communication, signal buffering, voltage translation, and cold
sparing. With V
DD
equal to zero volts, the UT54ACS164245S
outputs and inputs present a minimum impedance of 1MΩ mak-
ing it ideal for "cold spare" applications. Balanced outputs and
low "on" output impedance make the UT54ACS164245S well
suited for driving high capacitance loads and low impedance
backplanes. The UT54ACS164245S enables system designers
to interface 3.3 volt CMOS compatible components with 5 volt
CMOS components. For voltage translation, the A port inter-
faces with the 3.3 volt bus; the B port interfaces with the 5 volt
bus. The direction control (DIRx) controls the direction of data
flow. The output enable (OEx) overrides the direction control
and disables both ports. These signals can be driven from either
port A or B. The direction and output enable controls operate
these devices as either two independent 8-bit transceivers or one
16-bit transceiver.
LOGIC SYMBOL
O E1 (48)
O E2 (25)
DIR1
(1)
G1
2EN1 (BA)
2EN2 (AB)
1EN1 (BA)
1EN2 (AB)
G2
11
12
(24)
DIR2
1A1
1A2
1A3
(47)
(46)
(44)
(2)
(3)
(5)
(6)
(8)
1B1
1B2
1B3
1B4
(43)
1A4
(41)
1A5
(40)
1A6
(38)
1A7
(37)
1A8
(36)
2A1
2A2
2A3
(35)
(33)
21
22
1B5
(9)
1B6
(11)
1B7
(12)
1B8
(13)
2B1
(14)
2B2
(16)
2B3
(17)
2B4
(19)
2B5
(20)
2B6
(22)
2B7
(23)
2B8
(32)
2A4
(30)
2A5
(29)
2A6
(27)
2A7
(26)
2A8
PIN DESCRIPTION
Pin Names
OE x
DIRx
xAx
xBx
Description
Output Enable Input (Active Low)
Direction Control Inputs
Side A Inputs or 3-State Outputs (3.3V Port)
Side B Inputs or 3-State Outputs (5V Port)
FUNCTION TABLE
ENABLE
OE x
L
L
H
DIRECTION
DIRx
L
H
X
OPERATION
B Data To A Bus
A Data To B Bus
Isolation
1
PINOUTS
POWER TABLE
1
Port B
5 Volts
Port A
3.3 Volts
5 Volts
3.3 Volts
V
SS
3.3V or 5V
OPERATION
Voltage Translator
Non Translating
Non Translating
Cold Spare
Port B Cold Spare
48-Lead Flatpack
Top View
DIR1
1B1
1B2
V
SS
1B3
1B4
VDD1
1B5
1B6
V
SS
1B7
1B8
2B1
2B2
V
SS
2B3
2B4
VDD1
2B5
2B6
V
SS
2B7
2B8
DIR2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
OE1
1A1
1A2
V
SS
1A3
1A4
VDD2
1A5
1A6
V
SS
1A7
1A8
2A1
2A2
V
SS
2A3
2A4
VDD2
2A5
2A6
V
SS
2A7
2A8
O E2
5 Volts
3.3 Volts
V
SS
V
SS
NOTE:
1. V
DD2
cannot be tied to V
SS
while power is applied to V
D D 1
.
Control signals DIRx and OEx are 5 volt tolerant inputs. When
V
DD2
is at 3.3 volts, either 3.3 or 5 volt CMOS logic levels can
be applied to all control inputs. For proper operation connect
power to all V
DD
and ground all V
SS
pins (i.e., no floating V
DD
or V
SS
input pins). Tie unused inputs to V
SS
. If V
DD1
and
V
DD2
are not powered up together, then V
DD2
should be pow-
ered up first for proper control of OE and DIR. Until V
DD2
reaches 2.75V + 5%, control of the outputs by OE and DIR can-
not be guaranteed. During operation of the part, after power up,
insure V
DD1
> V
DD2
. Tie unused inputs to V
SS
.
2
LOGIC DIAGRAM
DIR1
(1)
(48)
O E1
DIR2
(24)
(25)
OE 2
1A1
(47)
(2)
1B1
2A1
(36)
(13)
2B1
1A2
(46)
(3)
1B2
2A2
(35)
(14)
2B2
1A3
(44)
(5)
1B3
2A3
(33)
(16)
2B3
3.3V PORT
3.3V PORT
1A4
(43)
2A4
(32)
(17)
(30)
(19)
2B5
2B4
5 V PORT
(6)
(41)
(8)
1A6
(40)
(9)
1A7
(38)
(11)
1A8
(37)
(12)
1B4
1A5
2A5
1B5
2A6
1B6
2A7
1B7
2A8
1B8
(26)
(27)
(29)
(20)
2B6
(22)
2B7
(23)
2B8
3
5 V PORT
RADIATION HARDNESS SPECIFICATIONS
PARAMETER
Total Dose
SEL Latchup
Neutron Fluence
2
1
LIMIT
1.0E5
>120
1.0E14
UNITS
rad(Si)
MeV-cm
2
/mg
n/cm
2
Notes:
1. Logic will not latchup during radiation exposure within the limits defined in the table.
2. Not tested, inherent of CMOS technology.
ABSOLUTE MAXIMUM RATINGS
1
SYMBOL
V
I/O
V
DD1
V
DD2
T
STG
T
J
Θ
J C
I
I
P
D
PARAMETER
Voltage any pin
Supply voltage
Supply voltage
Storage Temperature range
Maximum junction temperature
Thermal resistance junction to case
DC input current
Maximum power dissipation
LIMIT (Mil only)
-.3 to V
DD1
+.3
-0.3 to 6.0
-0.3 to 6.0
-65 to +150
+175
20
±10
1
UNITS
V
V
V
°C
°C
°C/W
mA
W
Note:
1. Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, functional operation of the device
at these or any other conditions beyond limits indicated in the operational sections is not recommended. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability and performance.
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