SN74LVC2G125DCUR - Dual Bus Buffer 3-State Output | Texas Instruments
MPN： SN74LVC2G125DCUR ✓ 啟用中SN74LVC2G125DCUR 概覽
A bus buffer (also called a line driver or 3-state buffer) is a non-inverting signal-routing building block used to isolate a source from a shared bus, increase fan-out, or provide bidirectional control over which device drives a line. Buffers belong to the broader logic IC family (combinational logic), which sits under the digital semiconductor hierarchy. The SN74LVC2G125 implements LVC (Low-Voltage CMOS) technology, which is a sub-family of CMOS logic optimized for low static power and 5 V-tolerant I/O on mixed-voltage rails.
Key features include a typical propagation delay (tpd) of 3.7 ns at 3.3 V, ±24 mA output drive capability (IoL/IoH) at 3.3 V, support of partial-power-down applications through Ioff circuitry that disables outputs to prevent backflow current, and an operating temperature range of -40 °C to +125 °C. The LVC2G family provides 5.5 V tolerance on the input pins even when VCC is lower, enabling level translation between 1.8 V, 3.3 V, and 5 V domains.
From an architectural perspective, the device uses TI's EPIC (Enhanced-Performance Implanted CMOS) submicron process, giving it ESD protection exceeding 2000 V per MIL-STD-883 Method 3015 and 200 V using the machine model (C = 200 pF, R = 0 Ω). Each buffer consists of an input stage, an output-enable gate, and a 3-state CMOS output stage with controlled rise/fall symmetry.
Typical applications include I2C/SPI bus isolation, point-to-point signal buffering on memory and module interfaces, GPIO expansion in microcontroller boards, level shifting between 1.8 V / 3.3 V / 5 V logic domains, and fan-out extension for low-drive clock or reset lines. The compact VSSOP-8 footprint makes it suitable for handheld and space-constrained designs.
When designing with this device, ensure the OE pin is driven to a defined logic level (tie to GND through a pull-down if unused) to prevent the output from floating into a high-impedance state unintentionally. Decoupling VCC with a 0.1 µF ceramic capacitor placed within 5 mm of the supply pin is recommended for clean switching at high frequencies.
This page synthesizes real-time distributor pricing, validated drop-in alternatives, and practical PCB design guidance for the SN74LVC2G125DCUR that goes beyond the manufacturer datasheet alone, helping engineers evaluate sourcing and design trade-offs at a glance.
直接替換替代品，適用於 SN74LVC2G125DCUR — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： SN74LVC2G125DCUR （相同外形與佔位） — 差異在於 Package, Operating Temperature, RoHS Status, ESD Protection (HBM), Function.
SN74LVC2G125DCURG4
✅ 直接替換📋 參考替代品（不在目錄中）
SN74LVC2G125DCUT
✅ 直接替換📋 參考替代品（不在目錄中）
SN74LVC2G125DCTR
✅ 直接替換📋 參考替代品（不在目錄中）
SN74LVC2G125YZPR
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
74LVC2G125DCURE4
✅ 直接替換📋 參考替代品（不在目錄中）
SN74LVC2G125DCU
✅ 直接替換📋 參考替代品（不在目錄中）
SN74LVC2G125DCUR 最大額定值與電氣特性
| Logic Type | Buffer, Non-Inverting |
| Number of Elements | 2 |
| Bits per Element | 1 |
| 輸出類型 | 3-State |
| Supply Voltage (VCC) | 1.65 V to 5.5 V |
| Input Voltage Tolerance | 5.5 V (5.5 V tolerant inputs) |
| Output Drive (IoL/IoH) at 3.3 V | ±24 mA |
| Output Enable | Active-Low (OE-bar), one per channel |
| 工作溫度 | -40 °C to +125 °C |
| 封裝 | 8-pin VSSOP (DCU) |
| 安裝類型 | Surface Mount |
| MSL 等級 | 1 (per TI packaging info) |
| RoHS 狀態 | Compliant |
| Lead-Free | Yes |
| Process Technology | EPIC CMOS (TI submicron) |
| ESD Protection (HBM) | >2000 V per MIL-STD-883 Method 3015 |
SN74LVC2G125DCUR 腳位配置
| 腳位 1 | 1OE — Output Enable for channel 1 (active LOW) |
| 腳位 2 | 1A — Channel 1 input |
| 腳位 3 | 2Y — Channel 2 output |
| 腳位 4 | GND — Ground |
| 腳位 5 | 2A — Channel 2 input |
| 腳位 6 | 1Y — Channel 1 output |
| 腳位 7 | 2OE — Output Enable for channel 2 (active LOW) |
| 腳位 8 | VCC — Supply voltage (1.65 V to 5.5 V) |
典型應用
SN74LVC2G125DCUR 適用於 6 應用s: I2C / SPI Clock and Data Line Buffering, Level Translation Between 1.8 V / 3.3 V / 5 V Domains, GPIO Expansion on Microcontroller Boards, Fan-Out Extension for Clock and Reset Lines, Shared Bus Multiplexing for Memory / Module Interfaces, Industrial Control Signal Conditioning.
