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TSH511
HiFi stereo/mono infrared receiver Stereo sub-carrier demodulator
s s s s s s s s
Supply voltage: 2.3V to 5.5V Carriers frequency range: 0.4 to 11 MHz Two FM receivers for stereo Integrated audio buffers Audio outputs: 20 mW into 16 ohms High sensitivity: 4V @12dB SINAD Flexibility: access pins for each section Receiver 2 Standby for mono operation
PACKAGE
DESCRIPTION The TSH511 is a 0.4 to 11 MHz dual FM receiver. This circuit offers the functions needed for a highly sensitive infrared HiFi STEREO receiver. Featuring high input sensitivity and high input dynamic range, each receiver integrates a RF front-end LNA, an intermediate amplifier with 2 external filters, a voltage limiter, a quadrature FM demodulator, and finally an audio buffer. The integrated audio buffers are able to drive directly a 16 ohms headphone with 20mW. A SQUELCH circuit mutes both audio amplifiers. Access pins to each section makes the TSH511 suited for a wide field of applications. For MONO applications, the STANDBY pin enables one receiver only, reducing the supply current. The TSH511 forms a chipset with the dual transmitter TSH512. APPLICATIONS
F TQFP44 10 x 10 mm
PIN CONNECTION (top view)
44
43
42
41
40
39
38
37
36
35
34
1 2 Standby 3 4 5 6 7 8 9 10 amp. amp. limiter FM demodulator
33 32 31 30 29
RX2
LNA
s s s s s
Infrared HiFi stereo receiver Infrared Multimedia Headsets Stereo sub-carrier demodulator FM IF receiver systems Power Line Carrier Intercoms
TSH511
RX1
Audio buffers
28 27 26
Vref
limiter
FM demodulator SQUELCH
25 24 23
ORDER CODE
11
Part Number TSH511CF TSH511CFT
Temperature Range -40C to +85C -40C to +85C
Package TQFP44 TQFP44
Conditionning Tray Tape & reel
Marking
12 13 14 15 16 17 18 19 20 21 22
TSH511C TSH511C
December 2002
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TSH511
ABSOLUTE MAXIMUM RATINGS
Symbol Vcc Toper Tstg Tj Rthjc ESD
except for pin 6
Parameter Supply Operating free air temperature range Storage temperature Maximum junction temperature Thermal resistance junction to case HBM: Human Body Model2) CDM: Charged Device Model3) MM: Machine HBM: Human Body Model CDM: Charged Device Model MM: Machine Model Model4) voltage1)
Value 7 -40 to +85 -65 to +150 150 14 2 1.5 0.2 1 1 0.1 A
Unit V C C C C/W
kV
ESD only
for pin 6
kV
Latch-up Class5)
1. 2. 3. 4. 5. All voltages values, except differential voltage, are with respect to network ground terminal ElectroStatic Discharge pulse (ESD pulse) simulating a human body discharge of 100 pF through 1.5k Discharge to Ground of a device that has been previously charged. ElectroStatic Discharge pulse (ESD pulse) approximating a pulse of a machine or mechanical equipment. Corporate ST Microelectronics procedure number 0018695
OPERATING CONDITIONS
Symbol Vcc faudio fcarrier Supply voltage Audio frequency range Carrier frequency range Parameter Value 2.3 to 5.5 20 to 20,000 0.4 to 11 Unit V Hz MHz
BLOC DIAGRAM
DEC-LIM2B DEC-LIM2A AMP-OUT2 MIX-OUT2 LIM-OUT2 MIX-IN2 BUF-IN2 34
LIM-IN2
GND
44
43
42
41
40
39
38
37
36
35
GND AMP-IN2 VCC LNA-OUT2 VCC LNA-IN GND LNA-OUT1 VCC AMP-IN1 DEC-LNA
1 2 Standby 3 4 5 6 7 8 9 10 11 amp. amp. limiter FM demodulator
GND
VCC
33 32 31 30 29
