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MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
General Description
The MAX3097E/MAX3098E feature three high-speed
RS-485/RS-422 receivers with fault-detection circuitry
and fault-status outputs. The receivers’ inputs have fault
thresholds that detect when the part is not in a valid state.
The MAX3097E/MAX3098E indicate when a receiver
input is in an open-circuit condition, short-circuit condition,
or outside the common-mode range. They also generate
a fault indication when the differential input voltage goes
below a preset threshold. See Ordering Information or the
Electrical Characteristics for threshold values.
The fault circuitry includes a capacitor-programmable
delay to ensure that there are no erroneous fault conditions
even at slow edge rates. Each receiver is capable of
accepting data at rates up to 32Mbps.
Applications
●● RS-485/RS-422 Receivers for Motor-Shaft Encoders
●● High-Speed, Triple RS-485/RS-422 Receiver with
Extended Electrostatic Discharge (ESD)
●● Triple RS-485/RS-422 Receiver with Input Fault
Indication
●● Telecommunications
●● Embedded Systems
Typical Application Circuit
●● ESD Protection
• ±15kV—Human Body Model
• ±15kV—IEC 1000-4-2, Air-Gap Discharge Method
• ±8kV—IEC 1000-4-2, Contact Discharge Method
●● Single +3V to +5.5V Operation
●● -10V to +13.2V Extended Common-Mode Range
●● Capacitor-Programmable Delay of Fault Indication
Allows Error-Free Operation at Slow Data Rates
●● Independent and Universal Fault Outputs
●● 32Mbps Data Rate
●● 16-Pin QSOP is 40% Smaller than IndustryStandard 26LS31/32 Solutions
Ordering Information
TEMP. RANGE
MAX3097ECEE
0°C to +70°C
16 QSOP
MAX3097ECSE
0°C to +70°C
16 SO
Pin Configuration
A, A, B, B, Z, Z
TOP VIEW
MAX3097E
MAX3098E
RECEIVER
OUTPUTS
ALARM
OUTPUTS
DSP
8
MAX547
12-BIT D/A
MOTOR
CONTROLLER
A 1
16 VCC
A 2
15 ALARMA
B 3
B 4
MAX3097E
MAX3098E
13 ALARMB
12 OUTB
Z 6
11 ALARMZ
10 OUTZ
9
DELAY 8
QSOP/SO/DIP
19-1727; Rev 1; 5/19
14 OUTA
Z 5
GND 7
MOTOR DRIVER
PINPACKAGE
PART
Ordering Information continued at end of data sheet.
ENCODED SIGNALS
MOTOR
Features
●● Detects the Following RS-485 Faults:
• Open-Circuit Condition
• Short-Circuit Condition
• Low Differential Voltage Signal
• Common-Mode Range Violation
ALARMD
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Absolute Maximum Ratings
Operating Temperature Ranges
MAX3097EC_E...................................................0°C to +70°C
MAX3098E_C_E.................................................0°C to +70°C
MAX3097E_E_E.............................................. -40°C to +85°C
MAX3098E_E_E.............................................. -40°C to +85°C
Storage Temperature Range............................. -65°C to +150°C
Junction Temperature.......................................................+150°C
Lead Temperature (soldering, 10s).................................. +300°C
Supply Voltage (VCC).............................................................+7V
Receiver Input Voltage (A, A, B, B, Z, Z).............................±25V
Output Voltage (OUT_, ALARM_)............. -0.3V to (VCC + 0.3V)
DELAY....................................................... -0.3V to (VCC + 0.3V)
Continuous Power Dissipation (TA = +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)..........667mW
16-Pin SO (derate 8.7mW/°C above +70°C)................696mW
16-Pin Plastic DIP (derate 10.53mW/°C
above +70°C)...............................................................762mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(VCC = +3V to +5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
