TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
Features
Single chip solution with only a few external
components
Stand-alone fixed-frequency user mode
Programmable multi-channel user mode
Low current consumption in active mode and
very low standby current
PLL-stabilized RF VCO (LO) with internal
varactor diode
Lock detect output in programmable
user mode
On-chip AFC for extended input frequency
acceptance range
3wire bus serial control interface
FSK/ASK mode selection
FSK for digital data or FM for analog signal
reception
RSSI output for signal strength indication and
ASK reception
Peak detector for ASK detection
Switchable LNA gain for improved dynamic
range
Automatic PA turn-on after PLL lock
ASK modulation achieved by PA on/off keying
32-pin Low profile Quad Flat Package (LQFP)
Ordering Information
Part Number
TH7122.1
(only for existing designs,
not for new design-ins)
TH7122.2
(for new design-ins)
Temperature Code
E (-40 °C to 85 °C)
E (-40 °C to 85 °C)
Package Code
NE (LQFP32)
NE (LQFP32)
Delivery Form
250 pc/tray
2000 pc/T&R
250 pc/tray
2000 pc/T&R
Application Examples
General bi-directional half duplex digital data
RF signaling or analog signal communication
Tire Pressure Monitoring Systems (TPMS)
Remote Keyless Entry (RKE)
Low-power telemetry systems
Alarm and security systems
Wireless access control
Garage door openers
Networking solutions
Active RFID tags
Remote controls
Home and building automation
Pin Description
LF
VEE_PLL
TNK_LO
VCC_PLL
FS1/LD
VEE_DIG
FS0/SDEN
24
OUT_PA
IN_LNA
VEE_LNA
OUT_LNA
GAIN_LNA
IN_MIX
VEE_IF
OUT_MIX
25
17
16
RE/SCLK
VCC_DIG
ASK/FSK
IN_DTA
FSK_SW
RO
VEE_RO
TH7122
32
1
8
9
General Description
The TH7122 is a single chip FSK/FM/ASK transceiver IC. It is designed to operate in low-power multi-
channel programmable or single-channel stand-alone, half-duplex data transmission systems. It can be used
for applications in automotive, industrial-scientific-medical (ISM), short range devices (SRD) or similar appli-
cations operating in the frequency range of 300 MHz to 930 MHz. In programmable user mode, the trans-
ceiver can operate down to 27 MHz by employing an external VCO varactor diode.
39010 07122
Rev. 010
Page 1 of 44
Data Sheet
Feb/09
IN_IFA
VCC_IF
IN_DEM
INT2/PDO
INT1
OUT_DEM
RSSI
OUT_DTA
TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
Document Content
1
Theory of Operation ...................................................................................................4
1.1
1.2
1.3
1.4
1.5
General ............................................................................................................................. 4
Technical Data Overview.................................................................................................. 4
Note on ASK Modulation .................................................................................................. 4
Block Diagram .................................................................................................................. 5
User Mode Features ......................................................................................................... 5
2
3
Pin Definitions and Descriptions ..............................................................................6
Functional Description ............................................................................................10
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.1.8
PLL Frequency Synthesizer ........................................................................................... 10
Reference Oscillator (XOSC)..................................................................................................... 11
Reference Divider ...................................................................................................................... 11
Feedback Divider ....................................................................................................................... 11
Frequency Resolution and Operating Frequency ...................................................................... 11
Phase-Frequency Detector ........................................................................................................ 12
Lock Detector............................................................................................................................. 12
Voltage Controlled Oscillator with external Loop Filter.............................................................. 13
Loop Filter .................................................................................................................................. 13
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
Receiver Part .................................................................................................................. 13
LNA ............................................................................................................................................ 14
Mixer .......................................................................................................................................... 14
IF Amplifier ................................................................................................................................. 14
ASK Demodulator ...................................................................................................................... 14
FSK Demodulator ...................................................................................................................... 15
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
Transmitter Part .............................................................................................................. 15
Power Amplifier.......................................................................................................................... 15
Output Power Adjustment .......................................................................................................... 16
Modulation Schemes ................................................................................................................. 16
ASK Modulation ......................................................................................................................... 16
FSK Modulation ......................................................................................................................... 17
