SN74HC640DWG4 Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
SN74HC640DWG4 is a high-speed CMOS octal bus transceiver with inverting logic, direction control, and 150 pF load drive in a 20-pin SOIC package from Texas Instruments. Available from stock with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN74HC640DWG4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74HC640DWG4?
- 8-bit bidirectional bus transceiver with common direction control pin and inverting output for flexible data bus isolation
- Drives 150 pF capacitive loads with 6 mA output sink current, suitable for buffering high-capacitance backplane and memory bus lines
- HC/UH family CMOS logic compatible with 2 V to 6 V supply, supporting both 3.3 V and 5 V bus standards in the same 20-pin SOIC footprint
What is SN74HC640DWG4 used for?
The SN74HC640DWG4 is used to buffer and isolate 8-bit data buses between microprocessors, memory devices, and peripheral ICs in embedded systems and single-board computers. Its bidirectional capability with a direction-control pin makes it suitable for address/data multiplexed bus architectures, FPGA I/O expansion, and legacy TTL-to-CMOS bus conversion where signal integrity must be maintained across 150 pF line capacitance.
What are the specifications of SN74HC640DWG4?
| YTEOL | 0 |
| Additional Feature | WITH DIRECTION CONTROL |
| Control Type | COMMON CONTROL |
| Count Direction | BIDIRECTIONAL |
| Family | HC/UH |
| JESD-30 Code | R-PDSO-G20 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 150pF |
| Logic IC Type | BUS TRANSCEIVER |
| Max I(ol) | 0.006A |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Number of Ports | 2 |
| Output Characteristics | 3-STATE |
| Output Polarity | INVERTED |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP20,.4 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Packing Method | TUBE |
| Peak Reflow Temperature (Cel) | 260 |
| Power Supply Current-Max (ICC) | 0.08mA |
| Prop. Delay@Nom-Sup | 26ns |
| Propagation Delay (tpd) | 235ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 6V |
| Supply Voltage-Min (Vsup) | 2V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | CMOS |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | NICKEL PALLADIUM GOLD |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| HTS Code | 8542.39.00.60 |
Where can I find the SN74HC640DWG4 datasheet?
SN74HC640DWG4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74HC640DWG4?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What bus load can SN74HC640DWG4 drive, and is 150 pF sufficient for a typical backplane trace?
The SN74HC640DWG4 is rated to drive 150 pF load capacitance per output, which covers most short PCB trace and single-slot backplane scenarios; for longer traces above 10 cm or multi-card backplanes with capacitances exceeding 200 pF per line, a stronger driver like the AHCT540 with 25 mA output should be evaluated.
How does the direction control pin of SN74HC640DWG4 work in a bidirectional data bus design?
A single direction-control input (DIR) selects the data flow direction for all 8 bits simultaneously: when DIR is high, data flows from port A to port B; when low, data flows from B to A; an output-enable pin (OE) tri-states all outputs, allowing the transceiver to be disconnected from the bus without glitching the lines.
Is SN74HC640DWG4 compatible with 3.3 V CMOS logic, and does it need a level shifter when interfacing 5 V legacy devices?
The SN74HC640DWG4 operates from 2 V to 6 V; when powered at 3.3 V it is fully compatible with 3.3 V CMOS inputs and outputs; when interfacing with 5 V TTL legacy devices, the HC family's 3.3 V output high level of approximately 3.1 V may not meet the 5 V TTL VIH minimum of 2 V — in practice it typically works, but a 5 V-powered AHCT640 is the safer choice for guaranteed TTL compatibility.
What output current does SN74HC640DWG4 provide, and how does this compare to the 74ABT640 for driving heavy bus loads?
The SN74HC640DWG4 sinks up to 6 mA and sources approximately 6 mA per output; the 74ABT640 provides 32 mA sink and 15 mA source capability, making it more appropriate for bus architectures with more than 8 receiving devices or trace lengths exceeding 15 cm where the HC family's 6 mA drive is insufficient to maintain valid logic levels.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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