MAX3097 MAXIM [Maxim Integrated Products], MAX3097 Datasheet - Page 7

• Manufacturer Part Number: MAX3097
• Manufacturer: MAXIM [Maxim Integrated Products]

Triple RS-422/RS-485 Receivers with Fault Detection
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.
Figure 1. Typical Receiver Test Circuit
Figure 3. Fault-Detection Timing
V
ALARM OR ALARMD
ID
F
-3.0V
DIFH
V
V
V
OH
OL
A
F
V
DIFL
A
OV
V
ID
t
_______________________________________________________________________________________
DFLH
A
A
Detailed Description
V
CC
/2
±15kV ESD-Protected, 32Mbps, 3V/5V,
C
C
LF
L
t
ALARMA
OR
ALARMD
OUTA
DFHL
(FAULT OUTPUT)
V
CC
/2
+3.0V
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.
Figure 2. Propagation Delay
Figure 4. Common-Mode Fault Propagation Delay
ALARM OR ALARMD
V
R
ID
O
F
F
CMH
CML
V
V
V
OV
OH
OL
+3V
V
IN
-3V
V
t
OH
CMFLH
OL
Test Circuits and Waveforms
V
CC
OV
t
PLH
/2
V
CC
V
/2
CC
t
CMFHL
/2
t
CMFLH
OV
t
PHL
RISE/FALL TIMES ≤2ns
V
CC
V
/2
CC
/2
V
CC
t
CMFHL
/2
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