19-2443; Rev 1; 2/03
卤50V Isolated, 3.0V to 5.5V,
250kbps, 2 Tx/2 Rx, RS-232 Transceiver
General Description
The MAX3250 is a 3.0V to 5.5V powered, 卤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 卤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 卤48V
power bus.
The MAX3250 is powered by a single 3V to 5.5V supply
on the logic side. Power is transferred from the logic
side to the isolated side by 卤100V external capacitors.
The MAX3250 has two receivers (Rx) and two drivers
(Tx) and is guaranteed to run at data rates of 250kbps
while maintaining RS-232 output levels. The trans-
ceivers have a proprietary low-dropout transmitter out-
put stage, delivering true RS-232 performance from a
3V to 5.5V supply with a dual charge pump. The device
features a
FAULT
open-drain output to signal an exces-
sive 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.
The MAX3250 is available in a space-saving 28-pin
SSOP package.
o
卤50V Isolation
o
20碌A Supply Current in Shutdown
o
250kbps Guaranteed Data Rate
o
FAULT
Output
o
High-Impedance Transmitter and Receiver
Outputs in Shutdown
o
Space-Saving SSOP Package
o
Inductorless/Transformerless Design Simplifies
EMI Compliance
o
Low-Cost Replacement for Opto-Isolated
Transceivers
o
Meets EIA/TIA-232 Specifications Down to 3.0V
Features
MAX3250
Ordering Information
PART
MAX3250CAI
MAX3250EAI
TEMP RANGE
0掳C to +70掳C
-40掳C to +85掳C
PIN-PACKAGE
28 SSOP
28 SSOP
Pin Configuration
TOP VIEW
C1- 1
R1OUT 2
R2OUT 3
T1IN 4
T2IN 5
N.C. 6
N.C. 7
C1+ 8
C3+ 9
V+ 10
C3- 11
C4+ 12
C4- 13
28 V
CC
27 C2-
26 GND
25 FAULT
24 SHDN
Applications
Industrial Control
Programmable Logic Controller
Point-of-Sale Equipment
PC-to-Router Connections
Diagnostic Ports
Telecom Equipment
MAX3250
23 N.C.
22 N.C.
21 C2+
20 ISOV
CC
19 R1IN
18 R2IN
17 T1OUT
16 T2OUT
15 ISOCOM
Typical Operating Circuit appears at end of data sheet.
V- 14
SSOP
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
1
2
3
4
5
6
7
8
9
10
