TH71102
315/433MHz
FSK/FM/ASK Receiver
Features
!
!
!
!
!
!
!
Double-conversion superhet architecture for high degree of image rejection
FSK for digital data and FM reception for analog signal transmission
FSK/FM demodulation with phase-coincidence demodulator
Low current consumption in active mode and very low standby current
Switchable LNA gain for improved dynamic range
RSSI allows signal strength indication and ASK detection
32-pin Low profile Quad Flat Package (LQFP)
Ordering Information
Part Number
TH71102
Temperature Code
E (-40 °C to 85 °C)
Package Code
NE (LQFP32)
Delivery Form
250 pc/tray
2000 pc/T&R
Application Examples
"
"
"
"
"
"
"
"
!
General digital data transmission
Tire Pressure Monitoring Systems (TPMS)
Remote Keyless Entry (RKE)
Wireless access control
Alarm and security systems
Garage door openers
Remote Controls
Home and building automation
Low-power telemetry systems
Pin Description
OUTP
VEE_BIAS
RSSI
OAP
OAN
OUT_OA
VCC_BIAS
24
VEE_RO
RO
VCC_PLL
ENRX
LF
VEE_LNA
IN_LNA
VCC_LNA
25
17
16
OUT_IFA
VCC_IF
FBC2
FBC1
IN_IFA
VEE_IF
OUT_MIX2
9
1
VEE_LNAC
GAIN_LNA
OUT_LNA
IN_MIX1
VEE_MIX
IF_1P
IF_1N
VCC_MIX
8
TH71102
32
General Description
The TH71102 FSK/FM/ASK double-conversion superheterodyne receiver IC is designed for applications in
the European 433 MHz industrial-scientific-medical (ISM) band, according to the EN 300 220
telecommunications standard. It can also be used for any other system with carrier frequencies ranging from
260 MHz to 510 MHz (e.g. for applications according to FCC part 15 and ARIB STD-T67).
39010 71102
Rev. 013
Page 1 of 22
Data Sheet
June/07
TH71102
315/433MHz
FSK/FM/ASK Receiver
Document Content
1
Theory of Operation ...................................................................................................3
1.1
1.2
1.3
1.4
1.5
1.6
1.6.1
1.6.2
General............................................................................................................................. 3
Technical Data Overview.................................................................................................. 3
Block Diagram .................................................................................................................. 4
Mode Configurations ........................................................................................................ 4
LNA GAIN Control ............................................................................................................ 4
Frequency Planning.......................................................................................................... 4
Selected Frequency Plans........................................................................................................... 5
Maximum Frequency Coverage................................................................................................... 5
2
3
Pin Definitions and Descriptions ..............................................................................6
Technical Data............................................................................................................9
3.1
3.2
3.3
3.4
3.5
Absolute Maximum Ratings .............................................................................................. 9
Normal Operating Conditions ........................................................................................... 9
Crystal Parameters ........................................................................................................... 9
DC Characteristics.......................................................................................................... 10
AC System Characteristics ............................................................................................. 11
4
Test Circuits .............................................................................................................12
4.1
4.1.1
4.1.2
Standard FSK Reception ................................................................................................ 12
Standard FSK Application Circuit .............................................................................................. 12
Standard FSK Component List .................................................................................................. 13
4.2
4.2.1
4.2.2
Narrow Band FSK Reception.......................................................................................... 14
Narrow Band FSK Application Circuit ........................................................................................ 14
Narrow Band FSK Component List............................................................................................ 15
4.3
4.3.1
4.3.2
FM Reception (Varactor-tuned AFC) .............................................................................. 16
FM Application Circuit ................................................................................................................ 16
FM Component List.................................................................................................................... 17
4.4
4.4.1
4.4.2
ASK Reception ............................................................................................................... 18
ASK Application Circuit .............................................................................................................. 18
ASK Component List.................................................................................................................. 19
5
Package Description ................................................................................................20
5.1
Soldering Information ..................................................................................................... 20
6
7
8
Reliability Information .............................................................................................21
ESD Precautions ......................................................................................................21
Disclaimer .................................................................................................................22
39010 71102
Rev. 013
Page 2 of 22
Data Sheet
June/07
TH71102
315/433MHz
FSK/FM/ASK Receiver
1
1.1
Theory of Operation
General
With the TH71102 receiver chip, various circuit configurations can be arranged in order to meet a number of
different customer requirements. For FM/FSK reception the IF tank used in the phase coincidence
demodulator can also be constituted by a ceramic discriminator with a varactor diode to create an AFC
circuit. In ASK configuration, the RSSI signal is fed to an ASK detector, which is constituted by the
operational amplifier.
