Page 1
RF2926
11
Typical Applications
• Wireless Meter Reading
• Keyless Entry Systems
• 433/868/915MHz ISM Band Systems
Product Description
The RF2926 is a monolithic integrated circuit intended for
use as a low cost FM transceiver. The device is provided
in 48-lead plastic TQFP packaging and is designed to
provide a dual conversion, half-duplex transceiver. The
chip is intended for linear (AM, FM) or digital (ASK, FSK,
OOK) applications in the North American 915 MHz and
European 433/868MHz ISM bands. The integrated VCO
has a buffered output to feed the RF signal back to the
PLL IC to form the frequency synthesizer. Separate RX
ENABL, TX ENABL, and PLL ENABL lines allow for half
duplex operation as well as turning on the VCO to give
the synthesizer time to settle and complete power downmode.
UHF DUAL CONVERSION TRANSCEIVER
• Wireless Data Transceiver
• Wireless Security Systems
• Battery Powered Portable Devices
.362
.346
7°MAX
0°MIN
.362
.346
.011
.007
.280
.272
.007
.031
.021 MAX
.280
.272
.057
.053
.006
.002
.020
Optimum Technology Matching® Applied
Si BJT GaAs MESFETGaAs HBT
ü
Si Bi-CMOS
2
TX OUT
4
RX IN
8
LNA OUT
43
MIX CA
10
MIX IN
12
MIX OUT+
13
MIX OUT-
SiGe HBT
PA INP
LVL ADJIF1 IN
Gain
Control
15 14 16 18 20 21 22 23 2425
IF1 BP-
IF1 BP+
LO-
LO+
3637 394446
RSSI
RSSI
IF1 OUT
VREF IF
IF2 IN
Si CMOS
UP CONV
IF2 BP-
IF2 BP+
35
34
31
30
28 DEMOD IN
26 FM OUT
27
ATA OUT
Functional Block Diagram
VCO OUT
MOD IN
RESNTR-
RESNTR+
DATA REF
Package Style: LQFP-48
Features
• Monolithic Integrated Transceiver
• 2.7V to 5.0V Supply Voltage
• Narrow Band and Wide Band FM/FSK
• 300MHz to 1000MHz Frequency Range
• 130MHz Bandwidth in First IF
• 5mW Output Power at 433MHz
Ordering Information
RF2926 UHF Dual Conversion Transceiver
RF2926 PCBA Fully Assembled EvaluationBoard
RF Micro Devices, Inc.
7625 Thorndike Road
Greensboro,NC 27409, USA
Tel (336)664 1233
Fax (336)664 0454
http://www.rfmd.com
11
TRANSCEIVERS
Rev A5 010404
11-185
Page 2
RF2926
Absolute Maximum Ratings
Parameter Ratings Unit
Supply Voltage -0.5 to +5.5 V
Control Voltages -0.5 to +5.0 V
Input RF Level +10 dBm
Output Load VSWR 50:1
Operating Ambient Temperature -40 to +85 ° C
Storage Temperature -40 to +150 °C
DC
DC
Caution! ESD sensitive device.
RF Micro Devices believes the furnished information is correct and accurate
at the time of this printing. However, RF Micro Devices reserves the right to
make changes to its products without notice. RF Micro Devices does not
assume responsibility for the use of the described product(s).
11
Parameter
Min. Typ. Max.
Overall
RF Frequency Range 300 to 1000 MHz
Specification
Unit Condition
T=25°C, VCC=3.6V, Freq=433MHz
VCO
VCO Frequency Range 300 to 1000 MHz
VCO OUT Level -18 dBm 50Ω load impedance
VCO OUT Impedance 50 Ω
Transmit Section
Max Modulation Frequency 2 MHz
Min Modulation Frequency Set by loop fi lter bandwidth
Maximum Power Level +2 dBm Freq=433MHz
Power Control Range 20 dB
Power Control Sensitivity TBD dB/V See plot
Max FM Deviation 200 kHz Instantaneous frequency deviation is
Antenna Port Impedance 50 Ω TX ENABL=“1”
Antenna Port Impedance TBD Ω TX ENABL=“0”
Antenna Port VSWR 1.5:1 TX Mode
Modulation Input Impedance 4 kΩ
Harmonics -50 dBm Measured on eval board with RF filters in
Spurious TBD dBc
inversely proportional with th e modulation
voltage
system.