Supply Voltage Range
VCC
Supply Current
ICC
No load
Receiver Differential Threshold
Voltage (Note 1)
VTH
-10V ≤ VCM ≤ 13.2V
ΔVTH
-10V ≤ VCM ≤ 13.2V
Receiver Input Hysteresis
Output High Voltage
VOH
Output Low Voltage
VOL
Receiver Input Resistance
RIN
Input Current
(A , A , B , B (Z , Z)
Output Short-Circuit Current
MIN
TYP
3
3.1
-200
MAX
UNITS
5.5
V
4.0
mA
+200
mV
40
VCC = 4.75V, IO = -4mA, VID = +200mV
VCC
-1.5
VCC = 3.0V, IO = -1mA, VID = +200mV
VCC
- 1.0
mV
V
VCC = 4.75V, IO = +4mA, VID = -200mV
0.4
VCC = 3.0V, IO = +1mA, VID = -200mV
0.4
-10V ≤ VCM ≤ 13.2V
IIN
VCC = 0 or 5.5V
IOSR
0 ≤ VRO ≤ VCC
90
160
VIN = 13.2V
(Note 2)
0.07
0.14
VIN = -10V
(Note 2)
-0.05
-0.11
V
kΩ
mA
±105
mA
FAULT DETECTION
MAX3097EA Fault-Detection
Receiver Differential Threshold
Voltage (Note 2)
FDIFH
MAX3098EA Fault-Detection
Receiver Differential Threshold
Voltage (Note 2)
FDIFH
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FDIFL
FDIFL
VCM = 0
VCM = 0
High limit
275
476
Low limit
-475
-275
High limit
0.12
0.20
Low limit
-0.20
-0.12
mV
V
Maxim Integrated │ 2
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Electrical Characteristics (continued)
(VCC = +3V to +5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MAX3098EB Fault-Detection
Receiver Differential Threshold
Voltage (Note 2)
FDIFH
Fault-Detection Receiver Input
Voltage Range (Note 3)
FCMH
High limit
FCML
Low limit
FDIFL
DELAY Current Source
VCM = 0
MIN
MAX
High limit
70
250
Low limit
-250
-70
13.2
-10
VCC = 5V, VDELAY = 0
DELAY Threshold
TYP
9
10
11
VCC = 3V
1.55
1.73
1.90
VCC = 5V
3.1
3.29
3.5
UNITS
mV
V
µA
V
ESD PROTECT
ESD Protection
(A , A , B , B (Z , Z )
Human Body Model
±15
IEC1000-4-2 (Air-Gap Discharge)
±15
IEC1000-4-2 (Contact Discharge)
±8
kV
Switching Characteristics
(VCC = +3V to +5.5V, VID = ±3.0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.)
PARAMETER
Propagation Delay from Input to
Output
Receiver Skew |tPLH - tPHL|
SYMBOL
tPLH, tPHL
tSKEW
Channel-to-Channel Propagation
Delay Skew
Maximum Data Rate
fMAX
CONDITIONS
CL = 15pF,
Figures 1, 2
MIN
TYP
MAX
VCC = 4.5V to 5.5V
75
VCC = 3.0V to 3.6V
85
UNITS
ns
CL = 15pF, Figures 1, 2
±10
ns
CL = 15pF, Figures 1, 2
±10
ns
CL = 15pF, Figure 1
32
Mbps
FAULT DETECTION
Differential Fault Propagation
Delay to Output (Note 5)
tDFLH
tDFHL
Minimum Differential Slew Rate
to Avoid False Alarm Output
Common-Mode Fault
Propagation Delay to Output
(Note 5)
tCMFLH
tCMFHL
15
CLF = 15pF, Figures 1, 3
1.2
MAX3097E (Note 6)
1.0
MAX3098E (Note 7)
0.33
CL = 15pF, Figures 1, 4
µs
V/µs
15
µs
1.5
Note
Note
Note
Note
1: VCM is the common-mode input voltage. VID is the differential input voltage.
2: VIN is the input voltage at pins A, A, B, B, Z, Z.
3: A differential terminating resistor is required for proper function of open-circuit fault detection (see Applications Information).
4: See Applications Information for a discussion of the receiver common-mode voltage range and the operating conditions for
fault indication.
Note 5: Applies to the individual channel immediate-fault outputs (ALARM_) and the general delayed-fault output (ALARMD) when
there is no external capacitor at DELAY.
Note 6: Equivalent pulse test: 1.3V/(tDFLH - tDFHL) ≥ SRD.
Note 7: Equivalent pulse test: 0.62V/(tDFLH - tDFHL) ≥ SRD.
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Maxim Integrated │ 3
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Typical Operating Characteristics
(Typical values are at VCC = +5V and TA = +25°C.)
