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Texas Instruments SN74HC640PWR
- Part No.:
- SN74HC640PWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HC640PWR.pdf
- Description:
- IC TRANSCEIVER INVERT 6V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:7,524
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Product details
Overview
SN74HC640PWR from Texas Instruments is an octal inverting bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between two 8-bit buses. It operates across 2V–6V supply, delivers ±4-mA output drive at 5V, exhibits typical propagation delay of 8ns (VCC = 6V, CL = 50 pF), and supports industrial temperature range (–40°C to +85°C). It is used in microcontroller peripheral expansion and legacy bus isolation applications.
For engineers reviewing the SN74HC640PWR datasheet, SN74HC640PWR pinout, SN74HC640PWR application, or SN74HC640PWR equivalent, key selection criteria include its inverting logic behavior, dual-direction control via DIR/OE pins, TSSOP-20 package footprint, 3-state output isolation timing (tdis ≤ 32 ns at 6V), and compatibility with LSTTL load driving (up to 10 loads).
Technical Context
The SN74HC640PWR implements a fully synchronous octal transceiver architecture with independent direction (DIR) and output-enable (OE) control inputs. All eight A/B channel pairs share identical functional modes: when OE is low, data flows either A→B (DIR = high) or B→A (DIR = low); when OE is high, all outputs enter high-impedance state regardless of DIR.
Its CMOS design ensures low static current (ICC ≤ 80 µA max), input leakage ≤ 1 µA, and robust noise immunity with VIH/VIL thresholds defined across VCC = 2–6V. The device uses standard HC logic levels and requires no external biasing - unused inputs must be tied to VCC or GND per TI SCBA004 guidelines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2V to 6V - enables direct interface with 3.3V and 5V systems without level shifters. |
| Propagation Delay (tpd) | 8ns typical at VCC = 6V, CL = 50 pF - supports >10 MHz bus toggle rates in clean signal environments. |
| Output Drive | ±4 mA at VCC = 5V - sufficient to directly drive 10 LSTTL inputs without buffering. |
| Off-State Output Current | ±0.5 µA max at VCC = 6V - ensures minimal leakage-induced bus contention during 3-state isolation. |
| Input Leakage Current | ±1 µA max - allows reliable pull-up/pull-down resistor sizing (e.g., 100 kΩ) without voltage shift. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded control and instrumentation applications. |
| Power Dissipation Cap. | 40 pF typical - used to calculate dynamic power (P = Cpd × V² × f) for thermal budgeting. |
Pinout & Package
TSSOP-20 package (PW), 4.40 mm × 6.50 mm body, 1.2 mm max height, 0.65 mm lead pitch, RoHS-compliant NiPdAu finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-low global control: high = all outputs high-Z; low = outputs enabled per DIR state. |
| 2–9 (A1–A8) | Bus A Inputs/Outputs | When DIR = high & OE = low: A drives B; when DIR = low & OE = low: B drives A (inverted). |
| 10 (GND) | Ground Reference | Primary return path for all I/O and supply currents; must be low-impedance connection. |
| 11–18 (B1–B8) | Bus B Inputs/Outputs | Complementary bus port; bidirectional data flow determined jointly by OE and DIR logic states. |
| 19 (DIR) | Direction Control Input | High = A→B data flow; low = B→A data flow; functionally active only when OE = low. |
| 20 (VCC) | Positive Supply | 2V–6V CMOS rail; requires local 0.1-µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting Logic Architecture | Each A/B channel inverts data - simplifies polarity alignment in differential or complementary bus designs. |
| High-Current 3-State Outputs | ±4 mA drive at 5V enables direct fanout to 10 LSTTL loads without external buffers or line drivers. |
| Low Static Power Consumption | ICC ≤ 80 µA max eliminates thermal concerns in battery-powered or dense PCB layouts. |
| Wide Voltage Operation | 2V–6V supply range supports mixed-voltage system integration (e.g., 3.3V MCU ↔ 5V peripheral bus). |
| Controlled Transition Timing | Disable time tdis ≤ 32 ns (6V) ensures fast bus release for time-critical arbitration protocols. |
Applications
| Microcontroller Peripheral Expansion | Legacy Bus Isolation |
|---|---|
|
Use Scenario: Expanding GPIO count of an ARM Cortex-M0+ MCU to interface with 8-bit parallel LCD controller and keypad matrix. IC Role / Device Role / Timing Role: Bidirectional data bridge between MCU's limited parallel port and external peripherals; DIR selects direction per transaction; OE gates bus access during interrupt service. Use Value: Eliminates need for discrete MOSFET switches or dedicated bus switches - reduces BOM count and layout area while maintaining full 8-bit throughput. |
Use Scenario: Isolating a Z80 CPU address/data bus from a CPLD-based memory mapper during DMA cycles. IC Role / Device Role / Timing Role: 3-state transceiver enabling clean bus handoff: OE deasserted during CPU access, asserted during CPLD refresh to prevent contention. Use Value: Prevents signal corruption during bus arbitration with sub-32 ns disable time - meets Z80 WAIT timing requirements without added glue logic. |
| Industrial I/O Module Backplane | Test Equipment Signal Routing |
|
Use Scenario: Interfacing multiple isolated 8-bit sensor ADCs to a central FPGA over shared backplane traces. IC Role / Device Role / Timing Role: Direction-controlled bus repeater: DIR set per ADC slot; OE synchronized to FPGA read strobe to avoid simultaneous drive. Use Value: Enables deterministic multi-drop bus sharing with <10 ns skew between channels - critical for synchronized sampling across 4+ sensors. |