Overall Receive Section
Frequency Range 300 to 1000 MHz
RX Sensitivity -99 dBm IF BW=400kHz, Freq=915MHz, S/N=8dB
RSSI DC Output Range 0.7 to 2.2 V R
RSSI Sensitivity 25 mV/dB See plot
RSSI Dynamic Range 70 80 dB
TRANSCEIVERS
LNA and Mixer
Cascaded Gain 18 dB Freq=915MHz; RX c urrent 12mA
Cascaded Noise Figure 7 dB Freq=915MHz; RX current 12mA
Cascaded Input IP
LO Leakage -70 dBm
3
-18.5 dBm Freq=915MHz; RX current 12mA
LOAD
=51kΩ
First IF Section
IF 3dB Bandwidth 130 MHz
Voltage Gain 34 dB IF=110.6MHz, Z
Noise Figure 13 dB
Input IP
3
IF1 Input Imped ance 330 Ω
IF1 Output Impedance 330 Ω
TBD mV
PP
=330Ω
L
11-186
Rev A5 010404
Page 3
RF2926
Parameter
Min. Typ. Max.
Specification
Unit Condition
Second IF Section
IF Frequency Range 0.1 10.7 22 MHz
VoltageGain 60 dB IF=10.7MHz
IF2 Input Impedance 330 Ω
IF2 Output Imped ance 1 kΩ At IF2 OUT pin
Demod Input Impedance 10 kΩ
FM Output Imped ance 500 Ω
Data Output Impedance >1 MΩ
FM Output Bandwidth 1.6 MHz
Data Output B andwidth 1.4 MHz
Data Output Level 0.3 V
FM Output DC Level 2.6 V Z
FM Output AC Level 200 mV
-0.3 V Z
CC
PP
=1MΩ || 3pF; O utput voltage is pro-
LOAD
portional with the instantaneous frequency
deviation.
>10kΩ
LOAD
Z
>10kΩ
LOAD
Power Down Control
Logical Controls “ON” 2.0 V Voltage supplied to the input
Logical Controls “OFF” 1.0 V Voltage supplied to the input
Control Input Impedance 25k Ω
Power Supply
Voltage 3.6 V Specifications
2.7 to 5.0 V Operating limits
Current Consumption 37.3 mA TX Mode, LVL ADJ=3.6V
10.9 mA TXMode, LVL ADJ=0V
10 to 18 mA RX Mode; Current is adjustable
1 µA Power Down Mode
3.8 mA PLL Only Mode
Rev A5 010404
11
TRANSCEIVERS
11-187
Page 4
RF2926
Pin Function Description Interface Schematic
1 TX ENABL
Enables the transmi tter circuits. TX ENABL>2.0V powers up all transmitter functions. TX ENABL<1.0V turns off all tra n smitter functions
except the PLL functions.
TX ENABL
20 k
40 k
Ω
Ω
11
2TXOUT
3 GND2
4RXIN
5 GND1
6LNAGND
7LNAGND
8LNAOUT
9 GND3
10 MIX IN
RF output pin for the transmitter electronics. TX OUT output impedance
is a low impedance (see output impedance plot in Figure TBD) when
the transmitter is enabled. TX OUT is a high impedance when the
transmitter is disabled.
Ground connection for the 40 dB IF limiting amplifier and Tx PA functions. Keep traces physically short and connect immediately to ground
plane for bes t performance.
RF input pi n for the receiver electronic s. RX IN input impedance is a
low impedance (see input impedance plot in Figure TBD) when the
receiver is enabled. RX IN is a high impedance when the receiver is
disabled.
Ground connecti on for RF receiver functions. Keep traces physically
short and connect immediately to ground plane for best performance.
Ground connection for the LNA.
Ground connection for the LNA.
Output pin for the receiver RF low noise amplifier. This pin is an open
collector output and requires an external pull up coil to provide bias and
tune the LNA output. A capacitor in series with this output can be used
to match the LNA to 50Ω impedance image filters.
Same as pin 4.
RF input to the RF Mixer. A n LC matching network between LNA OUT
and MIX IN can be used to connect the LNA output to the RF mixer
input in applications where an image filter is not needed or des ired.
V
CC
MIX IN
V
CC
20
TX OUT
500
RX IN
LNA OUT
GND5
11 GND5
12 MIX OUT+
GND5 is the ground connection shared by the input stage of the transmit power amplifier and the receiver RF mixer.
Complementary (with respect to pin 13) IF output from the RF mixer.
Alternately, an IF tank can be used to tailor the IF frequency and band-
MIX OUT-MIX OUT+
width to meet the needs of a given application.
TRANSCEIVERS
13 MIX OUT-
IF output from the RF mixer. For a balanced mixer output, pull-up inductors from pin 12 and 13 to V
and a capacitor between the pins should
CC
See pin 12.
15 pF 15pF
GND5 GND5
be used. The sum of the total pull-up inductance should be used to resonate the capacitor between pins 12 and 13.
14 IF1 BP+
15 IF1 IN
11-188
DC feedback node for the 40dB limiting amplifier strip. A 10nF bypass
capacitor from this pin to ground is required.
IF input to the 40dB limiting amplifier strip. A DC blocking capacitor is
required on this input. The value of this capacitor should be small
enough as t o not attenuate the IF frequency when terminated into the
330Ω input impedance.