The superheterodyne configuration is double conversion where MIX1 and MIX2 are driven by the internal
local oscillator signals LO1 and LO2, respectively. This allows a high degree of image rejection, achieved in
conjunction with an RF front-end filter. Efficient RF front-end filtering is realized by using a SAW, ceramic or
helix filter in front of the LNA and by adding an LC filter at the LNA output.
A single-conversion variant, called TH71101, is also available. Both Receiver ICs have the same die. At the
TH71101 the second mixer MIX2 operates as an amplifier.
The TH71102 receiver IC consists of the following building blocks:
#
#
#
#
#
#
#
#
PLL synthesizer (PLL SYNTH) for generation of the first and second local oscillator signals LO1 and
LO2, parts of the PLL SYNTH are: the high-frequency VCO1, the feedback dividers DIV_8 and DIV_2,
a phase-frequency detector (PFD) with charge pump (CP) and a crystal-based reference oscillator (RO)
Low-noise amplifier (LNA) for high-sensitivity RF signal reception
First mixer (MIX1) for down-conversion of the RF signal to the first IF (IF1)
Second mixer (MIX2) for down-conversion of the IF1 to the second IF (IF2)
IF amplifier (IFA) to amplify and limit the IF2 signal and for RSSI generation
Phase coincidence demodulator (DEMOD) with third mixer (MIX3) to demodulate the IF signal
Operational amplifier (OA) for data slicing, filtering and ASK detection
Bias circuitry for bandgap biasing and circuit shutdown
1.2
!
!
!
!
!
Technical Data Overview
!
Range of IF2: 400 kHz to 22 MHz
!
Maximum input level: -10 dBm @ ASK
0 dBm @ FSK
!
Image rejection: > 65 dB (e.g. with 433.92 MHz
SAW front-end filter and at 10.7 MHz IF2)
!
Spurious emission: < -70 dBm
!
Input frequency acceptance range: up to
±100
kHz
!
RSSI range: 70 dB
!
FM/FSK deviation range:
±2.5
kHz to
±80
kHz
!
Maximum analog modulation frequency: 15 kHz
Input frequency range: 260 MHz to 510 MHz
Power supply range: 2.3 V to 5.5 V @ ASK
Temperature range: -40 °C to +85 °C
Standby current: 50 nA
Operating current: 6.5 mA @ low gain mode
8.2 mA @ high gain mode
!
Sensitivity: -113 dBm @ ASK 1)
-107 dBm @ FSK 2)
!
Maximum data rate: 260 kbps NRZ @ ASK
180 kbps NRZ @ FSK
!
Range of IF1: 10 MHz to 80 MHz
1) at 4 kbps NRZ, BER = 3⋅10
-3
, 180 kHz IF filter BW, without SAW front-end-filter loss
2) at 4 kbps NRZ, BER = 3⋅10
-3
,
±
20 kHz FSK deviation, 180 kHz IF filter BW, without SAW front-end-filter loss
39010 71102
Rev. 013
Page 3 of 22
Data Sheet
June/07
TH71102
315/433MHz
FSK/FM/ASK Receiver
1.3
Block Diagram
IN_MIX1
OUT_MIX2
FBC1
IF1N
VCC_MIX
VEE_LNAC
GAIN_LNA
OUT_LNA
VEE_MIX
OUT_IFA
IN_DEM
IF1P
VEE_IF
IN_IFA
2
3
4
5
6
7
8
9
RSSI
1
10
11
12
13
21
14
15
16
IN_LNA
31
MIX1
LNA
LO1
IF1
MIX2
IF2
LO2
MIX3
OUTP
OUTN
23
24
IFA
OAP
OA
DIV8
DIV2
PFD
RO
VCO1
VCC_LNA
VEE_LNA
20
OAN
19
OUT_OA
BIAS
VCC_BIAS
VEE_BIAS
VCC_PLL
VEE_RO
18
CP
ENRX
32
30
29
LF
26
RO
25
27
28
22
17
Fig. 1: TH71102 block diagram
1.4
Mode Configurations
ENRX
0
1
Mode
RX standby
RX active
Description
RX disabled
RX enable
Note:
ENRX are pulled down internally
1.5
LNA GAIN Control
V
GAIN_LNA
< 0.8 V
> 1.4 V
Mode
HIGH GAIN
LOW GAIN
Description
LNA set to high gain
LNA set to low gain
Note:
hysteresis between gain modes to ensure stability
1.6
Frequency Planning
Frequency planning is straightforward for single-conversion applications because there is only one IF that
can be chosen, and then the only possible choice is low-side or high-side injection of the LO signal (which is
now the one and only LO signal in the receiver).
