PCA9545ADGVRG4 - 4-Ch I2C/SMBus Mux, 20-TVSOP | Texas Instruments
MPN: PCA9545ADGVRG4 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
PCA9545ADGVRG4 Overview
An I2C multiplexer is a form of bus switch IC within the broader interface IC family. It sits between a master controller and multiple I2C segments, allowing one SDA/SCL pair to be time-multiplexed onto up to four downstream channels. This solves address conflicts between identical slave devices, reduces bus capacitance, and isolates fault domains such as a shorted downstream device.
Key features include four selectable bidirectional channels controlled by a 2-wire register write, hardware reset (/RESET) that recovers a hung downstream bus without a full system power cycle, and four open-drain interrupt inputs (/INT0-/INT3) that are logically OR-ed onto a single master interrupt line. Passive pull-up compatible operation means no external level translation is required for pass-gate switching.
The pass-gate (transmission-gate) architecture makes the switch bidirectional and voltage-translating: the downstream voltage level is determined by VCC and the pass-gate limiting. Propagation delay through the switch is minimal because data is not buffered or re-timed, preserving I2C multi-master arbitration and clock stretching behavior across all channels.
Typical applications include server and telecom chassis management (multiple FRU EEPROMs and sensors on isolated segments), automotive body modules, and any system where I2C address space is exhausted or a hung slave must be quarantined.
Design tip: always connect /RESET to a supervisor or host GPIO - it is the fastest recovery path when a slave holds SDA low. Keep total downstream bus capacitance within I2C limits per selected channel.
This page synthesizes distributor pricing, drop-in alternatives, pinout, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for PCA9545ADGVRG4 — 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:
PCA9545ADGVR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PCA9546ADGVR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PCA9546ADGVRG4
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PCA9545APWR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PCA9545ADGVRG4 Maximum Ratings & Electrical Characteristics
| Function | 4-Channel I2C and SMBus Multiplexer / Switch |
| Number of Channels | 4 |
| Interface | I2C, SMBus |
| Nominal Supply Voltage | 2.5 V |
| I/O Tolerance | 5.5 V tolerant (all I/O pins) |
| Pass-Gate Voltage | 2.5 V nominal |
| Address Pins | A0, A1 (programmable slave address) |
| Reset Input | /RESET (hardware reset) |
| Interrupt Inputs | 4 (/INT0 to /INT3, open-drain) |
| Terminations | 20 |
| Package | 20-TFSOP / TVSOP (0.173 in, 4.40 mm width, 0.4 mm pitch) |
| Mounting Type | Surface Mount |
| Package Shape | Rectangular |
| Datasheet Pages | 37 |
PCA9545ADGVRG4 Pin Configuration
| Pin 1 | A0 — Address input 0 (tie to GND or VCC) |
| Pin 2 | A1 — Address input 1 (tie to GND or VCC) |
| Pin 3 | RESET — Active-low hardware reset input |
| Pin 4 | INT0 — Interrupt input, channel 0 (active-low, open-drain) |
| Pin 5 | SD0 — Serial data, channel 0 |
| Pin 6 | SC0 — Serial clock, channel 0 |
| Pin 7 | SD1 — Serial data, channel 1 |
| Pin 8 | SC1 — Serial clock, channel 1 |
| Pin 9 | GND — Ground |
| Pin 10 | INT1 — Interrupt input, channel 1 (active-low, open-drain) |
| Pin 11 | SD2 — Serial data, channel 2 |
| Pin 12 | SC2 — Serial clock, channel 2 |
| Pin 13 | SD3 — Serial data, channel 3 |
| Pin 14 | SC3 — Serial clock, channel 3 |
| Pin 15 | INT2 — Interrupt input, channel 2 (active-low, open-drain) |
| Pin 16 | INT3 — Interrupt input, channel 3 (active-low, open-drain) |
| Pin 17 | SCL — Serial clock, upstream bus |
| Pin 18 | SDA — Serial data, upstream bus |
| Pin 19 | VCC — Supply voltage (2.5 V nominal) |
| Pin 20 | NC — Not connected (per datasheet) |
Typical Applications
PCA9545ADGVRG4 is suitable for 6 applications: Server and Telecom Chassis Management, Automotive Body and Gateway Modules, Industrial Sensor Aggregation, Consumer Electronics Multi-Sensor Hosts, Battery Management Systems, Test and Measurement Instruments.
Server and Telecom Chassis Management
In ATCA/MicroTCA and server chassis, a BMC must reach dozens of FRU EEPROMs, power-supply controllers, and temperature sensors over I2C. The PCA9545ADGVRG4 partitions that traffic into four isolated segments, solving address conflicts between identical FRU devices and cutting per-segment bus capacitance. Its 5.5 V tolerant I/O allows a 2.5 V-side switch to interface with 5 V FRU rails without external translators, and the /RESET pin plus /INT0-/INT3 aggregation let the BMC quarantine a hung segment while the remaining three stay online - critical for 99.999% uptime designs.
Recommended
Automotive Body and Gateway Modules
Automotive body controllers and gateways aggregate sensors (seat, door, climate) that frequently reuse identical I2C addresses. The PCA9545ADGVRG4 places each door or zone on its own channel, eliminating address clashes with a single 20-pin TVSOP. The hardware /RESET input gives the host a deterministic recovery path when a slave locks SDA low - a documented field-failure mode in vehicles - and the four /INT inputs consolidate interrupt sources into one host line. Its 2.5 V nominal supply and 5.5 V tolerant I/O suit the mixed 3.3 V/5 V domains typical of automotive E/E architectures.
