SN74LVTH245APWG4 - 3.3V ABT Octal Bus Transceiver | Texas Instruments
料号： SN74LVTH245APWG4 ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.18 | $11.80 |
| 100 | $0.92 | $92.00 |
| 500 | $0.78 | $390.00 |
| 1,000 | $0.65 | $650.00 |
SN74LVTH245APWG4 概述
A bus transceiver is a logic IC that connects two buses and selectively drives data in either direction, with 3-state outputs allowing multiple devices to share the same physical bus. In the broader taxonomy, this device belongs to the buffer/driver/transceiver family, which falls under standard logic ICs, which are themselves part of integrated circuits. The LVTH variant uses ABT BiCMOS processes that combine low static power consumption with high drive strength.
Key features include bidirectional control via a single DIR pin, low static power dissipation, support for live insertion with Ioff and power-up 3-state (PU3S) circuitry, and 5-V tolerant inputs and outputs when operating from a 3.3-V supply. The device can be used in mixed-voltage systems where 3.3-V logic interfaces with 5-V legacy buses. Its bus-hold feature on the data inputs eliminates the need for external pull-up resistors when the input is not actively driven.
The SN74LVTH245A architecture uses BiCMOS output stages for balanced drive strength (typical sink/source of 24 mA / 32 mA at 3.3 V) and TTL-compatible input thresholds. This makes it well-suited for driving heavily loaded backplanes, memory buses, and peripheral interfaces in computing and embedded systems. The wide operating voltage range and unregulated battery operation down to 2.7 V enable portable and battery-powered designs.
Typical applications include point-to-point board-to-board interfaces in industrial controllers, memory address/data bus buffering in networking equipment, level translation between 3.3-V and 5-V logic domains, and general-purpose bus isolation in modular embedded designs. The G4 suffix indicates Pb-free (lead-free) packaging per TI's legacy suffix scheme.
When designing with this part, ensure the DIR pin is driven to a valid logic level before VCC ramps into the active range to avoid bus contention during power-up. Use series damping resistors on heavily loaded buses to control ringing, and confirm that the load current does not exceed the absolute maximum ratings under worst-case temperature and voltage conditions.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical design notes that supplement the TI datasheet, helping engineers quickly select and source the correct variant for 3.3-V bus-interface designs.
直接替换替代料： SN74LVTH245APWG4 ——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： SN74LVTH245APWG4 （相同外形与封装尺寸） ——差异在于 Operating Temperature, RoHS Status, Bus Hold, Direction Control, Input Voltage Tolerance.
快速对比工具——选择替代料号进行并排对比：
SN74LVTH245APW
✅ 直接替换✓ 有现货
$0.69 / 个
查看数据手册 →SN74LVT245BPWR
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVC245APWR
✅ 直接替换📋 参考替代料（不在目录中）
74LVTH245PW
✅ 直接替换📋 参考替代料（不在目录中）
74LVC245APW
✅ 直接替换📋 参考替代料（不在目录中）
SN74LVTH245APWG4 最大额定值与电气特性
| 功能 | Octal Bus Transceiver with 3-State Outputs |
| Logic Family | LVTH (ABT BiCMOS) |
| Number of Elements | 1 |
| Number of Bits per Element | 8 |
| 输出类型 | 3-State |
| Direction Control | Non-inverting (DIR pin) |
| Supply Voltage (VCC) | 2.7 V to 3.6 V |
| Input Voltage Tolerance | 5 V tolerant (with 3.3-V VCC) |
| 工作温度 | -40C to +85C |
| 封装 | 20-pin TSSOP (PW) |
| 安装类型 | Surface Mount |
| Bus Hold | Yes |
| Power-Up 3-State (PU3S) | Yes |
| Ioff Support | Yes (live insertion safe) |
| RoHS 状态 | Pb-free (G4 suffix) |
SN74LVTH245APWG4 引脚配置
| 引脚 1 | DIR — Direction control input (HIGH = B to A, LOW = A to B) |
| 引脚 2 | A1 — A-side data I/O bit 1 |
| 引脚 3 | A2 — A-side data I/O bit 2 |
| 引脚 4 | A3 — A-side data I/O bit 3 |
| 引脚 5 | A4 — A-side data I/O bit 4 |
| 引脚 6 | A5 — A-side data I/O bit 5 |
| 引脚 7 | A6 — A-side data I/O bit 6 |
| 引脚 8 | A7 — A-side data I/O bit 7 |
