RF2948B RF Micro Devices, RF2948B Datasheet - Page 6

• Manufacturer Part Number: RF2948B
• Description: 2.4GHz SPREAD-SPECTRUM TRANSCEIVER
• Manufacturer: RF Micro Devices

11-244
Pin
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
RF2948B
VREF1 BUF
TXQ DATA
BW CTRL
IF1 OUT+
TXI DATA
Function
IF1 OUT-
DCFB Q
RF OUT
TXQ BP
DCFB I
TXI BP
Q OUT
RF LO
VCC5
VCC4
I OUT
VCC2
PA IN
Description
Input to the power amplifier stage. This is a 50Ω input. Requires DC-
blocking/tuning cap.
Supply for the RF LO buffer, RF upconverter and amplifier.
Single-ended LO input for the transmit upconverter. External matching
to 50Ω and a DC-block are required.
Upconverted Transmit signal. This 50Ω output is intended to drive an
RF filter to suppress the undesired sideband, harmonics, and other out-
of-band mixer products.
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 V
The non-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 V
This is the in-phase modulator bypass pin. A 10nF capacitor to ground
is recommended.
I input to the baseband 5 pole Bessel LPF for the transmit modulator.
This is the quadrature phase modulator bypass pin. A 10nF capacitor
to ground is recommended.
Q input to the baseband 5 pole Bessel LPF for the transmit modulator.
Power supply for quadrature modulator.
Baseband analog signal output for in-phase channel.
700mV
Baseband analog signal output for quadrature channel.
700mV
Buffered version of the VREF1 output. See pin 31.
Sink/Source current <1mA.
DC feedback capacitor for in-phase channel. Requires capacitor to
ground. (22nF recommended)
DC feedback capacitor for quadrature channel. Requires decoupling
capacitor to ground. (22nF recommended)
This pin requires a resistor to ground to set the baseband LPF band-
width of the receiver and transmit GmC filter amps.
Supply for the I and Q baseband and GmC filters. This pin should be
bypassed with a 10nF capacitor.
P-P
P-P
linear output.
linear output.
CC
CC
to IF1 OUT-.
to IF1 OUT+.
Interface Schematic
See pin 12.
See pin 14.
See pin 14.
See pin 17.
RF VCO
From
TX VGA
RF LO
From
C
22 pF
22 nF
C
BLOCK
IF1 OUT+
BYP
V
CC
VCC5
Rev A6 040930
22 nF
C
VB
BYP
IF1 OUT-
V
CC
RF OUT
12 mA
Image Filter
To TX RF