Datasheet

MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers with Fault Detection
_______________________________________________________________________________________ 7
(FAULT OUTPUT)
ALARMA
OR
ALARMD
V
A
C
LF
C
L
A
V
ID
V
A
A
OUTA
Figure 1. Typical Receiver Test Circuit
+3V
V
ID
OV OV
RISE/FALL TIMES ≤2ns
V
CC
/2V
CC
/2
-3V
V
OH
R
O
V
OL
t
PHL
t
PLH
Figure 2. Propagation Delay
OV
V
ID
F
DIFL
V
CC
/2V
CC
/2
-3.0V
+3.0V
F
DIFH
V
OH
ALARM OR ALARMD
V
OL
t
DFHL
t
DFLH
Figure 3. Fault-Detection Timing
OV
V
IN
F
CMH
V
CC
/2
V
CC
/2
F
CML
V
OH
ALARM OR ALARMD
V
OL
t
CMFHL
t
CMFLH
t
CMFHL
t
CMFLH
V
CC
/2
V
CC
/2
Figure 4. Common-Mode Fault Propagation Delay
Test Circuits and Waveforms
Detailed Description
The MAX3097E/MAX3098E feature high-speed, triple
RS-485/RS-422 receivers with fault-detection circuitry
and fault-status outputs. The fault outputs are active
push-pull, requiring no pull-up resistors. The fault cir-
cuitry includes a capacitor-programmable delayed
FAULT_ output to ensure that there are no erroneous
fault conditions even at slow edge rates (see Delayed
Fault Output). The receivers operate at data rates up to
32Mbps.
The MAX3097E/MAX3098E are designed for motor-
shaft encoders with standard A, B, and Z outputs (see
Using the MAX3097E/MAX3098E as Shaft Encoder
Receivers). The devices provide an alarm for open-cir-
cuit conditions, short-circuit conditions, data nearing
the minimum differential threshold conditions, data
below the minimum threshold conditions, and receiver
inputs outside the input common-mode range. Tables 1
and 2 are functional tables for each receiver.