T2526 Datasheet, PDF (1/12 Pages) ATMEL Corporation – LOW-VOLTAGE IR RECEIVER ASSP

Features
• No External Components Except PIN Diode
• Supply-voltage Range: 2.7 V to 5.5 V
• Automatic Sensitivity Adaptation (AGC)
• Automatic Strong Signal Adaptation (ATC)
• Automatic Supply Voltage Adaptation
• Enhanced Immunity against Ambient Light Disturbances
• Available for Carrier Frequencies between 30 kHz to 76 kHz; adjusted by Zener-Diode
Fusing ±2.5%
• TTL and CMOS Compatible
Applications
• Audio Video Applications
• Home Appliances
• Remote Control Equipment
Low-voltage
IR Receiver
ASSP
Description
The IC T2526 is a complete IR receiver for data communication developed and opti-
mized for use in carrier-frequency-modulated transmission applications. Its function
can be described using the block diagram of Figure 1. The input stage meets two main
functions. First it provides a suitable bias voltage for the PIN diode. Secondly the
pulsed photo-current signals are transformed into a voltage by a special circuit which
is optimized for low noise applications. After amplification by a Controlled Gain Ampli-
fier (CGA) the signals have to pass a tuned integrated narrow bandpass filter with a
center frequency f₀ which is equivalent to the choosen carrier frequency of the input
signal The demodulator is used first to convert the input burst signal to a digital enve-
lope output pulse and to evaluate the signal information quality, i.e., unwanted pulses
will be suppressed at the output pin. All this is done by means of an integrated
dynamic feedback circuit which varies the gain as a function of the present enviromen-
tal conditions (ambient light, modulated lamps etc.). Other special features are used to
adapt to the current application to secure best transmission quality. The T2526 oper-
ates in a supply-voltage range from 2.7 V to 5.5 V. By default, the T2526 is optimized
for best performance within 2.7 V to 3.3 V.
Figure 1. Block Diagram
VS
T2526
IN
Input
CGA and
filter
Demo-
dulator
OUT _Micro-
controller
Oscillator
Carrier frequency f₀
T2526
Modulated IR signal
min 6 or 10 pulses
AGC/ATC
and digital control
GND
Rev. 4597C–AUTO–11/03