GND SBY1 SBY2 BUF-OUT2 VCC DEC-OUT GND BUF-OUT1 MUTE-OUT MUTE-INT MUTE-IN
RX2
LNA
TSH511
RX1
Audio buffers
28 27 26
Vref
limiter
FM demodulator SQUELCH
25 24 23
12 AMP-OUT1
13
14
15 DEC-LIM1
16 LIM-OUT1
17 DEC-LIM1B
18
19
20 MIX-OUT1
21
22
MIX-IN1
GND
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GND
BUF-IN1
LIM-IN1
VCC
TSH511
PIN DESCRIPTION
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 Pin name GND AMP-IN2 VCC LNA-OUT2 VCC LNA-IN GND LNA-OUT1 VCC AMP-IN1 DEC-LNA AMP-OUT1 GND LIM-IN1 DEC-LIM1A LIM-OUT1 DEC-LIM1B MIX-IN1 VCC MIX-OUT1 GND BUF-IN1 MUTE-IN MUTE-INT MUTE-OUT BUF-OUT1 GND DEC-OUT VCC BUF-OUT2 SBY2 SBY1 GND BUF-IN2 GND MIX-OUT2 VCC MIX-IN2 DEC-LIM2A LIM-OUT2 DEC-LIM2B LIM-IN2 GND AMP-OUT2 related to RX2 RX2 RX1 & RX2 RX1 RX1 RX1 & RX2 RX1 RX1 RX1 RX1 RX1 RX1 RX1 RX1 RX1 & RX2 RX1 & RX2 RX1 & RX2 RX1 RX1 & RX2 RX2 RX1 & RX2 RX1 & RX2 RX2 RX2 RX2 RX2 RX2 RX2 RX2 RX2 direction1) I O I O I O I O I O I I O O O I I I O I O I O Pin description GROUND Intermediate amplifier input SUPPLY VOLTAGE Low Noise Amplifier output SUPPLY VOLTAGE Low Noise Amplifier input GROUND Low Noise Amplifier output SUPPLY VOLTAGE Intermediate amplifier input Decoupling capacitor Intermediate amplifier input GROUND Limiter input Decoupling capacitor Limiter output Decoupling capacitor Mixer input SUPPLY VOLTAGE Mixer output (demodulated audio signal) GROUND Audio buffer input Noise amplifier input (Squelch circuit) Capacitor connection of the noise rectifier Capacitor connection (ramp generator to mute the audio) Audio buffer output GROUND Decoupling capacitor of Audio buffers SUPPLY VOLTAGE Audio buffer output Standby 2 Standby 1 GROUND Audio buffer input GROUND Mixer output SUPPLY VOLTAGE Mixer input Decoupling capacitor Limiter output Decoupling capacitor Limiter input GROUND Intermediate amplifier output
1. pin direction: I = input pin, O = output pin, - = pin to connect to supply or decoupling capacitors or external components
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TSH511
TYPICAL SCHEMATIC Stereo infrared receiver
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TSH511
INFRARED STEREO HEADPHONE APPLICATION The right side of the figure shows the block-diagram of an infrared stereo receiver using the TSH511. The sensitive LNA directly connected to the photodiode 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 16 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.
IR stereo HiFi transmitter (Television)
IR stereo HiFi receiver (Headphones)
Vcc: 2.3 to 5.5V Current < 15 mA
2.3 MHz
TSH512
Right channel
LNA + ALC
filter
TSH511
Audio buffer2 SQUELCH
20 mW / 16
buffer2
TX2
Vcc SBY
photodiode
RX2
LNA
Line inputs VOX
Left channel buffer1
TX1
LNA + ALC
rs rrie : ca reo Hz st e .8 M Fi Hi & 2 2.3
LED
RX1
SBY2
20 mW / 16
Audio buffer1
filter
Power supply: 2.3 to 5.5V Icc < 20 mA stereo
2.8 MHz
SBY1
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TSH511
MULTIMEDIA APPLICATION: HEADSET SIDE The TSH511 receives the HiFi stereo sound from the computer through 2.3 and 2.8 MHz stereo infrared carriers. The access pins to the RF amplifiers allow the use of a 1.7 MHz reject filter to cancel the transmitted signal of the microphone. The wide supply range (2.3 to 5.5 V) allows battery operation.
