SN74LVC8T245-EP_17 Datasheet, PDF (10/26 Pages) Texas Instruments – 8-Bit Dual-Supply Bus Transceiver With Configurable Voltage Translation and Tri-State Outputs

SN74LVC8T245-EP
SCES770A – DECEMBER 2008 – REVISED MARCH 2017
9 Detailed Description
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9.1 Overview
The SN74LVC8T245-EP is an 8-bit, dual supply non-inverting voltage level translation. Pin Ax and direction
control pin are support by V_CCA and pin Bx is support by V_CCB. The A port is able to accept I/O voltages ranging
from 1.65 V to 5.5 V, while the B port can accept I/O voltages from 1.65 V to 5.5 V. The high on DIR allows data
transmission from A to B and a low on DIR allows data transmission from B to A.
9.2 Functional Block Diagram
2
DIR
3
A1
22
OE
21
B1
To Seven Other Channels
Figure 2. Logic Diagram (Positive Logic)
9.3 Feature Description
9.3.1 Fully Configurable Dual-Rail Design Allows Each Port to Operate Over the Full 1.65-V to 5.5-V
Power-Supply Range
Both V_CCA and V_CCB can be supplied at any voltage between 1.65 V and 5.5 V making the device suitable for
translating between any of the voltage nodes (1.8 V, 2.5 V, 3.3 V and 5 V).
9.3.2 I_off Supports Partial-Power-Down Mode Operation
I_off prevents backflow current by disabling I/O output circuits when device is in partial-power-down mode.
9.4 Device Functional Modes
The SN74LVC8T245-EP is voltage level translator that can operate from 1.65 V to 5.5 V (V_CCA) and 1.65 V to 5.5
V (V_CCB). The signal translation between 1.65 V and 5.5 V requires direction control and output enable control.
When OE is low and DIR is high, data transmission is from A to B. When OE is low and DIR is low, data
transmission is from B to A. When OE is high, both output ports will be high-impedance.
Table 1. Function Table⁽¹⁾
(Each 8-Bit Section)
CONTROL INPUTS
OE
DIR
L
L
L
H
H
X
OUTPUT CIRCUITS
A PORT B PORT
Enabled
Hi-Z
Hi-Z
Enabled
Hi-Z
Hi-Z
OPERATION
B data to A bus
A data to B bus
Isolation
(1) Input circuits of the data I/Os are always active.
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