rev03
1
Complies with Directive 2002/95/EC (RoHS)
Product Overview
TRC101 is a highly integrated single chip, zero-IF, multi-channel, low
power RF transceiver. It is an ideal fit for low cost, high volume, two way
short-range wireless applications for use in the unlicensed 300-1000 MHz
frequency bands. All critical RF and baseband functions are completely
integrated in the chip, thus minimizing external component count and
simplifying and speeding design-ins. Use of a low cost, generic 10MHz
crystal and a low-cost microcontroller is all that is needed to create a
complete link. The TRC101 also incorporates different sleep modes to
reduce overall current consumption and extend battery life. Its small size
with low power consumption makes it ideal for various short range radio
applications.
Key Features
Modulation: FSK (Frequency Hopping Spread Spectrum
capability)
Frequency range: 300-1000 MHz
High sensitivity: (-105 dBm)
High data rate: Up to 256 kbps
Low current consumption
(RX current ~8.5mA)
Wide operating supply voltage: 2.2 to 5.4V
Low standby current (0.2uA)
Integrated PLL, IF, Baseband Circuitry
Automatic Frequency Adjust(TX/RX frequency alignment)
Programmable Analog/Digital Baseband Filter
Programmable Output RF Power
Programmable Input LNA Gain
Internal Valid Data Recognition
Transmit/Receive FIFO
Standard SPI Interface
TTL/CMOS Compatible I/O pins
Programmable CLK Output Freq
Automatic Antenna tuning circuit
Low cost, generic 10MHz Xtal reference
Integrated, Programmable Low Battery Voltage Detector
Programmable Wake-up Timer with programmable Duty Cycle
Integrated Selectable Analog/Digital RSSI
Integrated
Crystal
Oscillator
External Processor Interrupt pin
Programmable Crystal Load Capacitance
Programmable
Data
Rate
Integrated Clock & Data Recovery
Programmable, Positive/Negative FSK Deviation
External Wake-up Events
RF Monolithics, Inc.
4441 Sigma Road
Dallas, Texas 75244
(800) 704-6079 toll-free in U.S. and Canada www.rfm.com
Email: info@rfm.com
16-TSSOP package
Support for Multiple Channels
Power-saving sleep mode
Very few external components requirement
Small size plastic package: 16-pin TSSOP
Standard 13 inch reel, 2000 pieces.
Popular applications
Active RFID tags
Automated Meter reading
Home & Industrial Automation
Security
systems
Two way Remote keyless entry
Automobile
Immobilizers
Sports & Performance monitoring
Wireless
Toys
Medical
equipment
Low power two way telemetry systems
Wireless mesh sensors
Wireless
modules
[315/433 Bands] 380 Channels(25kHz)
[868 Band] 761 Channels(25kHz)
[915 Band] 1040 Channels(25kHz)
2
Table of Contents
Table of Contents
.......................................................................................................... 2
1.0 TRC101 Pin Configuration
...................................................................................... 2
1.1 Pin Description..................................................................................................... 3
2.0 Functional Description
........................................................................................... 4
2.1 TRC101 Applications ........................................................................................... 4
RF Transmitter Matching ..................................................................................... 4
Antenna Design Considerations........................................................................... 5
PCB Layout Considerations................................................................................. 5
3.0 TRC101 Functional Characteristics
....................................................................... 7
Input/Output
Amplifier ................................................................................................ 7
Baseband
Data
and Filtering ..................................................................................... 7
Transmit
Register....................................................................................................... 8
Receive
FIFO............................................................................................................. 8
Automatic Frequency Adjustment (AFA).................................................................... 8
Crystal
Oscillator........................................................................................................ 9
Frequency Control (PLL) and Frequency Synthesizer ............................................... 9
Data Quality Detector (DQD) ..................................................................................... 9
Valid
Data
Detector ................................................................................................... 9
Receive Signal Strength Indicator (RSSI) ................................................................ 10
Wake-Up
Mode ........................................................................................................ 10
Low
Battery
Detector ............................................................................................... 10
SPI
Interface ............................................................................................................ 11
4.0 Control and Configuration Registers
.................................................................. 12
Status
Register ....................................................................................................... 12
