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RF2948B
0
Typical Applications * IEEE 802.11b WLANs * Wireless Residential Gateways * Secure Communication Links Product Description
The RF2948B is a monolithic integrated circuit specifically designed for direct-sequence spread-spectrum systems operating in the 2.4GHz ISM band. The part includes: a direct conversion from IF receiver with variable 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 maximum) battery applications are supported by the part. The part is also designed to be part of a 2.4GHz chipset consisting of the RF2494 LNA/Mixer, one of the many RFMD high-efficiency GaAs HBT PA's and the RF3000 Baseband Processor. Optimum Technology Matching(R) Applied
Si BJT Si Bi-CMOS InGaP/HBT GaAs HBT SiGe HBT GaN HEMT Si CMOS
2.4GHz SPREAD-SPECTRUM TRANSCEIVER
* High Speed Digital Links * Wireless Security * Digital Cordless Telephones
IG N S
-A5.00 SQ. 2.50 TYP.
3
2 PLCS 0.10 C A
0.05 C 0.90 0.85 0.70 0.65
2 PLCS 0.10 C B
0.05 0.00
2 PLCS 0.10 C B
12 MAX
E S
-B-C2.37 TYP. 4.75 SQ.
0.10 M C A B 0.60 0.24 TYP. 0.30 0.18
2
SEATING PLANE
2 PLCS 0.10 C A
D
Shaded lead is pin 1.
Pin 1 ID R.20
Dimensions in mm.
W
3.45 SQ. 3.15
0.50 0.30
N E
0.50
Package Style: QFN, 32-Pin, 5x5
GaAs MESFET SiGe Bi-CMOS
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
FO
BW CTRL RX VGC VREF 1 32 31 30 VCC2 29
BW Control
R
DCFB Q 28
DC Feedback
gm-C LPF gm-C LPF
VREF1 BUF
DCFB I
27
26
25
PD 1
N O T
RX EN 2
Logic
RX IF BIAS 3
REF
DC Feedback
Q OUT
* 2.4GHz PA Driver
24 I OUT
TX Bias
VCC1 4
RX IF IN 5
23 VCC4
TX IF IN 6
gm-C LPF
22 TXQ DATA
VCC9 7
21 TXQ BP
Ordering Information
RF2948B RF2948BTR13 RF2948B PCBA 2.4GHz Spread-Spectrum Transceiver 2.4GHz Spread-Spectrum Transceiver (Tape & Reel) Fully Assembled Evaluation Board Tel (336) 664 1233 Fax (336) 664 0454 http://www.rfmd.com
TX VGC 8 /2
Phase Splitter
gm-C LPF
20 TXI DATA
19 TXI BP 18 IF1 OUT+
17 IF1 OUT9 IF LO 10 VCC8 11 VCC6 12 PA OUT 13 PA IN 14 VCC5 15 RF LO 16
Functional Block Diagram
RF Micro Devices, Inc. 7628 Thorndike Road Greensboro, NC 27409, USA
NOT FOR NEW DESIGNS
Rev A6 040930
RF OUT
11-239
RF2948B
Absolute Maximum Ratings Parameter
Supply Voltage Control Voltages Input RF Level LO Input Levels Operating Ambient Temperature Storage Temperature MSL JEDEC level 3 at 240oC
Refer to "Handling of PSOP and PSSOP Products" on page 16-15 for special handling information.
Rating
-0.5 to +3.6 -0.5 to +3.6 +12 +5 -40 to +85 -40 to +150
Unit
VDC VDC dBm dBm C C
Refer to "Soldering Specifications" on page 16-13 for special soldering information.
