ELECTRONIC COMPONENTS

SHARP IrDA Control Infrared Transceiver

SHARP Electronic Components

10

Rev. 1.0.1, November 26, ‘98

10. RESET Function

The “RESET” terminal is used to recover the receiver sensitivity to its maximum level. Since Sharp IrDA Control

Infrared Transceiver has a built-in capability to adjust the receiving sensitivity, as a result, a very weak IR signals may

not be correctly received just after receiving a very strong IR signals.

Following figure shows an example of “RESET” signal in order to recover the Sharp IrDA Control Infrared

Transceiver’s receiving sensitivity to its receiving sensitivity to its maximum level:

Optical

Signal

Vo

RESET

input

> 13

µsec

AGCN

Gap Time

tret

tret: The time period until AGCN

(NOTES)

This pinout is an Active Low terminal, and stays HIGH level when it is OPEN. The Low Level Pulse for the period of

> 13

µsec enables this function to work. This > 13µsec input must be pulsed within the period of Gap time in order for

the transceiver to have receiver sensitivity recovery. The timing for this “RESET” pulse should be adjusted at controller

side.

11. The Derating Curve of Peak Forward LED Current

0

100

200

300

400

500

600

-25

0

25

50

75

100

-10

70

Figure 11.1 Derating Curve of Peak LED Current

Pulse width < 3.3

µsec, Duty Ratio < 25%