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74ABT657
Datasheet
General description
The 74ABT657 high-performance BiCMOS device combines low static and dynamic power dissipation with high speed and high output drive.
The 74ABT657 is an octal transceiver featuring non-inverting buffers with 3-State outputs and an 8-bit parity generator/checker, and is intended for bus-oriented applications. The buffers have a guaranteed current sinking capability of 64 mA. The Transmit/Receive (T/R) input determines the direction of the data flow through the bidirectional transceivers. Transmit (active-HIGH) enables data from A ports to B ports; Receive (active-LOW) enables data from B ports to A ports.
The Output Enable (OE) input disables both the A and B ports by placing them in a high-impedance condition when the OE input is HIGH. The parity select (ODD/EVEN) input gives the user the option of odd or even parity systems. The parity (PARITY) pin is an output from the generator/checker when transmitting from the port A to B (T/R = HIGH) and an input when receiving from port B to A port (T/R = Low). When transmitting (T/R = HIGH) the parity select (ODD/EVEN) input is set, then the A port data is polled to determine the number of HIGH bits. The parity (PARITY) output then goes to the logic state determined by the parity select (ODD/EVEN) setting and by the number of HIGH bits on port A. For example, if the parity select (ODD/EVEN) is set LOW (even parity), and the number of HIGH bits on port A is odd, then the parity (PARITY) output will be HIGH, transmitting even parity. If the number of HIGH bits on port A is even, then the parity (PARITY) output will be LOW, keeping even parity. When in receive mode (T/R = LOW) the B port is polled to determine the number of HIGH bits. If parity select (ODD/EVEN) is LOW (even parity) and the number of HIGHs on port B is:
- (1) odd and the parity (PARITY) input is HIGH, then ERROR will be
HIGH, signifying no error.
- (2) even and the parity (PARITY) input is HIGH, then ERROR will
be asserted LOW, indicating an error.
Features
- Combinational functions in one package
- Low static and dynamic power dissipation with high speed and high output drive
- Output capability: +64 mA/-32 mA
- Power-up 3-State
- Latch-up protection exceeds 500 mA per JEDEC Std 17
- ESD protection exceeds 2000 V per MIL STD 883 Method 3015 and 200 V per Machine Model
Products/packages
| Type number | North American Type number | Ordering code (12NC) | Product status | Package | Packing | Marking | Chemical content | Leadfree conversion date |
|---|---|---|---|---|---|---|---|---|
| 74ABT657D | 74ABT657D | 9350 452 90602 | Volume production | SOT137-1
(SO24) | Tube (Signetics) | Standard Marking | 74ABT657D
| week 13, 2005 |
| 74ABT657D | 74ABT657D-T | 9350 452 90623 | Volume production | SOT137-1
(SO24) | Reel Pack, SMD, 13" (Signetics) | Standard Marking | 74ABT657D
| week 13, 2005 |
| 74ABT657DB | 74ABT657DB | 9350 691 80112 | Volume production | SOT340-1
(SSOP24) | Tube | Standard Marking | 74ABT657DB
| week 12, 2005 |
| 74ABT657DB | 74ABT657DB-T | 9350 691 80118 | Volume production | SOT340-1
(SSOP24) | Reel Pack, SMD, 13" | Standard Marking | 74ABT657DB
| week 12, 2005 |
| 74ABT657PW | 74ABT657PW | 9351 789 00112 | Volume production | SOT355-1
(TSSOP24) | Tube | Standard Marking | 74ABT657PW
| week 10, 2005 |
| 74ABT657PW | 74ABT657PW-T | 9351 789 00118 | Volume production | SOT355-1
(TSSOP24) | Reel Pack, SMD, 13" | Standard Marking | 74ABT657PW
| week 10, 2005 |
Pricing/ordering/availability
| Type number | Ordering code(12NC) | Indicative price/unit($) | Region | Distributor | In stock | Inventory date | Buy online | Samples |
|---|---|---|---|---|---|---|---|---|
| 74ABT657D | 9350 452 90602 | 1.4900 | not available | |||||
| 74ABT657D | 9350 452 90623 | 1.4900 | Order samples | |||||
| 74ABT657DB | 9350 691 80112 | 1.4900 | not available | |||||
| 74ABT657DB | 9350 691 80118 | 1.4900 | Order samples | |||||
| 74ABT657PW | 9351 789 00112 | 1.3000 | NA | DIGI-KEY CORPORATION | 1,575 | 8/5/2008 | Buy online | not available |
| 74ABT657PW | 9351 789 00118 | 1.3000 | Order samples |
Technical documents
Application Notes
AN203_2;
Test Fixtures for High Speed Logic (02-Apr-98)
Support Documents
Parametrics/similar products
| Type number | Package | Description | Propagation Delay(ns) | Voltage | Logic Switching Levels | Output Drive Capability |
|---|---|---|---|---|---|---|
| 74ABT657D | SOT137-1
(SO24) | Octal Transceiver with Parity Generator/Checker; Non-Inverting (3-State) | 3.3 | 4.5-5.5 V | TTL | -32/+64 mA |
| 74ABT657DB | SOT340-1
(SSOP24) | Octal Transceiver with Parity Generator/Checker; Non-Inverting (3-State) | 3.3 | 4.5-5.5 V | TTL | -32/+64 mA |
| 74ABT657PW | SOT355-1
(TSSOP24) | Octal Transceiver with Parity Generator/Checker; Non-Inverting (3-State) | 3.3 | 4.5-5.5 V | TTL | -32/+64 mA |
Similar products
74ABT657 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.
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