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 Receiver
RX Frequency Range Cascaded Voltage Gain Cascaded Noise Figure Cascaded Input IP3 Cascaded Input IP3 IF LO Leakage Quadrature Phase Variation Quadrature Amplitude Variation Output P1dB Distortion
Unit
D
3 +1 2 7.5 VREF1+15 35 0.1 30
50 115 -68 0 0
W
1.2
Gain Noise Figure IF Input Impedance
N E
IF AMP and Quad Demod
65
4.5 70 5.5 515-j994 2 700 VREF1 10
RX Baseband Filters
Passband Ripple Baseband Filter 3dB Frequency Accuracy Group Delay
Baseband Filter 3dB Bandwidth
FO
THD Output Voltage DC Output Voltage
R
RX Baseband Amplifiers
VREF1-15 1
N O T
10 15 400 >80 20
Group Delay Baseband Filter Ultimate Rejection Output Impedance
11-240
E S
dB VPP % dB dB % mVPP mV MHz dB % ns ns dB
45 65 0 5.5
374
500 76 3 35.0
MHz dB dB dB dBV dBV dBm
IG N S
Specification Min. Typ. Max.
Condition
T=25 C, VCC =3.0V, Freq=374MHz, RBW =10k
RX VGC =1.2V RX VGC =2.0V Varies with gain. VGC <1.2V VGC>2.0V f=374MHz, LO Power=-10dBm With expected LO amplitude and harmonic content. 1.45k, CL <15pF
5th order Bessel LPF. Set by BW CTRL (RBW)
At 35MHz, increasing as bandwidth decreases. At 2MHz.
Designed to drive>5k, <15pF load.
Rev A6 040930
RF2948B
Parameter
Transmit Modulator and LPF
Filter Gain Baseband Filter 3dB Bandwidth Passband Ripple Group Delay Group Delay Ultimate Rejection Input Impedance Input AC Voltage Input P1dB Input DC Offset Requirement IF Frequency Range Differential Output Resistance Differential Output Capacitance Shunt Output Capacitance I/Q Phase Balance I/Q Gain Balance Conversion Transconductance Carrier Output -18 0 1 15 400 >80 3 100 200 1.6 45 1.7 22 0.436 0.4 0 0 0.0185 -26 1.8 500 35 0.1 dB MHz dB ns ns dB k mVp-p mVp-p V MHz k pF pF Any setting 5th order Bessel LPF, Set by BW CTRL At 35MHz, increasing as bandwidth decreases. At 2MHz. Single-ended Linear, Single-ended. Single-ended. For correct operation. Between output pins. Open collector when TX on, Hi Z when TX off Between output pins. From each pin to ground.
Specification Min. Typ. Max.
Unit
Condition
E S
3 1 dB S
D
Harmonic Outputs
W
-30
VGA/Mixer Output Power
FO
R
VGA Gain Range VGA Control Voltage Range VGA Gain Sensitivity VGA Input Impedance RF Mixer Output Impedance VGA/Mixer Conversion Gain VGA/Mixer Output Power
N E
Transmit VGA and Upconverter
17 1.0 to 2.0 17 515-j994 50 -3 to +14 -9 -4
N O T
Rev A6 040930
IG N S
dBc dBc dB V dB/V dB dBm dBm Positive Slope
Single-ended voltage input to differential output current conversion gain. Without external offset adjustments. 374MHz. Compared to modulated signal, 100mVP-P input.
374MHz With matching elements. With 50 match on the output. 1dB compression - Single Sideband, TX GC=1.0V. (Desired signal power) 1dB compression - Single Sideband, TX GC=2.0V. (Desired signal power)
11-241
RF2948B
Parameter
Transmit Power Amp
Linear Output Power Gain Output P1dB Output Impedance Input Impedance 6 9 12 50 50 VCC +0.3V 0 >1 200 2 330 1.33 50 0.3 dBm dB dBm V V M ns s ns ms s
Specification Min. Typ. Max.
Unit
Condition
10
Nominal Nominal Voltage supplied to the input, not to exceed 3.6V. Voltage supplied to the input. Full step in gain, to 90% of final output level. I/Q output VALID To IF output VALID To I/Q output VALID To IF output VALID The IF LO is divided by 2 and split into quadrature signals to drive the frequency mixers. f=748MHz peak (2x IF Frequency) f=2.04GHz unmatched.
