SN74LVTH245APWE4 - 3.3V ABT Octal Bus Transceiver 20-TSSOP | TI
부품 번호: SN74LVTH245APWE4 ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.18 | $11.80 |
| 100 | $0.93 | $93.00 |
| 500 | $0.78 | $390.00 |
| 1,000 | $0.66 | $660.00 |
SN74LVTH245APWE4 개요
What is an octal bus transceiver? A bus transceiver is a digital logic interface IC that bridges two buses, allowing data to flow in either direction between them. It belongs to the broader family of buffers, drivers, and transceivers within the Logic ICs category, and is commonly used in microcontroller and memory interfaces to isolate bus segments, level-shift signals, or drive heavy capacitive loads. The LVTH sub-family from TI combines low-voltage (3.3-V) CMOS with the high-drive capability of ABT bipolar technology.
Key features of the SN74LVTH245APWE4 include bus-hold circuitry on the data inputs (eliminating the need for external pull-up resistors when drivers are tri-stated), typical propagation delay of around 3-4 ns, and Ioff support that allows partial-power-down operation without backfeeding current through the device. The bus-hold cells retain the last driven logic state, which simplifies hot-swap and live-insertion scenarios in modular backplanes and plug-in cards.
The SN74LVTH245A family is built on TI's state-of-the-art Advanced BiCMOS Technology (ABT) process, optimized for 3.3-V operation with low static power dissipation. Live insertion is supported, meaning the device can be plugged into a live backplane without disturbing active data on the bus, an important feature for CompactPCI, VME, and ATCA card designs. The high-drive output stage delivers strong edges into heavily loaded buses, which is critical for backplane signal integrity.
Typical applications include point-to-point bidirectional data transfer between processors and peripherals, memory-address/data buffering, bus isolation in hot-swappable systems, and level translation between 3.3-V and 5-V logic domains. Designers use this transceiver wherever two busses must communicate bidirectionally with controlled direction and high-impedance isolation, including PC motherboard chipset interfaces and industrial backplanes.
When designing with the SN74LVTH245APWE4, note that the DIR input controls data flow direction and OE bar enables or disables the outputs. Unused bus-hold inputs can be left floating, but unused standard inputs should be tied to VCC or GND through a resistor to define the logic state. The exposed thermal pad is not present on the TSSOP-20, so board layout relies on the standard TSSOP land pattern.
This page synthesizes distributor pricing, drop-in same-brand TSSOP-20 alternatives, and practical bus-interface design notes that are not consolidated in any single TI datasheet table.
드롭인 대체품: SN74LVTH245APWE4 — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: SN74LVTH245APWE4 (동일 폼 팩터 및 풋프린트) — 차이점: Package, Logic Family, Operating Temperature, RoHS Status, Bus Hold.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
SN74LVTH245APWR
✅ 드롭인✓ 재고 있음
$0.34 / 개
데이터시트 보기 →SN74LVTH245APWG4
✅ 드롭인✓ 재고 있음
$0.65 / 개
데이터시트 보기 →SN74LVTH245AIPWREP
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
SN74LVTH245ADBRE4
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
SN74LVT245BPWR
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
SN74LVTH245APWE4 최대 정격 & 전기적 특성
| 기능 | Octal bus transceiver with 3-state outputs |
| Logic Family | LVT (Low-Voltage Technology) / ABT |
| Number of Elements | 1 |
| Bits per Element | 8 |
| Direction Control | Yes (DIR pin) |
| Output Enable | Yes (active-low OE bar) |
| 출력 유형 | 3-State |
| Polarity | Non-Inverting |
| Supply Voltage (VCC) | 2.7 V to 3.6 V |
| Input Voltage Tolerance | 5 V (mixed-mode signal operation) |
| Output Voltage Tolerance | 5 V tolerant |
| 동작 온도 | -40C to +85C |
| 패키지 | 20-TSSOP (PW) |
| 실장 유형 | Surface Mount |
| Bus Hold | Yes (on data inputs) |
| Live Insertion Support | Yes |
| Ioff (Partial Power Down) | Yes |
| RoHS 상태 | Compliant |
SN74LVTH245APWE4 핀 구성
| 핀 1 | DIR — Direction control input (high: A to B; low: B to A) |
| 핀 2 | OE\u00A0bar — Output enable, active low (high: both buses high-Z; low: outputs enabled) |
| 핀 3 | A1 — A bus data I/O, channel 1 |
| 핀 4 | A2 — A bus data I/O, channel 2 |
| 핀 5 | A3 — A bus data I/O, channel 3 |
