The UT54LVDS032LVT receiver’s intended use is primarily in
an uncomplicated point-to-point configuration as is shown in
Figure 3. This configuration provides a clean signaling
environment for quick edge rates of the drivers. The receiver is
connected to the driver through a balanced media which may be
a standard twisted pair cable, a parallel pair cable, or simply
PCB traces. Typically, the characteristic impedance of the media
is in the range of 100. An integrated termination resistor of
100is used to match the media. The termination resistor
converts the current sourced by the driver into voltages that are
detected by the receiver. Other configurations are possible such
as a multi-receiver configuration, but the effects of a mid-stream
connector(s), cable stub(s), and other impedance discontinuities,
as well as ground shifting, noise margin limits, and total
termination loading must be taken into account.
R
IN1-
R
IN1+
R
OUT1
EN
R
OUT2
R
IN2+
R
IN2-
V
SS
1
2
3
4
5
6
7
8
UT54LVDS032LV
Receiver
16
15
14
13
12
11
10
9
V
DD
R
IN4-
R
IN4+
R
OUT4
EN
R
OUT3
R
IN3+
R
IN3-
Figure 2. UT54LVDS032LVT Pinout
ENABLE
TRUTH TABLE
Enables
EN
L
EN
H
Input
R
IN+
- R
IN
-
X
V
ID
> 0.1V
V
ID
< -0.1V
Full Fail-safe
OPEN/SHORT or
Terminated
PIN DESCRIPTION
Pin No.
2, 6, 10, 14
1, 7, 9, 15
3, 5, 11, 13
4
12
16
8
Name
R
IN+
R
IN-
R
OUT
EN
EN
V
DD
V
SS
Description
Non-inverting receiver input pin
Inverting receiver input pin
Receiver output pin
Active high enable pin, OR-ed
with EN
Active low enable pin, OR-ed
with EN
Power supply pin, +3.3 + 0.3V
Ground pin
Output
R
OUT
Z
H
L
H
DATA
INPUT
1/4 UT54LVDS031LV
RT 100
1/4 UT54LVDS032LV
+
-
DATA
OUTPUT
Figure 3. Point-to-Point Application
All other combinations
of ENABLE inputs
The UT54LVDS032LVT differential line receiver is capable of
detecting signals as low as 100mV, over a + 1V common-mode
range centered around +1.2V. This is related to the driver offset
voltage which is typically +1.2V. The driven signal is centered
around this voltage and may shift +1V around this center point.
The +1V shifting may be the result of a ground potential
difference between the driver’s ground reference and the
receiver’s ground reference, the common-mode effects of
coupled noise or a combination of the two. Both receiver input
pins should honor their specified operating input voltage range
of 0V to +2.4V (measured from each pin to ground).
The integrated termination resistor is a nominal 100when V
DD
is 3.0 to 3.6V. In cold spare mode, the integrated termination
resistor is 140
2
Receiver Fail-Safe
The UT54LVDS032LVT receiver is a high gain, high speed
device that amplifies a small differential signal (20mV) to
TTL logic levels. Due to the high gain and tight threshold of
the receiver, care should be taken to prevent noise from
appearing as a valid signal.
The receiver’s internal fail-safe circuitry is designed to
source/sink a small amount of current, providing fail-safe
protection (a stable known state of HIGH output voltage) for
floating, terminated or shorted receiver inputs.
1.
Open Input Pins.
The UT54LVDS032LVT is a quad
receiver device, and if an application requires only 1,
2 or 3 receivers, the unused channel(s) inputs should
be left OPEN. Do not tie unused receiver inputs to
ground or any other voltages. The input is biased by
internal high value pull up and pull down resistors to
set the output to a HIGH state. This internal circuitry
will guarantee a HIGH, stable output state for open
inputs.
2.
Terminated Input.
If the driver is disconnected
(cable unplugged), or if the driver is in a three-state
or power-off condition, the receiver output will again
be in a HIGH state, even with the end of cable 100
integratedtermination resistor across the input pins.
The unplugged cable can become a floating antenna
which can pick up noise. If the cable picks up more
than 10mV of differential noise, the receiver may see
the noise as a valid signal and switch. To insure that
any noise is seen as common-mode and not
differential, a balanced interconnect should be used.
