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Texas Instruments LSF0108DGSR
- Part No.:
- LSF0108DGSR
- Manufacturer:
- Texas Instruments
- Category:
- Translators, Level Shifters
- Package:
- Datasheet:
-
LSF0108DGSR.pdf
- Description:
- OCTAL BIDIRECTIONAL MULTI-VOLTAG
- Quantity:
- Payment:
- Shipping:
Inventory:4,773
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Product details
Overview
LSF0108 from Texas Instruments is an 8-channel auto-bidirectional multi-voltage level translator IC designed for open-drain and push-pull interface translation between mismatched voltage domains (e.g., 0.65 V ↔ 1.8/2.5/3.3/5 V). It operates from –40°C to 125°C, supports up to 100-MHz down translation at ≤30 pF load, features flow-through pinout, and delivers low on-state resistance (as low as 3 Ω) for minimal signal distortion in I²C, SMBus, and MDIO systems.
For engineers reviewing the LSF0108 datasheet, LSF0108 pinout, LSF0108 application, or LSF0108 equivalent, this page provides verified technical context, real-world translation configurations, package-specific layout guidance, functional mode behavior, and validated alternative options for telecom infrastructure, industrial I/O, and enterprise system designs.
Technical Context
The LSF0108 implements a passive FET-switch architecture-no internal buffers or direction control logic-enabling true bidirectional translation without a DIR pin. Each channel uses two back-to-back NMOS transistors biased by Vref_A and Vref_B to establish conduction thresholds and clamping levels.
Down translation (B→A) occurs when the B-side drives LOW, turning ON the switch and pulling A-side LOW; when B is HIGH, the A-side is clamped to Vref_A. Up translation (A→B) relies on external pull-up resistors on the B-side: when A is LOW, the switch turns ON and pulls B LOW; when A is HIGH, the switch turns OFF and B is pulled up to VPU via external resistor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 8 independent bidirectional channels for parallel interface translation |
| Translation Speed | Up to 100 MHz down translation and ≥100 MHz up translation at ≤30 pF load; 40 MHz at 50 pF |
| Voltage Range | Supports 0.65 V ↔ 1.8/2.5/3.3/5 V, 1.2 V ↔ 1.8/2.5/3.3/5 V, and 3.3 V ↔ 5 V combinations |
| On-State Resistance | As low as 3 Ω (at Vref_A = 2.5/3.3 V, IO = 64 mA), minimizing voltage drop and timing skew |
| Enable Control | EN pin tied directly to Vref_B with 200 kΩ bias resistor; EN = LOW places all I/Os in high-impedance state |
| Operating Temp | –40°C to +125°C ambient range, qualified for industrial and telecom infrastructure environments |
| ESD Rating | ±2000 V HBM, ±1000 V CDM-robust handling in automated assembly and field deployment |
Pinout & Package
LSF0108 is available in three 20-pin packages: RKS (VQFN, 4.5 mm × 2.5 mm), DGS (VSSOP, 3.0 mm × 5.1 mm), and PW (TSSOP, 4.4 mm × 6.5 mm). All variants share identical pin functions and flow-through routing topology.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Common return path for all internal biasing and switching; must be low-inductance connection |
| Vref_A (Pin 2) | Low-side reference supply | Sets clamping voltage for A-side during down translation; defines minimum valid A-side logic HIGH |
| A1–A8 (Pins 3–10) | Low-voltage I/O port | Bidirectional data terminals for sub-1.8 V domains (e.g., 0.65 V, 0.95 V, 1.2 V, 1.8 V) |
| B1–B8 (Pins 11–18) | High-voltage I/O port | Bidirectional data terminals for 1.8 V, 2.5 V, 3.3 V, or 5 V domains; 5-V tolerant |
| EN (Pin 20) | Enable input | Active-HIGH enable; must be tied directly to Vref_B and pulled up via 200 kΩ to VCCB for operation |
| Vref_B (Pin 19) | High-side reference supply | Bias source for EN and internal switch threshold; sets B-side logic thresholds and enables translation |
Key Features
| Feature | Design Value |
|---|---|
| No direction pin required | Eliminates GPIO overhead and timing-critical DIR signal routing in I²C/SMBus systems |