Power Down Control
Logical Controls "ON" Logical Controls "OFF" Control Input Impedance RX VGC Response TIme RX EN Response TIme TX EN Response TIme VPD to RX Response TIme VPD to TX Response TIme VCC -0.3V -0.3
RF LO Input
Input Impedance Input Power Range Input Frequency 33-j110 -10 2000
D
0 2400 1 VREF1+10 1.8 3.6 85 136
Input Impedance Input Power Range Input Frequency
-15 90
1050-j1200 -10
0 1000
VREF1 Buffered
Source/Sink Current Output Voltage VREF1 VREF1-10 1.6 2.7
W
1.7 3.3 1 18 65 70 110 95 105 115
Power Supply
Voltage Total Current Consumption Sleep Mode Current PA Driver Current RX Current BW (MHz) 9 12-20 20-30 TX Current BW (MHz) 9 12-20 20-30
N E
R
FO
N O T
11-242
E S
dBm MHz dBm MHz mA mV V V A mA mA mA mA mA mA mA
IF LO Input
IG N S
VCC =3.3V, Baseband BW 1MHz to 40MHz PD=0, RX EN=1 TX EN=1
Rev A6 040930
RF2948B
Pin 1 Function PD Description
This pin is used to power up or down the transmit and receive baseband sections. A logic high powers up the quad demod mixers, TX and RX GmC LPF's, baseband VGA amps, data amps, and IF LO buffer amp/ phase splitter. A logic low powers down the entire IC for sleep mode. Also, see State Decode Table.
Interface Schematic
VCC Pins 3, 4, 5 10 k ESD
To Logic
2
RX EN
Power supply for RX VGA amplifier, IC logic and RX references.
6
TX IF IN
D
IF input for receiver section. Must have DC-blocking cap. The capacitor See pin 6. value should be appropriate for the IF frequency. For half-duplex operation, connect RX IF IN and TX IF IN signals together after the DC blocking caps, then run a transmission line from the output of the IF SAW. AC coupling capacitor must be less than 150pF to prevent delay in switching RX to TX/TX to RX. Input for the TX IF signal after SAW filter. External DC-blocking cap IF required. For half-duplex operation, connect RX IF IN and TX IF IN sigSAW nals together after the DC-blocking caps, then run a transmission line Filter from the output of the IF SAW. AC coupling capacitor must be less than 150pF to prevent delay in switching RX to TX/TX to RX.
E S
IG N S
IF VCO
From TX RF Image Filter
3 4 5
RX IF BIAS VCC1 RX IF IN
Enable pin for the receiver 15dB gain IF amp and the RX VGA amp. Powers up all receiver functions when PD is high, turns off the receiver IF circuits when low. Also, see State Decode Table. When this pin is a logic "high", the device is in receive mode. When this pin is a logic "low", the device is in transmit mode. Shunt resistor of 23.71% to ground. Biases IF AMPS.
See pin 1.
50 strip
DC Block Pin 7
Pin 8
IF LO input. Must have DC-blocking cap. The capacitor value should be appropriate for the IF frequency. LO frequency=2xIF. Quad mod/demod phase accuracy requires low harmonic content from IF LO, so it is recommended to use an n=3 LPF between the IF VCO and IF LO. This is a high impedance input and the recommended matching approach is to simply add a 100 shunt resistor at this input to constrain the mismatch.
W
7 8 9
VCC9 TX VGC IF LO
Power supply for the TX 15dB gain amp and TX VGA. Gain control setting for the transmit VGA. Positive slope.
Recommended Matching Network for IF LO C2 150 pF IF LO
Pin 9
N E
100
FO
10 11 12
VCC8 VCC6 PA OUT
R
Power supply for IF LO buffer and quadrature phase network. Power supply for transmitter bias generator.
VCC
This is the output transistor of the power amp stage. It is an open collector output. The output match is formed by an inductor to VCC, which supplies DC and a series cap.
22 nF
CBYP
L C Power Amp Output
N O T
PA OUT
14 mA
PA IN Bias
Rev A6 040930
11-243
RF2948B
Pin 13 14 Function PA IN VCC5 Description
Input to the power amplifier stage. This is a 50 input. Requires DCblocking/tuning cap. Supply for the RF LO buffer, RF upconverter and amplifier.