Twisted pair cable offers better balance than flat
ribbon cable.
3.
Shorted Inputs.
If a fault condition occurs that shorts
the receiver inputs together, thus resulting in a 0V
differential input voltage, the receiver output remains
in a HIGH state. Shorted input fail-safe is not
supported across the common-mode range of the
device (V
SS
to 2.4V). It is only supported with inputs
shorted and no external common-mode voltage
applied.
3
OPERATIONAL ENVIRONMENT
PARAMETER
Total Ionizing Dose (TID)
Single Event Latchup (SEL)
Neutron Fluence
1
Notes:
1. Guarnteed but not tested.
LIMIT
1.0E6
>100
1.0E13
UNITS
rad(Si)
MeV-cm
2
/mg
n/cm
2
ABSOLUTE MAXIMUM RATINGS
1
(Referenced to V
SS
)
SYMBOL
V
DD
V
I/O
PARAMETER
DC supply voltage
Voltage on any pin during operation
Voltage on any pin during cold spare
T
STG
P
D
T
J
JC
I
I
Storage temperature
Maximum power dissipation
Maximum junction temperature
2
Thermal resistance, junction-to-case
3
DC input current
LIMITS
-0.3 to 4.0V
-0.3 to (V
DD
+ 0.3V)
-.3 to 4.0V
-65 to +150C
1.25 W
+150C
10C/W
±
10mA
Notes:
1. Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, and functional operation of the device
at these or any other conditions beyond limits indicated in the operational sections of this specification is not recommended. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability and performance.
2. Maximum junction temperature may be increased to +175C during burn-in and life test.
3. Test per MIL-STD-883, Method 1012.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
DD
T
C
V
IN
PARAMETER
Positive supply voltage
Case temperature range
DC input voltage, receiver inputs
DC input voltage, logic inputs
LIMITS
3.0 to 3.6V
-55 to +125C
2.4V
0 to V
DD
for EN, EN
4
DC ELECTRICAL CHARACTERISTICS *
1
(V
DD
= 3.3V + 0.3V; -55C < T
C
< +125C); Unless otherwise noted, Tc is per the temperature range ordered
SYMBOL
V
IH
V
IL
V
OL
V
OH
I
IN
I
I
I
CS
V
TH4
V
TL4
V
CMR4
I
OZ
V
CL
I
OS2, 3
I
CC
I
CCZ
R
TERM
PARAMETER
High-level input voltage
Low-level input voltage
Low-level output voltage
High-level output voltage
Logic input leakage current
(TTL)
(TTL)
I
OL
= 2mA, V
DD
= 3.0V
I
OH
= -0.4mA, V
DD
= 3.0V
Enables = EN/EN = 3.6V,
V
DD
= 3.6
V
IN
= 2.4V, V
DD
= 3.6V
V
IN
=3.6V, V
DD
=V
SS
V
CM
= +1.2V
V
CM
= +1.2V
V
ID
= 200mV peak to peak
Disabled, V
OUT
= 0 V or V
DD
I
CL
= +18mA
Enabled, V
OUT
= 0 V
2
EN, EN = V
DD
or V
SS
Inputs Open
EN = V
SS
, EN = V
DD
Inputs Open
V
DD
= 3.0V to 3.6V
V
DD
= 0.0V
83
125
-100
0.1
-10
-1.5
-15
-130
15
2.3
+10
2.7
-10
+10
CONDITION
MIN
2.0
0.8
0.25
MAX
UNIT
V
V
V
V
A
mV
mV
V
V
mA
mA
Receiver input Current
Cold Spare Leakage Current
Differential Input High Threshold
Differential Input Low Threshold
Common Mode Voltage Range
Output Three-State Current
Input clamp voltage
Output Short Circuit Current
Supply current, receivers enabled
-15
-20
+15
+20
+100
Supply current, receivers disabled
mA
4
114
154
Termination Resistor
Notes:
* For devices procured with a total ionizing dose tolerance guarantee, the post-irradiation performance is guaranteed at 25
o
C per MIL-STD-883 Method 1019, Condition
A up to the maximum TID level procured.
1. Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground.
2. Output short circuit current (I
OS
) is specified as magnitude only, minus sign indicates direction only. Only one output should be shorted at a time, for a maximum
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