Texas Instruments TXS02612ZQSR

Overview

TXS02612ZQSR from Texas Instruments is a 6-to-12 SDIO port expander with integrated voltage-level translation across three independent supply rails (VCCA, VCCB0, VCCB1), supporting 1.1 V to 3.6 V operation per rail. It enables a single baseband SDIO host to interface with two SDIO peripherals (e.g., Bluetooth + WLAN) via SPDT switching controlled by SEL, with push-pull data rates up to 120 Mbps and clock frequencies up to 60 MHz.

For engineers reviewing the TXS02612ZQSR datasheet, TXS02612ZQSR pinout, TXS02612ZQSR application, or TXS02612ZQSR equivalent, key selection criteria include its triple-rail level-shifting capability, B-port deselection pull-up behavior (70 kΩ to VCCB), guaranteed timing skew <0.7 ns, and MicroStar Junior™ BGA (ZQS) 24-ball 4×4 mm package with exposed thermal pad.

Technical Context

The TXS02612ZQSR implements a bidirectional 6-channel SPDT switch architecture with separate A-port (host-side) and dual B-ports (peripheral-side), where SEL selects between B0 and B1. Each data/command path includes dedicated level translators with speed-up circuitry for both A→B and B→A directions, enabling asymmetric voltage operation (e.g., VCCA = 1.8 V, VCCB0 = 3.3 V).

Its clock path features active translation with P-ch/N-ch output drivers referenced to respective VCCBx rails, while deselected B-port I/Os are weakly pulled high (70 kΩ ±30%) to their VCCB rail - not tri-stated - ensuring defined logic levels during port switching. The device requires strict power-up sequencing: GND → VCCA → SEL → VCCB0/VCCB1.

Key Specifications

Pinout & Package

TXS02612ZQSR uses the ZQS package: 24-ball MicroStar Junior™ BGA (4 mm × 4 mm, 0.5 mm pitch), with an exposed center thermal pad that must be connected to ground or left electrically open per TI design guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SDIO port expansion applications.

Compared with TXS02612RTWR, the TXS02612ZQSR offers identical functionality but trades higher thermal resistance (171.6 vs. 66 °C/W) for BGA density advantages; TS3USB221A lacks SDIO protocol support, level translation, and dual-B-port switching - making it unsuitable as a direct replacement.

Availability

TXS02612ZQSR is available at Aetrix Electronics and suitable for smartphone baseband expansion, tablet SDIO multiplexing, and industrial handheld terminal designs requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for TXS02612ZQSR 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 specializing in analog, embedded processing, and digital signal processing technologies, with leadership in interface, power management, and signal chain solutions.

The TXS02612ZQSR belongs to TI's SDIO port expander product line, designed specifically to solve SDIO interface scarcity in space-constrained portable electronics by enabling one host port to drive two peripherals with full voltage-level translation and timing compliance.

FAQ

What is the primary function of the TXS02612ZQSR in an SDIO system?

The TXS02612ZQSR functions as a 6-to-12 SDIO port expander with integrated voltage-level translation, allowing a single SDIO host interface to connect to two independent SDIO peripherals (e.g., SD card and Bluetooth module) via SEL-controlled switching. It translates signals across three independent supply rails (VCCA, VCCB0, VCCB1), supports data rates up to 120 Mbps, and maintains timing integrity with sub-2 ns skew - all within the TXS02612ZQSR device.

How does the TXS02612ZQSR handle deselected B-port signals?

When the TXS02612ZQSR deselects a B-port (e.g., SEL = Low disables B1), all B1-port I/Os (DAT0B1–DAT3B1, CMDB1, CLKB1) are actively pulled high to VCCB1 through internal 70 kΩ resistors (±30% tolerance), not placed in high-impedance state. This prevents floating nodes and bus contention, ensuring deterministic logic levels during port switching - a defined behavior of the TXS02612ZQSR.

What are the power-up sequencing requirements for reliable TXS02612ZQSR operation?

The TXS02612ZQSR requires strict power-up order: (1) GND connected first, (2) VCCA applied to power internal SEL logic, (3) SEL set to desired state (Low or High) synchronized with VCCA ramp, then (4) VCCB0 and VCCB1 applied. Violating this sequence may cause excessive supply current, bus contention, or undefined outputs - critical for stable TXS02612ZQSR deployment in production systems.

Can the TXS02612ZQSR support different voltage levels on VCCA, VCCB0, and VCCB1 simultaneously?

Yes, the TXS02612ZQSR supports independent voltage operation: VCCA, VCCB0, and VCCB1 each operate from 1.1 V to 3.6 V, enabling mixed-voltage configurations such as VCCA = 1.8 V (baseband), VCCB0 = 3.3 V (SD card), and VCCB1 = 1.2 V (low-power modem). This triple-rail flexibility is intrinsic to the TXS02612ZQSR architecture and eliminates external level-shifting components.

What is the role of the exposed center pad in the TXS02612ZQSR ZQS package?

The exposed center pad in the TXS02612ZQSR ZQS package serves as a thermal and electrical interface: it must be connected to PCB ground plane (or left electrically open) to ensure proper heat dissipation (θJA = 171.6 °C/W) and reduce EMI. TI documentation explicitly states grounding is required for thermal management - a mandatory design rule for reliable TXS02612ZQSR operation at 85°C ambient.