TSH511 & 512 supply: 2.3 to 5.5V, 25 mA
HiFi stereo from the PC: 2x 20 mW /16
1.7 MHz reject filter
2.3 MHz Band-pass filter
TSH511
Voice transmitted to the PC Audio buffer2 SQUELCH
RX2
LNA
photodiode
TSH512
LNA + ALC
buffer2
SBY2
Vcc SBY MIC. BIAS Vcc
Audio buffer1
VOX
MIC. BIAS LED
SBY1 filter 1.7 MHz reject
TX2
RX1
filter 2.8 MHz Band-pass
buffer1
TX1
LNA + ALC 1.7 MHz filter Band-pass
Stereo Rx: 2.3 & 2.8 MHz
Microphone Tx: 1.7 MHz carrier
MULTIMEDIA APPLICATION: COMPUTER SIDE In multimedia application, the TSH511 receives the voice of the user through the 1.7 MHz infrared carrier. The standby pins can disable the unused receiver and audio amplifier to reduce the supply current.
TSH511 & 512 supply: 2.3 to 5.5V, 24 mA
HiFi stereo
Voice from the headset microphone
mono Rx: 1.7 MHz TSH511
photodiode
Audio buffer2
LNA
TSH512
LNA + ALC
buffer2
TX2
RX1
SBY1 SBY2 Vcc
SQUELCH Audio buffer1
HiFi stereo Tx: 2.3 & 2.8 MHz
RX2
SBY LED
VOX
filter LNA + ALC 1.7 MHz Band-pass
buffer1
TX1
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TSH511
ELECTRICAL CHARACTERISTICS Vcc = 2.7V, Tamb = 25C, faudio = 1 kHz, fcarrier = 2.8 MHz, frequency deviation = +/-75 kHz (unless otherwise specified)
Symbol Parameter Test condition Min Typ Max Unit
Overall Circuit (refering to typical application schematic, without reject filters) ICC_OX Current consumption, RX1 is on, RX2 is on. Current consumption ICC_10 RX1 is on, RX2 is off RX1 audio buffer is on RX2 audio buffer is on Current consumption ICC_11 RX1 is on, RX2 is off RX1 audio buffer is on, RX2 audio buffer is off with audio SINAD=12 dB, audio BW=30 kHz with audio SINAD=26 dB, audio BW=30 kHz Vcarrier = 1 mVRMS, with psophometric filter output S/N reduced by 3dB, in BW = 30kHz output S/N reduced by 3dB, psophometric filter Vcarrier = 1 mVRMS, with psophometric filter 4 19 58 dB SBY1 = 'High', SBY2 = 'High' 9.5 11.5 mA SBY1 = 'High', SBY2 = 'Low' 11 13 mA SBY1 = 'Low', SBY2 = X (X = don't care) 15 18 mA
MAUS
Maximum Usable Average Sensitivity
VRMS
SNOUT
Output audio signal to noise ratio
Vi
Input limiting voltage
80 60 0.6
VRMS
THD
Total Harmonic Distortion
%
Low Noise Amplifier (LNA) Section GLNA BWLNA En_LNA In_LNA ZLNA_IN ZLNA_OUT P1dB_LNA IIP3LNA LNA voltage gain -3dB LNA Bandwidth Equivalent input noise voltage Equivalent input noise current Input impedance definied as RLNA_IN in paralell with CLNA_IN Output impedance 1dB compression point Input 3rd order interception point ZL= 2 k ZL= 2 k, fcarrier=10 MHz ZL= 2 k ZL= 2 k, fcarrier=10 MHz ZL= 2 k, fcarrier = 10 MHz ZL = 2 k Rs = 0 Rs = 0 RLNA_IN CLNA_IN 18 22 20 3.4 0.6 30 2 200 127 95 30 22 28 dB MHz nV/Hz pA/Hz k pF mVRMS mVRMS
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TSH511
Symbol Amplifier (AMP) Section GAMP ZAMP_IN
Parameter
Test condition
Min
Typ
Max
Unit
Amplifier Voltage Gain Input impedance defined as RAMP_IN in parallel with CAMP_IN
