SN74LVTH245APWR - 3.3V ABT Octal Bus Transceiver TSSOP-20 | TI
料号： SN74LVTH245APWR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.95 | $0.95 |
| 10 | $0.78 | $7.80 |
| 100 | $0.58 | $58.00 |
| 500 | $0.46 | $230.00 |
| 1,000 | $0.39 | $390.00 |
| 2,000 | $0.34 | $680.00 |
SN74LVTH245APWR 概述
A bus transceiver is a buffer/driver that electrically interfaces and routes signals between two buses. The 74x245 family is the industry-standard octal bidirectional bus transceiver; the LVT variant adds low-voltage (3.3 V) operation with TTL-compatible input thresholds, enabling direct interface to legacy 5-V TTL logic while running the part on a 3.3-V rail. The '245' family falls under the broader logic IC hierarchy: bus transceiver -> buffer/driver -> interface IC -> standard logic.
Key features include bidirectional data flow controlled by a single DIR pin, an active-low OE (output enable) for 3-state output control, partial-power-down capability via Ioff and live-insertion support, bus-hold circuitry on data inputs (eliminates need for external pull-up resistors), and ±24 mA balanced output drive. The device uses TI's Advanced BiCMOS Technology (ABT) for low static power dissipation combined with high switching speed.
Typical propagation delay is 3.5 ns (typical) at 3.3 V VCC and 25 °C, making it suitable for moderately fast bus interfaces including PCI, memory buses, and backplane buffering. The TSSOP-20 package provides a compact 6.5 mm x 4.4 mm footprint suitable for high-density PCB designs.
Common applications include memory data routing, address/control bus buffering, board-to-board interface in telecom equipment, industrial automation backplanes, and level translation between 3.3 V logic and 5-V TTL inputs. The bus-hold feature is particularly valuable in hot-swap and live-insertion scenarios where floating inputs must be avoided.
When designing with this device, ensure DIR is not allowed to float (use a defined logic level via bus-hold or external pull resistor) to prevent bus contention. Decoupling: place a 0.1 µF X7R ceramic capacitor as close as possible to the VCC pin to suppress switching noise. For mixed-voltage designs, confirm that the higher-voltage side does not exceed the absolute maximum ratings of 4.6 V on any input or output.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the manufacturer datasheet to accelerate your 74LVT245 selection.
直接替换替代料： SN74LVTH245APWR ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： SN74LVTH245APWR （相同外形与封装尺寸） ——差异在于 Live Insertion Support, Operating Temperature, Logic Type, Package.
快速对比工具——选择替代料号进行并排对比：
SN74LVTH245APWRG4
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVTH245APW
✅ 直接替换✓ 有现货
$0.69 / 个
查看数据手册 →SN74LVTH245AIPWREP
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVTH245A-EP
✅ 直接替换📋 参考替代料（不在目录中）
74LVT245BPW,112
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVT245BPWR
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVTH245APWR 最大额定值与电气特性
| 功能 | Octal Bus Transceiver with 3-State Outputs |
| Logic Family | LVT (Low-Voltage Technology) / ABT |
| Number of Elements | 1 |
| Bits per Element | 8 |
| Logic Type | Transceiver, Non-Inverting |
| 输出类型 | 3-State |
| Supply Voltage (VCC) | 2.7 V to 3.6 V |
| Output Drive (IOH/IOL) | 64 mA source / 32 mA sink |
| Input Compatibility | TTL-compatible |
| 工作温度 | -40 °C to +85 °C |
| 封装 | TSSOP-20 (PW) |
| Package Dimensions | 6.5 mm x 4.4 mm |
| 安装类型 | Surface Mount |
| MSL 等级 | 1 (unlimited at <30 °C/85 % RH) |
| RoHS 状态 | Compliant |
| Bus-Hold Feature | Yes (on data inputs) |
| Live Insertion Support | Yes (Ioff / PU3S) |
| Lead-Free / Halogen-Free | Yes (per TI product page) |
SN74LVTH245APWR 引脚配置
| 引脚 1 | DIR — Direction control input (HIGH = A to B, LOW = B to A) |
| 引脚 2 | OE — Output enable, active-low (HIGH = outputs in high-impedance state) |
| 引脚 3 | A1 — A-bus data input/output 1 |
| 引脚 4 | A2 — A-bus data input/output 2 |
| 引脚 5 | A3 — A-bus data input/output 3 |