Interface Schematic
See pin 12.
VCC
VCC CBYP 22 nF
CBYP 22 nF
To TX RF Image Filter
VCC5 From TX VGA
RF OUT
12 mA
VB
15 16 17
RF LO RF OUT IF1 OUT-
18
IF1 OUT+
19 20 21 22 23 24 25 26 27 28 29 30
TXI BP TXI DATA TXQ BP TXQ DATA VCC4 I OUT Q OUT
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. 700mVP-P linear output. Baseband analog signal output for quadrature channel. 700mVP-P linear output. 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 bandwidth 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.
N O T
VREF1 BUF DCFB I
DCFB Q
BW CTRL VCC2
11-244
FO
R
N E
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 VCC to IF1 OUT+.
D
Single-ended LO input for the transmit upconverter. External matching See pin 14. to 50 and a DC-block are required. Upconverted Transmit signal. This 50 output is intended to drive an See pin 14. RF filter to suppress the undesired sideband, harmonics, and other outof-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 IF1 OUT+ 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-.
E S
IG N S
From RF VCO CBLOCK 22 pF
RF LO
IF1 OUT-
See pin 17.
W
Rev A6 040930
RF2948B
Pin 31 32 Pkg Base Function VREF 1 RX VGC Description
This is a bypass pin for the bias circuits of the GmC filter amps and for I/Q inputs. No current should be drawn from this pin (<10A). 1.7V nominal. Receiver IF and baseband amp gain control voltage. Negative slope. Ground for all circuitry in the device. A very low inductance from the base to the PCB groundplane is essential for good performance. Use an array of vias immediately underneath the device. This diode structure is used to provide electrostatic discharge protection to 3kV using the Human body model. The following pins are protected: 1-4, 7, 8, 10, 19-32.
Interface Schematic
ESD
VCC
N O T
Rev A6 040930
FO
R
N E
W
D
E S
IG N S
11-245
RF2948B
State Decode Table Sleep Mode Receive Mode Transmit Mode NOTES BB_EN Enables:
TX_LPF's and buffers Baseband Amps and gm-C LPF's IF LO buffer/phase splitters
Input Pins PD RX EN 0 x 1 1 1 0
Internally Decoded Signals BB EN RXIF EN TXRF EN 0 0 0 1 1 0 1 0 1
RXIF_EN Enables:
Front-end IF amplifier (RX) RX IF VGA amplifiers
TXRF_EN Enables:
TX VGA PA driver
Front-end IF amplifier (TX) RF upconverter and buffer RF LO buffer
Quad Modulator mixers
N O T
11-246
FO
R
N E
W
D
E S
Rev A6 040930
IG N S
Quad Demodulator mixers
RF2948B
Detailed Functional Block Diagram
VREF1 BUF
BW CTRL
RX VGC
DCFB Q
VREF 1
DCFB I
32
31
30
29
28
27
26
25
BW Control
PD 1
RX EN 2
Logic
RX IF BIAS 3
REF
VCC1 4
E S
IG N S
DC Feedback
gm-C LPF
DC Feedback
gm-C LPF
Q OUT 24 I OUT 23 VCC4
gm-C LPF
VCC2
RX IF IN 5
D W
TX Bias
TX IF IN 6
22 TXQ DATA
VCC9 7
N E
21 TXQ BP
gm-C LPF
TX VGC 8
20 TXI DATA
R
/2
Phase Splitter
FO
19 TXI BP 18 IF1 OUT+
17 IF1 OUT11 VCC6 12 PA OUT 13 PA IN 14 VCC5 15 RF LO 16 RF OUT
N O T
IF LO
9
10 VCC8
Rev A6 040930
11-247
RF2948B
Theory of Operation