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
100
VCC = 5V
10
100
1000
MAX3097E/8E toc03
VCC = 3.3V
2
1
-40
-20
0
20
40
60
0
80
-40
-20
0
20
40
60
RECEIVER OUTPUT LOW VOLTAGE
vs. OUTPUT CURRENT
RECEIVER OUTPUT HIGH VOLTAGE
vs. OUTPUT CURRENT
DELAYED ALARM OUTPUT
MAX3097E/8E toc04
OUTPUT LOW VOLTAGE (V)
VCC = 5.0V
3
TEMPERATURE (°C)
VCC = 5.0V
3.0
2.5
VCC = 3.3V
2.0
1.5
1.0
6
VCC = 5.0V
5
-45 -40 -35 -30 -25 -20 -15 -10 -5
OUTPUT CURRENT (mA)
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0
80
CH 1
GND
4
VCC = 3.3V
3
2
1
0.5
0
4
TEMPERATURE (°C)
4.5
3.5
40
30
10,000
VCC = 5.0V
NO LOAD
CAPACITANCE (pF)
5.0
4.0
50
5
MAX3097E/8E toc06
1
VCC = 3.3V
MAX3097E/8E toc05
1
VCC = 3V
OUTPUT HIGH VOLTAGE (V)
10
60
MAX3097E/8E toc02
1000
70
RECEIVER PROPAGATION DELAY (ns)
MAX3097E/8Etoc01
ALARMD OUTPUT DELAY (µs)
10,000
SUPPLY CURRENT vs.
TEMPERATURE
SUPPLY CURRENT (mA)
ALARMD OUTPUT DELAY
vs. CAPACITANCE
0
0
5
10
15
20
OUTPUT CURRENT (mA)
25
30
CH 2
GND
CH 3
GND
20µs/div
CH1: VA, 5V/div
CH2: VALARMA, 5V/div
CH3: VALARMD, 5V/div
VA = GND, CDELAY = 270pF
Maxim Integrated │ 4
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Typical Operating Characteristics (continued)
(Typical values are at VCC = +5V and TA = +25°C.)
COMMON-MODE VOLTAGE FAULT
(HIGH SIDE)
MAX3097E
LOW DIFFERENTIAL INPUT FAULT
GND
CH 1
CH 2
GND
CH 2
CH 3
GND
CH 3
CH 1
GND
GND
CH 2
GND
GND
2ms/div
CH1: VA + AC(60Hz), 10V/div
CH2: VOUTA, 5V/div
CH3: VALARMA, 5V/div
VCC = 3V
2ms/div
CH1: VA + AC(60Hz), 10V/div
CH2: VOUTA, 5V/div
CH3: VALARMA, 5V/div
VCC = 3V
100µs/div
CH1: VA, 200mV/div
CH2: VALARMA, 5V/div
VA = GND
FAULT-DETECTION RECEIVER DIFFERENTIAL
THRESHOLD VOLTAGE SHIFT vs.
COMMON-MODE VOLTAGE
GND
CH 1
CH 2
GND
CH1: VA, 5V/div
CH2: VALARMA, 5V/div
SLEW RATE = 0.05V/µs
VA = GND
12
THRESHOLD SHIFT (mV)
MAX3097E/8E toc09
SLEW-RATE FAULT
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GND
MAX3097E/8E toc10
CH 1
MAX3097E/8E toc08
MAX3097E/8E toc07a
MAX3097E/8E toc07b
COMMON-MODE VOLTAGE FAULT
(LOW SIDE)
8
MAX3097E
4
0
MAX3098E
-4
-8
-10
-5
0
5
10
COMMON-MODE VOLTAGE (V)
Maxim Integrated │ 5
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Pin Description
PIN
NAME
1
A
Noninverting Receiver A Input
FUNCTION
2
A
Inverting Receiver A Input
3
B
Noninverting Receiver B Input
4
B
Inverting Receiver B Input
5
Z
Noninverting Receiver Z Input
6
Z
Inverting Receiver Z Input
7
GND
8
DELAY
Ground
Programmable Delay Terminal. Connect a capacitor from DELAY to GND to set the ALARMD
output delay time. To obtain a minimum delay, leave DELAY unconnected. See Capacitance
vs. ALARMD Output Delay in the Typical Operating Characteristics.
9
ALARMD
Delayed Fault Output. This output is the logic OR of ALARMA, ALARMB, and ALARMZ.