I2C / SPI Clock and Data Line Buffering
The SN74LVC2G125DCUR is well-suited for buffering unidirectional clock and data lines in I2C and SPI interfaces because its 5.5 V-tolerant inputs and 1.65-5.5 V VCC range allow level shifting between 1.8 V microcontrollers and 3.3 V or 5 V peripherals without external translators. Placed between the controller SCK/MOSI pins and the peripheral side with the OE pin tied low for always-enabled, the device's ±24 mA output drive can fan out to multiple downstream devices. Unlike a passive pull-up, this active buffer provides controlled rise/fall times that improve signal integrity on long PCB traces. Note: for bidirectional SDA isolation use a dedicated I2C buffer like TCA9517 instead.
推薦
Level Translation Between 1.8 V / 3.3 V / 5 V Domains
The SN74LVC2G125DCUR is ideal for voltage domain translation because it accepts 5.5 V on its inputs even when VCC is as low as 1.65 V, enabling up-translation from 1.8 V GPIO to 3.3 V or 5 V peripherals. The output drive is referenced to VCC, so a 3.3 V VCC produces 3.3 V outputs regardless of input voltage. With two independent buffers per IC, it replaces two discrete level-shifters (e.g., discrete MOSFET circuits) on the same PCB footprint. The LVC family's low static current (~10 µA ICC) makes it suitable for battery-powered IoT devices that must bridge to legacy 5 V sensors.
推薦
GPIO Expansion on Microcontroller Boards
The SN74LVC2G125DCUR enables GPIO expansion and bus isolation on microcontroller boards where the MCU has insufficient output pins or where multiple slaves share a common bus. By placing each device's output-enable pin under an MCU GPIO, the designer can selectively connect or disconnect downstream peripherals without power-cycling them, enabling hot-swappable daughter cards and modular architectures. The VSSOP-8 footprint occupies only 2.3 x 2.0 mm of board area, ideal for compact designs like wearables and sensor modules.
推薦
Fan-Out Extension for Clock and Reset Lines
The SN74LVC2G125DCUR extends fan-out for low-current clock and reset lines where the source device cannot drive multiple loads simultaneously. With ±24 mA output drive at 3.3 V, a single MCU clock pin can drive multiple peripherals through one buffer per load group, preventing rise/fall time degradation. The 3-state OE enables clean multiplexing - tie one buffer always-enabled (OE=low) for the active clock, and use the second buffer for a gated reset that is high-impedance during normal operation.
推薦
Shared Bus Multiplexing for Memory / Module Interfaces
The SN74LVC2G125DCUR enables shared-bus multiplexing between two source devices driving a common load, which is essential in multi-master memory systems and modular interface designs. With OE controlled by an arbiter, exactly one buffer drives the bus at any time while the other enters high-impedance, preventing contention. The 3-state output's sub-5 ns enable/disable time supports MHz-rate bus turnaround. Common use cases include selecting between primary and backup memory, or arbitrating between internal and external processor buses.
