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SN74LVC646A

ACTIVE

Octal Bus Transceiver And Register With 3-State Outputs

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Data sheet

SN74LVC646A

ACTIVE
Data sheet Order now

Product details

Supply voltage (min) (V) 1.65 Supply voltage (max) (V) 3.6 Number of channels 8 IOL (max) (mA) 24 IOH (max) (mA) -24 Input type TTL/CMOS Output type LVTTL Features Balanced outputs Technology family LVC Rating Catalog Operating temperature range (°C) -40 to 85
Supply voltage (min) (V) 1.65 Supply voltage (max) (V) 3.6 Number of channels 8 IOL (max) (mA) 24 IOH (max) (mA) -24 Input type TTL/CMOS Output type LVTTL Features Balanced outputs Technology family LVC Rating Catalog Operating temperature range (°C) -40 to 85
SOIC (DW) 24 159.65 mm² 15.5 x 10.3 SSOP (DB) 24 63.96 mm² 8.2 x 7.8 TSSOP (PW) 24 49.92 mm² 7.8 x 6.4
  • Operate From 1.65 V to 3.6 V
  • Inputs Accept Voltages to 5.5 V
  • Max tpd of 7.4 ns at 3.3 V
  • Typical VOLP(Output Ground Bounce)
       <0.8 V at VCC = 3.3 V, TA = 25°C
  • Typical VOHV (Output VOH Undershoot)
       >2 V at VCC = 3.3 V, TA = 25°C
  • Supports Mixed-Mode Signal Operation on All Ports (5-V Input/Output Voltage With 3.3-V VCC)
  • Ioff Supports Partial-Power-Down Mode Operation
  • Latch-Up Performance Exceeds 250 mA Per JESD 17
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)
  • Operate From 1.65 V to 3.6 V
  • Inputs Accept Voltages to 5.5 V
  • Max tpd of 7.4 ns at 3.3 V
  • Typical VOLP(Output Ground Bounce)
       <0.8 V at VCC = 3.3 V, TA = 25°C
  • Typical VOHV (Output VOH Undershoot)
       >2 V at VCC = 3.3 V, TA = 25°C
  • Supports Mixed-Mode Signal Operation on All Ports (5-V Input/Output Voltage With 3.3-V VCC)
  • Ioff Supports Partial-Power-Down Mode Operation
  • Latch-Up Performance Exceeds 250 mA Per JESD 17
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)

The SN54LVC646A octal bus transceiver and register is designed for 2.7-V to 3.6-V VCC operation, and the SN74LVC646A octal bus transceiver and register is designed for 1.65-V to 3.6-V VCC operation.

These devices consist of bus-transceiver circuits, 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 are performed with the ’LVC646A devices.

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

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 low. In the isolation mode (OE\ high), A data is stored in one register and B data can be stored in the other register.

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

Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of these devices as translators in a mixed 3.3-V/5-V system environment.

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

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.

The SN54LVC646A octal bus transceiver and register is designed for 2.7-V to 3.6-V VCC operation, and the SN74LVC646A octal bus transceiver and register is designed for 1.65-V to 3.6-V VCC operation.

These devices consist of bus-transceiver circuits, 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 are performed with the ’LVC646A devices.

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

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 low. In the isolation mode (OE\ high), A data is stored in one register and B data can be stored in the other register.

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

Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of these devices as translators in a mixed 3.3-V/5-V system environment.

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

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.
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Technical documentation

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Type Title Date
* Data sheet SN54LVC646A, SN74LVC646A datasheet (Rev. J) 31 Jul 2003
Application note Implications of Slow or Floating CMOS Inputs (Rev. E) 26 Jul 2021
Selection guide Little Logic Guide 2018 (Rev. G) 06 Jul 2018
Selection guide Logic Guide (Rev. AB) 12 Jun 2017
Application note How to Select Little Logic (Rev. A) 26 Jul 2016
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) 02 Dec 2015
User guide LOGIC Pocket Data Book (Rev. B) 16 Jan 2007
Product overview Design Summary for WCSP Little Logic (Rev. B) 04 Nov 2004
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection 08 Jul 2004
Application note Selecting the Right Level Translation Solution (Rev. A) 22 Jun 2004
User guide Signal Switch Data Book (Rev. A) 14 Nov 2003
Application note Use of the CMOS Unbuffered Inverter in Oscillator Circuits 06 Nov 2003
User guide LVC and LV Low-Voltage CMOS Logic Data Book (Rev. B) 18 Dec 2002
Application note Texas Instruments Little Logic Application Report 01 Nov 2002
Application note TI IBIS File Creation, Validation, and Distribution Processes 29 Aug 2002
More literature Standard Linear & Logic for PCs, Servers & Motherboards 13 Jun 2002
Application note 16-Bit Widebus Logic Families in 56-Ball, 0.65-mm Pitch Very Thin Fine-Pitch BGA (Rev. B) 22 May 2002
Application note Power-Up 3-State (PU3S) Circuits in TI Standard Logic Devices 10 May 2002
More literature STANDARD LINEAR AND LOGIC FOR DVD/VCD PLAYERS 27 Mar 2002
Application note Migration From 3.3-V To 2.5-V Power Supplies For Logic Devices 01 Dec 1997
Application note Bus-Interface Devices With Output-Damping Resistors Or Reduced-Drive Outputs (Rev. A) 01 Aug 1997
Application note CMOS Power Consumption and CPD Calculation (Rev. B) 01 Jun 1997
Application note LVC Characterization Information 01 Dec 1996
Application note Input and Output Characteristics of Digital Integrated Circuits 01 Oct 1996
Application note Live Insertion 01 Oct 1996
Design guide Low-Voltage Logic (LVC) Designer's Guide 01 Sep 1996
Application note Understanding Advanced Bus-Interface Products Design Guide 01 May 1996

Design & development

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Evaluation board

14-24-LOGIC-EVM — Logic product generic evaluation module for 14-pin to 24-pin D, DB, DGV, DW, DYY, NS and PW packages

The 14-24-LOGIC-EVM evaluation module (EVM) is designed to support any logic device that is in a 14-pin to 24-pin D, DW, DB, NS, PW, DYY or DGV package,

User guide: PDF | HTML
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Simulation model

SN74LVC646A IBIS Model (Rev. A)

SCEM057A.ZIP (9 KB) - IBIS Model
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Package Pins CAD symbols, footprints & 3D models
SOIC (DW) 24 Ultra Librarian
SSOP (DB) 24 Ultra Librarian
TSSOP (PW) 24 Ultra Librarian
TI's Standard Terms and Conditions for Evaluation Items apply.

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