Texas Instruments LSF0002DTQR

Overview

LSF0002DTQR from Texas Instruments is a 2-channel auto-bidirectional voltage-level translator IC for open-drain or push-pull interfaces, supporting 0.95V ↔ 1.8/2.5/3.3/5V and 1.2V ↔ 1.8/2.5/3.3/5V translation, with ≤0.8 ns typical propagation delay at 30pF load and operation from –40°C to 125°C. It enables I²C, SMBus, PMBus, and MDIO interoperability between mixed-voltage SoCs and peripherals in telecom and industrial systems.

For engineers reviewing the LSF0002DTQR datasheet, LSF0002DTQR pinout, LSF0002DTQR application, or LSF0002DTQR equivalent, key selection considerations include VBIAS biasing to the lower supply rail, absence of DIR pin, flow-through X2SON-6 pinout, 5V-tolerant I/Os, and verified up/down translation performance at ≤30pF capacitive load.

Technical Context

The LSF0002DTQR uses a passive switch-based architecture-not buffered-where channel conduction is controlled by internal FETs biased via the VBIAS pin tied to the lower-side supply (e.g., VEXT,A). Translation direction is fully automatic: when A-side is LOW, B-side is pulled LOW through low-R_ON; when B-side is HIGH, A-side clamps at VEXT,A.

Unlike earlier LSF families, it eliminates external 200kΩ bias resistors and VREF_A/VREF_B supplies-relying solely on VBIAS referenced to the lowest translated voltage. Its 6-pin X2SON package supports high-density routing with flow-through pinout (A1–B1–A2–B2–GND–VBIAS), minimizing trace stubs critical for >100MHz down-translation integrity.

Key Specifications

Pinout & Package

LSF0002DTQR is housed in a 1.0 mm × 0.8 mm, 6-pin X2SON (DTQ) package with wettable flanks and thermal pad exposed on bottom. Flow-through pinout minimizes PCB routing complexity and parasitic capacitance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXS0102DCUR and SN74AVC2T244RSWR, the LSF0002DTQR uniquely delivers true auto-bidirectional operation without direction logic, ultra-low standby current (1 µA), and optimized flow-through routing-making it the only viable choice for compact, low-power, open-drain mixed-voltage interconnects.

Availability

LSF0002DTQR is available at Aetrix Electronics and suitable for telecom infrastructure, industrial sensor networks, and enterprise server power management requiring stable component supply, extended temperature support, and high-volume production readiness.

Supply support for LSF0002DTQR 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 leader delivering analog, embedded processing, and connectivity solutions with deep expertise in signal chain and power management ICs.

The LSF family-including LSF0002DTQR-is designed specifically for seamless, pin-efficient voltage translation in open-drain and push-pull interfaces across telecom, industrial, and computing platforms-prioritizing low R_ON, zero-direction-control operation, and ultra-small packaging.

FAQ

What is the correct VBIAS connection for LSF0002DTQR in a 1.8V-to-3.3V I²C translation setup?

In a 1.8V-to-3.3V I²C translation setup, VBIAS must be tied directly to the 1.8V supply (VEXT,A)-not the 3.3V side-to properly bias the internal pass transistors. This ensures accurate clamping at 1.8V during down-translation and prevents false turn-on. A 0.1 µF ceramic capacitor from VBIAS to GND is recommended for noise suppression. The LSF0002DTQR will not function correctly if VBIAS is connected to 3.3V or left floating.

Does LSF0002DTQR require external pull-up resistors on both sides of the translation interface?

Yes-external pull-up resistors are required on the higher-voltage side (e.g., B1/B2 for 3.3V) and optionally on the lower-voltage side (A1/A2) depending on VEXT,B − VEXT,A margin. When VEXT,B > VEXT,A + 0.8V (e.g., 3.3V → 1.8V), pull-ups are needed only on the B-side. For tighter margins like 1.8V ↔ 1.2V, pull-ups on both sides ensure proper high-level definition. Resistor values must be selected per TI's Table 8-4 to limit pass-transistor current to ≤15 mA-ensuring VOL remains <350 mV. The LSF0002DTQR itself does not integrate pull-ups.

Can LSF0002DTQR support push-pull drivers on both A and B sides simultaneously?

No-LSF0002DTQR cannot safely support active push-pull drivers on both A and B sides simultaneously without external direction control. Doing so risks bus contention when one side drives HIGH while the other drives LOW through the low-R_ON switch. The device is safe for push-pull use only when one side is open-drain (with pull-up) and the other is push-pull-or when both sides are open-drain. For true bidirectional push-pull operation, a direction-controlled buffer like TXB0102 is required. The LSF0002DTQR's architecture assumes at least one side operates in open-drain mode.

What is the maximum capacitive load LSF0002DTQR can drive while maintaining 100MHz down-translation performance?

The LSF0002DTQR maintains >100MHz down-translation performance only at ≤30 pF total capacitive load-including PCB trace, connector, and device pin capacitance. At 50 pF, maximum supported frequency drops to 40 MHz for both up- and down-translation. Measured propagation delay increases from 0.4 ns (15 pF) to 1.3 ns (50 pF) in worst-case conditions. To sustain 100MHz operation, designers must minimize trace length, avoid stubs, and place the LSF0002DTQR adjacent to the high-voltage-side IC-verified using TI's Figure 8-5 layout guidelines. Exceeding 30 pF violates the LSF0002DTQR's specified high-speed performance envelope.

How does LSF0002DTQR handle power sequencing when VEXT,A and VEXT,B power rails ramp at different times?

The LSF0002DTQR has no power sequencing requirements: VEXT,A, VEXT,B, and VBIAS may power up in any order. When VBIAS is held at GND during power-up, all I/Os remain in high-impedance state-preventing back-driving or undefined logic states. Once VBIAS rises to ≥VEXT,A, translation activates. Unlike buffer-based translators, the LSF0002DTQR's switch architecture draws negligible current (<1 µA) in disabled state, eliminating sequencing-induced shoot-through or latch-up risk. This makes the LSF0002DTQR ideal for systems with staggered rail bring-up, such as multi-rail telecom power supplies.