ZL=2 k, fcarrier =10 MHz RAMP_IN CAMP_IN ZL = 2 k
16
20 10 2 350 560
dB k pF mVRMS
ZAMP_OUT Output impedance P1dBAMP BWAMP 1dB compression point -3dB AMP Bandwidth ZL = 2 k, fcarrier=10 MHz ZL = 2 k Limitor (LIM) Section GLIM ZLIM_IN VLIM_OUT Voltage gain Input impedance defined as RLIM_IN in parallel with CLIM_IN Output Voltage ZL=15k tied to GND RLIM_IN CLIM_IN ZL = 15 k tied to GND 50 220
380 11 MHz
54 15 2 170
60
dB k pF mVpp
FM Demodulator Section +-75 kHz FM deviation VDEM Output voltage
typical application schematic
700
800 100
900
mVRMS
ZL = 4 k ZDEM_OUT Output impedance Squelch Section Audio attenuation on each receiver when audio buffers are muted. Noise Amplifier Input impedance from MUTED to UNMUTED state, VN_TH Comparator threshold RMUTE = 22 k, fIN = 100 kHz VN_HYS Comparator hysteresis RMUTE = 22 k, fIN = 100 kHz Voltage on pin 25 = 1.7V 1 mVRMS 9 mVRMS RX1 and RX2 audio buffers muted ZL = 16 on both audio buffers
ATT ZN_IN
55
65
dB
2
k
IMUTE_SINK
Current sinked on pin 25 to discharge CMUTE capacitor: ramp generator controlling the attenuation from ON to OFF states of audio buffers. Current sourced on pin 25 to charge IMUTE_SOU CMUTE capacitor: ramp generator conRCE trolling the attenuation from OFF to ON states of audio buffers.
24
A
Voltage on pin 25 = 1.7V
14
A
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TSH511
Symbol Audio Buffers ZOD-IN BW1dB POUT_OD
Parameter
Test condition
Min
Typ
Max
Unit
Input Impedance -1dB bandwith Output power
200 ZL = 16 ZL= 16 VOD_IN = 70mVRMS Vout = 0.5 VRMS, ZL= 10k with decoupling capacitor CDEC = 1F/ceramic on pin 28. Pout = 20 mW, ZL = 16 15 35 20
k kHz mW
THDOD
Distortion in Line Driver mode
0.2
0.3
%
THDOD
Distortion in Power Amplifier mode Crosstalk: isolation between the two Audio Buffers
0.35
0.8
%
VISOL Standby VSBY_L VSBY_H TON TOFF
Pout = 20 mW, ZL = 16
51
dB
Low level input voltage of Standby inputs (Pins 31 & 32) High level input voltage of Standby inputs (Pins 31 & 32) Turn-on time from Standby mode to Active mode Turn-off time from Active mode to Standby mode 0.9xVcc 0.5 0.5
0.1xVCC
V V s s
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TSH511
OVERALL CIRCUIT Supply current vs. Supply voltage
20 18 16 14 ICC(mA) 12 10 8 6 4 2 0 0 1 2 3 VCC(V) 4 5 6
RX1+ (RX1 Buffer) RX1+RX2+Buffers RX1+Buffers
Squelch Threshold vs. RMUTE Input Resistor
60 50 40 30 20
FIN = 1 MHz VCC = 2.7V FIN = 100 kHz
VN_TH(mVRMS)
10 0
1
10 RMUTE(k)
100
S/N vs. 2.8 MHz Input Level
Supply current vs. Temperature
20
60 50 Total S/N (dB) 40 30
BW = 30 kHz PSOPH
18 16 14 ICC(mA) 12 10 8 6
V CC = 2.7V TX1+TX2 TX1+TX2+Buffers
20 10 0 1 10 100 Input Level (V) 1000
TX1+Buffers TX1
VCC = 2.7 V Deviation = +/-75 kHz
4 2 0 -40 -20 0 20 TAMB(C)
40
60
80
PSOPH: Signal on Noise Ratio curve measured with a CCITT standard psophometric bandpass characteristic. It approximates the response of human hearing.
