ROHM RPM851A

Communication ICs
IrDA wireless communication
transceiver IC (supports Ver.1.0)
RPM851A Series
The RPM851A series is an IC that supports IrDA Ver 1.0, and is ideal for wireless communications.
An infrared LED, a pin-photo diode, and a receiver frequency formation LSI are all contained in a single package.
Also equipped with low power consumption and power down functions making this IC perfect for mobile sets.
Applications
Personal computers, PDAs, DVCs, digital cameras, printers, cellular phones, PHS systems, hand-held terminals, and
others
Features
1) Supports IrDA Ver. 1.0
2) Low power consumption while standing by for reception (typ. 220µA).
3) A power-down function is perfect for battery applications.
4) Supports a broad power supply voltage range from 2.7V to 5.5V.
5) The package supports mounting on both the upper and side surfaces.
6) Integrated shield case (RPM851A-H6)
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
Series
651
Communication ICs
Block diagram
652
RPM851A Series
Communication ICs
RPM851A Series
Pin descriptions
653
Communication ICs
RPM851A Series
Electrical characteristics (unless otherwise noted, LEDVCC = VCC = PINVCC = 3V, Ta = 25C)
Optical characteristics (unless otherwise noted, LEDVCC = VCC = PDVCC = 3V, Ta = 25C)
654
Communication ICs
RPM851A Series
Circuit operation
Timing charts
Application example
655
Communication ICs
Recommended values (at VCC = 3V)
656
RPM851A Series
Communication ICs
FOperation notes
(1) LEDVCC (pin5), VCC (pin122) and PINVCC (pin13)
S Other power source can be used within ± 0.2 [V] voltage difference between LEDVCC and VCC. VCC and
PINVCC should be supplied from the same source.
(2) Caution in designing board lay-out
S Pin1 is radiaton pin from LED as well. Wider pattern is
better.
S The line of RXDSIR (pin10) should be connected at
backside via through hole close to RPM851A pin lead.
Better not to be close to photo diode side (pin13).
This is to minimize feedback supplied to photo diode
from RXDSIR.
S Capacitors for pin12 (VCC) and pin13 (PINVCC) should
be placed close to RPM851A.
RPM851A Series
S Better to be placed more than 1.0cm in radius from
photo diode (pin13) and also away from the parts
which generates noise, such as DC / DC converter.
Digital signal line, such as clock pulse, bus etc, are
also away more than 1.0cm in radius from photo diode.
S As for C1, C2 and, GND should be close to pin7 and
placed close to pins11, 12 and 13 (within 5mm).
(3) Please be sure to set up the TXD (pin6) input to be
ā€œLā€ (under 0.5 [V]) except transmitting data (for < 90
µ s. ON Duty < 20%).
(4) Powerdown current might increase if exposed by
strong light (ex. direct sunlight) at powerdown mode.
(5) Please use by the signal form which is specified by
IrDA Ver1.0. There might be on error if used by different signal form.
FExternal dimensions (Units: mm)
657