Texas Instruments TCA5405RUGR

Overview

TCA5405RUGR from Texas Instruments is a low-voltage 5-bit self-timed single-wire output expander IC with push-pull outputs, operating from 1.65 V to 3.6 V supply, delivering up to 20 mA per output, and housed in an 8-pin X2QFN (RUG) package. It serves as a compact GPIO extender for space-constrained portable electronics where minimal interconnect and low quiescent current are critical.

For engineers reviewing the TCA5405RUGR datasheet, TCA5405RUGR pinout, TCA5405RUGR application, or TCA5405RUGR equivalent, this device offers deterministic single-wire serial control of five parallel outputs without external clocking - ideal for battery-powered systems requiring ultra-low standby current (≤2 µA), wide V_CC tolerance, and direct LED drive capability.

Technical Context

The TCA5405RUGR implements a self-timed serial protocol: it samples the DIN signal's bit period during a Setup phase, then generates an internal synchronized clock to sample five consecutive data bits over the Data Transfer phase. No master clock line is required - only a stable periodic DIN signal with t_PER between 1 µs and 10 ms.

Each of its five Q0–Q4 outputs functions as an independent push-pull buffer capable of sourcing or sinking 20 mA at V_CC = 3.3 V, with VOL ≤ 0.3 V and VOH ≥ 1.7 V under load. The device enters low-power standby mode (<2 µA ICC) when DIN is held static at V_CC or GND.

Key Specifications

Pinout & Package

Package: X2QFN-8 (RUG), 1.5 mm × 1.5 mm, 0.4 mm max height, wettable flank terminals, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-wire GPIO expansion applications.

Compared with MAX6953ATL+ and PCA9555DBR, the TCA5405RUGR uniquely delivers 5-bit parallel output control using only one GPIO pin and zero standby power overhead - making it optimal for cost-sensitive, space-constrained portable devices where wire count and battery life are primary constraints.

Availability

TCA5405RUGR is available at Aetrix Electronics and suitable for cell phones, portable media players, handheld instrumentation, and industrial PDAs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for TCA5405RUGR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer markets.

The TCA5405RUGR belongs to TI's low-voltage interface and GPIO expansion product line, engineered specifically for portable electronics where minimal pin count, ultra-low power, and direct LED drive capability are essential design requirements.

FAQ

What is the maximum data rate supported by the TCA5405RUGR single-wire interface?

The TCA5405RUGR accepts DIN bit periods from 1 µs to 10 ms, corresponding to a maximum effective data rate of 1 MHz (minimum t_PER) and minimum of 100 Hz (maximum t_PER). For reliable operation, TI recommends maintaining t_PER stability within ±5% across the five-bit transfer - the TCA5405RUGR does not support asynchronous or variable-rate bursts.

Can the TCA5405RUGR drive LEDs directly without current-limiting resistors?

No - while the TCA5405RUGR provides ±20 mA per output, external current-limiting resistors are mandatory to set LED forward current and prevent damage due to V_F variation and temperature drift. The TCA5405RUGR's VOL and VOH specifications assume defined load conditions; omitting resistors risks exceeding absolute maximum ratings.

Does the TCA5405RUGR require a specific startup sequence or initialization command?

No - the TCA5405RUGR has no register map or initialization requirement. It begins operation immediately upon power-up: holding DIN static places outputs in last-known state; a valid DIN burst (five rising/falling edges with stable t_PER) updates Q0–Q4 synchronously after the fifth bit. Power-on reset triggers at V_CC ≥ 1.4 V.

Is the TCA5405RUGR compatible with 1.2 V microcontrollers?

No - the TCA5405RUGR's minimum V_CC is 1.65 V, and its input threshold (V_IL ≤ 0.3 × V_CC, V_IH ≥ 0.7 × V_CC) is incompatible with 1.2 V logic levels. Using it with a 1.2 V MCU requires level translation on DIN; direct connection may cause metastability or incorrect sampling.

How does the TCA5405RUGR handle noise on the DIN line during the Setup phase?

The TCA5405RUGR samples the DIN period during S1/S2 (two consecutive rising edges) and rejects glitches outside that window. However, noise causing false edges during S0 (start detection) or S1/S2 will corrupt timing acquisition. TI recommends adding a 10–100 pF capacitor from DIN to GND near the TCA5405RUGR package to suppress RF coupling without violating trise/tfall specs.