Place a capacitor from the DELAY pin to GND to set the delay (see Setting Delay Time). A
high logic level indicates a fault condition on at least one receiver input pair. A low level on
this pin indicates no fault condition is present.
10
OUTZ
Z Receiver Output. If VZ - V Z ≥ +200mV, OUTZ will be high. If VZ - V Z ≤ -200mV, OUTZ will
be low. If Z or Z exceeds the receiver’s input common-mode voltage range, the ALARMZ
output will be high and OUTZ will be indeterminate.
11
ALARMZ
Z Fault Output. When ALARMZ is high, OUTZ is indeterminate. Tables 1 and 2 show all the
possible states for which an alarm is set.
12
OUTB
B Receiver Output. If VB - V B ≥ +200mV, OUTB will be high. If VB - V B ≤ -200mV, OUTB will
be low. If B or B exceeds the input receiver’s common-mode voltage range, the ALARMB
output will be high and OUTB will be indeterminate.
13
ALARMB
B Fault Output. When ALARMB is high, OUTB is indeterminate. Tables 1 and 2 show all the
possible states for which an alarm is set.
14
OUTA
A Receiver Output. If VA - V A ≥ +200mV, OUTA will be high. If VA - V A ≤ -200mV, OUTA will
be low. If A or A exceeds the receiver’s input common-mode voltage range, the ALARMA
output will be high and OUTA will be indeterminate.
15
ALARMA
A Fault Output. When ALARMA is high, OUTA is indeterminate. Tables 1 and 2 show all the
possible states for which an alarm is set.
16
VCC
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Power Supply
Maxim Integrated │ 6
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Detailed Description
The MAX3097E/MAX3098E are designed for motorshaft encoders with standard A, B, and Z outputs (see Using the MAX3097E/MAX3098E as Shaft
Encoder Receivers). The devices provide an alarm for
open-circuit 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.
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 circuitry
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.
Test Circuits and Waveforms
ALARMA
OR (FAULT OUTPUT)
CLF ALARMD
A
VA
OUTA
VID
CL
A
RO
VA
Figure 1. Typical Receiver Test Circuit
FDIFH
VID
-3.0V
+3V
-3V
VOH
RISE/FALL TIMES 2ns
OV
OV
tPLH
tPHL
VCC/2
VCC/2
VOL
Figure 2. Propagation Delay
+3.0V
OV
FDIFL
VOH
ALARM OR ALARMD
VOL
VID
FCMH
VIN
OV
FCML
tDFHL
tDFLH
VCC/2
Figure 3. Fault-Detection Timing
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VCC/2
tCMFLH
VOH
ALARM OR ALARMD
VOL
tCMFHL tCMFLH
VCC/2
VCC/2
tCMFHL
VCC/2
VCC/2
Figure 4. Common-Mode Fault Propagation Delay
Maxim Integrated │ 7
MAX3097E/MAX3098E
±15kV ESD-Protected, 32Mbps, 3V/5V,
Triple RS-422/RS-485 Receivers
with Fault Detection
Table 1. MAX3097E Alarm Function Table (Each Receiver)
INPUTS
VID
(DIFFERENTIAL
INPUT VOLTAGE)
COMMON-MODE
VOLTAGE
OUTPUTS
OUT_
ALARM_
ALARMD
t ≥ DELAY
(NOTE 1)
FAULT CONDITION
≥0.475V
1
0
0
Normal Operation
-0.475V
0
Indeterminate
Indeterminate
≤-0.475V
0
0
0
X
Indeterminate
(Note 3)
1
1
≤0.2V and ≥-0.2V
≤13.2V and ≥-10V
+13.2V
Indeterminate
Outside Common-Mode Voltage
Range
X = Don’t care
Note 1: ALARMD indicates fault for any receiver.
Note 2: Receiver output may oscillate with this differential input condition.
Note 3: See Applications Information for conditions leading to input range fault condition.
Table 2. MAX3098EA Alarm Function Table (Each Receiver)
INPUTS
VID
(DIFFERENTIAL
INPUT VOLTAGE)
COMMON-MODE
VOLTAGE
OUTPUTS
OUT_
ALARM_
ALARMD
t ≥ DELAY
(NOTE 1)
FAULT CONDITION
≥0.2V
1
0
0
Normal Operation