Sensitivity vs. Supply Voltage
25 Sensitivity (V) @ 26 dB SINAD
20
15
10
FCARRIER = 2.8MHz FMOD = 1 kHz Deviation = +/- 75kHz BW = 30 kHz
5
0
2
3
4 VCC(V)
5
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TSH511
AUDIO BUFFERS Output THD+N vs. Output Power (RL = 16 )
10
VCC = 2.3V
Output THD+N vs. Output Power (RL = 16 )
10
F = 20 kHz
THD+NBUFFER (%)
VCC = 5.5V
1
THD+NBUFFER (%)
VCC = 2.7V
1
F = 1 kHz
RL = 16 F = 1 kHz BW = 30 kHz
0.1
1
10 POUT-BUF(mW)
100
0.1
F = 20 Hz
RL = 16 VCC = 2.7 V
1
10 POUT-BUF(mW)
100
Output THD+N vs. Output Power (RL = 32 )
10
Output THD+N vs. Output Power (RL = 32 )
10
RL = 32 F = 1 kHz BW = 30 kHz
VCC = 2.3V VCC = 2.7V
THD+NBUFFER (%)
THD+NBUFFER (%)
F = 20 kHz
1
1
F = 1 kHz F = 20 Hz
VCC = 5.5V
RL = 32 VCC = 2.7 V
0.1
1
10 POUT-BUF(mW)
100
0.1
1
10 POUT-BUF(mW)
100
Output THD+N vs. Output Power (RL = 600 )
Output THD+N vs. Output Power (RL = 600 )
10
VCC = 2.3V
1 THD+NBUFFER (%)
THD+NBUFFER (%)
VCC = 2.7V VCC = 5.5V
F = 20 kHz
1
F = 20 Hz F = 1 kHz RL = 600 VCC = 2.7 V
0.1
RL = 600 F = 1 kHz BW = 30 kHz
0.1 0.1 POUT-BUF(mW)
0.1
1 POUT-BUF(mW)
10
1
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TSH511
Output THD+N vs. Output Voltage (RL = 10k)
10
RL = 10 k F = 1 kHz BW = 30 kHz VCC = 2.3V
Output THD+N vs. Output Voltage (RL = 10k)
10
RL = 10 k VCC = 2.7 V
THD+NBUFFER (%)
1
VCC = 5.5V
THD+NBUFFER (%)
VCC = 2.7V
1
F = 20 Hz F = 1 kHz F = 20 kHz
0.1 0.1 VOUT-BUF(Vrms) 1
0.1 0.1 VOUT-BUF(Vrms) 1
Output THD+N vs. Frequency (RL = 16 )
10
VCC = 2.7 V Vin = 50 mVrms RL = 16
Output THD+N vs. Frequency (RL = 32 )
10
VCC = 2.7 V Vin = 50 mVrms RL = 32
THD+NBUFFER (%)
THD+NBUFFER (%)
1
1
0.1 20
100
1000 Frequency (Hz)
10000
0.1 20
100
1000 Frequency (Hz)
10000
Output THD+N vs. Frequency (RL = 600 )
Output THD+N vs. Frequency (RL = 10 k)
10
10
VCC = 2.7 V Vin = 50 mVrms RL = 600
THD+NBUFFER (%)
THD+NBUFFER (%)
VCC = 2.7 V Vin = 50 mVrms RL = 10 k
1
1
0.1 20
100
1000 Frequency (Hz)
10000
0.1 20
100
1000 Frequency (Hz)
10000
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TSH511
Output Power vs. Temperature
24 22 POUT-BUF(mW) 20 18 16 14 12 10 -40 -20 0 20 TAMB(C)
VCC = 2.7V RL = 16 VIN = 70 mVRMS
40
60
80
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TSH511
GENERAL DESCRIPTION The TSH511 is a 0.4 to 11 MHz dual FM analogue receiver. The incoming signal is amplified with a 22 dB Low Noise Amplifier (LNA section). The good noise performance of the LNA allows the photodiode for infrared applications to be connected directly to the TSH511 without any external preamplifier. The access pins for each section and the two standby configurations allow a high versatility for many applications: HiFi stereo infrared receiver, mono/stereo subcarrier receiver, power line carrier audio. Figure 1 : TSH511 block diagram
DEC-LIM2B DEC-LIM2A AMP-OUT2 MIX-OUT2 LIM-OUT2 LIM-IN2 MIX-IN2 BUF-IN2
Buffers or only one depending on the combination on SBY1 & SBY2. To avoid noise at the audio output, a Squelch section mutes the Audio Buffers when no carrier is received. The Squelch Section uses the demodulated signal of the first receiver (RX1). This signal is highpass filtered, rectified and compared to a threshold to produce the Mute signal (pin 25). When no carrier is received on RX1, the wideband 'FM noise' on the demodulator increases and the Mute signal mutes the both Audio Buffers. When the carrier is present, the wideband noise on the demodulator output decreases, enabling the Audio Buffers. Figure 2 : Infrared audio frequencies
GND
44
43
42
41
40
39
38
37
36
35
GND
VCC
34