推薦
Industrial Control Signal Conditioning
The SN74LVC2G125DCUR is well-suited for industrial control signal conditioning over its -40 °C to +125 °C operating temperature range and ESD protection exceeding 2000 V per MIL-STD-883. Used as the input buffer between field-side sensors/actuators and a controller-side MCU, it provides noise immunity through controlled output edges and protects downstream logic through 5.5 V input tolerance. The EPIC CMOS process gives reliable operation in factory-automation environments with electromagnetic interference.
推薦
推薦產品摘要
工程參考資料，適用於 SN74LVC2G125DCUR — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | SN74LVC2G125DCURG4 | SN74LVC2G125DCUT | SN74LVC2G125DCTR | SN74LVC2G125YZPR | 74LVC2G125DCURE4 | SN74LVC2G125DCU |
|---|---|---|---|---|---|---|---|
| Package | 8-VSSOP (DCU) 2.3x2.0 mm | 8-VSSOP (DCU) - same | 8-VSSOP (DCU) - same | 8-SSOP (DCT) 2.95x2.8 mm | 8-DSBGA (YZP) wafer-level | 8-VSSOP (DCU) - same | 8-VSSOP (DCU) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Logic Function | Dual non-inverting buffer | Dual non-inverting buffer | Dual non-inverting buffer | Dual non-inverting buffer | Dual non-inverting buffer | Dual non-inverting buffer | Dual non-inverting buffer |
| Supply Voltage (VCC) | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V |
| Output Drive at 3.3 V | ±24 mA | ±24 mA | ±24 mA | ±24 mA | ±24 mA | ±24 mA | ±24 mA |
| Output Enable Polarity | Active-Low (per channel) | Active-Low | Active-Low | Active-Low | Active-Low | Active-Low | Active-Low |
| Operating Temperature | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
| RoHS / Lead-Free | Compliant / Yes | Compliant / Yes | Compliant / Yes | Compliant / Yes | Compliant / Yes | Compliant / Yes | Compliant / Yes |
主要差異化特點
- Compact dual-channel VSSOP-8 footprint (對比SN74LVC1G125DCKR (single-channel SC-70))
- 5.5 V input tolerance with low-voltage VCC (對比Generic CMOS buffers without Ioff)
- Independent OE per channel (對比Single OE buffer variants)
設計說明
Decouple VCC (pin 8) with a 0.1 µF X7R ceramic capacitor placed within 5 mm of the supply pad, plus a 1 µF bulk capacitor on the same VCC rail. The SN74LVC2G125 has switching transients of tens of mA during output edges; insufficient decoupling will cause VCC droop that propagates to neighboring logic and may corrupt the buffered signal. Connect the GND pad directly to the ground plane via a short via array.
The VSSOP-8 (DCU) package is 2.3 mm × 2.0 mm with 0.5 mm pitch pads - use the TI land pattern from the package datasheet SCES644 for accurate footprints. Expose the GND pad underneath the package to a continuous ground plane; do not route signal traces under the body. For high-speed signals (>50 MHz), use controlled-impedance traces (typically 50 Ω single-ended) and avoid 90° bends.
Always drive the OE pin to a defined logic level - do not leave it floating, or the output state becomes undefined and may oscillate or float into high-Z unintentionally. Tie unused OE inputs to GND via 10 kΩ pull-down resistors to keep outputs enabled by default. For level-translation use cases, ensure VCC of the buffer matches the HIGH-level voltage of the receiving side, since output swing is VCC-referenced.
The ±24 mA output drive is rated at 3.3 V VCC; at lower VCC (e.g., 1.8 V), the actual drive current is reduced proportionally and may not meet fast rise-time requirements for long traces. For clock distribution at >50 MHz with cable or backplane loads, use a stronger buffer like SN74LVC2G17 or SN74LVC1G34. Add a small series resistor (22-33 Ω) near the output to dampen transmission-line reflections on long traces.
合規資訊
RoHS compliant per TI product page and distributor listings. AEC-Q100 not applicable for standard grade - the part is qualified to industrial temperature range -40C to +125C. Halogen-free status not explicitly stated in verified data - marked unknown per data authenticity rules.