See pin 16.
IF1 BP+ IF1 BP-
60 k
Ω
330 330
IF1 IN+
60 k
Ω
Rev A5 010404
Page 5
RF2926
Pin Function Description Interface Schematic
16 IF1 BP17 GND7
18 IF1 OUT
See pin 14. See pin 15.
Ground connection for 40dB IF limiting amplifier. Keep traces physically
short and connect immediately to ground plane for best performance.
IF output from the 40dB limiting amplifier.The IF1 OUT o utput presents
a nominal330 Ω output resistance and interfaces directly to 10.7MHz
ceramic filters.
IF1 OUT
19 GND6
20 VREF IF
21 IF2 IN
22 I F2 BP+
23 IF2 BP-
24 DATA OUT
25 RSSI
26 FM OUT
Ground connection for 60dB IF limiting amplifier. Keep traces physically
short and connect immediately to ground plane for best performance.
DC voltage reference for the IF limiting amplifiers. A 10nF capacitor
from this pin to ground is required.
IF input to the 60dB limiting amplifier strip. A 10nF DC blocking capacitor is required on this input. The IF2 IN input presents a nominal 330 Ω
input resistance and interfaces directly to 10.7MHz ceramic filters.
DC feedback node for the 60dB li miting amplifier strip. A 10nF bypass
60 k
330 330
IF2 IN
See pin 20.
capacitor from this pin to ground is required.
See pin 21. See pin 20.
Demodulated data output from the dem odulator. Outpu t levels on this
are TTL/CMOS compatible. The magnitude of the load impedance is
intended to be 1MΩ or greater.
A DC voltage proportional to the received signal strength is output from
this pin. The output voltage range is 0.5V to 2.5V and increases with
increasing signal strength.
Linear output from the FM demodulator. This pin is used in analog
applications when signal fidelity is important.
IF2 BP+ IF2 BP-
Ω
DATA OUT
V
CC
RSSI
FM OUT
60 k
Ω
11
27 DATA REF
28 DEMOD IN
29 VCC4
Rev A5 010404
This pin is used for setting the adaptive Data Slicer DC reference level.
A capacitor from this pin to ground can be used to set the reference
level at the average DC level of the data bit stream.The DC level determines the bit decision threshold.
This pin is the input to the FM demodulator. This pin is NOT AC coupled. Therefore, a DC blocking capacitor is required on this pin to avoid
shorting the demodulator input with the LC tank. A ceramic discriminator or DC blocked LC tank resonant at the IF should be connected to
this pin.
This pin is used is supply DC bias to the 60dB IF limiting amplifier. An
IF bypass capacitor should be connected directly to this pin and
returned to ground. A 10nF capacitor is recommended for 10.7MHz IF
applications.
IF Output
DEMOD IN
50 k
Ω
DATA REF
V
CC
V
CC
10 k
Ω
11-189
TRANSCEIVERS
Page 6
RF2926
Pin Function Description Interface Schematic
30 RESNTR+
31 RESNTR32 VCC2
33 GND4
34 MOD IN
35 VCO OUT
This port is used to supply DC voltage to the VCO as well as to tune the
center frequency of the VCO. Equal value inductors should be connected to this pin and pin 31 although a small imbalance can be used
to tune in the prope r frequency range.
See RESNTR+ description. See pin 30.
This pin is used is supply DC bias to the VCO and buffer amps. A 10nF
capacitor is recommended for 10.7MHz IF applications.
GND4 is the ground shared on chip by the V CO, prescaler, and PLL
electronics.
FM analog or digital modulation can be imparted to the VCO through
this pin. Th e VCO varies in accordance to the voltage level presented
to this pin. To set the deviation to a desired level, a voltage divider referenced to V
upon the overall capacitance of the external resonant circuit.
This pin is used is supply a buffered VCO output to go to the PLL chip.
This pin has a DC bias and needs to be AC c oupled.
is the recommended. This deviation is also dependent
CC
See pin 30.
RESNTR-RESNTR+
4k
VCO OUT
Ω
MOD IN
11
36 LO-
37 LO+
38 GND8
39 UP CONV
40 GND9
41 VCC1
42 MUTE
TRANSCEIVERS
43 MIX CA
44 PA INP
45 VCC3
Balanced input for the first LO. This signal is presented to both the
receiver second downconverter and transmit upconvertor.
Complementary input of LO-. See pin 36.
Ground for LO amp and transmit upconvertor. Keep traces physically
short and immediately to the ground plane for best performance.
The output of the transmit signal upconvertor. This signal should be fil-
tered to remove the undesired sideband and spurs before being applied
to the PA input, pin 45.
Same as pin 38. See pin 38.
