Texas Instruments TRF3703 User manual

TRF3703 Quadrature ModulatorEvaluation Module
User's Guide
December 2006 Wireless Infrastructure Radio
SLWU042A

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Contents
1 Overview ................................................................................................................... 51.1 Purpose............................................................................................................ 51.2 EVM Circuit Overview ........................................................................................... 51.3 Power Requirements ............................................................................................ 51.4 TRF3703 EVM Operating Procedure .......................................................................... 62 Physical Description .................................................................................................. 112.1 PCB Layout ...................................................................................................... 112.2 Parts List ......................................................................................................... 183 Circuit Description ..................................................................................................... 183.1 Circuit Function ................................................................................................. 184 Circuit Board ............................................................................................................ 195 Schematic ................................................................................................................ 20
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List of Figures
1 Un-Optimized Sideband Suppression ..................................................................................... 72 Optimized Sideband Suppression ......................................................................................... 83 GSM EDGE EVM at 1800 MHz ............................................................................................ 94 1.5-V Interface Network for 19.2 mA Full Scale ........................................................................ 105 3.3-V Interface Network for 19.2 mA Full Scale ........................................................................ 106 Top Layer .................................................................................................................... 117 Top Layer–NH .............................................................................................................. 128 Ground Plane L2 ........................................................................................................... 139 Ground Plane L3 ........................................................................................................... 1410 Layer 4—Bottom Layer .................................................................................................... 1511 Layer 4—Bottom Layer–NH............................................................................................... 1612 Drill Pattern .................................................................................................................. 1713 Silkscreen Top Layer ...................................................................................................... 1914 TRF3703 EVM Schematic ................................................................................................ 20
List of Tables
1 Bill of Materials for TRF3703 EVM ....................................................................................... 182 Power Supply J1 ........................................................................................................... 18
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1 Overview
1.1 Purpose
1.2 EVM Circuit Overview
1.3 Power Requirements
User's GuideSLWU042A – October 2006 – Revised December 2006
TRF3703 Quadrature Modulator Evaluation Module
This document relates to the TRF3703-33 and TRF3703-15 (hereinafter referred to as TRF3703) directquadrature modulator for applications in the transmit path of base stations and communicationsequipment. The TRF3703 operates between 400 MHz and 4 GHz. The quadrature modulator is used forupconversion of signals from the transmit chain DAC to the RF power amplifier device. Evaluatingmodulator complex performance involves careful bias-voltage setup, an LO signal, and two differential(I/Q) signals at the input of the modulator. This document describes the wide range of test optionsavailable and the factors that must be considered in using this EVM.
The TRF3703 evaluation module (EVM) is intended for the evaluation of the TRF3703-33 andTRF3703-15 direct-launch quadrature modulators. Unless otherwise stated, the functionality described inthis manual applies to both the TRF3703-33 and TRF3703-15 devices.
The EVM comes configured for differential I/Q input signals via four SMA connectors as shown in theschematic, Figure 14 , and Table 1- 1.
The I signals are connected to J4 (I+) and J3 (I–). The Q signals are connected to J5 (Q+) and J6 (Q–).The LO signal is fed to SAM connectorr J1, while J2 must be terminated with 50 Ωto ground. SMAconnector J3 is used to monitor the RF output signal from the quadrature modulator (U1).
The quadrature modulator requires a supply voltage of 4.5 V–5.5V at 235 mA from a regulated powersupply through headers W1 and W2. The TRF3703-33 requires a 235 mA current limit, whereas theTRF3703-15 requires 205 mA.
The TRF3703-33 and TRF3703-15 quadrature modulators require a dc common-mode bias voltage (3.3VDC and 1.5 VDC, respectively) on all four input pins.
The TRF3703 EVM requires two 5-V V
CC
dc power-supply connectors through headers W1 and W2.Header W1 supplies 5 V to the LO circuitry, and W2 supplies 5 V to the modulator circuitry.
CAUTION
Voltage Limits
Exceeding 5.6 V may damage the TRF3703.
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1.4 TRF3703 EVM Operating Procedure
1.4.1 Typical Test Results
1.4.1.1 Un-Optimized Sideband Suppression
Overview
Set up the EVM as follows:1. Power-supply connection:a. Switch on the V
CC
(5-V) supply and set the current limit set to 235 mA.b. Connect the 5-V supply to headers W1 and W2.c. Verify that the current drawn is approximately ≤205 mA for the TRF3703-15 and ≤235 mA for theTRF3703-33.
