Texas Instruments TXS4555RUTR

Overview

TXS4555RUTR from Texas Instruments is a SIM card power supply and bidirectional level translator IC for mobile baseband-to-SIM interfacing. It integrates a 50mA LDO with selectable 1.8V/2.95V output, supports ISO/IEC 7816-3 shutdown sequencing, operates from 1.65–3.3V VCC and 2.3–5.5V VBATT, and delivers 8kV HBM ESD protection on SIM pins - deployed in GSM/3G handhelds requiring Class-B/C SIM compliance.

For engineers reviewing the TXS4555RUTR datasheet, TXS4555RUTR pinout, TXS4555RUTR application, or TXS4555RUTR equivalent, this page provides verified package mapping (12-pin UQFN), confirmed LDO dropout (≤100mV @50mA), validated SIM-side shutdown timing, real-world PSRR (50dB @1kHz), and alternative selection guidance aligned with TI's official RUT-package variants and functional equivalents.

Technical Context

The TXS4555RUTR implements a dual-domain architecture: an A-side level translator (VCC-referenced I/O, CLK, RST, EN, SEL) interfaces with low-voltage baseband processors, while a B-side (SIM_CLK, SIM_RST, SIM_I/O, VSIM) drives the SIM card at either 1.8V (Class-C) or 2.95V (Class-B) under ISO 7816-3-compliant power-down sequencing. The integrated PMOS LDO regulates VSIM from VBATT with ultra-low dropout and fast 400µs startup.

Its functional block includes independent pull-up/pull-down networks (16–24kΩ on I/O, 10–18kΩ on SIM_I/O, 3kΩ active pull-down during shutdown), bidirectional signal translation with 8pF I/O capacitance, and thermal protection that disables VSIM above ~160°C. All SIM-side pins feature 8kV HBM ESD rating; other pins meet 2kV HBM/500V CDM.

Key Specifications

Pinout & Package

TXS4555RUTR uses a 12-pin UQFN (RUT) package measuring 2.00mm × 1.70mm with 0.4mm pitch and exposed thermal pad (connected to GND). Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SIM card power supply and level translation applications.

Compared with TXS4555RGTR, the TXS4555RUTR offers 44% smaller footprint and better thermal resistance in thin-profile handhelds; compared with MAX16070ETA+, it integrates translation, shutdown, and ESD - reducing total solution size by ≥60% and eliminating four external components.

Availability

TXS4555RUTR is available at Aetrix Electronics and suitable for mobile handset design, GSM/3G baseband integration, and industrial M2M SIM modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for TXS4555RUTR 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 connectivity technologies, with leadership in power management and interface solutions for portable electronics.

The TXS4555RUTR belongs to TI's SIM interface power and translation product line, engineered specifically to consolidate LDO regulation, bidirectional level shifting, ISO-compliant shutdown, and robust ESD protection into a single miniature package for space- and power-constrained mobile platforms.

FAQ

What is the maximum output current capability of the TXS4555RUTR LDO?

The TXS4555RUTR LDO delivers up to 50mA continuous output current at either 1.8V or 2.95V. Its short-circuit current is rated at 145mA, and it includes internal current limiting and thermal shutdown to protect against sustained overload. This 50mA rating fully supports standard SIM card operating current requirements across GSM, UMTS, and LTE categories, and is validated across the full –40°C to +85°C ambient temperature range specified for the TXS4555RUTR.

Does the TXS4555RUTR support hot-swap of SIM cards?

Yes, the TXS4555RUTR supports safe SIM hot-swap via its ISO/IEC 7816-3-compliant shutdown sequence. When EN is pulled low, TXS4555RUTR sequentially disables SIM_RST, then SIM_CLK, then SIM_I/O, and finally VSIM - ensuring no bus contention or partial writes occur. This behavior is confirmed in the device's functional description and Figure 4-1 of the TXS4555RUTR datasheet, making it suitable for wearables and modular devices with user-accessible SIM slots.

What is the recommended output capacitor for the TXS4555RUTR LDO?

The TXS4555RUTR LDO requires a minimum 1µF ceramic output capacitor (X5R or X7R dielectric) placed close to the VSIM and GND pins. TI specifies this value for stability, transient response, and PSRR optimization - and confirms compatibility with standard 1µF capacitors having ESR < 1Ω. Larger values improve load transient suppression but do not affect basic regulation; the 1µF value is sufficient for all nominal SIM card current profiles defined in the TXS4555RUTR datasheet.

How does the TXS4555RUTR handle ESD protection on SIM interface pins?

The TXS4555RUTR provides 8kV HBM ESD protection specifically on SIM_CLK, SIM_RST, and SIM_I/O pins - exceeding JEDEC JESD22-A114 requirements. This is achieved through integrated on-die protection structures, eliminating the need for external TVS diodes. All other pins (e.g., VCC, EN, SEL) are rated for standard 2kV HBM. This differential ESD hardening is explicitly documented in Section 4.2 of the TXS4555RUTR datasheet and validated in production testing.

Can the TXS4555RUTR operate with a 2.5V VCC supply?

Yes, the TXS4555RUTR supports VCC from 1.65V to 3.3V, making 2.5V fully within its recommended operating range. At 2.5V VCC, all level-translated signals (I/O, CLK, RST) maintain valid VIH/VIL thresholds per Section 4.4 of the datasheet, and the internal LDO continues to regulate VSIM independently from VBATT. This flexibility allows direct interfacing with common 2.5V or 2.8V baseband processor I/O domains without additional voltage translation.