TH7121 Datasheet, PDF (2/28 Pages) List of Unclassifed Manufacturers – 300 to 930MHz FSK/FM/ASK Transceiver

TH7121
300 to 930MHz
FSK/FM/ASK Transceiver
General Description
The TH7120 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 ISM,
SRD or any other application operating in the frequency ranging of 300 MHz to 930 MHz.
The TH7120 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 demodulator with external ceramic discriminator (FSK Demodulator)
" Operational amplifier, connected to demodulator output (OA1)
" Operational amplifier, integrator circuit at FSK-AFC mode (OA2)
PRELIMINARY ^{" 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 control oscillator (VCO) with internal varactor
" Power amplifier (PA) with adjustable output power
The transceiver 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 fixed-frequency mode. 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.
The logic levels at pins FS0/SDEN and FS1/LD must not be changed after power up in order to remain in
fixed-frequency mode.
Channel frequency
FS0/SDEN
433.92 MHz
1
868.3 MHz
0
315.0 MHz
1
915.0 MHz
0
FS1/LD
0
0
1
1
After the first logic level change at pin FS0/SDEN, the transceiver enters into programmable mode while pin
FS1/LD is now a PLL lock detector output. In this mode, the user can set any PLL frequency or mode of op-
eration by the SCI.
In the fixed-frequency mode, the user can set the transceiver to Standby, Receive, Transmit or Idle (only PLL
synthesizer active) mode via control pins RE/SCLK and TE/SDTA.
Operation mode
RE/SCLK
TE/SDTA
Standby
Receive
Transmit
Idle
0
1
0
1
0
0
1
1
3901007121
Rev. 001
Page 2 of 28
Data Sheet
Jan. 2002