RECEIVER RX IF AGC/Mixer Being essentially high impedance, RX IF IN responds to the input voltage (rather than power), and amplifies that voltage by the gain specified in the datasheet, then presents the output voltage at a high impedance (after downconversion). For characterization purposes, a 50 shunt resistor is placed on the IF signal path, before AC-coupling to the input. A 50 signal source is applied directly across the shunt resistor, through a coaxial test lead. The signal source sees the shunt resistor and therefore a low SWR. Voltage gain is then simply the ratio of the output voltage to the input voltage. The front end of the IF AGC starts with a single-ended input and a constant gain amp of 15dB. This first amp stage sets the noise figure and input impedance of the IF section, and its output is taken differentially. The rest of the signal path is differential until the final baseband output, which is converted back to single-ended. Following the front end amp are multiple stages of variable gain differential amplifiers, giving the IF signal path a gain range of 4.0dB to 70.0dB. The noise figure (in max gain mode) of the IF amplifiers is 5dB, which should not degrade the system noise figure. The IF to BB mixers are double-balanced, differential in, differential out, mixers with negligible conversion gain. The LO for each of these mixers is shifted 90 so that the I and Q signals are separated in the mixers. RX Baseband Amps, Filters, and DC Feedback At baseband frequency, there are fully integrated gm-C low pass filters to further filter out-of-band signals and spurs that get through the SAW filter, anti-alias the signal prior to the A/D converter, and to band-limit the signal and noise to achieve optimal signal-to-noise ratio. The 3dB cut-off frequency of these low pass filters is programmable with a single external resistor, and continuously variable from 1MHz to 35MHz. A five-pole Bessel type filter response was chosen because it is optimal for data systems due to its flat delay response and clean step response. Butterworth and Chebychev type filters ring when given a step input making them less ideal for data systems. The filter outputs drive the linear 700mVPP signal off-chip. DC feedback is built into the baseband amplifier section to correct for input offsets. Large DC offsets can arise when a mixer LO leaks to the mixer input and then mixes with itself. DC offsets can also result from random transistor mismatches. A large external capacitor is needed for the DC feedback to set the high pass cutoff. LO INPUT BUFFERS RF LO Buffer The RF LO input has a limiting amplifier before the mixer on both the RF2494 (RX) and RF2948B (TX). This limiting amplifier design and layout is identical on both ICs, which will make the input impedance the same as well. Having this amplifier between the VCO and mixer minimizes any reverse effect the mixer has on the VCO, expands the range of acceptable LO input levels, and holds the LO input impedance constant when switching between RX and TX. The LO input power range is -18dBm to +5dBm, which should make it easy to interface to any VCO and frequency synthesizer. IF LO Buffer The IF LO input has a limiting amplifier before the phase splitting network to amplify the signal and help isolate the VCO from the IC. Also, the LO input signal must be twice the desired intermediate frequency. This simplifies the quadrature network and helps reduce the LO leakage onto the RX_IF input pin (since the LO input is now at a different frequency than the IF). The amplitude of this input needs to be between -15dBm and 0dBm. Excessive IF LO harmonic content affects phase balance of the modulator and demodulator so it is recommended that IF LO harmonics be kept below -30dBc.
