SN74HC646

ACTIVE

Octal Bus Transceivers And Registers With 3-State Outputs

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Product details

Parameters

Technology Family HC VCC (Min) (V) 2 VCC (Max) (V) 6 Bits (#) 8 Voltage (Nom) (V) 6 F @ nom voltage (Max) (MHz) 28 ICC @ nom voltage (Max) (mA) 0.08 Propagation delay (Max) (ns) 29 IOL (Max) (mA) 6 IOH (Max) (mA) -6 Operating temperature range (C) -40 to 85 open-in-new Find other Registered transceiver

Package | Pins | Size

SOIC (DW) 24 160 mm² 15.5 x 10.3 open-in-new Find other Registered transceiver

Features

  • Wide Operating Voltage Range of 2 V to 6 V
  • High-Current 3-State Outputs Can Drive Up To 15 LSTTL Loads
  • Low Power Consumption, 80-µA Max ICC
  • Typical tpd = 11 ns
  • ±6-mA Output Drive at 5 V
  • Low Input Current of 1 µA Max
  • Independent Registers for A and B Buses
  • Multiplexed Real-Time and Stored Data
  • True Data Paths

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Description

The ’HC646 devices consist of bus-transceiver circuits with 3-state outputs, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the input bus or from the internal registers. Data on the A or B bus is clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the ’HC646 devices.

Output-enable (OE)\ and direction-control (DIR) inputs control the transceiver functions. In the transceiver mode, data present at the high-impedance port may be stored in either or both registers.

The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. DIR determines which bus receives data when OE\ is active (low). In the isolation mode (OE\ high), A data may be stored in one register and/or B data may be stored in the other register.

To ensure the high-impedance state during power up or power down, OE\ should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

When an output function is disabled, the input function is still enabled and can be used to store data. Only one of the two buses, A or B, may be driven at a time.

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Technical documentation

= Top documentation for this product selected by TI
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Type Title Date
* Datasheet SN54HC646, SN74HC646 datasheet (Rev. C) Mar. 18, 2003
Selection guide Logic Guide (Rev. AB) Jun. 12, 2017
Application note Implications of Slow or Floating CMOS Inputs (Rev. D) Jun. 23, 2016
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) Dec. 02, 2015
User guide LOGIC Pocket Data Book (Rev. B) Jan. 16, 2007
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection Jul. 08, 2004
User guide Signal Switch Data Book (Rev. A) Nov. 14, 2003
More literature Logic Cross-Reference (Rev. A) Oct. 07, 2003
Application note TI IBIS File Creation, Validation, and Distribution Processes Aug. 29, 2002
Application note CMOS Power Consumption and CPD Calculation (Rev. B) Jun. 01, 1997
Application note Designing With Logic (Rev. C) Jun. 01, 1997
Application note Input and Output Characteristics of Digital Integrated Circuits Oct. 01, 1996
Application note Live Insertion Oct. 01, 1996
Application note SN54/74HCT CMOS Logic Family Applications and Restrictions May 01, 1996
Application note Using High Speed CMOS and Advanced CMOS in Systems With Multiple Vcc Apr. 01, 1996

Design & development

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Hardware development

EVALUATION BOARD Download
10
Description
This EVM is designed to support any logic device that has a D, DW, DB, NS, PW, P, N, or DGV package in a 14 to 24 pin count.
Features
  • Board design allows for versatility in evaluation
  • Supports a wide-range of logic devices

CAD/CAE symbols

Package Pins Download
SOIC (DW) 24 View options

Ordering & quality

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