TOIM5232

www.vishay.com

Vishay Semiconductors

Rev. 1.3, 04-Jul-12

3

Document Number: 81749

THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT

OPERATION DESCRIPTION

The block diagram shows a typical example of an RS232

port interface. The TOIM5232 connects to an RS232 level

converter on one side, and an infrared transceiver on the

other. The internal TOIM5232 baud rate generator can be

software controlled.



When BR/D = 0, the TOIM5232 interprets the channels

TD_232 to TD_IR and RD_IR to RD_232 as data channels.



On the other hand, whenever BR/D = 1, the TOIM5232

interprets TD_232 as control word for setting the baud rate.

The baud rate can be programmed to operate from 1200

bit/s to 115.2 kbit/s. As RS232 level converter, EIA232 or

MAX232 or equivalent are recommended.



When using the TOIM5232 directly connected to an UART it

is compatible to 5 V TTL and 3.3 V CMOS logic.



Typical external resistors and capacitors are needed as

shown in the TFDU4...,TFBS4...-series references.



The output pulse duration can also be programmed, see

chapter “operation description”. It is strongly recommended

using 1.627 μs output pulses to save battery power. As

frequency determining component a Vishay XT49M crystal

is recommended, when no external clock is available.







We strongly recommend not to use this 3/16 mode

because 3/16 pulse length at lower bit rates consumes

more power than the shorter pulse. At a data rate of

9600 bit/s, the ratio of power consumption of both

modes is a factor of 12 (!)

PROGRAMMING THE TOIM5232

For correct data rate dependent timing the TOIM5232 is

using a built-in baud rate generator. This is used when no

external clock is not available as in RS232 IR-dongle

applications. For programming the BR/D pin has to be set

active, BR/D = 1.



In this case the TOIM5232 interprets the 7 LSBs at the

TD_232 input as a control word. The operating baud rate will

change to its supposedly new baud rate when the BR/D

returns back to low (“0”) set the UART to 8 bit, no parity,

1 stop bit.

ABSOLUTE MAXIMUM RATINGS

PARAMETER

SYMBOL

MIN.

TYP.

MAX.

UNIT

NOTES

Supply voltage

- 0.5

3.6

V

Input voltage

- 0.5

5.5

V

All pins

Output voltage

- 0.5

V

All pins

Output sinking current

8

mA

All pins

Junction temperature

125

°C

Ambient temperature (operating)

- 25

85°C

Storage temperature

- 25

85°C

Soldering temperature

260

°C

DC CHARACTERISTICS

PARAMETER

TEST CONDITIONS

SYMBOL

MIN.

TYP.

MAX.

UNIT

Operating voltage

2.7

3.3

3.6

V

Input high voltage

Inputs tolerate levels as high as

5.5 V maximum. All inputs are

Schmitt trigger inputs

2

V

Input low voltage

0.8V

Input Schmitt trigger hysteresis

0.6

V

Input leakage no pull-up/down

- 10

± 1

10

µA

Output high voltage

2

V

2.4

V

Output low voltage

0.4

V

Consumption current standby

Inputs grounded, no output load

1µA

Consumption current dynamic

Inputs grounded, no output load

2mA