N O T
11-248
FO
R
N E
W
D
E S
IG N S
Rev A6 040930
RF2948B
TRANSMITTER TX LPF and Mixers The transmit section starts with a pair of 5-pole Bessel filters identical to the filters in the receive section and with the same 3dB frequency. These filters pre-shape and band-limit the digital or analog input signals prior to the first upconversion to IF. These filters have a high input impedance and expect an input signal of 100mVPP typical. Following these low pass filters are the I/Q quadrature upconverter mixers. Each of these mixers is half the size and half the current of the RF to IF downconverter on the RF2494. Recall that this upconverted signal may drive the same SAW filter (in half-duplex mode) as the RF2494 and therefore share the same load. Having the sum of the two BB to IF mixers equal in size and DC current to the RF to IF mixer, will minimize the time required to switch between RX and TX, and will facilitate the best impedance match to the filter. TX VGA Being essentially high impedance, TX IF IN responds to the input voltage (rather than power), and amplifies that voltage by the gain specified in the datasheet, then presents the output voltage at a 50 impedance (after upconversion). For characterization purposes, a 50 shunt resistor is placed on the IF signal path, before AC-coupling to the input. A 50 signal source is applied directly across the shunt resistor, through a coaxial test lead. The signal source sees the shunt resistor and therefore a low SWR. Voltage gain is then the same as power gain, simply the difference in dB between the output power and the input power. The AGC after the SAW filter starts with a switch and a constant gain amplifier of 15dB, which is identical to the circuitry on the receive IF AGC. This was done so that the input impedance will remain constant for different gain control voltages. Following this 15dB gain amplifier is a single stage of gain control offering 15dB gain range. The main purpose of adding this variable gain is to give the system the flexibility to use different SAW filters and image filters with different insertion loss values. This gain could also be adjusted real time, if desired. TX Upconverter The IF to RF upconverter is a double-balanced differential mixer with a differential to single-ended converter on the output to supply 0dBm peak linear power to the image filter. The upconverted SSB signal should have -6dBm power at this point, and the image will have the same power, but due to the correlated nature of the signal and image, the output must support 0dBm of linear power to maintain linearly. +6dBm PA Driver The SSB output of the upconverter is -6dBm of linear power. The image filter should have at most 4dB of insertion loss while removing the image, LO, 2LO and any other spurs. The filter output should supply the PA driver input -10dBm of power. The PA driver is a one-stage class A amplifier with 10dB gain and capable of delivering 6dBm of linear power to a 50 load, and has a 1dB compression point of 12dBm. For lower power applications, this PA driver can be used to drive a 50 antenna directly.
N O T
Rev A6 040930
