TSH511 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

TSH511

Hi-fi stereo/mono infrared receiver and stereo sub-carrier demodulator

STMicroelectronics 

Application information

7

Application information

TSH511

This section provides application information for some typical applications.

7.1

Infrared stereo headphone application

The right side of Figure 21 shows the block diagram of an infrared stereo receiver using the

TSH511. The sensitive LNA, directly connected to the photo diode, does not require an

external pre-amplifier. After filtering, the amplified signals are limited and demodulated with

quadrature demodulators. The two integrated audio buffers directly drive the stereo

headphones. The audio power reaches 2x20mW in two 16Ω loads. The built-in squelch

function fades out the audio when the incoming infrared signal is low. The standby inputs

SBY1 and SBY2 enable only one receiver for the mono applications.

Figure 21. Hi-fi stereo headphone block diagram

IR stereo HiFi transmitter

(Television)

IR stereo HiFi receiver

(Headphones)

Vcc: 2.3 to 5.5V

Current < 15 mA

Right

channel

LNA + ALC

Line inputs

Left

channel

LNA + ALC

TSH512

TX2

VOX

buffer2

SBY

TX1

buffer1

Power supply:

2.3 to 5.5V

Icc < 20 mA stereo

photodiode

Vcc

LNA

LED

Hi2F.i3s&te2re.8o:MHz

carriers

2.3 MHz

filter

RX2

TSH511

Audio

buffer2

20 mW / 16 Ω

RX1

filter

2.8 MHz

Audio

buffer1

20 mW / 16 Ω

The infrared carriers are detected by the photo diode and the signal is directly amplified by

the TSH511. Each receiver has a standard bandpass filter (filters F1 & F2) to select the

2.3MHz and 2.8MHz carriers. After the FM demodulators, the potentiometer P1 controls the

volume levels. The stereo headphones are directly connected to the integrated audio

buffers. The potentiometer P2 allows adjustment of the sensitivity of the Squelch. The

Squelch function fades in and fades out the audio signal, depending on the level of the

2.8MHz carrier.

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