Texas Instruments LSF0108QWRKSRQ1

Overview

LSF0108QWRKSRQ1 from Texas Instruments is an AEC-Q100 qualified automotive 8-channel bidirectional multi-voltage level translator in wettable-flank VQFN-20 (RKS) package. It enables voltage translation between 0.65 V and 5.5 V domains without direction control, supports up to 100 MHz down-translation at ≤30-pF load, delivers <5 Ω on-state resistance at 1.8 V/5 V translation, and operates across –40°C to +125°C for infotainment and ADAS domain controllers.

For engineers reviewing the LSF0108QWRKSRQ1 datasheet, LSF0108QWRKSRQ1 pinout, LSF0108QWRKSRQ1 application, or LSF0108QWRKSRQ1 equivalent, key selection criteria include verified 0.65 V compatibility (RKS only), EN-to-Vref_B biasing requirement, channel-specific reference voltage pairing, and absence of direction pin - all critical for I²C, SMBus, and PMBus interface bridging in safety-critical automotive systems.

Technical Context

The LSF0108QWRKSRQ1 implements passive MOSFET-based switch architecture with auto-bidirectional operation: when either A-side or B-side port is driven LOW, the internal pass transistor conducts, establishing low-impedance path; when HIGH, the switch turns OFF and clamps the opposite side to its reference voltage (Vref_A or Vref_B). This eliminates need for DIR control logic and supports mixed-mode translation across eight independent channels.

Vref_A and Vref_B are independently configurable supply references - Vref_A accepts 0.65 V to 5.5 V (RKS package only), Vref_B accepts 1.8 V to 5.5 V - enabling asymmetric voltage pairs like 0.65 V ↔ 3.3 V or 1.2 V ↔ 5 V. The EN pin must be tied directly to Vref_B and pulled up via ~200 kΩ resistor to enable translation; EN = LOW forces all I/Os into high-impedance state.

Key Specifications

Pinout & Package

LSF0108QWRKSRQ1 uses a 4.5 mm × 2.5 mm wettable-flank VQFN-20 (RKS) package with exposed thermal pad. Wettable flanks support automated optical inspection (AOI) of solder fillets and improve reflow yield in automotive PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXS0108E-Q1 and SN74AVC8T245-Q1, the LSF0108QWRKSRQ1 uniquely supports 0.65 V operation and true auto-bidirectional translation without DIR control - essential for next-gen automotive MCUs and safety-critical I²C/SMBus links where pin count, power, and layout simplicity are design constraints.

Availability

LSF0108QWRKSRQ1 is available at Aetrix Electronics and suitable for infotainment domain controllers, ADAS sensor hubs, body control modules, electric powertrain gateways, and passive safety ECUs requiring stable component supply across automotive production lifecycles.

Supply support for LSF0108QWRKSRQ1 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 and embedded processing technologies, with leadership in automotive-grade ICs, power management, and signal chain solutions.

The LSF0108QWRKSRQ1 belongs to TI's LSF family of auto-bidirectional level translators, designed specifically for AEC-Q100-compliant automotive interfaces requiring mixed-voltage interoperability without direction control - targeting infotainment, ADAS, and electrification systems.

FAQ

What voltage ranges does the LSF0108QWRKSRQ1 support for Vref_A and Vref_B?

The LSF0108QWRKSRQ1 supports Vref_A from 0.65 V to 5.5 V and Vref_B from 1.8 V to 5.5 V - but 0.65 V operation is exclusive to the RKS (VQFN) package. Vref_B must always be ≥ Vref_A + 0.6 V to ensure reliable translation. These ranges allow combinations such as 0.65 V ↔ 3.3 V, 1.2 V ↔ 5 V, or 2.5 V ↔ 3.3 V. The LSF0108QWRKSRQ1 datasheet specifies these limits under Recommended Operating Conditions section 6.3.

Does the LSF0108QWRKSRQ1 require external pull-up resistors?

Yes - pull-up resistors are mandatory on the high-voltage side (B-side) for up-translation, and recommended on the low-voltage side (A-side) if driving open-drain signals or if receiver leakage exceeds 1 µA. For push-pull drivers, A-side pull-ups may be omitted. The LSF0108QWRKSRQ1 itself contains no internal pull-ups; its operation relies entirely on external biasing per the application schematics in section 9.2 of the datasheet.

How is the EN pin configured on the LSF0108QWRKSRQ1?

The EN pin of the LSF0108QWRKSRQ1 must be tied directly to Vref_B and pulled up to Vref_B via a ~200 kΩ bias resistor. This configuration ensures proper channel enablement during normal operation. When EN is pulled LOW (e.g., by an open-drain driver), all A/B ports enter high-impedance state - a feature used for hot insertion and power sequencing. The LSF0108QWRKSRQ1 functional description in section 8.3.2 details this biasing requirement.

Can the LSF0108QWRKSRQ1 translate I²C signals reliably?

Yes - the LSF0108QWRKSRQ1 is explicitly validated for I²C, SMBus, and PMBus interfaces per its Applications section. Its auto-bidirectional architecture eliminates direction pin conflicts during I²C arbitration, and its ≤1.5 ns typical propagation delay at 30-pF load supports standard-mode (100 kHz) and fast-mode (400 kHz) I²C without timing violations. The LSF0108QWRKSRQ1 also supports 100 MHz down-translation, exceeding typical I²C speed requirements.

What is the significance of the wettable flank feature in the LSF0108QWRKSRQ1 package?

The wettable flank design on the LSF0108QWRKSRQ1's RKS package provides extended solderable surfaces on the side walls of the VQFN leads, enabling reliable side-fillet formation during reflow. This allows automated optical inspection (AOI) to verify solder joint quality - a critical requirement for zero-defect automotive manufacturing. The LSF0108QWRKSRQ1 mechanical drawings and packaging notes confirm wettable flank implementation per JEDEC MO-220 standards.