Recommended
Industrial Sensor Aggregation
Factory automation nodes routinely host multiple identical I2C sensors - four of the same temperature or pressure IC would normally collide on one bus. The PCA9545ADGVRG4 assigns one sensor bank per channel so each device keeps its default address. Because the pass-gate switch is unbuffered, sensor read timing and clock stretching behavior are preserved exactly, simplifying firmware. The passive architecture adds essentially no propagation delay, and channel isolation means a cable fault on one sensor run cannot drag down the other three segments, improving overall line availability.
Recommended
Consumer Electronics Multi-Sensor Hosts
Smart TVs, set-top boxes, and audio hubs often need to reach ambient light sensors, touch controllers, HDMI bridge EEPROMs, and audio codecs, several sharing default addresses. The PCA9545ADGVRG4 expands one SoC I2C port to four independent buses inside the compact 4.4 mm wide TVSOP, fitting dense consumer PCBs. Low quiescent overhead suits battery-adjacent standby domains, and enabling only the channel in use electrically disconnects idle slaves, trimming standby leakage and eliminating cross-talk between segments during audio playback or display operations.
Recommended
Battery Management Systems
A BMS host often must access multiple battery-monitoring front-ends that use identical I2C addresses. The PCA9545ADGVRG4 routes the host to each monitor on a dedicated channel, enabling sequential cell-pack telemetry without firmware address tricks. The /RESET input provides a safety-relevant recovery path if a front-end hangs during pack fault events, and channel isolation prevents a faulted pack segment from blocking communication with healthy packs. Its 2.5 V nominal supply and 5.5 V tolerant I/O match the mixed domains between low-voltage logic and pack-side circuitry.
Recommended
Test and Measurement Instruments
Bench instruments and modular test systems use I2C for calibration EEPROMs, front-panel peripherals, and internal sensors. The PCA9545ADGVRG4 isolates each subsystem so a hot-plugged front-panel card cannot corrupt bus traffic to precision calibration data. The 5.5 V tolerant I/O protects the switch in instruments where 5 V legacy cards and 2.5 V logic coexist, and the interrupt aggregation reduces host GPIO usage. Passive pass-gate operation preserves I2C multi-master arbitration, allowing multiple instrument boards to contend for shared peripherals without external arbitration logic.
Recommended
Recommended Products Summary
Engineering reference data for PCA9545ADGVRG4 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9545ADGVR | PCA9546ADGVR | PCA9545APWR |
|---|---|---|---|---|
| Package | 20-TVSOP (DGV, 4.40 mm, 0.4 mm pitch) | 20-TVSOP (DGV) - same | 20-TVSOP (DGV) - same | TSSOP-20 (6.40 mm, 0.5 mm pitch) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Number of I2C Channels | 4 | 4 | 4 | 4 |
| Interrupt Inputs (/INT0-/INT3) | Yes | Yes | No (enable inputs instead) | Yes |
| Hardware Reset | Yes (/RESET) | Yes (/RESET) | Yes (/RESET) | Yes (/RESET) |
| I/O Tolerance | 5.5 V tolerant | 5.5 V tolerant | 5.5 V tolerant | 5.5 V tolerant |
| Nominal Supply Voltage | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Pin-to-Pin Drop-In on Same Footprint | - | Yes (identical) | Yes (function of pins 4/10/15/16 differs) | No (different package) |
Key Differentiators
- Four dedicated interrupt inputs aggregate downstream slave interrupts (vs PCA9546ADGVR)
- Compact TVSOP footprint saves PCB area versus TSSOP (vs PCA9545APWR)
- Identical die available in both interrupt (9545A) and enable (9546A) versions (vs PCA9546ADGVRG4)
Design Notes
Always route /RESET to a host GPIO or supervisor. The PCA9545A resets its channel register to all-deselected on power-up, but if a downstream slave holds SDA low, only /RESET electrically isolates the hung segment quickly. Firmware-only bus-clearing (toggling SCL nine times) can fail if the slave's fault is persistent. Estimated: without /RESET wired, recovery time in a fault case can exceed seconds versus microseconds with a hardware reset pulse.
Place 0.1 uF decoupling ceramic capacitor within 2 mm of pin 19 (VCC) to ground. The TVSOP 0.4 mm pitch requires careful land-pattern adherence to the TI DWG for the DGV suffix; do not substitute a TSSOP-20 (PW) pattern. Keep the four downstream SDA/SCL pairs length-matched on fan-out to preserve setup/hold margins, and add series 22 to 33 ohm resistors on long or cable-connected segments to damp ringing.
The switch is a passive pass-gate: total I2C bus capacitance still counts per selected channel, not the switch itself. When multiple channels are enabled simultaneously, their pull-up resistors parallel and the combined capacitance rises - ensure pull-up sizing keeps rise times within I2C standard-mode or fast-mode limits (per datasheet application curves). Estimated: with 4 channels enabled and 4.7 kohm pull-ups each, the effective pull-up seen at the master drops to about 1.2 kohm, which is acceptable for fast-mode but increases static sink current.
Compliance Information
The G4 suffix on TI ordering part numbers conventionally denotes the RoHS/green ordering variant, but explicit compliance statements were not present in the retrieved data; verify on the TI product page.
