LSF0108PWR - 8-Ch Bidirectional Level Translator | TI
MPN: LSF0108PWR ✓ Hoạt độngLSF0108PWR Tóm tắt
A voltage level translator is an interface IC that lets digital signals in different voltage domains communicate safely by shifting signal levels as they pass between two logic families. Within the system hierarchy, a level translator is a type of logic interface IC within the broader integrated circuits category. The LSF0108 uses a pass-gate (series MOSFET) architecture with external pull-up resistors, providing automatic direction sensing without a direction-control pin.
Key features include bidirectional translation without a direction pin, support for both open-drain and push-pull drivers, and an operating temperature range of -40C to +125C. The LSF family covers the 0.95 V to 5 V translation range, spanning nearly all common logic levels (1.2V, 1.8V, 2.5V, 3.3V, 5V). Low standby current and the compact TSSOP-20 footprint suit space-constrained mixed-voltage boards.
Technically, each channel employs a series pass transistor. Direction is determined automatically by whichever side drives, eliminating direction-control signals and simplifying firmware. The reference side (VREF_A or VREF_B) sets the lower voltage domain; pull-up resistors on the opposite side set the higher domain.
Typical applications include I2C bus level shifting between 1.8V and 3.3V or 5V domains, UART interfacing between microcontrollers and peripherals, SPI communication between different logic voltages, and mixed-voltage sensor or memory interfaces.
Design tip: size external pull-up resistors according to bus capacitance and target speed (1-10 kOhm for 400 kHz I2C). Correct VREF sequencing at power-up is essential; refer to TI datasheet SCPS229 for power-up requirements.
Bộ thay thế dễ dàng lắp đặt cho LSF0108PWR — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với LSF0108PWR (cùng hình factor và footprint) — khác nhau ở Channels, Features, Output Type.
LSF0108PW-Q100J
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LSF0108QPWRQ1
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →TXS0108EQPWRQ1
⚡ Đồng góiLiên hệ để biết giá
Xem tài liệu →TXB0108QPWRQ1
⚡ Đồng góiLiên hệ để biết giá
Xem tài liệu →TXB0108PWR
⚡ Đồng gói ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →LSF0108PWR Thông số kỹ thuật
| Translator Type | Voltage Level Translator |
| Kênh | 8 |
| Circuits | 1 |
| Direction | Bidirectional (auto-direction sensing) |
| A-Side Voltage Range | 0 V to 5 V |
| B-Side Voltage Range | 0 V to 5 V |
| Translation Range (Family) | 0.95 V to 5 V |
| Propagation Delay | Approx. 1.5 ns |
| Kiểu đầu ra | Open-Drain / Push-Pull |
| Tính năng | No direction pin required |
| Nhiệt độ hoạt động | -40C to +125C |
| Hộp | 20-TSSOP (PW) |
| Kiểu lắp đặt | Surface Mount |
| Applications | I2C, SMBus, UART, SPI |
| Logic Family Compatibility | Multi-voltage level translation |
| Trạng thái RoHS | Compliant |
Cấu hình chân LSF0108PWR
| Chân 1 | A1 — A-side data port 1 (low-voltage domain) |
| Chân 2 | A2 — A-side data port 2 |
| Chân 3 | A3 — A-side data port 3 |
| Chân 4 | A4 — A-side data port 4 |
| Chân 5 | GND — Ground |
| Chân 6 | A5 — A-side data port 5 |
| Chân 7 | A6 — A-side data port 6 |
| Chân 8 | A7 — A-side data port 7 |
| Chân 9 | A8 — A-side data port 8 |
| Chân 10 | OE — Output enable (connect high to enable) |
| Chân 11 | B8 — B-side data port 8 |
| Chân 12 | B7 — B-side data port 7 |
| Chân 13 | B6 — B-side data port 6 |
| Chân 14 | B5 — B-side data port 5 |
| Chân 15 | GND — Ground |
| Chân 16 | B4 — B-side data port 4 |
| Chân 17 | B3 — B-side data port 3 |
| Chân 18 | B2 — B-side data port 2 |
| Chân 19 | B1 — B-side data port 1 |
| Chân 20 | VREF_B — B-side reference voltage supply |
Ứng dụng tiêu biểu
LSF0108PWR phù hợp cho 6 Áp dụngs: I2C Bus Level Shifting, UART Interface Translation, SPI Mixed-Voltage Interfacing, Industrial Control Systems, Portable and Battery-Powered Devices, Automotive Infotainment and Body Electronics.
I2C Bus Level Shifting
The LSF0108PWR is purpose-built for I2C and SMBus level translation between 1.8V, 3.3V, and 5V domains. Its pass-gate architecture with external pull-up resistors (typically 1-10 kOhm) supports open-drain bidirectional signaling with automatic direction sensing, so no DIR pin or firmware control is needed. The approx. 1.5 ns pass-through delay adds negligible timing overhead even at 400 kHz Fast-mode or 1 MHz Fast-mode Plus operation, provided pull-ups are sized to the bus capacitance.