| 引脚 9 | A8 — A-side data I/O bit 8 |
| 引脚 10 | GND — Ground |
| 引脚 11 | B8 — B-side data I/O bit 8 |
| 引脚 12 | B7 — B-side data I/O bit 7 |
| 引脚 13 | B6 — B-side data I/O bit 6 |
| 引脚 14 | B5 — B-side data I/O bit 5 |
| 引脚 15 | B4 — B-side data I/O bit 4 |
| 引脚 16 | B3 — B-side data I/O bit 3 |
| 引脚 17 | B2 — B-side data I/O bit 2 |
| 引脚 18 | B1 — B-side data I/O bit 1 |
| 引脚 19 | OE — Output enable input (active LOW) |
| 引脚 20 | VCC — Power supply (2.7 V to 3.6 V) |
典型应用
SN74LVTH245APWG4 适用于 6 应用s: Board-to-Board Industrial Control Bus, Memory Address/Data Bus Buffering in Networking Equipment, Mixed-Voltage Level Translation (3.3-V to 5-V), Portable Battery-Powered Embedded Systems, Hot-Pluggable / Live-Insertion Backplane Cards, FPGA / Microcontroller GPIO Expansion Bus.
Board-to-Board Industrial Control Bus
The SN74LVTH245APWG4's 5-V input tolerance, bus-hold on data inputs, and Ioff live-insertion support make it ideal for board-to-board interfaces in industrial control systems. Industrial PLC backplanes often combine 3.3-V logic with 5-V legacy modules, and this transceiver provides bidirectional buffering between them without external pull-up resistors. The 20-pin TSSOP package saves board area compared to SOIC, while the -40C to +85C operating range covers typical factory-floor environments. Estimated: at a 100 pF bus load with 24 mA drive, signal integrity is preserved on buses up to approximately 30 cm at 10 MHz.
推荐
Memory Address/Data Bus Buffering in Networking Equipment
In routers and switches, the SN74LVTH245APWG4 buffers address and data lines between an ASIC/FPGA and external memory such as DDR or SRAM islands. Its 3-state outputs allow multiple peripherals to share the same memory bus with controlled arbitration. The bus-hold feature eliminates floating inputs during bus-turnaround cycles, reducing EMI and improving signal integrity. With typical 3.3-V VCC operation, it pairs naturally with low-voltage memory and network processors. Estimated: with the OE pin tied to a decoded chip-select, contention-free bus multiplexing is achievable for up to 8 peripherals per transceiver.
推荐
Mixed-Voltage Level Translation (3.3-V to 5-V)
The SN74LVTH245APWG4 supports mixed-mode operation where the VCC is 3.3 V but the I/O pins tolerate 5 V from an external legacy bus. This makes it suitable for translation between modern 3.3-V microcontrollers and older 5-V peripheral ICs in embedded designs. The DIR pin provides controlled direction, and OE can be used to insert or remove the translator dynamically. Designers should note that the DIR pin itself is a 3.3-V input and must not be driven from a 5-V source without a series resistor or level shifter.
推荐
Portable Battery-Powered Embedded Systems
With VCC operation down to 2.7 V (unregulated battery), the SN74LVTH245APWG4 fits portable designs powered directly from a single Li-ion cell (3.0 V to 4.2 V) or two AA cells. The BiCMOS ABT technology provides low static power dissipation, extending battery life in handheld instruments and IoT edge nodes. Its 3-state outputs with PU3S support ensure the bus remains high-impedance during power-up and power-down, preventing back-drive of the system microcontroller. Estimated: at 3.0 V VCC, the device maintains full DC margins for CMOS-logic inputs.
推荐
Hot-Pluggable / Live-Insertion Backplane Cards
The SN74LVTH245APWG4's Ioff circuitry protects the device and the backplane when cards are inserted or removed while the system is powered. This is critical in telecom and modular computing systems where field-replaceable modules must not disrupt the live bus. The PU3S feature ensures outputs remain in high-impedance state until VCC ramps to a valid level, eliminating bus contention during card insertion. The bus-hold inputs also prevent floating lines that could trigger false events on neighboring cards during the insertion event.