Crystal Tuning............................................................................................................................ 17
4
Description of User Modes......................................................................................18
4.1
4.1.1
4.1.2
4.1.3
4.1.4
Stand-alone User Mode Operation ................................................................................. 18
Frequency Selection .................................................................................................................. 18
Operation Mode ......................................................................................................................... 18
Modulation Type ........................................................................................................................ 19
LNA Gain Mode ......................................................................................................................... 19
4.2
4.2.1
Programmable User Mode Operation............................................................................. 19
Serial Control Interface Description ........................................................................................... 19
5
Register Description ................................................................................................20
Page 2 of 44
Data Sheet
Feb/09
39010 07122
Rev. 010
TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
Register Overview .......................................................................................................... 21
Default Register Settings for FS0, FS1...................................................................................... 21
A – word ..................................................................................................................................... 22
B – word ..................................................................................................................................... 23
C – word..................................................................................................................................... 24
D – word..................................................................................................................................... 25
6
Technical Data..........................................................................................................26
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
Absolute Maximum Ratings ............................................................................................ 26
Normal Operating Conditions ......................................................................................... 26
DC Characteristics.......................................................................................................... 27
PLL Synthesizer Timings ................................................................................................ 29
AC Characteristics of the Receiver Part ......................................................................... 29
AC Characteristics of the Transmitter Part ..................................................................... 30
Serial Control Interface ................................................................................................... 30
Crystal Parameters ......................................................................................................... 30
7
Application Circuit Examples..................................................................................31
7.1
7.2
7.3
7.4
7.5
7.6
7.7
FSK Application Circuit Programmable User Mode (internal AFC option)...................... 31
FSK Application Circuit Stand-alone User Mode ............................................................ 32
FSK Test Circuit Component List (Fig. 14 and Fig. 15) .................................................. 33
ASK Application Circuit Programmable User Mode (normal data slicer option) ............. 34
ASK Test Circuit Component List (Fig. 16)..................................................................... 35
ASK Application Circuit Programmable User Mode (peak detector option).................... 36
ASK Test Circuit Component List (Fig. 17)..................................................................... 37
8
Extended Frequency Range ....................................................................................38
8.1
Board Component List (Fig. 18) ..................................................................................... 38
9
TX/RX Combining Network......................................................................................39
9.1
9.2
9.3
Board Component List (Fig. 19) ..................................................................................... 39
Typical LNA S-Parameters in Receive Mode ................................................................. 39
LNA Input Impedances in Transmit Mode ...................................................................... 40
10
Package Description ................................................................................................41
Soldering Information ..................................................................................................... 41
10.1
11
12
13
Reliability Information..............................................................................................42
ESD Precautions ......................................................................................................42
Disclaimer .................................................................................................................44
39010 07122
Rev. 010
Page 3 of 44
Data Sheet
Feb/09
TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
1
1.1
Theory of Operation
General
The main building block of the transceiver is a programmable PLL frequency synthesizer that is based on an
integer-N topology. The PLL is used for generating the carrier frequency during transmission and for
generating the LO signal during reception. The carrier frequency can be FSK-modulated either by pulling the
crystal or by modulating the VCO directly. ASK modulation is done by on/off keying of the power amplifier.
The receiver is based on the principle of a single conversion superhet. Therefore the VCO frequency has to
be changed between transmit and receive mode. In receive mode, the default LO injection type is low-side
injection.
