Texas Instruments LSF0102DTMR

Overview

LSF0102DTMR from Texas Instruments is a 2-channel auto-bidirectional multi-voltage level translator for open-drain and push-pull interfaces, supporting up to 100 MHz up-translation and >100 MHz down-translation at ≤30 pF load, 0.95V ↔ 5V voltage translation pairs, 5V-tolerant I/O, and operation from –40°C to 125°C. It enables seamless I²C, SMBus, and MDIO interfacing between mixed-voltage SoCs and peripherals in telecom infrastructure.

For engineers reviewing the LSF0102DTMR datasheet, LSF0102DTMR pinout, LSF0102DTMR application, or LSF0102DTMR equivalent, key selection considerations include its directionless switch architecture, Vref_A/Vref_B biasing requirements, EN pin tie-to-Vref_B implementation, flow-through X2SON-8 layout, and R_ON–dependent signal integrity at 50pF/30pF loads.

Technical Context

The LSF0102DTMR implements a passive FET-based bidirectional switch architecture-no internal buffers or direction control logic-where translation direction is determined dynamically by relative voltage levels on A and B ports. Each channel operates as a low-R_ON pass transistor (8–30 Ω depending on Vref_A/Vref_B), enabling both up- and down-translation without external direction signals.

Its enable function relies on EN tied directly to Vref_B with a 200 kΩ pull-up to VCCB; when EN is low, all I/Os enter high-impedance state. The device requires no external clock or timing reference and supports mixed-mode per-channel pull-up voltages (e.g., 1.8V ↔ 3.3V on Channel 1, 1.8V ↔ 5V on Channel 2) within a single package.

Key Specifications

Pinout & Package

LSF0102DTMR uses the DTM package: 8-pin X2SON (1.35 mm × 0.80 mm), ultra-compact footprint with flow-through pinout optimized for minimal trace length and reduced parasitic capacitance in high-speed I²C/SMBus routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional voltage translation applications.

Compared with TXS0102DSGR and SN74AVC2T244RSWR, LSF0102DTMR uniquely eliminates direction control overhead and preserves native I²C/SMBus arbitration-making it the only choice for systems requiring true bidirectional, pin-efficient, low-R_ON translation without firmware intervention.

Availability

LSF0102DTMR is available at Aetrix Electronics and suitable for telecom infrastructure, enterprise server power management, and industrial PLC I/O modules requiring stable component supply across extended temperature and mixed-voltage interface demands.

Supply support for LSF0102DTMR 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 delivering analog and embedded processing solutions, with leadership in interface, power management, and signal chain technologies since 1930.

The LSF family-including LSF0102DTMR-is designed specifically for auto-bidirectional, multi-voltage level translation in open-drain and push-pull systems such as I²C, SMBus, PMBus, MDIO, and GPIO, eliminating direction-pin complexity in resource-constrained embedded designs.

FAQ

What is the correct way to connect the EN pin on the LSF0102DTMR?

The EN pin on the LSF0102DTMR must be tied directly to the Vref_B pin and pulled up to the high-side supply (VCCB) via a 200 kΩ resistor. This configuration ensures proper internal biasing and enables automatic translation. Driving EN with a push-pull output is a common design error that disrupts functionality. A 0.1 µF capacitor from Vref_B to GND is recommended for noise filtering. The LSF0102DTMR will not operate correctly if EN is left floating or connected incorrectly.

Can the LSF0102DTMR translate between 1.2V and 5V?

Yes, the LSF0102DTMR supports 1.2V ↔ 5V bidirectional translation, as explicitly listed in its supported voltage pairs. Vref_A must be set to 1.2V and Vref_B to 5V, with EN tied to Vref_B and pulled up to VCCB. The device maintains <30 Ω R_ON and full timing compliance at this combination under ≤30 pF load. This capability makes the LSF0102DTMR suitable for interfacing ultra-low-power sensors to legacy 5V controllers without additional logic.

Does the LSF0102DTMR require external pull-up resistors?

Yes-external pull-up resistors are mandatory on the high side (B-port) for both up- and down-translation, and may be required on the low side (A-port) depending on driver type. For open-drain interfaces like I²C, pull-ups are needed on both sides. Resistor values must be selected based on VPU and desired sink current (e.g., 10 kΩ for 3.3V→1.8V at ~15 mA). The LSF0102DTMR itself contains no internal pull-ups; their sizing directly impacts rise time and VOL compliance.

How does the LSF0102DTMR handle mixed-voltage translation across its two channels?

The LSF0102DTMR supports per-channel mixed-voltage translation using shared Vref_A and Vref_B references. For example, Channel 1 can translate 1.8V ↔ 3.3V while Channel 2 translates 1.8V ↔ 5V-both using the same Vref_A = 1.8V and Vref_B = 5V. Pull-up resistors on each B-port define the final high-level voltage. This flexibility allows single-package integration of heterogeneous interfaces (e.g., I²C + PMBus) without cross-talk or timing skew, as confirmed in TI's Figure 8-4 application schematic.

What is the maximum capacitive load the LSF0102DTMR supports at 100 MHz operation?

The LSF0102DTMR supports up to 100 MHz up-translation and >100 MHz down-translation only at ≤30 pF total capacitive load (including trace, probe, and device capacitance). At 50 pF, maximum speed drops to 40 MHz in either direction. This is specified in TI's AC performance tables (Sections 5.6–5.9) and verified with 250 Ω pull-up resistors. Exceeding 30 pF at 100 MHz risks timing violations and signal integrity loss-designers must verify layout parasitics when targeting full-speed operation.