TRUTH TABLE
PIN DESCRIPTION
APPLICATIONS INFORMATION
The UT54LVDM031LV Bus-LVDS driver’s intended use is for
both point-to-point (single termination) and multipoint (double
termination) data transmissions over controlled impedance
media. The transmission media may be printed-circuit board
traces, backplanes, or cables. Note: The ultimate rate and distance
of data transfer is dependent upon the attenuation characteristics
of the media, the noise coupling to the environment, and other
application specific characteristics.
The UT54LVDM031LV differential line driver is a balanced
current source design. A current mode driver, has a high output
impedance and supplies a constant current for a range of loads (a
voltage mode driver on the other hand supplies a constant voltage
for a range of loads). Current is switched through the load in one
direction to produce a logic state and in the other direction to
produce the other logic state. The current mode requires (as
discussed above) that a resistive termination be employed to
terminate the signal and to complete the loop as shown in Figure
3. AC or unterminated configurations are not allowed. The 10mA
loop current will develop a differential voltage of 350mV across
the 35 termination resistor which the receiver detects with a
250mV minimum differential noise margin neglecting resistive
line losses (driven signal minus receiver threshold (340mV -
100mV = 250mV)). The signal is centered around +1.2V (Driver
Offset, VOS) with respect to ground as shown in Figure 4. Note:
The steady-state voltage (VSS) peak-to-peak swing is twice the
differential voltage (VOD) and is typically 700mV.
Enables Input Output
EN EN DIN DOUT+ DOUT-
L H X Z Z
All other combinations
of ENABLE inputs
L L H
H H L
Pin No. Name Description
1, 7, 9, 15 DIN Driver input pin, TTL/CMOS
compatible
2, 6, 10, 14 DOUT+ Non-inverting driver output pin,
LVDS levels
3, 5, 11, 13 DOUT- Inverting driver output pin,
LVDS l evels
4 EN Active high enable pin, OR-ed
with EN
12 EN Active low enable pin, OR-ed
with EN
16 VDD Power supply pin, +3.3V + 0.3V
8V
SS Ground pin
Figure 2. UT54LVDM031LV Pinout
UT54LVDM031LV
Driver
16
15
14
13
12
11
10
9
VDD
DIN4
DOUT4+
DOUT4-
EN
DOUT3-
DOUT3+
DIN3
1
DIN1
2
DOUT1+
3
DOUT1-
4
EN
5
DOUT2-
6
DOUT2+
7
DIN2
8
VSS
ENABLE
DATA
INPUT
1/4 UT54LVDM031LV
1/4 UT54LVDS032LV
+
-DATA
OUTPUT
Figure 3. Point-to-Point Application
RT 35