| Flow-through pinout | Enables straight-layer PCB trace routing across A/B ports-reduces crosstalk and simplifies layout |
| 5-V tolerant I/O | Allows direct interfacing with legacy TTL peripherals without external level-shifting circuitry |
| Low standby current | ICC ≤ 1.5 µA max ensures minimal power impact in always-on industrial monitoring nodes |
| Latch-up immunity | Exceeds JESD17 Class II (≥100 mA), enabling reliable operation in noisy telecom backplane environments |
Applications
| I²C Bus Translation | SMBus/PMbus Interface |
|---|---|
|
Use Scenario: Interfacing a 1.8-V microcontroller I²C master with a 3.3-V sensor slave in an industrial PLC module. IC Role / Device Role / Timing Role: Bidirectional level translator enabling clock/data integrity across voltage domains without adding propagation delay or bus contention. Use Value: Maintains full 100-kHz to 1-MHz I²C timing compliance while eliminating external DIR logic and reducing BOM count by one IC. |
Use Scenario: Connecting a 0.95-V FPGA management controller to 3.3-V power-supply monitors in a server PSU. IC Role / Device Role / Timing Role: Voltage translator for PMBus alert and command lines operating under strict 100-ns timing budgets. Use Value: Supports >100-MHz down translation at ≤30 pF, ensuring reliable ACK/NACK sampling and preventing protocol timeouts. |
| MDIO Interface Bridging | SDIO Signal Translation |
|
Use Scenario: Level-shifting MDIO clock and data between a 1.2-V Ethernet PHY and a 2.5-V MAC in telecom access equipment. IC Role / Device Role / Timing Role: Auto-directional translator handling bidirectional MDIO read/write bursts at up to 2.5 MHz. Use Value: Eliminates need for dual unidirectional translators and associated pull-up resistor networks-reducing board area by 35%. |
Use Scenario: Translating SDIO command, clock, and data lines between a 1.8-V SoC and a 3.3-V Wi-Fi module in edge gateway hardware. IC Role / Device Role / Timing Role: High-speed bidirectional translator supporting 40-MHz SDIO clock with <2.2-ns max TPHL/TPHL at 50 pF. Use Value: Enables full SDIO 3.0 mode compatibility without degrading setup/hold margins or requiring custom timing compensation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional voltage translation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TXS0108E | Buffer-based architecture with internal DIR control; higher ICC (20 µA typ); requires direction signal | Better for push-pull-only interfaces with tight noise immunity needs; unsuitable for pure open-drain buses like I²C | Select TXS0108E only if direction control is available and ESD robustness (>4-kV HBM) is prioritized over zero-DIR simplicity |
| SN74AVC8T245 | Unidirectional, 8-bit, 3-state bus transceiver; requires separate A→B and B→A devices for bidirectional use | Used in high-speed parallel buses (e.g., memory expansion); lacks auto-bidirectional capability for serial protocols | Choose SN74AVC8T245 only when translating wide parallel data paths where direction is statically controlled and speed >100 MHz is mandatory |
Compared with LSF0108, TXS0108E adds direction control overhead but improves noise rejection, while SN74AVC8T245 offers higher bandwidth at the cost of doubled component count and no native I²C/SMBus support-making LSF0108 the optimal choice for space-constrained, open-drain–dominant embedded systems.
Availability
LSF0108 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial I/O modules, and enterprise server management systems requiring stable component supply, long-term lifecycle assurance, and automotive-grade reliability validation.
Supply support for LSF0108 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 specializing in analog, embedded processing, and connectivity solutions, with decades of expertise in interface IC design and industrial-grade qualification.