GND AMP-IN2 VCC LNA-OUT2 VCC LNA-IN GND LNA-OUT1 VCC AMP-IN1 DEC-LNA
1 2 Standby 3 4 5 6 7 8 9 10 11 amp. amp. limiter FM demodulator
33 32 31 30 29
GND SBY1 SBY2 BUF-OUT2 VCC DEC-OUT GND BUF-OUT1 MUTE-OUT MUTE-INT MUTE-IN
IR frequency 1.6 MHz 1.7 MHz 2.3 MHz 2.8 MHz
applications AM mono FM mono FM right channel FM left channel or mono
RX2
LNA
TSH511
RX1
Audio buffers
28 27 26
Vref
limiter
FM demodulator SQUELCH
25 24 23
LNA section: Low Noise Amplifier
12 AMP-OUT1 13 14 15 DEC-LIM1 16 LIM-OUT1 17 DEC-LIM1B 18 19 20 MIX-OUT1 21 22
The LNA is common to both receivers but the output is split in two: one for each receiver. Each LNA output can be connected to a first optional filter for bandpass or reject filtering. The filtered signal is amplified with an intermediate Amplifier (AMP section) followed by a second filter. The AMP sections have 20 dB typical gain. Finally, the signal is amplified and limited in the Limiter (LIM section). The 60 dB amplifier-limiter LIM provides a constant amplitude signal to the demodulator. It reduces AM parasitics demodulation in the FM demodulator. The FM demodulator is a classical quadrature detector using an external tank. The demodulated signal can be amplified by the Audio Buffer section after de-emphasis. Each Audio Buffer can drive a 16 ohms headphone with 20 mW power. The two standby pins SBY1 & SBY2 allow the second receiver RX2 to be put into standby for mono operation. In mono, it is possible to use both Audio
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The Low Noise Amplifier (LNA) has a typical gain of 22 dB to amplify the incoming RF signal from the photodiode. The LNA is common to both receivers sections RX1 and RX2. Figure 3 : LNA schematic
GND
BUF-IN1
LIM-IN1
MIX-IN1
GND
VCC
TSH511
The LNA output is directly connected to LNA-OUT1 and LNA-OUT2 pins in parallel (pin 8 and 4 respectively). As the LNA minimum impedance load is 1 k, the load impedance on each pin LNA-OUT1 or LNA-OUT2 must be 2 k minimum. The series 50 resistor and the 100 nF capacitor decouple the LNA supply voltage (pin 5), improving noise performance. AMP and LIM sections: Amplifier and Limitor The first filter output is connected to the intermediate amplifier AMP. The gain of AMP is typically 20 dB. The second filter is connected between the output of AMP and the input of the limitor LIM. The 60 dB limitor LIM provides a constant amplitude signal to the FM demodulator. It reduces the AM parasitic effects into the FM demodulator. Figure 4 : AMP and LIM schematic allows to adjustment of the demodulation characteristic. For a given transmitting deviation, a lower value of Rlo gives a lower demodulated amplitude and reduces the distortion. The AC amplitude on pin 18 must not exceed 300 mVRMS to prevent clipping by the internal ESD diodes of the circuit. The low output impedance of the demodulator (MIX-OUT pins) drives the external volume control and the de-emphasis filter. Figure 5 : FM demodulator schematic
SQUELCH section To avoid audio 'FM noise' at the speakers when no carrier is received, the TSH511 has a built-in Squelch circuit. The Squelch detects the wideband 'FM noise' on the demodulated output and fades-out the audio of both audio buffers. The audio is filtered from the 'FM noise' using the high-pass RC filter. The cut-off frequency is typically 100kHz. The squelch level depends on the value of the RMUTE resistor in serie with the input pin of the noise amplifier MUTE-IN (pin 23). The detected noise is integrated with the Cpeak capacitor connected to MUTE-INT pin. The DC voltage on this pin follows the amplitude of the noise.