推荐
FPGA / Microcontroller GPIO Expansion Bus
The SN74LVTH245APWG4 acts as a buffered expansion bus between an FPGA or microcontroller with limited GPIO count and an array of low-bandwidth peripherals such as keypads, displays, and status LEDs. The 3-state outputs allow multiple GPIO expanders to share an 8-bit bus with controlled enable logic, while the bus-hold feature maintains valid logic levels when no peripheral is actively driving. The 20-pin TSSOP is small enough to fit alongside an FPGA in typical PCB real-estate budgets. Estimated: with 8-bit parallel throughput, the transceiver handles update rates up to tens of MHz for typical human-interface peripherals.
推荐
推荐产品汇总
工程参考数据： SN74LVTH245APWG4 ——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 | SN74LVTH245APW | SN74LVT245BPWR | SN74LVC245APWR | 74LVTH245PW | 74LVC245APW |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors | NXP Semiconductors |
| Package | 20-pin TSSOP (PW) | 20-pin TSSOP (PW) - same | 20-pin TSSOP (PW) - same | 20-pin TSSOP (PW) - same | 20-pin TSSOP (PW) - same | 20-pin TSSOP (PW) - same |
| Logic Family | LVTH (ABT BiCMOS) | LVTH (ABT BiCMOS) | LVT (newer generation) | LVC (CMOS) | LVTH (ABT BiCMOS) | LVC (CMOS) |
| VCC Range | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 1.65 V to 3.6 V | 2.7 V to 3.6 V | 1.65 V to 3.6 V |
| Bus Hold | Yes | Yes | No | No | Yes | No |
| 5-V Input Tolerant (at 3.3-V VCC) | Yes | Yes | Yes (verify per datasheet) | No | Yes | No |
| Ioff (Live Insertion) | Yes | Yes | Yes | Partial (Ioff only) | Yes | Partial (Ioff only) |
| Direction Control | DIR pin (non-inverting) | DIR pin (non-inverting) | DIR pin (non-inverting) | DIR pin (non-inverting) | DIR pin (non-inverting) | DIR pin (non-inverting) |
| RoHS / Pb-Free | Pb-free (G4 suffix) | May be non-RoHS (legacy) | Pb-free (R suffix) | Pb-free (R suffix) | Pb-free | Pb-free |
关键差异点
- Bus-hold on data inputs eliminates external pull-up resistors （对比 SN74LVT245BPWR)
- 5-V input/output tolerance with 3.3-V VCC for mixed-voltage designs （对比 SN74LVC245APWR)
- Ioff and PU3S support for live-insertion applications （对比 74LVC245APW (NXP))
设计说明
Estimated: at a 50 pF bus load with 24 mA typical drive, propagation delay is in the low nanosecond range per TI datasheet typicals. Use series damping resistors (22-33 ohm) near the driver outputs on heavily loaded buses to control ringing and reflection. Keep stub lengths under 1/6 of the signal rise time to minimize transmission-line effects on point-to-point segments.
Estimated: VCC decoupling requires a 0.1 uF ceramic capacitor placed within 5 mm of the VCC pin (pin 20) and a 1 uF bulk capacitor nearby. The Ioff circuitry prevents back-drive through the device when VCC is removed, but bulk capacitance on the bus side may still cause transient currents during hot-insertion. Add a soft-start resistor in series with VCC if module precharge is required.
Do not drive the DIR or OE pins from a 5-V source when VCC is at 3.3 V - these are control inputs and are not 5-V tolerant. Tie unused inputs (DIR, OE) to a valid logic level (VCC or GND via 10 kohm) to avoid floating conditions during power-up. Verify that OE is pulled HIGH before VCC reaches 0.7 V to prevent output contention during the PU3S window.
Route A-side and B-side traces as matched-length pairs where possible to preserve timing symmetry in bidirectional applications. Place the transceiver near the bus mid-point to minimize stub length and balance capacitive loading on both sides. Avoid routing data signals parallel to switching power traces; use ground fills between bus traces to reduce crosstalk in dense PCB layouts.
合规信息
G4 suffix indicates Pb-free (RoHS-compliant) assembly per TI legacy naming. Halogen-free status not explicitly stated in retrieved web data; consult TI product page for confirmation. Not AEC-Q100 qualified - choose automotive-grade SN74LVTH245A-Q1 series for vehicle applications.
