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MAX3250CAI+T

P1-P3P4-P6P7-P9P10-P10
MAX3250
±50V Isolated, 3.0V to 5.5V,
250kbps, 2 TX/2 RX, RS-232 Transceiver
4 _______________________________________________________________________________________
Typical Operating Characteristics
(V
CC
= 3.3V, 250kbps data rate, see Typical Operating Circuit and Table 1 for capacitor values, all transmitters loaded with 3kΩ and
C
L
to ISOCOM, T
A
= +25°C, unless otherwise noted.)
MAX3250 toc05
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
603510-15
-200
-100
0
100
200
300
400
-300
-40 85
SHUTDOWN CURRENT
vs. TEMPERATURE
ISOCOM = -50V
ISOCOM = 0V
ISOCOM = +50V
TIME TO EXIT SHUTDOWN
V
ISOCOM
= 0V
TOUT
5V/div
MAX3250 toc04
100µs/div
SHDN
5V/div
MAX3250 toc03
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
4000300020001000
10
20
30
40
50
60
70
80
90
0
0 5000
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 20kbps
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
250kbps
120kbps
20kbps
MAX3250 toc02
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
4000300020001000
5
10
15
20
25
30
0
0 5000
SLEW RATE
vs. LOAD CAPACITANCE
-SLEW
+SLEW
FOR DATA RATES UP TO 250kbps
COMMON-MODE FAULT RESPONSE
ISOCOM
50V/div
MAX3250 toc07
FAULT
5V/div
4ms/div
PEAK GROUND OFFSET VOLTAGE
vs. FREQUENCY
MAX3250 toc06
FREQUENCY (Hz)
PEAK GROUND OFFSET (±V)
300100 200 400 500
10
20
30
40
50
60
0
0600
V
CC
= 3.3V
V
CC
= 5V
MAX3250
±50V Isolated, 3.0V to 5.5V,
250kbps, 2 TX/2 RX, RS-232 Transceiver
_______________________________________________________________________________________ 5
Pin Description
PIN NAME FUNCTION
1 C1-
Negative Terminal of the Power Isolation Capacitor. Connect a 100V capacitor from C1- to C1+.
See Table 1 for values.
2 R1OUT TTL/CMOS Receiver Output
3 R2OUT TTL/CMOS Receiver Output
4 T1IN TTL/CMOS Transmitter Input
5 T2IN TTL/CMOS Transmitter Input
6, 22, 23 N.C. No Connection. Not internally connected.
7 N.C. No Connection. Leave unconnected or connect to ISOCOM.
8 C1+
Positive Terminal of the Power Isolation Capacitor. Connect a 100V capacitor from C1+ to C1-.
See Table 1 for values.
9 C3+
Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect a 0.1µF capacitor from
C3+ to C3-.
10 V+
+5.5V Generated by the Charge Pump, Referenced to ISOCOM. Bypass V+ to ISOCOM with a
0.47µF capacitor.
11 C3-
Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect a 0.1µF capacitor from
C3- to C3+.
12 C4+
Positive Terminal of the Inverting Charge-Pump Capacitor. Connect a 0.47µF capacitor from
C4+ to C4-.
13 C4-
Negative Terminal of the Inverting Charge-Pump Capacitor. Connect a 0.47µF capacitor from
C4- to C4+.
14 V-
-5.5V Generated by the Charge Pump, Referenced to ISOCOM. Bypass V- to ISOCOM with a 0.47µF
capacitor.
15 ISOCOM Isolated Ground
16 T2OUT RS-232 Transmitter Output
17 T1OUT RS-232 Transmitter Output
18 R2IN RS-232 Receiver Input
19 R1IN RS-232 Receiver Input
20 ISOVCC
Internally Generated Isolated Power-Supply Voltage, Referenced to ISOCOM. Bypass ISOVCC to
ISOCOM with a 2.2µF capacitor.
21 C2+
Positive Terminal of the Power Isolation Capacitor. Connect a 100V capacitor from C2+ to C2-.
See Table 1 for values.
24 SHDN
Shutdown Control. Drive SHDN low to enter low-power shutdown mode. Drive SHDN high or connect
to V
CC
for normal operation.
25 FAULT Overvoltage Indicator. Active low, open drain.
26 GND Ground
27 C2-
Negative Terminal of the Power Isolation Capacitor. Connect a 100V capacitor from C2- to C2+.
See Table 1 for values.
28 V
CC
3.0V to 5.5V Supply Voltage. Bypass V
CC
to GND with a 1µF capacitor.
MAX3250
±50V Isolated, 3.0V to 5.5V,
250kbps, 2 TX/2 RX, RS-232 Transceiver
6 _______________________________________________________________________________________
Detailed Description
The MAX3250 is a 3.0V to 5.5V powered, ±50V isolated
EIA/TIA-232 and V.28/V.24 communications interface
with high data-rate capabilities. The MAX3250 is a dual
die part that operates with up to ±50V difference
between the RS-232 side and the logic side (ISOCOM
to GND). This makes the device ideal for operation in
noisy conditions with high common-mode voltages.
This feature prevents damage to the device if RS-232
lines are inadvertently short-circuited to a +24V or ±48V
power bus.
The MAX3250 typically draws 15mA of supply current
when unloaded. Supply current drops to 20µA when
the device is placed in shutdown mode.
The MAX3250 has two receivers and two drivers and is
guaranteed to operate at data rates up to 250kbps. The
device features a FAULT open-drain output to signal an
excessive isolated-side voltage condition on any of the
RS-232 inputs. This output can drive an alarm LED or can
be monitored by the processor to prevent operation
under these conditions. The receiver outputs are high
impedance in shutdown, allowing multiple interfaces
(IrDA, RS-232, RS-485) to be connected to the same
UART (Figure 1). The MAX3250 is a low-cost replacement
for opto-isolated transceivers.
Isolated Power Supply
The MAX3250 drives a high-frequency square wave into
C1 and a complementary square wave into C2. These
POWER
CONTROLLER
FAULT
SHDN
GND C1- C2- C1+ C2+ ISOCOM
TOUT2
RIN2
ISOVCC
C3+
C3-
C4+
C4-
V+
V-
TIN1
ROUT1
ROUT2
TIN2
TOUT1
RIN1
RS-232
CHARGE
PUMP
V
CC
MAX3250
FAULT
DETECTOR
OSC
Figure 1. Functional Diagram
P1-P3P4-P6P7-P9P10-P10

MAX3250CAI+T

Mfr. #:
Buy MAX3250CAI+T
Manufacturer:
Maxim Integrated
Description:
RS-232 Interface IC 3-5.5V 250kbps Transceiver
Lifecycle:
New from this manufacturer.
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