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RF2948B Schematic ( PDF Datasheet ) - RF Micro Devices

Teilenummer RF2948B
Beschreibung 2.4GHz SPREAD-SPECTRUM TRANSCEIVER
Hersteller RF Micro Devices
Logo RF Micro Devices Logo 




Gesamt 18 Seiten
RF2948B Datasheet, Funktion
0
Typical Applications
• IEEE 802.11b WLANs
• Wireless Residential Gateways
• Secure Communication Links
RF2948B
2.4GHz SPREAD-SPECTRUM TRANSCEIVER
• High Speed Digital Links
• Wireless Security
• Digital Cordless Telephones
Product Description
The RF2948B is a monolithic integrated circuit specifi-
cally designed for direct-sequence spread-spectrum sys-
tems operating in the 2.4GHz ISM band. The part
includes: a direct conversion from IF receiver with vari-
able gain control; quadrature demodulator; I/Q baseband
amplifiers; and, on-chip programmable baseband filters.
For the transmit side, a QPSK modulator and upconverter
are provided. The design reuses the IF SAW filter for
transmit and receive reducing the number of SAW filters
required. Two-cell or regulated three-cell (3.6V maxi-
mum) battery applications are supported by the part. The
part is also designed to be part of a 2.4GHz chipset con-
sisting of the RF2494 LNA/Mixer, one of the many RFMD
high-efficiency GaAs HBT PA’s and the RF3000 Base-
band Processor.
2 PLCS
-A-
5.00 SQ.
0.10 C A
2.50 TYP.
3 2 PLCS
0.10 C B
0.05 C
0.90
0.85
0.70
0.65
0.05
0.00
2 PLCS
0.10 C B
-B-
2 PLCS
0.10 C A
4.75 SQ.
2.37 TYP.
Shaded lead is pin 1.
0.60
0.24
TYP.
Dimensions in mm.
0.50
0.30
12°
MAX
-C-
0.10 M C A B
0.30 2
0.18
Pin 1 ID
R.20
3.45
3.15
SQ.
0.50
SEATING
PLANE
Optimum Technology Matching® Applied
Si BJT
9Si Bi-CMOS
GaAs HBT
SiGe HBT
GaAs MESFET
Si CMOS
InGaP/HBT
GaN HEMT
SiGe Bi-CMOS
PD 1
RX EN 2
RX IF BIAS 3
VCC1 4
RX IF IN 5
TX IF IN 6
VCC9 7
TX VGC 8
32 31
30
29
BW
Control
Logic
REF
÷2
Phase
Splitter
9
10 11 12
13
28 27
26
25
DC
Feedback
gm-C
LPF
DC
Feedback
gm-C
LPF
TX
Bias
Σ
14 15 16
24 I OUT
23 VCC4
gm-C
LPF
22 TXQ DATA
21 TXQ BP
gm-C
LPF
20 TXI DATA
19 TXI BP
18 IF1 OUT+
17 IF1 OUT-
Functional Block Diagram
Package Style: QFN, 32-Pin, 5x5
Features
• 45MHz to 500MHz IF Quad Demod
• On-Chip Variable Baseband Filters
• Quadrature Modulator and Upconverter
• 2.7V to 3.6V Operation
• Part of IEEE802.11b Chipset
• 2.4GHz PA Driver
Ordering Information
RF2948B
2.4GHz Spread-Spectrum Transceiver
RF2948BTR13 2.4GHz Spread-Spectrum Transceiver (Tape & Reel)
RF2948B PCBA Fully Assembled Evaluation Board
RF Micro Devices, Inc.
7628 Thorndike Road
Greensboro, NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Rev A6 040930
NOT FOR NEW DESIGNS
11-239