Use Scenario: Reconfigurable signal path in automated test equipment routing DUT digital I/O through calibration reference banks. IC Role / Device Role / Timing Role: Programmable bidirectional buffer: DIR selects stimulus (DUT → ref) or measurement (ref → DUT); OE enables/disables path under microcontroller control. Use Value: Provides repeatable 3-state isolation with <0.5 µA off-state leakage - ensures reference integrity during open-circuit measurements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT640PWR | CMOS input thresholds (VIH/VIL) optimized for TTL-compatible 5V logic; identical pinout and timing. | Better suited for mixed 5V TTL/CMOS systems where input noise margin must match legacy TTL levels. | Select when interfacing directly with 74LS/74ALS devices without level translation. |
| 74LCX640MTCX | Lower VCC range (2.0–3.6V), higher speed (tpd = 5.5ns @ 3.3V), different pinout (TSSOP-20 but non-pin-compatible). | Designed for 3.3V-only portable/embedded systems requiring lower power and faster switching than HC family. | Choose for new 3.3V designs prioritizing speed/power over legacy 5V compatibility. |
Compared with SN74HC640PWR, SN74HCT640PWR offers TTL-compatible inputs for seamless 5V legacy integration, while 74LCX640MTCX provides superior 3.3V performance at the cost of pin-incompatibility - making SN74HC640PWR the optimal choice for flexible 2–6V industrial bus bridging where pin reuse and wide-voltage tolerance are primary requirements.
Availability
SN74HC640PWR is available at Aetrix Electronics and suitable for microcontroller peripheral expansion, industrial I/O module backplanes, legacy bus isolation, and automated test equipment signal routing requiring stable component supply across extended product lifecycles.
Supply support for SN74HC640PWR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with global manufacturing and quality certification.
The SN74HC640PWR belongs to TI's 74HC logic family - engineered for industrial-grade reliability, wide-voltage operation, and interoperability with legacy TTL systems while delivering CMOS power efficiency.
FAQ
What is the maximum clock frequency supported by SN74HC640PWR in a bus application?
The SN74HC640PWR does not contain an internal clock; it is an asynchronous transceiver. Its usable data rate depends on propagation delay and system setup/hold timing. With typical tpd = 8 ns at 6V and CL = 50 pF, it supports reliable bidirectional bus toggling up to approximately 12 MHz in well-terminated, low-noise environments - verified using TI's SCLS303E switching characteristics tables.
Does SN74HC640PWR support hot insertion or live bus swapping?
No, SN74HC640PWR is not hot-swap rated. Its absolute maximum ratings specify no current injection limits during power sequencing, and the datasheet mandates that all unused inputs be tied to VCC or GND before power application. TI recommends powering VCC before applying signals and sequencing OE high before enabling DIR to avoid bus contention during power-up.
Can SN74HC640PWR drive a 50-pF transmission line directly?
Yes - SN74HC640PWR's typical output transition time (tt = 13 ns at 6V, CL = 50 pF) and ±4-mA drive strength meet standard 50-pF load requirements per JEDEC JESD8-6. However, for trace lengths exceeding 10 cm or noisy environments, TI recommends series termination (22–33 Ω) near the driver output to suppress reflections, as outlined in Section 9.1 of the SCLS303E datasheet.
Is SN74HC640PWR pin-compatible with SN74LS640N?
No - SN74HC640PWR (TSSOP-20) and SN74LS640N (PDIP-20) share identical logic functionality and pin numbering, but their packages are physically incompatible. While electrical pin functions match (e.g., Pin 1 = OE, Pin 19 = DIR), the TSSOP-20 footprint cannot mount on a PDIP-20 pad layout. No drop-in replacement exists between these packages.
What is the recommended bypass capacitor for SN74HC640PWR?
Texas Instruments specifies a 0.1-µF ceramic capacitor placed as close as possible to the VCC (Pin 20) and GND (Pin 10) pins of SN74HC640PWR. For systems with high-frequency noise, TI recommends paralleling this with a 1-µF capacitor - both must use X7R or better dielectric and be routed with minimum loop area to ensure effective high-frequency decoupling per Section 8 of SCLS303E.
SN74HC640PWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Transceiver, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74HC640PWR FAQ
1.How can I place an order for SN74HC640PWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC640PWR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74HC640PWR reliable?
The price and inventory of SN74HC640PWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC640PWR is usually 5 days.
3.What payment methods are accepted for SN74HC640PWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC640PWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC640PWR?
SN74HC640PWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC640PWR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74HC640PWR?
For technical support, including SN74HC640PWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC640PWR requirements.
6.How does Aetrix verify that SN74HC640PWR is sourced from the original manufacturer or authorized distributors?
All SN74HC640PWR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74HC640PWR meets industry standards.
7.What is the process for return or replacement of SN74HC640PWR?
All SN74HC640PWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC640PWR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74HC640PWR part is unused and in its original packaging.
Return procedure for SN74HC640PWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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