Document
RF2908
11
Typical Applications
• Digital Cordless Telephones • Secure Communication Links • Wireless LANs • Inventory Tracking • Wireless Security • Battery Powered Applications
915MHZ SPREAD SPECTRUM RECEIVER WITH PLL FREQUENCY SYNTHESIZER
Product Description
The RF2908 is a monolithic integrated circuit specifically designed for direct-sequence spread-spectrum systems operating in the 902MHz to 928MHz ISM band. The part includes a direct conversion receiver, quadrature demodulator, dual IF amplifiers with gain control and RSSI, onchip programmable baseband filters, dual data comparators, and a serially programmable 86-channel PLL frequency synthesizer. Two cell or regulated three cell (3.6V maximum) battery applications are supported by the part. The part is also designed to operate in compliance with FCC Part 15.247. The device is provided in 48-lead plastic LQFP packaging.
.362 .346 .006 .002 .020 .362 .346 .280 .272 .011 .007 .057 .053
.280 .272 7°MAX 0°MIN
.031 .021
.007 MAX
Optimum Technology Matching® Applied
Package Style: LQFP-48
üSi Bi-CMOS
Si BJT
GaAs HBT SiGe HBT
GaAs MESFET Si CMOS
Features
• FCC Part 15.247 Compliant • Direct Conversion Receiver
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TRANSCEIVERS
MOUT Q± 1,2 LNA LNA IN 6
IN Q± 47,48 IF Amp Q Data Amp 39 Q DATA
• On-Chip 86 Channel Frequency Synthesizer • On-Chip Selectable IF Bandwidths • 2.7V to 3.6V Operation
+45° -45°
RSSI Gain Control
42 IF OUT Q 19 IF OUT I
PLL Freq. Synth. IF Amp 23 24 11,12 MOUT I± Ref 13,14 IN I± I Data Amp
21 I DATA
Ordering Information
RF2908 915MHz Spread Spectrum Receiver with PLL Frequency Synthesizer
Refer to the Detailed Functional Block Diagram for description of full functionality
Functional Block Diagram
RF Micro Devices, Inc. 7628 Thorndike Road Greensboro, NC 27409, USA
Tel (336) 664 1233 Fax (336) 664 0454 http://www.rfmd.com
Rev C1 010904
11-85
RF2908
Absolute Maximum Ratings Parameter
Supply Voltage Control Voltages Input RF Level Output Load VSWR Operating Ambient Temperature Storage Temperature
Ratings
-0.5 to +3.6 -0.5 to +3.6 +20 50:1 -40 to +85 -40 to +150
Unit
VDC VDC dBm °C °C 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).
Parameter
Overall
Frequency Range Cascaded Voltage Gain Cascaded Noise Figure Cascaded Input IP3 RX Sensitivity LO Leakage RSSI DC Output Range RSSI Sensitivity RSSI Dynamic Range
Specification Min. Typ. Max.
902 to 928 100 6.0 -12 +5.5 -100 -65 0.35 to 3.1 30 65 902 to 928 22 6.0 50 -20 -12 +5.5 ±3 ±1 200 33
Unit
MHz dB dB dBm dBm dBm dBm V mV/dB dB MHz dB dB Ω dBm dBm ° dB Ω mA
Condition
T=25 °C, VCC =3.6V, Freq=915MHz
8.0
High Gain Low Gain IF BW =960kHz, Freq=915MHz, S/N=8dB At LNA IN RLOAD =51kΩ
60
LNA and Mixer
Operating Frequency Range Voltage Gain Noise Figure RF Input Impedance RF Input VSWR Input IP3
8.0 2:1
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TRANSCEIVERS
Quadrature Phase Balance Quadrature Amplitude Balance Mixer Output Impedance DC Current Consumption
±5
At maximum gain. ATTN=LOW At minimum gain. ATTN=HIGH With expected LO amplitude and harmonic content. Differential Operating at a 3.3V supply voltage.
150 26
250 39
11-86
Rev C1 010904
RF2908
Parameter
IF and Data Amplifiers
IF Frequency Range Voltage Gain Noise Figure Input IP3 Output DC Offset Gain Control Range Gain Control Voltage Range Gain Control Sensitivity VGA Output Voltage VGA DC Output Voltage Output P1dB RSSI Range RSSI Output Voltage Compliance Input Impedance Note 1 77 80 5 35 -65 +2 0 70 -0.08 500 1.7 1.64 60 0.5 to 2.4 2 2.5 9.6 83 MHz dB dB dB dBm dBm mV dB V dB/mV mVPP V VPP dB V kΩ
Specification Min. Typ. Max.
Unit
Condition
At maximum gain setting At minimum gain setting At maximum gain setting At minimum gain setting
25 2.0
65 1.2
1 55 1.5
Driving a 5kΩ load At maximum gain setting Maximum RSSI is 2.5V or VCC -0.3, whichever is less. Differential Note 1. The lower cutoff frequency is a function of: a) input DC blocking cap size; b) DC feedback capacitor; and, c) gain setting. But, recommended component values will yield a cutoff of <10kHz. Five pole Bessel internal LPF. Three pole external LPF. Selectable from 1, 2, 4, and 8MHz. Refer to “IF Bandwidth Response” chart. At 8MHz, increasing as bandwidth decreases.
Filters
Characteristics Bandwidth Passband Ripple Group Delay Ultimate Rejection 80 100 100 10 2 VCC -0.3V 0.3 5 Five pole Bessel 1, 2, 4, 8 1 100 MHz dB ns dB dB MHz ns V V
Data Amplifiers
Voltage Gain Bandwidth Rise and Fall Time Logic High Output Logic Low Output
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Can sink/source 1mA and maintain these logic levels. Can sink/source 1mA and maintain these logic levels. TRANSCEIVERS
PLL, Synthesizer, VCO and LO
VCO Tuning Range VCO Sensitivity Charge Pump Current Reference Frequency Crystal Reference Crystal Rs Phase Noise LO.