| 引脚 6 | A4 — A-bus data input/output 4 |
| 引脚 7 | A5 — A-bus data input/output 5 |
| 引脚 8 | A6 — A-bus data input/output 6 |
| 引脚 9 | A7 — A-bus data input/output 7 |
| 引脚 10 | A8 — A-bus data input/output 8 |
| 引脚 11 | GND — Ground |
| 引脚 12 | B8 — B-bus data input/output 8 |
| 引脚 13 | B7 — B-bus data input/output 7 |
| 引脚 14 | B6 — B-bus data input/output 6 |
| 引脚 15 | B5 — B-bus data input/output 5 |
| 引脚 16 | B4 — B-bus data input/output 4 |
| 引脚 17 | B3 — B-bus data input/output 3 |
| 引脚 18 | B2 — B-bus data input/output 2 |
| 引脚 19 | B1 — B-bus data input/output 1 |
| 引脚 20 | VCC — Supply voltage (3.3 V nominal) |
典型应用
SN74LVTH245APWR 适用于 6 应用s: Memory Data Bus Buffering, Board-to-Board Interface in Industrial Backplanes, 5-V TTL to 3.3-V Level Translation Interface, LED Display Multiplex Drive Buffering, Test & Measurement Equipment Digital I/O, Telecom Line Card Bus Isolation.
Memory Data Bus Buffering
The SN74LVTH245APWR's 8-bit bidirectional interface and 64 mA source / 32 mA sink drive make it well-suited for buffering memory data buses between a microcontroller and external SRAM or DDR memories. The DIR/OE control allows the same data lines to be shared with a DMA controller or coprocessor, with the '245 acting as the bus arbiter. With propagation delays of approximately 3-4 ns, it adds minimal latency to 50-100 MHz memory operations. The bus-hold on data inputs eliminates floating inputs during bus contention, critical for hot-pluggable memory cards.
推荐
Board-to-Board Interface in Industrial Backplanes
Industrial backplanes require reliable high-drive bus buffering between plug-in cards, and the SN74LVTH245APWR is purpose-built for this role. Its ±24 mA balanced drive fans out to multiple downstream receivers on a backplane while maintaining 3.3-V signal integrity, and the TTL-compatible inputs accept 5-V control signals from legacy interface cards. Live-insertion support (Ioff) allows hot-swap of cards without powering down the entire rack. The TSSOP-20 package's 6.5 mm footprint leaves room for card-edge connectors and ESD protection diodes on dense backplane cards.
推荐
5-V TTL to 3.3-V Level Translation Interface
The SN74LVTH245APWR's TTL-compatible inputs accept 5-V TTL logic levels even when its VCC is only 3.3 V, making it ideal for bridging 5-V legacy peripherals to modern 3.3-V controllers. The 74LVT input thresholds (VIH = 2.0 V, VIL = 0.8 V) align precisely with TTL specs, and outputs swing rail-to-rail at 3.3 V to drive CMOS loads. Each '245 channel can handle one direction of translation via DIR control; for full bidirectional translation, use two '245s back-to-back. This is the de-facto interface between legacy 5-V peripheral buses and modern FPGAs.
推荐
LED Display Multiplex Drive Buffering
Large LED matrix displays (16x32, 32x64) need strong drive current to multiplex rows and columns at low duty cycle without flicker, and the SN74LVTH245APWR provides the necessary ±24 mA drive without external driver transistors. The 8-bit width maps directly to a half-row (8 columns) of common multiplexed displays, and the DIR pin enables row/column multiplexing through a single shared bus. With 3.3-V supply and 5-V tolerant inputs, it interfaces cleanly with LED driver chips like the TLC5947 or HT1632. The TSSOP-20 footprint keeps PCB area minimal in compact sign designs.
推荐
Test & Measurement Equipment Digital I/O
Test instruments and logic analyzers require buffered, high-drive digital I/O that can both source and sink current into cables and backplanes. The SN74LVTH245APWR's 64 mA source / 32 mA sink capability ensures clean logic edges across 1-2 meter cable runs, and the bus-hold feature prevents floating inputs on disconnected cables. The 3-state outputs allow multiple instruments to share a common test bus. With the OE pin under software control, individual channels can be selectively enabled during automated test sequences - a common requirement in ATE (automatic test equipment) designs.