The TH7122 transceiver IC consists of the following building blocks:
Low-noise amplifier (LNA) for high-sensitivity
RF signal reception with switchable gain
Mixer (MIX) for RF-to-IF down-conversion
IF amplifier (IFA) to amplify and limit the IF
signal and for RSSI generation
Phase-coincidence FSK demodulator with
external ceramic discriminator or LC tank
Operational amplifier (OA1), connected to
demodulator output
Operational amplifier (OA2), for general use
Peak detector (PKDET) for ASK detection
Control logic with 3wire bus serial control
interface (SCI)
Reference oscillator (RO) with external crystal
Reference divider (R counter)
Programmable divider (N/A counter)
Phase-frequency detector (PFD)
Charge pump (CP)
Voltage controlled oscillator (VCO) with internal
varactor
Power amplifier (PA) with adjustable output
power
1.2
Technical Data Overview
Frequency range: 300 MHz to 930 MHz in
programmable user mode
Extended frequency range with external VCO
varactor diode: 27 MHz to 930 MHz
315 MHz, 433 MHz, 868 MHz or 915 MHz fixed-
frequency settings in stand-alone mode
Power supply range: 2.2 V to 5.5 V
Temperature range: -40 °C to +85 °C
Standby current: 50 nA
Operating current in receive: 6.5 mA (low gain)
Operating current in transmit: 12 mA (at -2 dBm)
Adjustable RF power range: -20 dBm to +10dBm
Sensitivity: -105 dBm at FSK with 180 kHz
IF filter BW
Sensitivity: -107 dBm at ASK with 180 kHz
IF filter BW
Max. data rate with crystal pulling: 20 kbps NRZ
Max. data rate with direct VCO modulation:
115 kbps NRZ
Max. input level: -10 dBm at FSK
and -20 dBm at ASK
Input frequency acceptance:
±
10 to
±
150 kHz
(depending on FSK deviation)
FM/FSK deviation range:
±2.5
to
±80
kHz
Analog modulation frequency: max. 10 kHz
Crystal reference frequency: 3 MHz to 12 MHz
External reference frequency: 1 MHz to 16 MHz
1.3
Note on ASK Operation
Optimum ASK performance can be achieved by using an 8-MHz crystal for operation at 315 MHz, 434 MHz
and 915 MHz. For details please refer to the software settings shown in sections 7.4 and 7.6. FSK operation
is the preferred choice for applications in the European 868MHz band.
39010 07122
Rev. 010
Page 4 of 44
Data Sheet
Feb/09
TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
1.4
Block Diagram
GAIN_LNA
OUT_LNA
VEE_LNA
IN_MIX
VEE_IF
OUT_MIX
VCC_IF
IN_IFA
RSSI
27
29
28
30
32
31
1
2
7
3
IN_DEM
6
OUT_DEM
PKDET
SW1
1.5pF
bias
OA2
4
FSK Demodulator
MIX
SW2
200k
INT2/PDO
5
IN_LNA
26
MIX
LNA
LO
IF
INT1
IFA
OA1
8
OUT_DTA
Control Logic
ASK
SCI
SDEN
SDTA
SCLK
N
counter
VCO
R
counter
RO
RO
FSK_SW
FSK
FS0/SDEN
OUT_PA
25
PA
ASK/FSK
RE/SCLK
VEE_RO
24
PS_PA
21
TNK_LO
20
VCC_PLL
23
LF
22
VEE_PLL
10
RO
FS1/LD
11
19
9
12
13
15
16
17
18
14
Fig. 1:
TH7122 block diagram
1.5
User Mode Features
The transceiver can operate in two different user modes. It can be used either as a 3wire-bus-controlled
programmable or as a stand-alone fixed-frequency device. After power up, the transceiver is set to Stand-
alone User Mode (SUM). In this mode, pins FS0/SDEN and FS1/LD must be connected to V
EE
or V
CC
in
order to set the desired frequency of operation. There are 4 pre-defined frequency settings: 315MHz,
433.92MHz, 868.3MHz and 915MHz. The logic level at pin FS0/SDEN must not be changed after power up
in order to remain in fixed-frequency mode.
After the first logic level change at pin FS0/SDEN, the transceiver enters into Programmable User Mode
(PUM). In this mode, the user can set any PLL frequency or mode of operation by the SCI. In SUM pins
FS0/SDEN and FS1/LD are used to set the desired frequency, while in PUM pin FS0/SDEN is part of the
3-wire serial control interface (SCI) and pin FS1/LD is the look detector output signal of the PLL synthesizer.
A mode control logic allows several operating modes. In addition to standby, transmit and receive mode, two
idle modes can be selected to run either the reference oscillator only or the whole PLL synthesizer. The PLL
settings for the PLL idle mode are taken over from the last operating mode which can be either receive or
transmit mode.
The different operating modes can be set in SUM and PUM as well. In SUM the user can program the trans-
ceiver via control pins RE/SCLK and TE/SDTA. In PUM the register bits OPMODE are used to select the
modes of operation while pins RE/SCLK and TE/SDTA are part of the SCI.
39010 07122
Rev. 010
Page 5 of 44
Data Sheet
Feb/09
VCC_DIG
VEE_DIG
TE/SDTA
IN_DTA
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