Configuration
Register
[POR=8008h]
.......................................................................... 13
Automatic Frequency Adjust Register
[POR=C4F7h]
.................................................. 14
Transmit Configuration Register
[POR=9800h]
........................................................... 16
Transmit
Register
[POR=B8AAh]
................................................................................ 17
Frequency Setting Register
[POR=A680h]
.................................................................. 18
Receiver Control Register
[POR=9080h]
..................................................................... 19
Baseband Filter Register
[POR=C22Ch]
..................................................................... 21
FIFO Read Register
[POR=B000h]
............................................................................. 22
FIFO and RESET Mode Configuration Register
[POR=CA88h]
................................... 23
Data Rate Setup Register
[POR=C623h]
..................................................................... 24
Power Management Register
[POR=8208h]
................................................................ 25
Wake-up Timer Period Register
[POR=E196h]
........................................................... 26
Duty Cycle Set Register
[POR=C80Eh]
....................................................................... 27
Battery Detect Threshold and Clock Output Register
[POR=C000h]
........................... 28
5.0 Maximum Ratings
.................................................................................................. 29
6.0 DC Electrical Characteristics
............................................................................... 29
7.0 AC Electrical Characteristics
............................................................................... 30
8.0 Package Information
............................................................................................. 33
3
1. Pin Configuration
1
SDI
2
SCK
3
nCS
4
SDO
5
IRQ
6
DATA/nFSEL
7
CR/FINT/FCAP
8
CLKOUT
nINT/DDET
RSSIA
VDD
RF_N
RF_P
GND
RESET
Xtal/Ref
TOP VIEW
TRC101
9
10
11
12
13
14
15
16
1.1 Pin Descriptions
Pin Name
Description
1 SDI
SPI Data In
2 SCK
SPI Data Clock
3 nCS
Chip Select Input
Selects the chip for an SPI data transaction. The pin must be pulled `low' for a 16-
bit read or write function. See Figure 6 for timing specifications.
4 SDO
SPI Data Out
5 nIRQ
Interrupt Request Output
- The receiver will generate an active low interrupt request for the
microcontroller on the following events:
The TX register is ready to receive the next byte
The FIFO has received the preprogrammed amount of bits
Power-on reset
FIFO overflow/TX register underrun
Wake-up timer timeout
Negative pulse on the interrupt input pin nINT
Supply voltage below the preprogrammed value is detected
6 Data/nFSel
Data In
When the internal TX register is not used, this pin may be used to manually modulate data
from an external host processor. If the internal TX register is enabled, this pin must be tied to GND.
Data Out
When the internal FIFO is not used this pin is used in conjunction with pin 7 (Recovered
Clock) to receive data.
FIFO Select
When reading the FIFO, this pin selects the FIFO and the first bit appears on the next
clock. Use this pin in conjunction with Pin 7.
7 CR/FINT/FCAP
Recovered Clock Output
When the digital filter is used (
Baseband Filter Register
, Bit [4]) and FIFO
disabled (
Configuration Register,
Bit [6]), this pin provides the recovered clock from the incoming data.
FIFO INT
When the internal FIFO is enabled (
Configuration Register,
Bit [6]), this pin acts as a FIFO
Fill interrupt indicating that the FIFO has filled to its pre-programmed limit (
FIFO Configuration Register
,
Bit [7..4]).
External Data Filter Capacitor
When the Analog filter is used (
Baseband Filter Register
, Bit [4]), this
pin is the raw baseband data that may be used by a host processor for data recovery. The external
capacitor forms a simple lowpass filter with an internal 10KOhm series resistor. The capacitor value
may be chosen for a Max data rate up to 256kbps.
8 ClkOut
Optional host processor Clock Output
9 Xtal/Ref
Xtal
- Connects to a 10MHz series crystal or an external oscillator reference.
The circuit contains an
integrated load capacitor (See
Configuration Register
) in order to minimize the external component
count. The crystal is used as the reference for the PLL, which generates the local oscillator frequency.
The accuracy requirements for production tolerance, temperature drift and aging can be determined
from the maximum allowable local oscillator frequency error. Whenever a low frequency error is
essential for the application, it is possible to "pull" the crystal to the accurate frequency by changing the
load capacitor value.
Ext Ref
An external reference, such as an oscillator, may be connected as a reference source.
Connect through a .01uF capacitor.
10 nRESET
Reset Output
with internal pull-up
11 GND
System Ground
12
RF_P
RF Diff I/O
13 RF_N
RF Diff I/O
14 VDD
Supply Voltage
15 RSSIA
Analog RSSI Output
The Analog RSSI can be used to determine the actual signal strength. The
response and settling time depends on an external filter capacitor. Typically, a 1000pF capacitor will
provide optimum response time for most applications.