FO
R
N E
W
D
E S
IG N S
11-249
RF2948B
RF Micro Devices 2.4 GHz ISM Chipset
IL = 1-3 dB 2.4 to 2.483 GHz
RX VGC
RF2948B
RF2494 SSOP-16 EPP
Gain Select OUT Q
SAW
IL = 10 dB max
RX
LNA Dual Gain Modes
RX IF Amp TX
OUT I
Filter
2.4 to 2.483 GHz Base Band Amp. Active Selectable LPF (fC = 1 MHz to 40 MHz)
TX
T/R Switch
Dual Frequency Synthesizer
RF VCO IF VCO x2
IG N S
+45 -45
Filter
I INPUT
RF2189
E S
10 dBm PA Driver
Filter
Selectable LPF Q INPUT
TX VGC
N O T
11-250
FO
R
N E
W
Figure 1. Entire Chipset Functional Block Diagram
D
IL = 1-3 dB 2.4 to 2.483 GHz
Rev A6 040930
RF3000
RF2948B
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
R43 10 VCC C68 100 pF VREF1 BUF C65 10 nF R42 10 k C58 22 nF C57 22 nF J2 Q OUT RX VGC 32 PD C72 10 nF VCC R1 51 J1 X/TX IF IN R10* 0 C77 100 pF C76 100 pF R49 10 C73 100 pF RX/TX EN 1 2 3 4 5 6 VCC R56 130 R61 220 R9 0 C74 10 nF J11 IF LO R11* 0 R62 51 50 strip R32 47 J6 IF OUT VCC C70 100 pF VCC P1 C24 10 nF P1-2 P1-3 C82 100 pF 1 2 3 CON3 P3-1 GND VCC TX VGC P3 1 J10 PA OUT VREF1 BUF 50 strip R27 10 C69 10 nF R28* 270 k TX VGC 7 8 9 10 11 12 13 14 15 16 31 30 29 28 27 26 25 24 23 22 J4 TXQ DATA C47 1 nF VCC C52 10 nF J3 I OUT
R44 23.7k, 1%
IG N S
21 20 19 18 17 C48 1 nF C90 5 pF L16 3.9 nH R48 10 VCC C54 22 pF R45 47 50 strip R5 0 R6* 0 J7 RF OUT
J5 TXI DATA
C91 5 pF L14 33 nH
R54 10 VCC C43 1 nF
E S
C40 22 pF
R39 2.2 k
VCC
L15 27 nH IN
C44 12 pF FL2 374 MHz
C60 10 nF 50 strip
C50 3 pF
GND OUT L12 33 nH
GND 2 CON2 C12 10 nF P2-2 P2-3 C20 10 nF P2-4 C19 100 pF P2 1 2 3 GND RX/TX EN PD
W
Populate R11 R10 Unpopulate Changes R62 N/A R9, R61 R56 to 0
D
C40 22 pF C95 22 pF 50 strip R7 0 OUT R8* 0 50 strip J9 PA IN
J8 RF LO
IN
GND
RX VGC 4 CON4
TX Upconverter
N O T
Rev A6 040930
FO
R
N E
*Configured for RX Demod and TX Cascaded Evaluation Evaluate TX Mod Out
11-251
RF2948B
Evaluation Board Layout Board Size 2.2" x 2.1"
Board Thickness 0.031", Board Material FR-4, Multi-Layer
N O T
11-252
FO
R
N E
W
D
E S
Rev A6 040930
IG N S
RF2948B
RX Voltage Gain versus VGC and VCC (Temp=25oC; RX IF
75.00 70.00 65.00 60.00 55.00 50.00 45.00 40.0 39.5 39.0 38.5 38.0 37.5 37.0 36.5 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 Gain, 25C Gain, 85C
RX Gain versus IF LO Amplitude and Temp (VCC=3V; RX
VGC=1.6V; RX IF IN=375MHz, I and Q OUT~650mVP-P; IF LO=748MHz)
41.5 41.0 40.5
IN=375MHz; I and Q out 300mVP-P IF LO=748MHz @ -10dBm)
Gain, 2.7V Gain, 3V Gain, 3.3V
Gain (dB)
40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 -5.00 1.20
Gain (dB)
-30.0
IG N S
-25.0 -20.0 -15.0 -10.0
Gain, -40C
-5.0
0.0
5.0
RX VGC (VDC)
RX IQ Amplitude and Phase Error versus IF LO Amplitude and Temp
(VCC=3V; RX VGC=1.6V; RX IF IN=375MHz, I&Q OUT~650mVP-P; IF LO=748MHz)
LO Ampl. (dBm)
E S
1400.0 1350.0 1300.0 1250.0 1200.0 1150.0 1100.0 1050.0 1000.0 950.0 900.0 850.0 800.0
RX OP1dB versus VGC and Temp (VCC = 3 V; RX IFIN = 375
MHz; IF LO = 748 MHz at -10 dBm)
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -30.0 -25.0 -20.0 Ampl. Err, 25C Ampl. Err, 85C Ampl. Err, -40C Phase Err, 25C Phase Err, 85C Phase Err, -40C
5
4.5
Amplitude Error (dB)
N E R
W
2.5 2 1.5 1 0.5 0
3
