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Introduction
2
SCEU015 – May 2019
Copyright © 2019, Texas Instruments Incorporated
SN74AXC4T774 Evaluation Module User Guide
1
Introduction
The AXC devices are a new family of direction controlled level translators from Texas Instruments. AXC
devices have dual-supply pins enabling configurable voltage translation between 0.65 V and 3.6 V and
any intermediate voltage ranges. The SN74AXC4T774EVM can be used to evaluate
translator device in the PW or the RSV packages. Refer to the competitive advantages of the AXC Family
in the application report
Power sequencing for the AXC family of devices
). Watch
to the AXC family of direction controlled translation device
.
1.1
Features
The AXC family of direction controlled translation devices are dual-supply with configurable voltage
translation and an operating range from 0.65 V to 3.6 V. The A port is designed to track V
CCA
. V
CCA
accepts
any supply voltage from 0.65 V to 3.6 V. The B port is designed to track V
CCB
. V
CCB
accepts any supply
voltage from 0.65 V to 3.60 V. The SN74AXC4T774 device is fully specified for partial-power-down
applications using I
OFF
. The I
OFF
circuitry disables the outputs, thus preventing damaging current backflow
through the device when the device is powered down. The V
CC
isolation feature ensures that if either V
CC
input is at ground, both A and B data I/O ports are in the high-impedance state.
The eight channel
device has two direction control pins, each controlling 4 data I/Os
enabling independent and simultaneous up and down translation. Refer to
for
testing SN74AXC8T245PW package.
The four channel
device has individual direction control pins for each of it's IO(A and B)
ports to allow configurable up and down translation.
The functional table of the
is listed in
.This EVM is pre-configured to support
translation for Serial Peripheral Interface (SPI) and Joint Test Action Group (JTAG) interface as shown in
.Refer to the low voltage translation for standard interfaces in the application report
Low voltage
translation for SPI, UART, RGMII, and JTAG interfaces
).
Table 1. SN74AXC4T774 Functional Table(Each 1-bit section)
OE
DIRx
Signal Direction
H
X
Hi-Z
L
L
B data to A bus
L
H
A data to B bus
Table 2. SPI, JTAG Interface EVM setup
PINS
PULL-UP (PW
AND RSV)
PULL-DOWN (PW
AND RSV)
DEFAULT STATE
STATUS
OE
R1, R6
R13, R14
10k
Ω
to GND
DEVICE
ENABLED
DIR1
R2, R7
NO
10k
Ω
to Vcca
A1(Input) TO
B1(Output)
DIR2
R3, R8
NO
10k
Ω
to Vcca
A2(Input) TO
B2(Output)
DIR3
R4, R9
NO
10k
Ω
to Vcca
A3(Input) TO
B3(Output)
DIR4
R5, R10
R15, R16
10k
Ω
to GND
B4(Input) TO
A4(Output)