CD74HC640EE4 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
The CD74HC640EE4 is a high-speed CMOS octal inverting bus transceiver from Texas Instruments with bidirectional direction control in a 20-pin PDIP package. It supports 50 pF load capacitance with common control for all 8 channels using the HC/UH logic family. RoHS-compliant and in stock worldwide for bus buffering and interface bridging applications.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- CD74HC640EE4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -55.0°C to 125.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of CD74HC640EE4?
- Octal inverting bidirectional bus transceiver with direction control enabling flexible 8-bit data bus bridging between two logic domains
- HC/UH high-speed CMOS family operation at 50 pF load capacitance supporting fast bus switching in backplane and memory interface designs
- Common control architecture with single direction pin managing all 8 channels simultaneously for simple firmware-controlled bus arbitration
What is CD74HC640EE4 used for?
The CD74HC640EE4 is used as a bidirectional bus buffer in microprocessor memory interfaces, PCIe backplane bridges, and FPGA-based data bus expansion designs requiring 8-bit inverted signal routing. Its 50 pF load capacitance handling makes it suitable for driving multiple parallel logic devices from a single address or data bus in embedded computing systems. Legacy industrial control boards and test equipment also rely on its 20-pin PDIP package for easy prototyping and through-hole assembly of bus transceiver functions.
What are the specifications of CD74HC640EE4?
| Pbfree Code | Yes |
| YTEOL | 0 |
| Additional Feature | WITH DIRECTION CONTROL |
| Control Type | COMMON CONTROL |
| Count Direction | BIDIRECTIONAL |
| Family | HC/UH |
| JESD-30 Code | R-PDIP-T20 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 50pF |
| 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 | DIP20,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 0.16mA |
| Prop. Delay@Nom-Sup | 27ns |
| Propagation Delay (tpd) | 135ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 6V |
| Supply Voltage-Min (Vsup) | 2V |
| Supply Voltage-Nom (Vsup) | 4.5V |
| Surface Mount | NO |
| Technology | CMOS |
| Temperature Grade | MILITARY |
| Terminal Finish | Nickel/Palladium/Gold (Ni/Pd/Au) |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Where can I find the CD74HC640EE4 datasheet?
CD74HC640EE4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for CD74HC640EE4?
Compatible alternatives and drop-in replacements for CD74HC640EE4:
Rochester Electronics LLC HC/UH SERIES, 8-BIT TRANSCEIVER, INVERTED OUTPUT, PDIP20
Frequently Asked Questions
How does the CD74HC640EE4's inverting output affect bus signal polarity and how do designers compensate for this?
The CD74HC640EE4 inverts all 8 data signals as they pass through the transceiver, meaning a logic high on the input side becomes a logic low on the output side. Designers compensate by connecting two CD74HC640EE4 devices in cascade for a non-inverting path, or by accounting for the inversion in firmware when data polarity reversal is acceptable, such as in active-low bus architectures where the inversion simplifies address decoding logic in 8-bit microprocessor systems.
For a 3.3 V to 5 V logic level bus bridge design, can the CD74HC640EE4 HC-family device handle both supply voltages simultaneously?
The CD74HC640EE4 belongs to the HC/UH family with VCC typically ranging from 2 V to 6 V, allowing it to operate as a 5 V bus transceiver for legacy 5 V TTL-compatible bus systems. However, mixing 3.3 V and 5 V domains directly requires careful voltage tolerance verification, as HC-family inputs may not be guaranteed 5 V tolerant at 3.3 V VCC. Designers bridge the 3.3 V and 5 V domains using the LVC or LVCH logic family with specified 5 V-tolerant inputs rated at 50 pF load capacitance and below.
In a multi-board backplane with 8-bit parallel data buses, what advantage does the CD74HC640EE4's common direction control provide over individual per-channel control?
The CD74HC640EE4's single common direction control pin switches all 8 channels simultaneously with a single GPIO signal, eliminating the 8 individual direction pins that would be required if each channel were independently controlled. This reduces firmware complexity from 8 GPIO writes to 1 GPIO write per bus turnaround, decreasing bus arbitration latency from potentially 8 clock cycles to 1 cycle in a 50 pF loaded backplane operating at logic switching speeds typical of HC-family devices.
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Why Buy from FindMyChip
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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