply Voltage Range | 1.65 V to 5.5 V |
| Interface | I2C, SMBus |
| Maximum Clock Frequency | 1 MHz |
| Registers | Configuration, Input Port, Output Port, Polarity Inversion |
| Automotive Qualification | AEC-Q100 qualified (Q1 grade) |
| Operating Temperature | -40C to +125C |
| Package | 8-X2SON (1.35 mm x 0.8 mm) |
| Mounting Type | Surface Mount |
TCA9536-Q1 8-x2son (1.35 mm x 0.8 mm) Pin Configuration Guide
Pin configuration for TCA9536-Q1 (8-x2son (1.35 mm x 0.8 mm) 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 TCA9536-Q1.
Refer to the datasheet for full pin configuration.
Typical Applications
TCA9536-Q1 is suitable for 6 applications: Automotive Body Control Modules, Space-Constrained Sensor Node GPIO Expansion, Keypad and Switch Monitoring, LED and Relay Driver Control, Power Rail Sequencing Enables, Cluster and Infotainment Display Control.
Automotive Body Control Modules
The TCA9536-Q1's AEC-Q100 qualification and -40C to +125C operating range make it a natural fit for automotive body control modules that must switch or monitor discrete loads such as door locks, mirror motors, and lamp diagnostics. Its four I2C-controlled GPIO pins let a central MCU add control lines over the existing two-wire bus without routing additional harnesses. The 1.65V to 5.5V supply range allows direct interface with 3.3V or 5V module logic. Placed near the load cluster, the expander reduces MCU pin count and PCB trace count, and its 4-bit register set supports per-pin input/output reconfiguration during fault-handling routines without firmware redesign.
Recommended
Space-Constrained Sensor Node GPIO Expansion
The 8-X2SON package of the TCA9536-Q1 measures only 1.35 mm x 0.8 mm, which is smaller than a 0402 passive footprint, making it ideal for sensor nodes and modules where board area is the dominant constraint. A microcontroller can monitor four additional switches, interrupt flags, or sensor status lines through the single I2C bus. Because the device draws its power from a 1.65V to 5.5V rail, it matches common coin-cell and LDO-fed node designs. The Input Port register allows polling of all four status lines in a single bus transaction, reducing bus traffic and average power compared with discrete GPIO monitoring.
Recommended
Keypad and Switch Monitoring
With four independently configurable inputs and a Polarity Inversion register supporting active-HIGH or active-LOW sensing, the TCA9536-Q1 suits compact keypad, door-switch, and limit-switch monitoring panels. Inputs default to inputs at power-on reset, giving a safe state for switch monitoring. The 1 MHz fast-mode I2C bus allows rapid polling, and reading the Input Port register returns the debounced-by-firmware state of all four lines at once. In automotive cabin controllers, the AEC-Q100 grade covers the -40C to +125C ambient swings typical of door and dashboard environments, while the tiny X2SON footprint fits directly under or beside switch flex circuits.
Recommended
LED and Relay Driver Control
Configured as outputs, the four GPIO pins of the TCA9536-Q1 drive logic-level MOSFET gates, transistor bases, or LED driver enable pins through the Output Port register. A single I2C write updates all four outputs simultaneously, giving glitch-free multi-channel control for status indicators, backlight enables, or relay coils driven via external switches. In automotive lighting modules the Q1 qualification covers the required temperature range, and the 5.5V maximum supply allows direct 5V logic output levels to meet MOSFET gate-threshold requirements. The 4-bit width matches typical indicator clusters of two to four channels in cluster and infotainment display boards.
Recommended
Power Rail Sequencing Enables
Multi-rail systems commonly need several enable lines asserted in a defined order. The TCA9536-Q1 provides four individually programmable enables controlled over I2C, letting a management controller sequence power modules or DC-DC converters with software-controlled timing. Because outputs are updated by register write rather than hardware strapping, sequencing order can be changed in firmware without PCB modification. The 1.65V to 5.5V operation lets the expander sit on either a standby 3.3V rail or a 5V always-on rail, and its small X2SON footprint fits on power-management sections of automotive cluster and infotainment boards where space is tight.
Recommended
Cluster and Infotainment Display Control
Automotive display modules need scattered discrete control points such as backlight enables, regulator shutdown pins, panel reset lines, and cover-sensor inputs. The TCA9536-Q1 aggregates four of these on one I2C bus, reducing the MCU pin budget on already crowded display controllers. The AEC-Q100 qualification and -40C to +125C range address the automotive cabin environment, while the 1 MHz bus keeps control latency negligible relative to human-perceptible timing. The 4-bit Polarity Inversion register lets designers accommodate both active-high and active-low panel signals without inverter gates, saving BOM count on high-volume display boards.
Recommended
Recommended Products Summary
Engineering reference data for TCA9536-Q1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TCA9536ADTMR | PCA9536 (NXP) |
|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | NXP Semiconductors |
| Package | 8-X2SON (1.35 mm x 0.8 mm) | 8-X2SON (1.35 mm x 0.8 mm) - same footprint | TSSOP-type variants - different footprint, not drop-in |
| Number of I/O Pins | 4 | 4 | 4 |
| Register Set | Configuration / Input / Output / Polarity Inversion | Configuration / Input / Output / Polarity Inversion | Configuration / Input / Output / Polarity Inversion |
Key Differentiators
- Automotive qualification (vs TCA9536ADTMR)
- Minimal board footprint (vs PCA9536 (NXP))
- Broad logic compatibility (vs TCA9536ADTMR)
Design Notes
The X2SON (1.35 mm x 0.8 mm) package routes its connections to lands beneath the package body. Follow the TI datasheet recommended land pattern exactly, place via-in-pad connections on each under-package land, and keep vias small and filled/plated where possible to prevent solder wicking that causes opens. Use a solder paste stencil per TI's recommended aperture design and confirm with X-ray or AOI inspection that all lands wet correctly on first-article builds.
Decouple VCC with a 0.1 uF ceramic capacitor placed as close to the supply pin as the land pattern allows. The 1.65V to 5.5V supply range permits operation on shared 3.3V or 5V rails, but ensure the I2C bus pull-up resistors tie to a rail that is never below the TCA9536-Q1's VCC during power-up, or use bus buffers, to keep SDA/SCL levels valid. Verify bus pull-up sizing against the 1 MHz fast-mode rise-time requirement.
After power-on reset all pins default to inputs; write output values to the Output Port register before changing the Configuration register to outputs, otherwise pins glitch low momentarily during the transition - a common cause of unintended relay or LED blips at startup. Also confirm the device I2C address does not collide with other bus peripherals before finalizing firmware addressing.
Compliance Information
AEC-Q100 qualification confirmed by TI -Q1 designation per the TI product page. RoHS, REACH, lead-free, and halogen-free status were not stated in the provided web data and must be confirmed on the TI product page before order release.