Được đề xuất
UART Interface Translation
UART links between a 1.8V microcontroller and a 3.3V or 5V peripheral run through the LSF0108PWR with one channel per TX/RX line. Push-pull UART signals pass through the series pass transistor with about 1.5 ns delay; pull-up resistors restore the high level on the higher-voltage side. Because the LSF is direction-agnostic, it handles full-duplex TX and RX lines without any control signal, simplifying mixed-voltage MCU-to-module designs such as GPS, Bluetooth, or cellular modules.
Được đề xuất
SPI Mixed-Voltage Interfacing
SPI clocks up to tens of MHz remain usable through the LSF0108PWR thanks to its ~1.5 ns propagation delay, though series pass-gate translators attenuate signal swing and rely on pull-ups, so keep traces short and use low-value pull-ups (1-2 kOhm) for high-speed SCK and MOSI lines. It is commonly used to connect 3.3V SPI flash or sensors to 1.8V MCU domains. For very high SPI rates, evaluate TXS0108E or dedicated push-pull translators instead.
Được đề xuất
Industrial Control Systems
Industrial mixed-voltage backplanes often combine 5V legacy logic with 3.3V or 1.8V modern controllers. The LSF0108PWR bridges these domains across eight channels in one TSSOP-20, operating from -40C to +125C to meet industrial temperature requirements. Its low standby current suits always-on control nodes, and auto-direction sensing means no firmware changes when migrating an existing 5V board to a lower-voltage processor family.
Được đề xuất
Portable and Battery-Powered Devices
Battery-powered designs frequently pair a low-voltage (1.8V) low-power MCU with 3.3V sensors, displays, or memory cards. The LSF0108PWR consumes minimal standby current and requires no active drivers, making it energy-efficient for sleep-mode retention. Eight channels in a compact 20-TSSOP conserve board area in wearables and handheld instruments, and pull-up resistor values can be increased (10 kOhm) to further cut idle current on slow buses like I2C.
Được đề xuất
Automotive Infotainment and Body Electronics
For automotive designs, the pin-compatible Nexperia LSF0108PW-Q100J (AEC-Q100) and TI's TXB0108QPWRQ1 provide qualified 8-bit translation options on the same TSSOP-20 footprint. Automotive ECUs routinely mix 5V sensor rails with 3.3V processors; the LSF architecture's open-drain support handles LIN/K-line style and I2C diagnostics buses, while the -40C to +125C range covers under-dash and engine-bay ambient conditions per the base device rating.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho LSF0108PWR — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | LSF0108PW-Q100J | LSF0108 | TXS0108EQPWR | TXB0108QPWRQ1 |
|---|---|---|---|---|---|
| Package | TSSOP-20 (PW) | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same |
| Brand | Texas Instruments | Nexperia | Diodes Incorporated | Texas Instruments | Texas Instruments |
| Channels | 8 | 8 | 8 | 8 | 8 |
| Architecture | Pass-gate with external pull-ups | Pass-gate with external pull-ups | Pass-gate with external pull-ups | Integrated one-shot drivers | Integrated drivers (auto-direction) |
| Voltage Range | 0.95 V to 5 V | 0.95 V to 5 V | 0.95 V to 5 V | 1.2 V to 3.6 V (VCCA) / 1.65-5.5 V (VCCB) | 1.2 V to 3.6 V / 1.65-5.5 V |
| Open-Drain Support | Yes (native) | Yes (native) | Yes (native) | Limited (weak one-shot) | Limited |
| Direction Pin | None (auto) | None (auto) | None (auto) | None (auto) | None (auto) |
| Automotive Grade | No | Yes (AEC-Q100) | No | No (Q1 variant exists) | Yes (AEC-Q100) |
Bảo phân biệt quan trọng
- Native open-drain bus support (I2C/SMBus) (vsTXS0108EQPWR)
- Wider low-voltage capability (vsTXB0108QPWRQ1)
- Automotive-qualified drop-in available (vsLSF0108PW-Q100J)
Ghi chú thiết kế
Power-up sequencing is critical: the VREF supply of the reference (lower-voltage) side must be stable before or rise together with the other rail, otherwise outputs can be undefined or latch incorrectly. TI datasheet SCPS229 section on power-up requirements details the valid sequencing. Add a supervisor or RC delay if rail order is uncontrolled.
The LSF pass-gate attenuates signal swing, so the high level on the higher-voltage side is set entirely by the pull-up resistor. Size pull-ups against bus capacitance: 1-2 kOhm for fast SPI/SCK lines, 4.7-10 kOhm for 100-400 kHz I2C. Undersized (too high) pull-ups round rising edges and limit maximum bus speed.
Place 0.1 uF decoupling capacitors at VREF_A and VREF_B pins within 2 mm of the package, and route the eight translated traces as short, direct point-to-point connections. Because the pass-gate is bidirectional, avoid stubs and bus contention: only one driver may be active on a channel at a time.
Thông tin tuân thủ
RoHS compliance per TI product page. Not AEC-Q100 qualified - use Nexperia LSF0108PW-Q100J for automotive.