2. Use a suitable 50- Ωoutput signal generator (LO = ±5 dBm) or the TRF3761 to supply the LO signal atdesired frequency to J1, and terminate J2 with 50 Ωto ground.3. Use a DAC or an arbitrary waveform generator to provide the I/Q input signals. A typical setup is asfollows: a 1-Vp-p sine wave, a frequency of 50 KHz, a dc-offset of 0 V, and an output impedance of50 Ω(typically an ESG vector signal generator or similar).4. Set the common mode on the ESG to either 1.65 V or 0.75 V, depending on device type (set to 1.65 Vfor the TRF3703-33, set to 0.75 V for the TRF3703-15).5. Use an arbitrary waveform generator to suppress the sideband. Adjust the I/Q amplitude and phase ofthe CW signal coming from the arbitrary waveform generator.6. Connect a spectrum analyzer to the SMA connector marked RFOUT (J7) and monitor the TRF3703output.
measures the amount by which the unwanted sideband of the input signal is attenuated in the output ofthe modulator, relative to the wanted sideband. This assumes that the baseband inputs delivered to themodulator input pins are perfectly matched in amplitude and are exactly 90 °out of phase. Un-optimizedsideband suppression is measured in dBc. An iterative test is required in order to match perfectly theinputs to the modulator. This ensures that any equipment, board, or signal conditioning componentimbalances are corrected before the signals are applied to the device under test. Once the basebandinputs to the modulator are balanced, the amount of suppression attained is a measure of the internalmismatches of the modulator, inherent to any modulator design. This suppression is the one specified inthe TRF3703 datasheet. See Figure 1 .
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C003
1.4.1.2 Optimized Sideband Supression
Overview
Figure 1. Un-Optimized Sideband Suppression
There are two ways to change the sideband suppression of the TRF3703. One is the amplitude betweenthe four inputs, and the second is the phase of the four inputs. The ideal condition is when all four inputs(I, I, Q, and Q) have exactly the same amplitude and the phase relationship is: I = 0 °, I = 180 °, Q = 90 °,and Q = 270 °. Also, the optimization of the sideband is controlled by the amplitude and phase of the I andQ signals, which are controlled with the gain settings of the DAC. This is an iterative procedure that resultsin optimized suppression levels that exceeds 60 dBc. The level of suppression observed depends on theamount of resolution available from the DAC driving the modulator. By using TI’s DAC568X, the user cantake advantage of built-in features (DAC fine gain) to optimize the sideband suppression by changing theamplitude relationship of the signals. If another DAC is used, then the user must provide this level ofadjustment by controlling the regular digital inputs to the DAC. See Figure 2 .
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C002
1.4.1.3 Carrier Feedthrough
1.4.1.4 GSM (EDGE EVM Measurements)
Overview
Figure 2. Optimized Sideband Suppression
Carrier feedthrough is the amount of the LO that leaks onto the output spectrum of the modulator. Ideallyfor the TRF3703, inputs (I, I, Q, and Q) must be at approximately 3.3 V for TRF3703-33 and 1.5 V forTRF3703-15. The DAC dc settings are also useful to correct the dc mismatch between I and I andbetween Q and Q to correct for the LO feedthrough. If using TI's DAC568X, then the internal controls forthe IQ offsets provide excellent carrier suppression (very low LO leakage). Alternatively,if an ESG is beingused, adjust the I and Q voltage offsets in mV steps until you obtain the minimum carrier feedthrough. Atypical carrier feedthrough value exceeds 50 dBm. See Figure 2 .
1. Provide a GSM edge signal of the desired frequency into the differential baseband inputs (examplesample rate = 4.33 MHz).2. Use a spectrum analyzer with edge personality to measure the transmit power to either 0 or –5 dBm.3. PSA: Mode →GSM(w/ EDGE) →measure →Transmit Pwr(usually 0 or –5 dBm) →more →EDGEEVM.
4. ESG: Mode setup →select waveform →highlight EDGE →select waveform →ARB setup →type4.33333 MHz →I/Q →I/Q output control →Common mode I/Q offset →(set to either 1.65 V forTRF3703-33 or to 0.75 V for TRF3703-15) →I/Q →I/Q output control →I/Q output atten (adjust to getdesired transmit power to either 0 or –5 dBm).See Figure 3 .
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C001
1.4.2 Interface to TI's DAC
Overview
Figure 3. GSM EDGE EVM at 1800 MHz
Both the TRF3703-33 and the TRF3703-15 work well with TI's DACs. The TRF3703-33 is well suited towork with TI's DAC568X family, and the TRF3703-15 is well suited to work with TI's DAC56X2 series.Each DAC series is optimized to work at certain common-mode voltage. The DAC568X has acommon-mode of 3.3 V, while the DAC56X2 has a 0.7-V common-mode voltage. Figure 1 shows aninterface network to interfgace both DAC series to the TRF3703.
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DAC56x2 TRF3703-15
I I
Q
S0225-01
Q
II
QQ
R2
R2
R2
R2
5 V
5 V
R1
R1
R3
R3
R1
R1
R3
R3
DAC568x TRF3703-33
I I
S0226-01
II
R5
R5
5 V
5 V
R6
R1
R1
R3
R3
Overview
TYPICAL VALUES
R1 R2 R3
53 Ω210 Ω931 Ω
NOTE: A DAC interface calculator is available (SLWC083 ).
