74F657
74F657 is Octal Bidirectional Transceiver manufactured by Fairchild Semiconductor.
Description
The 74F657 contains eight non-inverting buffers with 3STATE outputs and an 8-bit parity generator/checker. It is intended for bus-oriented applications. The buffers have a guaranteed current sinking capability of 24 m A at the A Port and 64 m A at the B Port.
Features s 300 Mil 24-pin slimline DIP s bines 74F245 and 74F280A functions in one package s 3-STATE outputs s B Outputs sink 64 m A s 12 m A source current, B side s Input diodes for termination effects
Ordering Code:
Order Number 75F657SC 74F657SPC Package Number M24B N24C Package Description
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide 24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-100, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
© 1999 Fairchild Semiconductor Corporation
DS009584
.fairchildsemi.
Unit Loading/Fan Out
U.L. Pin Names A0- A7 Description
HIGH/LOW Data Inputs/ 3-STATE Outputs B0- B7 Data Inputs/ 3-STATE Outputs T/R OE PARITY Transmit/Receive Input Enable Input Parity Input/ 3-STATE Output ODD/EVEN ERROR ODD/EVEN Parity Input Error Output 4.5/0.15 150/40 (33.3) 3.5/0.117 600/106.6 (80) 2.0/0.067 2.0/0.067 3.5/0.117 600/106.6 (80) 1.0/0.033 600/106.6 (80) Input IIH/IIL Output IOH/IOL 90 µA/- 90 µA
- 3 m A/24 m A (20 m A) 70 µA/- 70 µA
- 12 m A/64 m A (48 m A) 40 µA/- 40 µA 40 µA/- 40 µA 70 µA/- 70µA
- 12 m A/64 m A (48 m A) 20 µA/- 20 µA
- 12 m A/64 m A (48 m A)
Functional Description
The Transmit/Receive (T/R) input determines the direction of the data flow through the bidirectional transceivers. Transmit (active HIGH) enables data from the A Port to the B Port; Receive (active LOW) enables data from the B Port to the A Port. The Output Enable (OE) input disables the parity and ERROR outputs and both the A and B Ports by placing them in a HIGH-Z condition when the Output Enable input is HIGH. When transmitting (T/R HIGH), the parity generator...