推荐
Telecom Line Card Bus Isolation
Telecom line cards (T1/E1, DSL, GPON) require robust bus isolation between the central processor and multiple hot-pluggable line interface units. The SN74LVTH245APWR provides bidirectional buffering with Ioff (partial-power-down) leakage under 50 µA, allowing individual line cards to be removed without disrupting system operation. The TTL-compatible inputs accept 5-V control signals from telecom ASICs, while the 3.3-V VCC aligns with modern FPGA/MCU rails. Live-insertion tested to TI specifications, it ensures glitch-free insertion/removal cycles in central-office environments.
推荐
推荐产品汇总
工程参考数据： SN74LVTH245APWR ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | SN74LVTH245APWRG4 | SN74LVTH245APW | SN74LVTH245A-EP | SN74LVTH245AIPWREP | 74LVT245BPW,112 | SN74LVT245BPWR |
|---|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Nexperia | Texas Instruments |
| Package | TSSOP-20 (PW) | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same | TSSOP-20 (PW) - same |
| Operating Voltage (VCC) | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V |
| Output Drive (mA) | 64 mA source / 32 mA sink | 64 / 32 | 64 / 32 | 64 / 32 | 64 / 32 | 32 / 32 | 32 / 32 |
| Bus-Hold on Inputs | Yes | Yes | Yes | Yes | Yes | No | No |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -55 °C to +125 °C (MIL) | -40 °C to +85 °C | -40 °C to +85 °C |
| Ioff / Live-Insertion | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Approx. Unit Price (USD, qty 1) | 0.95 | 0.95 | 0.95 | 1.80 | 4.50 | 0.45 | 0.55 |
关键差异点
- Higher output drive (64 mA source vs 32 mA source) （对比 74LVT245BPW,112)
- Built-in bus-hold eliminates external pull-up resistors （对比 SN74LVT245BPWR)
- Same TSSOP-20 footprint across full TI LVT245 family （对比 SN74LVTH245AIPWREP)
设计说明
Place a 0.1 µF X7R ceramic decoupling capacitor as close as possible to the VCC pin (pin 20) of the SN74LVTH245APWR, with a trace length under 5 mm to minimize parasitic inductance. For designs with multiple '245 chips sharing a power rail, add a 10 µF bulk tantalum or ceramic capacitor at the rail entry point. The TSSOP-20 package has relatively low thermal mass (~70 °C/W theta-JA), so high-frequency switching can elevate junction temperature - derate above 50 MHz operation or use additional copper pour under the exposed pad area to reduce junction temperature rise.
The SN74LVTH245APWR's edge rate is approximately 2-3 ns at 50 pF load. For capacitive loads above 100 pF (long PCB traces, multiple receivers), use a series damping resistor (22-33 Ω) near the output to limit overshoot and ringing. The DIR pin should never be allowed to float - either tie it to VCC or GND via a defined logic level, or rely on bus-hold (which is present on data I/O but not on control inputs DIR/OE). For high-speed designs, keep trace lengths matched within 5 mm to avoid skew across the 8 bits.
Do not apply voltage above 4.6 V to any pin (per absolute maximum ratings) - even though the device is TTL-compatible, sustained over-voltage on outputs can trigger latch-up. When using SN74LVTH245APWR for 5-V-to-3.3-V translation, ensure the 5-V driver outputs do not exceed the VCC + 0.5 V limit; if they can, add a series resistor (1 kΩ) at each input. Also verify that the higher-voltage side never goes above the absolute maximum - using the SN74HCT245 family is safer for true 5-V environments since it operates from 5 V VCC natively.
Route the 8-bit A-bus and B-bus pairs with matched impedance (50 Ω single-ended to ground is typical) and keep the DIR/OE control signals perpendicular or routed on a separate layer to avoid coupling. The TSSOP-20 package's 0.65 mm pin pitch requires 4-5 mil traces with 4 mil clearance - verify your PCB manufacturer's minimum trace/space rules. Place the decoupling capacitor directly under or beside the IC on the same layer, with the via-in-pad technique preferred to minimize loop area. Estimated: with 1 oz copper and 4-layer stackup, the VCC/GND plane capacitance provides ~0.5 nF distributed decoupling per square inch.
合规信息
RoHS and REACH compliant per TI product page. Lead-free (Pb-free) and halogen-free finish per TI's 'Green' product designation. Not AEC-Q100 qualified - use SN74LVTH245A-EP for enhanced-product traceability or qualify another variant for automotive.