This pin is used to supply DC bias to the receiver RF electronics. A RF
bypass capacitor should b e connected directly to this pin and returned
to ground. A 100pF capacitor is recommended for 91 5MHz applications. A 220pF capacitor is recommended for 433MHz applications.
This pin is used to mute the data output (DATA OUT). MUTE>2.0V
turns the DATA OUT signal on. MUTE<1.0V turns the DATAOUT signal
off. The MUTE signal should be logic low in the Sleep Mode.
Mixer Current Adjust. This pin is used to adjust the current in the
receiver.A resistor connected to ground controls the bias current in the
mixer.The resistor should vary between 1kΩ to open circuit to vary the
current from 18mA to 10.6mA
Input of the transmit power amplifier.
This pin is used to supply DC bias to the transmitte r PA. A RF bypass
capacitor should be connected directly to this pin and returned to
ground. A 100pF capacitor i s recommended for 915MHz applications.
A 220pF capacitor is recommended for 433MHz applications.
MUTE
75 k
LO+LO-
Ω
25 k
Ω
11-190
Rev A5 010404
Page 7
RF2926
Pin Function Description Interface Schematic
46 LVL ADJ
This pin is used to vary the transmitter output power. An output level
adjustment range greater than 12dB is provided through analog voltage
control of this pin. DC current of the transmitter power amp is also
reduced with output power. This pin MUST be low when the transmitter
is disabled.
40 k
400 4k
Ω
LVL ADJ
Ω
47 PLL ENABL
48 RX ENABL
TX ENABL
TX OUT
GND2
RX IN
This pin is used to power up or down the VCO and PLL. A logic high
(PLL ENABL>2.0V) powers up the VCO and PLL electronics. A logic
low (PLL ENABL<1.0V) powers down the PLL and VCO.
Enable pin for the receiver circuits. RX ENABL>2.0V powers up all
receiver functions. RX ENABL<1.0V turns off all receiver functions
except the PLL f unctions and the RF mixer.
Pin Out
RX ENABL
PLL ENABL
LVL ADJ
VCC3
PA INPUT
MIX CA
MUTE
VCC1
GND9
UP CONV
48 454647 44 43 42 41 40 39 38 37
1
2
3
4
Gain
Control
GND8
LO+
PLL ENABL
RX ENABL
LO-
36
VCO OUT
35
MODIN
34
GND4
33
50 k
50 k
Ω
Ω
11
Rev A5 010404
GND1
LNA GND
LNA GND
LNA OUT
GND3
MIX IN
GND5
MIX OUT+
5
6
7
8
9
GND7
RSSI
IF1 OUT
GND6
IF2 IN
VREF IF
10
11
12
13 161514 17 18 19 20 21 22 23 24
IF1 IN
IF1 BP+
MIX OUT-
IF1 BP-
IF2 BP+
IF2 BP-
DATA OUT
VCC2
32
RESNTR-
31
RESNTR+
30
VCC4
29
DEMOD IN
28
DATA REF
27
FM OUT
26
RSSI
25
TRANSCEIVERS
11-191
Page 8
RF2926
Application Schematic
915MHz
CC
V
10 Ω
LO INPUT
51 Ω
0.1 µF22 pF
Filter
22 pF
VCO OUT
MOD IN
1nF
1nF
22 pF
36
10 kΩ
VCC
10 Ω
10 Ω
22 pF 0.1 µF
35
34
33
32
LOOP FILTER
VCC
22 pF 0.1 µF
4.7 nH
2pF
31
VCC
10 Ω
22 pF 0.1µF
10 kΩ
4.7 nH
D1
30
29
10 nF
1.5 kΩ
5pF
28
FM Disc.
27
26
RSSI
FM OUT
25
22 nF
22 nF 22 nF 22 nF
DATA OUT
RSSI
10 pF
47 kΩ
Filter
11
Gain
Control
0.1 µF 22 pF
48 454647 44 43 42 41 40 39 38 37
1
2
3
4
5
6
7
8
9
10
11
22 pF
22 pF
6pF
5pF
22 pF
18 nH
22 nF
13 161514 17 18 19 20 21 22 23 24
12
5pF
560 nH
5pF
390 nH
Filter
2.7 kΩ
TRANSCEIVERS
2pF
Filter
10 Ω
0.1 µF 22 pF
CC
V
LNA OUT
MIX IN
MIX OUT
Rev A5 010404
11-192
18 nH
22 pF220 pF0.1 µF
4pF4pF
8.2 nH
CC
V
MUTE
LVL ADJ
RX ENABL
PLL ENABL
RF
TX ENABL
10 Ω
CC
V
Page 9
Evaluation Board Layout
Board Size 3.04” x 3.04”
Board Thickness 0.031”, Board Material FR-4
RF2926
Rev A5 010404
11
TRANSCEIVERS
11-193
Page 10
RF2926
11
TRANSCEIVERS
11-194
Rev A5 010404
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