FM demodulator section The FM demodulator is a classical quadrature demodulator based on a multiplier. The quadrature is performed with the tank circuit Llo inductor and Clo capacitor. The tank circuit is tuned on the receiving frequency. The Rlo resistor is connected in parallel with Llo and Clo to reduce the Q factor of the tank circuit. It
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TSH511
The comparator and the CMUTE capacitor generate the fade-in and fade-out control ramps for the audio buffers. The Squelch has been designed with particular attention to avoid audio pop-noise. Figure 6 : Squelch schematic The Audio Buffers can also drive the other usual impedances used in audio: 32, 600 and 10k (see the corresponding distorsion curves). The high input impedances of the Audio Buffers reduce the coupling capacitors to less than 0.1 F allowing space and cost saving. Standby section Depending on the states of the logic inputs SBY1 and SBY2, RX2 and the Audio Buffer2 can be disabled separately. The TSH511 receiver can adapt to different applications by using SBY1 & SBY2 standby pins:
SBY1 pin 32 SBY2 pin 31 RX1 & audio buffer1
RX2
audio buffer 2
typical use
Low Low High High
Low High Low High ON ON ON ON OFF OFF ON ON OFF
stereo mono on the two outputs mono on one output
The squelch section is driven by the receiver RX1 but controls both audio buffers. Audio Buffer sections The audio signal from a FM demodulator enters into the 6dB/octave low-pass filter for de-emphasis. 50s and 75s are standard de-emphasis values. After the de-emphasis network, the potentiometer controls the volume. The Rail-to-Rail output stage of each Audio Buffer is able to drive 20 mW into 16 at 2.3V supply voltage. In this condition, the distortion is typically 0.3% before saturation.
In the standard stereo mode, the configuration is: SBY1 = SBY2 = 'Low' In mono mode with one load(example: a single loadspeaker), RX2 and Audio Buffer 2 are disabled, the configuration is SBY1 = SBY2 = 'High'. In mono mode with a stereo load (example: a stereo headphone), the configuration is SBY1 = 'high', SBY2 = 'Low'. A pin connected to Vcc is at 'High' state, and if connected to GND is at 'Low' state.
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TSH511
APPLICATION SCHEMATIC The infrared carriers are detected by the photodiode and the signal is directly amplified by the TSH511. Optional reject filters can be added in each channel to improve crosstalk performances. Each receiver has a standard bandpass filter (filters F1 & F3) to select the 2.3 and 2.8 MHz carriers. After the FM demodulators, the potentiometers P1 and P2 control the volume levels. The stereo headphones are directly connected to the integrated audio buffers. The potentiometer P3 allows adjustment of the sensitivity of the Squelch. The Squelch function fade-in and fade-out the audio signal depending on the level of the 2.8 MHz carrier.
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TSH511
PACKAGE MECHANICAL DATA 44 PINS - PLASTIC PACKAGE
A A2 44 e A1 34 0,10 mm .004 inch SEATING PLANE B 11 23
c
1
33
12
D3 D1 D
22
L1
L
E3 E1 E
K
0,25 mm .010 inch GAGE PLANE
Dimensions Min. A A1 A2 B C D D1 D3 e E E1 E3 L L1 K 0.05 1.35 0.30 0.09
Millimeters Typ. Max. 1.60 0.15 1.45 0.40 0.20 Min. 0.002 0.053 0.012 0.004
Inches Typ. Max. 0.063 0.006 0.057 0.016 0.008
1.40 0.37 12.00 10.00 8.00 0.80 12.00 10.00 8.00 0.60 1.00
0.055 0.015 0.472 0.394 0.315 0.031 0.472 0.394 0.315 0.024 0.039
0.45
0.75
0.018
0.030
0 (min.), 7 (max.)
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 2002 STMicroelectronics - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom http://www.st.com
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