Figure 4. 1.5-V Interface Network for 19.2 mA Full Scale
LOSS 1 dB 2 dB 3 dB 4 dB 5 dB
Pullup R1 115 115 115 115 115Pulldown R3 634 634 634 634 634Series R5 11 21 30 37.4 45.3Shunt R6 187 165 147 130 118
Figure 5. 3.3-V Interface Network for 19.2 mA Full Scale
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2 Physical Description
2.1 PCB Layout
K001
Physical Description
This chapter discusses the four-layer PCB layout, component placement, and list of components used onthe evaluation module.
The EVM is constructed on a four-layer, 38,1-mm ×38,1-mm ×1,579-mm thick PCB using FR-4 material.Figure 6 through Figure 12 show the individual layers.
Figure 6. Top Layer
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K002
Physical Description
Figure 7. Top Layer–NH
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K003
Physical Description
Figure 8. Ground Plane L2
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K004
Physical Description
Figure 9. Ground Plane L3
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K005
Physical Description
Figure 10. Layer 4—Bottom Layer
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K006
Physical Description
Figure 11. Layer 4—Bottom Layer–NH
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22
72
156
4
254
10 mil
12 mil
13 mil
37 mil
Total
0.254 mm
0.3048 mm
0.3302 mm
0.9398 mm
PTH
PTH
PTH
PTH
D001
Physical Description
Figure 12. Drill Pattern
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2.2 Parts List
3 Circuit Description
3.1 Circuit Function
3.1.1 Power
Circuit Description
Table 1. Bill of Materials for TRF3703 EVM
Value Footprint QTY Part Number Vendor Digi-Key Number REF DES Not
Installed
Tantalum 4.7- µF, 3216 2 T491A475K010AS KEMET 399-1561-1-ND C6, C710-V, 10%capacitor
1000-pF, 50-V, 603 2 ECJ-1VC1H102J Panasonic PCC2151CT-ND C4, C55% capacitor
100-pF, 50-V, 5% 603 3 ECJ-1VC1H101J Panasonic PCC101ACVCT-ND C1, C2, C3capacitor
Capacitor 603 0 C8, C90- Ωresistor, 603 5 ERJ-3GEY0R00V Panasonic P0.0GCT-ND R1, R2,1/10-W, 5% R3, R4, R5TRF3703 24-QFN-PP- 1 TI U14X4MMSMA connectors SMA_END_ 6 16F3627 Newark 142-0711-821 J1, J2, J3,SMALL J4, J5, J6,J72POS_HEADER 2POS_JUMP 2 HTSW-150-07-L-S SAMTEC N/A W1, W2
This chapter discusses the various functions of the EVM.
•Headers W1 and W2 supply 5-V V
CC
dc power to the modulator. Header W1 supplies 5 V to the LOcircuitry, and W2 supplies 5 V to the modulator circuitry.•Four SMA connectors are provided on the EVM for inputting differential I/Q signals directly to the inputpins of the TRF3703. Connectors J3, J4, J5, and J6 are used to connect the signal source I/Q signalsdirectly to the TRF3703.•Two SMA connectors are provided for LO input: J1 = LOP and J2 = LON. Terminate whichever LOport is not being used through 50 Ωto ground.•One SMA connector is for RF_OUT: J7.
Table 2. Power Supply J1
J1 Pin Description
W1 5-V (V
CC
), U1 analog supplyW2 5-V (V
CC
), U1 analog supply
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4 Circuit Board
BBQP BBQN
+5 V
BBIPBBIN
LOP
LON
+5 V
GND GND
50 W
RF_OUT
K001
Circuit Board
This chapter shows the circuit board test points.
Figure 13. Silkscreen Top Layer
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5 Schematic
C1
100 pF
C2
100 pF
1
J1
SMA_END NC
1
GND
2
LOP
3
LON
4
GND
5
NC
6
NC
7
GND
8
QN
9
QP
10
GND
11
GND
12
NC 13
GND 14
NC 15
RFOUT 16
GND 17
VCCMOD 18
GND19 GND 20
IP21
IN 22
GND23
VCCLO 24
LOP
1
22 33 44 55
J2
SMA_END
LON
1
2 3 4 5
J3
SMA_END
IN
1
2 3 4 5
J4
SMA_END
IP
C5
1000 pF
1
2 3 4 5
J7
SMA_END
C3
100 pF
C4
1000 pF
1
2
3 4 5
J5
SMA_END
QN
1
2
3 4 5
J6
SMA_END
QP
RF_OUT
W1
2POS_JUMPER
W2
2POS_JUMPER
C8 C9
R1
0
+
C6
+
C7
4.7uF
R4
0
R5
0
R2
0
R3
0
S0214-01
0.1 F
(Note 1)
m0.1 F
(Note 1)
m
4.7 Fm
U1
TRF3703
Schematic
This chapter shows the EVM schematic.
(1) Do not install.
Figure 14. TRF3703 EVM Schematic
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