| 핀 6 | A4 — A bus data I/O, channel 4 |
| 핀 7 | A5 — A bus data I/O, channel 5 |
| 핀 8 | A6 — A bus data I/O, channel 6 |
| 핀 9 | A7 — A bus data I/O, channel 7 |
| 핀 10 | A8 — A bus data I/O, channel 8 |
| 핀 11 | GND — Ground reference |
| 핀 12 | B8 — B bus data I/O, channel 8 |
| 핀 13 | B7 — B bus data I/O, channel 7 |
| 핀 14 | B6 — B bus data I/O, channel 6 |
| 핀 15 | B5 — B bus data I/O, channel 5 |
| 핀 16 | B4 — B bus data I/O, channel 4 |
| 핀 17 | B3 — B bus data I/O, channel 3 |
| 핀 18 | B2 — B bus data I/O, channel 2 |
| 핀 19 | B1 — B bus data I/O, channel 1 |
| 핀 20 | VCC — Supply voltage (2.7 V to 3.6 V) |
일반적인 애플리케이션
SN74LVTH245APWE4 적합 용도: 6 애플리케이션s: Backplane Bus Isolation, Memory Address/Data Buffering, Level Translation 3.3V to 5V, Industrial Control I/O Expansion, Hot-Swap Card Live Insertion, Test and Measurement Equipment.
Backplane Bus Isolation
The SN74LVTH245APWE4 isolates two bus segments on a backplane, allowing multiple cards to share a common bus without contention. Its Ioff feature prevents backfeeding current when one card is powered down, and bus-hold inputs keep floating signals at their last driven state, both critical for live-insertion backplanes such as CompactPCI, VME, and ATCA. The 3-state outputs provide clean high-impedance isolation between segments, and the 2.7-V to 3.6-V VCC range with 5-V tolerant I/O makes it compatible with 3.3-V and 5-V mixed logic. Designers place the device between the bus connector and the local card logic so a faulty card can be tri-stated without disrupting active traffic on the backplane. Compared to discrete buffers, this single IC saves board area while delivering sub-5-ns propagation delay typical of LVTH ABT technology.
추천
Memory Address/Data Buffering
The SN74LVTH245APWE4 buffers address and data lines between a microcontroller or memory controller and external memory such as SRAM, DDR, or Flash. Its 8-bit non-inverting bidirectional configuration handles byte-wide buses cleanly, and the high-drive ABT output stage delivers strong edges into memory bus capacitance, reducing signal-integrity issues at higher clock rates. The DIR pin selects whether the controller is reading or writing memory, while OE bar provides a hardware reset or power-down path for the memory bus. Industrial temperature rating (-40C to +85C) makes this part suitable for embedded systems and industrial PCs where memory expansion must operate reliably across wide thermal ranges. Compared to a passive resistor network, the active transceiver adds noise immunity and bus-hold protection against floating memory data lines during system reset.
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Level Translation 3.3V to 5V
The SN74LVTH245APWE4 bridges 3.3-V logic on a microcontroller or ASIC to 5-V logic on legacy peripherals without external level shifters. According to TI mixed-mode signal operation, the inputs accept 5-V signals even when VCC is only 3.3 V, and the outputs tolerate 5-V pull-ups, allowing bidirectional translation across the 3.3-V/5-V domain boundary. The DIR pin selects translation direction, and OE bar can disable both sides for isolation during system reset. This is widely used in industrial control, motor drives, and test equipment where 5-V peripherals must interface to modern 3.3-V processors. Compared to dedicated voltage-level translator ICs, the LVTH245A is a more flexible choice when 8 bits of bidirectional translation are required.
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Industrial Control I/O Expansion
In PLC and industrial control systems, the SN74LVTH245APWE4 expands the I/O of a microcontroller or FPGA to interface with sensor arrays, opto-isolated inputs, and relay-driver boards. The bus-hold inputs retain last logic state during controller reset, preventing spurious commands to actuators, and the -40C to +85C industrial temperature range handles factory-floor environments. The DIR pin allows the controller to read sensors and write to actuator latches through a single 8-bit bus, halving the I/O pin count on the host MCU. Compared to GPIO expanders over I2C/SPI, this parallel bus transceiver delivers faster update rates suitable for high-speed digital I/O. The TSSOP-20 package fits compact industrial PCBs while keeping traces short for noise immunity.