RF2948B Datasheet, Funktion
RF2948B
Pin
13
14
Function
PA IN
VCC5
Description
Input to the power amplifier stage. This is a 50input. Requires DC-
blocking/tuning cap.
Supply for the RF LO buffer, RF upconverter and amplifier.
Interface Schematic
See pin 12.
CBYP
22 nF
From
TX VGA
VCC
CBYP
22 nF
VCC5
VB
VCC
To TX RF
Image Filter
RF OUT
12 mA
RF LO
From
RF VCO
CBLOCK
22 pF
15
RF LO
Single-ended LO input for the transmit upconverter. External matching See pin 14.
to 50and a DC-block are required.
16 RF OUT Upconverted Transmit signal. This 50output is intended to drive an See pin 14.
RF filter to suppress the undesired sideband, harmonics, and other out-
of-band mixer products.
17 IF1 OUT- The inverting open collector output of the quadrature modulator. This
pin needs to be externally biased and DC isolated from other parts of
the circuit. This output can drive a Balun with IF1 OUT+, to convert to
unbalanced to drive a SAW filter. The Balun can be either broadband
(transformer) or narrowband (discrete LC matching). Alternatively, just
IF1 OUT+ can be used to drive a SAW single-ended with an RF choke
(high Z at IF) from VCC to IF1 OUT-.
IF1 OUT+
IF1 OUT-
18 IF1 OUT+ The non-inverting open collector output of the quadrature modulator. See pin 17.
This pin needs to be externally biased and DC isolated from other parts
of the circuit. This output can drive a Balun with IF1 OUT-, to convert to
unbalanced to drive a SAW filter. The Balun can be either broadband
(transformer) or narrowband (discrete LC matching). Alternatively, just
IF1 OUT+ can be used to drive a SAW single-ended with an RF choke
(high Z at IF) from VCC to IF1 OUT+.
19
TXI BP
This is the in-phase modulator bypass pin. A 10nF capacitor to ground
is recommended.
20 TXI DATA I input to the baseband 5 pole Bessel LPF for the transmit modulator.
21 TXQ BP This is the quadrature phase modulator bypass pin. A 10nF capacitor
to ground is recommended.
22 TXQ DATA Q input to the baseband 5 pole Bessel LPF for the transmit modulator.
23
VCC4
Power supply for quadrature modulator.
24
I OUT
Baseband analog signal output for in-phase channel.
700mVP-P linear output.
25
Q OUT
Baseband analog signal output for quadrature channel.
700mVP-P linear output.
26 VREF1 BUF Buffered version of the VREF1 output. See pin 31.
Sink/Source current <1mA.
27 DCFB I DC feedback capacitor for in-phase channel. Requires capacitor to
ground. (22nF recommended)
28 DCFB Q DC feedback capacitor for quadrature channel. Requires decoupling
capacitor to ground. (22nF recommended)
29 BW CTRL This pin requires a resistor to ground to set the baseband LPF band-
width of the receiver and transmit GmC filter amps.
30
VCC2
Supply for the I and Q baseband and GmC filters. This pin should be
bypassed with a 10nF capacitor.
11-244
Rev A6 040930

6 Page









RF2948B pdf, datenblatt
RF2948B
RF Micro Devices
2.4 GHz ISM Chipset
IL = 1-3 dB
2.4 to 2.483 GHz
Gain
Select
Filter
2.4 to 2.483 GHz
T/R
Switch
LNA
Dual Gain Modes
Dual
Frequency
Synthesizer
RF
VCO
IF
VCO
RF2189
RF2494
SSOP-16 EPP
SAW
IL = 10 dB max
RX
RX
IF Amp
TX
TX
RX VGC
RF2948B
OUT Q
Base Band Amp.
Active Selectable LPF
(fC = 1 MHz to 40 MHz)
OUT I
+45°
x2
-45°
10 dBm
PA Driver
IL = 1-3 dB
2.4 to 2.483 GHz
Σ
TX VGC
Filter
I INPUT
Filter
Selectable LPF
Q INPUT
Figure 1. Entire Chipset Functional Block Diagram
11-250
Rev A6 040930

12 Page





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