VOUT (mVP-P)
D
4 3.5
750.0 700.0 650.0 600.0 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
-15.0
-10.0
-5.0
0.0
5.0
FO
LO Amplitude (dBm)
RX VGC (VDC)
RX 3dB BW versus RBW (Temp=Ambient, VCC=3.15V, VGC=1.6V,
30.0 RX IFIN =-67dBm, IF LO=560MHz@-10dBm)
TX 3dB BW Point versus RBW (Broadband 50 match on IFOUT, Temp=Ambient,
VCC=3.15V, GCTX=1.5V, I&Qin=100mVP-P, IFLO=560MHz@-10dBm)
50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0
3 dB BW Point [MHz]
N O T
25.0
20.0
15.0
10.0
5.0 5.0 0.0 1.0 10.0 100.0 1000.0 0.0 1.0 10.0 100.0 1000.0
RBW [k]
3dB BW Point [MHz]
RBW [k]
Rev A6 040930
11-253
RF2948B
Modulator Amplitude Error and Image Suppression versus IF LO Amplitude and Temp (VCC=3V; IF LO=748MHz; IQ IN=1MHz @ 100mVP-P)
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -30.0 -26.0 -22.0 -18.0 -14.0 -10.0 -6.0 -2.0 2.0 Ampl.Err, 25C Ampl. Err, 85C Ampl. Err, -40C Image Supp, 25C Image Supp, 85C Image Supp, -40C
60.0
Modulator LO Suppression versus IF LO Amplitude and Temp (VCC=3V; IF LO=748MHz; IQ IN=1 MHz @ 100mVP-P)
28.0 LO Supp, 25C
54.0
27.5 LO Supp, 85C 27.0 26.5 LO Supp, -40C
48.0
Amplitude Error (dB)
42.0
LO Supp (dBc)
36.0
26.0 25.5 25.0 24.5 24.0 23.5 23.0 -30.0
30.0
24.0
12.0
6.0
0.0
6.0
IG N S
-26.0 -22.0 -18.0 -14.0 -10.0 -6.0
18.0
-2.0
2.0
6.0
LO Amplitude (dBm)
LO Ampl (dBm)
TX IF IN=374MHz @ -35dBm, RF LO=2068MHz @ -5dBm)
14.0 13.0 12.0 11.0 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 -6.0 0.2 0.4 0.6 0.8 1.0 Gain, 2.7V Gain, 3V Gain, 3.3V
Gain (dB)
W N E
Gain (dB)
D
2.0 0.0 -2.0 -4.0 -6.0 -8.0 -10.0 -12.0 -14.0 -16.0 -18.0 -20.0 -22.0 1.8 2.0 2.2 2.4 -26.0 -22.0 -18.0 -14.0 -10.0 -6.0 -2.0 2.0 6.0 Gain, 25C Gain, 85C Gain, -40C
FO
R
1.2
1.4
1.6
E S
8.0 6.0 4.0 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 OP1dB, 2.7V OP1dB, 3V OP1dB, 3.3V
Upconverter Voltage Gain versus VGC and VCC (Temp=25oC;
Upconverter Voltage Gain versus RF LO Amplitude and Temp (VCC=3V; TX VGC=1.6V; TX IF IN=374MHz@-35dBm, RF LO=2068MHz)
TX VGC (VDC)
LO Amplitude (dBm)
Upconverter Output P1dB versus RF LO Amplitude and Temp (VCC=3V; TX VGC=1.6V; TX IF IN=374MHz, RF LO=2068MHz)
0.0 -2.0
Upconverter Output P1dB versus VGC and VCC (Temp=25oC;
TX IF IN=374MHz, RF LO=2068MHz @ -5dBm)
N O T
-4.0 -6.0 -8.0
OP1dB (dBm)
OP1dB, 25C OP1dB, 85C OP1dB, -40C -14.0 -10.0 -6.0 -2.0 2.0 6.0
-10.0 -12.0 -14.0 -16.0 -18.0 -20.0 -22.0 -24.0 -26.0
-5.0 -5.5 -6.0 -6.5 -7.0 -7.5 -8.0 -8.5 -9.0 -9.5 -10.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Gain (dB)
-26.0
-22.0
-18.0
LO Amplitude (dBm)
TX VGC (VDC)
11-254
Rev A6 040930
RF2948B
PA Gain versus VCC and Temp
10.1 10.0 9.9 9.8 9.7 9.6 9.5 9.4 9.3 9.2 9.1 9.0 8.9 8.8 8.7 8.6 8.5 8.4 8.3 8.2 8.1 8.0 2.7
PA Output P1dB versus VCC and Temp
15.0 14.5 14.0 13.5 13.0
(PA IN=2442MHz @ -30dBm)
(PA IN=2442MHz)
OP1dB (dBm)
Gain (dB)
12.5 12.0 11.5 11.0 10.5
Gain, 25C Gain, 85C Gain, -40C 3.0 3.3
IG N S
3.0
10.0 9.5 9.0
OP1dB, 25C OP1dB, 85C OP1dB, -40C 3.3
2.7
VCC (VDC)
VCC (VDC)
N O T
Rev A6 040930
FO
R
N E
W
D
E S
11-255
RF2948B
N O T
11-256
FO
R
N E
W
D
E S
Rev A6 040930
IG N S

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