16 nINT/DDet
nINT
This pin may be configured as an active low external interrupt to the chip. When a logic `0' is
applied to this pin, it causes the nIRQ pin (5) to toggle, signaling an interrupt to an external processor.
Reading the first four (4) bits of the status register tells the source of the interrupt. This pin may be used
as a wake-up event from sleep.
Valid Data Detector Output
This pin may be configured to indicate Valid Data when the synchronous
pattern recognition circuit indicates potentially real incoming data.
4
2. Functional Description
The TRC101 is a low power, frequency agile, zero-IF, multi-channel FSK transceiver for use in the 315,
433, 868, and 916 MHz bands. All RF and baseband functions are completely integrated requiring only a
single 10MHz crystal as a reference source and an external low-cost processor. Functions include:
PLL
synthesizer
Power
Amp
LNA
I/Q
Mixers
I/Q
Demodulators
Baseband
Filters
Baseband
Amplifiers
RSSI
Low
Battery
Detector
Wake-up Timer/Duty Cycle Mode
Valid Data Detection/Data Quality
The TRC101 is ideal for Frequency Hopping Spread Spectrum (FHSS) applications requiring frequency
agility to meet FCC requirements. Use of a low-cost microcontroller is all that is needed to create a
complete data link. The TRC101 incorporates different sleep modes to reduce overall current
consumption and extend battery life. It is ideal for applications operating from typical lithium coin cells.
2.1 TRC101 Typical Application Circuit
Figure 1. Typical Application Circuit
RF Transmitter Matching
The RF pins are high impedance and differential. The optimum differential load for the RF port at a given
frequency band is shown in Table 1.
TABLE 1.
TRC101
Admittance
Impedance (Ohm)
L
315 MHz
1.5e-3 j5.14e-3
52 + j179
98nH
433 MHz
1.4e-3 j7.1e-3
27 + j136
52nH
868 MHz
2e-3 j1.5e-2
8.7 + j66
12.5nH
916 MHz
2.2e-3 j1.55e-2
9 + j63
11.2nH
5
These values are what the RF port pins want to "see" as an antenna load for maximum power transfer.
Antennas ideally suited for this would be a Dipole, Folded Dipole, and Loop. For all transmit antenna
applications a bias or "choke" inductor must be included since the RF outputs are open-collector type.
The matching component values for each band are given in Table 2.
Table 2.
Ref
Des
315 433 868 916
C1 6.8pF 5.1pF 2.7pF 2.7pF
C2 3.9pF 2.7pF 1.2pF 1.2pF
L1 56nH
33nH
8.2nH
8.2nH
L2 390nH 390nH 100nH 100nH
L3 68nH 47nH 22nH 22nH
Antenna Design Considerations
The TRC101 was designed to drive a differential output such as a Dipole antenna or a Loop. The loop
antenna is ideally suited for applications where compact size is required. The dipole is typically not an
attractive option for compact designs due to its inherent size at resonance and distance needed away
from a ground plane to be an efficient antenna. A monopole antenna can be used with the addition of a
balun or by using the matching circuit in Figure 1.
PCB Layout Considerations
Optimal PCB layout is very critical. For optimal transmit and receive performance, the trace lengths at the
RF pins must be kept as short as possible. Using small, surface mount components, like 0402 or 0603,
will yield the best performance as well as keep the RF port compact. Make all RF connections short and
direct. A good rule of thumb to adhere to is add 1nH of series inductance for every 0.1" of trace length.
The crystal oscillator is also affected by additional trace length as it adds parasitic capacitance to the
overall load of the crystal. To minimize this effect place the crystal as close as possible to the chip and
make all connections short and direct. This will minimize the effects of "frequency pulling" that stray
capacitance may introduce and allows the internal load capacitance of the chip to be more effective in
properly loading the crystal oscillator circuit.
If using an external processor, the TRC101 provides an on-chip clock for that purpose. Even though this
is an integrated function, long runs of the clock signal may radiate and cause interference. This can
degrade receiver performance as well as add harmonics or unwanted modulation to the transmitter.
Keep clock connections as short as possible and surround the clock trace with an adjacent ground plane
pour where needed. This will help in reducing any radiation or crosstalk due to long runs of the clock
signal.
Good power supply bypassing is also essential. Large decoupling capacitors should be placed at the
point where power is applied to the PCB. Smaller value decoupling capacitors should then be placed at
each power point of the chip as well as bias nodes for the RF port. Poor bypassing lends itself to
conducted interference which can cause noise and spurious signals to couple into the RF sections,
significantly reducing performance.
Assembly View
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