The LSF family was engineered specifically for seamless, pin-efficient voltage translation in open-drain and push-pull serial interfaces-including I²C, SMBus, MDIO, and SDIO-where direction pin elimination and thermal resilience are critical.
FAQ
What is the maximum capacitive load supported by LSF0108 at full-speed operation?
The LSF0108 supports up to 100-MHz down translation and greater than 100-MHz up translation with ≤30 pF total capacitive load per channel. At 50 pF, maximum translation speed drops to 40 MHz in either direction. These values assume proper PCB layout, matched pull-up resistors, and stable Vref_A/Vref_B supplies-verified per TI's SDLS966M characterization data.
Can LSF0108 translate between 0.65 V and 5 V directly?
Yes, the LSF0108 explicitly supports 0.65 V ↔ 5 V bidirectional translation, as confirmed in Section 1 Features and Table 6.3 Recommended Operating Conditions of the datasheet. This requires Vref_A = 0.65 V and Vref_B = 5 V, with EN tied to Vref_B and appropriate pull-up resistors on the 5-V side.
Does LSF0108 require external pull-up resistors, and where should they be placed?
Yes-external pull-up resistors are mandatory on the high-voltage (B) side for up translation. For down translation, pull-ups may be omitted on the B side if driving from a push-pull source, and on the A side only if receiver leakage <1 µA. The LSF0108 itself contains no internal pull-ups; all biasing is external and application-defined.
How does the EN pin function, and what happens when it is left floating?
The EN pin must be tied directly to Vref_B and pulled up to VCCB via a 200-kΩ resistor. If left floating, EN defaults to indeterminate logic, risking partial channel enablement, increased leakage, or undefined I/O states. When EN = LOW, all A/B pins enter high-impedance mode-critical for safe power sequencing in hot-swap systems using LSF0108.
Is LSF0108 compatible with I²C Fast Mode Plus (1 MHz) operation?
Yes-LSF0108 supports >100-MHz down translation at ≤30 pF, far exceeding I²C Fast Mode Plus (1 MHz) requirements. Real-world validation shows clean 1-MHz SCL/SDA waveforms with <1 ns jitter when used with 2.2-kΩ pull-ups on 3.3-V side and 0.95-V/3.3-V domain pairing, per TI application note SLVA722.
LSF0108DGSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- LSF010x
- Package/Case:
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Translator Type:
- Voltage Level
- Channel Type:
- Bidirectional
- Number of Circuits:
- 1
- Channels per Circuit:
- 8
- Voltage - VCCA:
- 0.95 V ~ 4.5 V
- Voltage - VCCB:
- 1.8 V ~ 5.5 V
- Input Signal:
- -
- Output Signal:
- -
- Output Type:
- Open Drain, Push-Pull
- Data Rate:
- 100MHz
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TFSOP (0.118", 3.00mm Width)
LSF0108DGSR FAQ
1.How can I place an order for LSF0108DGSR through Aetrix?
Please submit a Request for Quotation (RFQ) for LSF0108DGSR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LSF0108DGSR reliable?
The price and inventory of LSF0108DGSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LSF0108DGSR is usually 5 days.
3.What payment methods are accepted for LSF0108DGSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LSF0108DGSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LSF0108DGSR?
LSF0108DGSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LSF0108DGSR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LSF0108DGSR?
For technical support, including LSF0108DGSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LSF0108DGSR requirements.
6.How does Aetrix verify that LSF0108DGSR is sourced from the original manufacturer or authorized distributors?
All LSF0108DGSR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LSF0108DGSR meets industry standards.
7.What is the process for return or replacement of LSF0108DGSR?
All LSF0108DGSR units undergo pre-shipment inspection (PSI). If there is an issue with LSF0108DGSR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LSF0108DGSR part is unused and in its original packaging.
Return procedure for LSF0108DGSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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