19-1402; Rev 0; 11/98
3V to 5.5V, IrDA Infrared Transceiver with
Integrated RS-232 Interface
General Description
The MAX3130/MAX3131 combine an IrDA 1.2 compati-
ble infrared transceiver with an RS-232 interface—all in
a single 3V-powered hybrid microcircuit. The infrared
transceiver supports IrDA data rates of 2.4kbps to
115kbps. The infrared receive channel provides a high-
gain/low-noise PIN-diode amplifier with 100µA of ambi-
ent photodiode current rejection at a +3V supply. A
high-power LED driver capable of sinking 200mA is
included in the infrared transmit path. The on-board
encoder/decoder (ENDEC) compresses/stretches sig-
nals to and from the external UART, allowing IrDA com-
munication even with non-IrDA UARTs.
A 2-driver/2-receiver RS-232 transceiver supports data
rates up to 120kbps. A proprietary, high-efficiency, dual
charge-pump power supply and a low-dropout trans-
mitter combine to deliver true RS-232 performance from
a single +3.0V to +5.5V supply. Selectable shutdown
for IR and RS-232 circuitry reduces supply current to
1µA.
The MAX3130 is optimized for applications using a sin-
gle UART for both infrared and RS-232 communication.
The infrared transmitter input and infrared receiver out-
put are multiplexed with one RS-232 transmitter input
and one RS-232 receiver output, respectively. The
MAX3131’s IrDA transceiver and RS-232 transceivers
are separate and have their own data inputs and outputs.
Both these devices require a minimum of external com-
ponents: four small 0.1µF capacitors, a photodiode, an
infrared LED, and a current-setting resistor.
Features
o
Integrated RS-232 and IrDA in Single 28-Pin SSOP
Package
o
370µA Supply Current
o
IrDA 1.2 Compatible: 2.4kbps to 115kbps
Data Rate
o
On-Board IR Encoder/Decoder Allows Use of
Non-IrDA UARTs
o
+3.0V to +5.5V Single-Supply Operation
o
Meet EIA/TIA-232 Specifications Down to +3V
o
200mA, High-Current Infrared LED Drive
o
1µA Low-Power Shutdown with RS-232
Receivers Active
MAX3130/MAX3131
Ordering Information
PART
MAX3130CAI
MAX3130EAI
MAX3131CAI
MAX3131EAI
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
28 SSOP
28 SSOP
28 SSOP
28 SSOP
Pin Configuration
TOP VIEW
EDGEDET (RXD) 1
28 R2OUT
27 R2IN
26 T2OUT
25 RSSD
24 V-
Applications
Personal Digital Assistants (PDAs)
Palmtop Computers
Battery-Powered Systems
Hand-Held Equipment
Peripherals
IrDA Applications
Cellular Phones
T1IN 2
T2IN 3
IRMODE (TXD) 4
R1OUT 5
R1IN 6
T1OUT 7
BAUD16 8
GND 9
V
CC
10
N.C. 11
AV
CC
12
AGND 13
PINC 14
MAX3130
MAX3131
23 C2-
22 C2+
21 C1-
20 C1+
19 V+
18 N.C.
17 LEDC
16 PGND
15 IRSD
( ) ARE FOR MAX3131
SSOP
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