The receiver’s double-conversion architecture requires careful frequency planning. Besides the desired RF
input signal, there are a number of spurious signals that may cause an undesired response at the output.
Among them are the image of the RF signal (that must be suppressed by the RF front-end filter), spurious
signals injected to the first IF (IF1) and their images which could be mixed down to the same second IF (IF2)
as the desired RF signal (they must be suppressed by the LC filter at IF1 and/or by low-crosstalk design).
39010 71102
Rev. 013
Page 4 of 22
Data Sheet
June/07
TH71102
315/433MHz
FSK/FM/ASK Receiver
By configuring the TH71102 for double conversion and using its internal PLL synthesizer with fixed feedback
divider ratios of N1 = 8 (DIV_8) and N2 = 2 (DIV_2), four types of down-conversion are possible: low-side
injection of LO1 and LO2 (low-low), LO1 low-side and LO2 high-side (low-high), LO1 high-side and LO2
low-side (high-low) or LO1 and LO2 high-side (high-high). The following table summarizes some equations
that are useful to calculate the crystal reference frequency (REF), the first IF (IF1) and the VCO1 or first LO
frequency (LO1), respectively, for a given RF and second IF (IF2).
Injection type
REF
LO1
IF1
LO2
IF2
high-high
(RF – IF2)/14
16•REF
LO1 – RF
2•REF
LO2 – IF1
low-low
(RF – IF2)/18
16•REF
RF – LO1
2•REF
IF1 – LO2
high-low
(RF + IF2)/14
16•REF
LO1 – RF
2•REF
IF1 – LO2
low-high
(RF + IF2)/18
16•REF
RF – LO1
2•REF
LO2 – IF1
1.6.1
Selected Frequency Plans
The following table depicts crystal, LO and image signals considering the examples of 315 MHz and
433.92 MHz RF reception at IF2 = 10.7 MHz. The columns in bold depict the selected frequency plans to
receive at 315 MHz and 433.92 MHz, respectively.
RF =
315
MHz
21.73571
347.77143
32.77143
43.47143
Signal type
RF =
315
MHz
low-low
16.90556
270.48889
44.51111
33.81111
225.97778
23.11111
RF =
315
MHz
high-low
23.26429
372.22857
57.22857
46.52857
429.45714
35.82857
RF =
315
MHz
low-high
18.09444
289.51111
25.48889
36.18889
264.02222
46.88889
RF =
433.92
MHz
high-high
30.23000
483.68000
49.76000
60.46000
533.44000
71.16000
RF =
433.92
MHz
low-low
23.51222
376.19556
57.72444
47.02444
318.47112
36.32444
RF =
433.92
MHz
high-low
31.75857
508.13714
74.21714
63.51714
582.35428
52.81717
RF =
433.92
MHz
low-high
24.70111
395.21778
38.70222
49.40222
356.51556
60.10222
Injection type high-high
REF / MHz
LO1 / MHz
IF1 / MHz
LO2 / MHz
RF image/MHz 380.54286
IF1 image/MHz
54.17143
1.6.2
Maximum Frequency Coverage
f
min
high-low
251.8
18.75
300
48.2
37.5
10.7
f
max
low-low
516.95
28.125
450
66.95
56.25
10.7
The selection of the reference crystal
frequency is based on some assumptions. As
for example: the first IF and the image
frequencies should not be in a radio band
where strong interfering signals might occur
(because they could represent parasitic
receiving signals), the LO1 signal should be in
the range of 300 MHz to 450 MHz (because
this is the optimum frequency range of the
VCO1). Furthermore the first IF should be as
high as possible to achieve highest RF image
rejection.
Parameter
Injection type
RF / MHz
REF / MHz
LO1 / MHz
IF1 / MHz
LO2 / MHz
IF2/ MHz
39010 71102
Rev. 013
Page 5 of 22
Data Sheet
June/07
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