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Hot-Swap Card Live Insertion
The SN74LVTH245APWE4 supports live insertion in card-based systems where a new card may be plugged into a powered backplane. Ioff prevents parasitic current paths through the I/O pins during VCC ramp-up, and bus-hold cells maintain valid logic states on floating lines so the backplane never sees a glitch. Together these features allow the card to be inserted without crashing the system. The DIR and OE bar pins can be driven by host logic to bring the new card online only after contact bounce settles, a critical sequencing feature for ATCA, cPCI, and proprietary modular systems. Compared to discrete FET switches or resistor-divider approaches, the integrated transceiver offers faster enable/disable and tighter timing control.
추천
Test and Measurement Equipment
In test instruments such as logic analyzers, oscilloscope probes, and protocol analyzers, the SN74LVTH245APWE4 buffers and isolates DUT buses from the instrument's measurement circuitry. The 3-state outputs allow the instrument to disconnect electronically when not in use, protecting sensitive DUT signals. The 5-V tolerant I/O lets the instrument probe both 3.3-V and 5-V targets without external protection. Bus-hold inputs retain the DUT's last driven state when the probe is disconnected, which prevents accidental glitches on the target board. Compared to discrete CMOS switches, the LVTH245A delivers much lower propagation delay (around 3-4 ns) and cleaner edges required for accurate timing analysis.
추천
추천 제품 요약
엔지니어링 참조 데이터: SN74LVTH245APWE4 — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | SN74LVTH245APWR | SN74LVTH245APWG4 | SN74LVTH245AIPWREP |
|---|---|---|---|---|
| Package | 20-TSSOP (PW) | 20-TSSOP (PW) - same | 20-TSSOP (PW) - same | 20-TSSOP (PW) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Function | Octal bus transceiver, non-inverting, 3-state | Octal bus transceiver, non-inverting, 3-state | Octal bus transceiver, non-inverting, 3-state | Octal bus transceiver, non-inverting, 3-state |
| Supply Voltage | 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 |
| Bus Hold | Yes | Yes | Yes | Yes |
| Ioff Support | Yes | Yes | Yes | Yes |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -55C to +125C (EP flow) |
| Shipping Carrier | Tube | Tape and Reel | Tube (G4 Pb-free) | Tape and Reel |
주요 차별점
- Bus-hold inputs eliminate external pull-up resistors (vs SN74LVC245APWR)
- Ioff partial-power-down support for hot-swap designs (vs SN74LVC245APWR)
- Tube carrier for prototype and low-volume assembly (vs SN74LVTH245APWR (Tape and Reel))
설계 노트
Place a 0.1 uF decoupling capacitor as close as possible to the VCC pin (pin 20) of the SN74LVTH245APWE4, with a short, wide trace to the ground plane. For heavily loaded backplane applications (greater than 50 pF per output), add a bulk 10 uF tantalum or ceramic capacitor near the device to provide instantaneous charge during high-to-low transitions. Avoid routing the DIR and OE bar signals next to high-frequency switching lines; cross-coupling on these control pins can cause bus contention. The TSSOP-20 thermal pad is not present, so use wide VCC and GND traces for heat dissipation rather than relying on package conduction.
Never leave OE bar floating on the SN74LVTH245APWE4; an undriven enable pin can drift to a mid-supply level and cause both A and B buses to drive simultaneously, resulting in high shoot-through current and possible device damage. Tie OE bar high through a 10 kohm pull-up if not actively driven, or drive it directly from the host controller. Similarly, do not leave DIR floating - tie it high or low through a resistor. When cascading multiple transceivers on a wide bus, ensure only one device has OE bar asserted at a time to prevent bus contention. Live-insertion designs must sequence VCC before driving DIR or OE bar to avoid partial-power glitches.
When designing with the SN74LVTH245APWE4 for high-speed bus isolation, keep A and B bus traces matched in length within 1-2 mm to minimize propagation skew. Maintain a continuous ground plane beneath the TSSOP-20 footprint to provide a low-impedance return path. Avoid 90-degree bends on bus traces - use 45-degree or curved bends to reduce reflection losses. For backplane designs, add series termination resistors (22-33 ohm) near the driver outputs to dampen ringing on heavily capacitive loads. The bus-hold inputs retain last state during connector mating, so board designers can omit external pull-up resistors on A and B lines in most cases.
규정 준수 정보
RoHS and lead-free per TI product page. Not AEC-Q100 qualified (commercial/industrial grade only). Halogen-free status not explicitly stated in verified web data - marked unknown.
