RF2942 0 UHF QUADRATURE MODULATOR AND TRANSMITTER Typical Applications • 915MHz ISM Band Products • Quadrature Modulation • Digital Communications • Portable Battery-Powered Equipment Product Description 2 PLCS 0.25 C A -A- The RF2942 is an integrated power amplifier and quadrature modulator IC. The quadrature modulator is driven with a single-ended local oscillator (LO) source. The quadrature phase generation of the LO is accomplished using an internal passive network tuned for twice the operating frequency. The LO frequency is at twice the RF frequency to avoid interfering with an external synthesizer. 2.00 TYP 2 PLCS Dimensions in mm. 12° MAX 0.20 C B 2 PLCS 1.88 TYP -B- -C- 1.85 SQ. 1.55 0.23 0.13 4 PLCS 0.65 GaAs MESFET Si Bi-CMOS SiGe HBT Si CMOS InGaP/HBT GaN HEMT 9SiGe Bi-CMOS Shaded lead is pin 1. 0.35 0.23 0.65 0.30 4 PLCS GaAs HBT SEATING PLANE 3.75 SQ. 2 PLCS 0.20 C A 0.10 M C A B Si BJT 0.05 0.01 0.80 0.65 0.25 C B 0.60 0.24 TYP Optimum Technology Matching® Applied 0.05 C 1.00 0.85 4.00 SQ. 0.75 0.50 Package Style: QFN, 16-Pin, 4x4 Features • 2.0V to 3.6V Power Supply I DATA+ I DATA- TX EN • 902MHz to 928MHz Frequency Range 4 3 12 • 200mW Output Power • Low LO Input Level • Low Broadband Noise Floor • Small Footprint LO IN+ 14 +45° -45° ÷2 Σ 9 RF OUT LO2 OUT 15 1 Q DATA- Q DATA+ 2 Functional Block Diagram Rev A4 040115 Ordering Information RF2942 RF2942 PCBA UHF Quadrature Modulator and Transmitter 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 11-195 RF2942 Absolute Maximum Ratings Parameter Supply Voltage Power Down Voltage (VPD) Input LO and RF Levels Operating Ambient Temperature Storage Temperature Parameter Rating Unit -0.5 to +3.6 VCC +0.4 +6 -40 to +85 -40 to +150 VDC VDC dBm °C °C Specification Min. Typ. Max. 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). Unit Condition Power Supply Voltage Current 2.8 2.0 170 10 225 -15 1800 to 1860 -6 50 3.6 260 24 V V mA mA Carrier Input (LO IN) Frequency Range Power Level Input Impedance MHz dBm Ω Specifications Operating limits TXEN=0.0V T=25 °C, VCC =2.8V 1830MHz Modulation Input Frequency Range Modulation for POUT Power (I & Q) Quadrature Phase Error I/Q Amplitude Imbalance Input Impedance DC 2 400 10 MHz mVP-P +2 0.2 >10 +5 ° dB kΩ RF Output Power Output Second Harmonic Output Third Harmonic Output Sideband Suppression Carrier Suppression Broadband Noise Floor 11-196 21 -20 -35 -25 -25 23 22 -25 -45 -40 -90 27 dBm dBm dBc dBc dBc dBc 50Ω source, I,Q=400mVp-p Differential T=25°C, VCC =2.8V, LO power=-6dBm, SSB, I/Q=400mVP-P sine wave, 500kHz VCC =3.0V VCC =2.8V Modulation DC offset can be externally adjusted for optimum suppression. Carrier suppression is then typically better than 40dB. dBm/Hz Rev A4 040115 RF2942 Pin 1 Function QSIG- Description Reference voltage for the I and Q mixer. This voltage should be the same as the DC voltage supplied to the I and Q SIG pin. To obtain a carrier suppression of better than 40dB it may be tuned ±0.15V (relative to the I and Q SIG DC voltage). Without tuning, the carrier suppression will typically be better than 25dB. The input impedance of this pin is typically >10 kΩ. Interface Schematic DATA+ DATA BIAS 2 3 4 QSIG+ ISIGISIG+ 5 6 7 8 9 N/C GND PA VCC N/C RF OUT 10 11 12 N/C VCC3 TX EN 13 14 VCC1 LO IN Same as pin 1, except complementary input. See pin 1. Same as pin 4, except complementary input. See pin 1. This pin is used to supply Vcc to the modulator circuits. A RF bypass capacitor should be connected directly to this and ground. Baseband input to the I mixer. A DC bias of approximately 1.2V is present at this pin.A DC blocking capacitor is needed if the signal has a different DC level. Maximum output power is obtained when the input signal has a peak to peak amplitude of 1V. The input impedance of this pin is about 3 kΩ. The SIG- and SIG+ inputs are interchangeable. If swapping the I SIG+ and I SIG- pins, the Q SIG+ and Q SIG- also need to be swapped to maintain the correct phase. The SIG+ and SIG- pins may be driven differentially for BPSK to increase conversion gain. No connection. See pin 1. Voltage supply for PA driver. No connection. Power Amp output, open collector output. VCC3 RF OUT No connection. Voltage supply for PA buffer. TX enabled when >2.0V. When TX EN is held low, only the LO buffer, LO divider and LO divider buffer are left on. To power all of the circuitry down, TX EN and VCC1 must be held low. Voltage supply for LO buffer and divider. The LO input level should be greater than -15dBm for proper operation. LO IN+ LO IN- BIAS 15 16 LO/2 OUT VCC2 Rev A4 040115 LO divide-by-2 output. Voltage supply for mixers. 11-197 RF2942 11-198 VCC2 LO DIV2 LO IN VCC1 Pin Out 16 15 14 13 QSIG- 1 12 TX EN QSIG+ 2 11 VCC3 5 6 7 8 NC 9 RF OUT PA VCC ISIG+ 4 PA GND 10 NC NC ISIG- 3 Rev A4 040115 RF2942 Theory of Operation Modulator The modulator is a direct conversion double balanced quadrature mixer architecture. The local oscillator signal is buffered then split with internal phase shifters that are optimized for twice the operating frequency. The LO buffer provides isolation from load changes that may occur as the power amplifier section is turned on and off. In addition, the LO buffer may be left on when the transmit section is turned off to prevent load pulling of the external oscillator, by holding TX EN low and leaving the bias on VCC1. The baseband I and Q pins are connected to the internal mixer bias, therefore it is recommended that the modulation signal be DC-blocked if a similar external reference voltage cannot be provided. The baseband drive may be either single-ended with the complementary input AC-grounded with a capacitor or driven differentially. Power Amplifier The power amplifier requires matching on the output (RF OUT) and the interstage transistor (PA VCC). Rev A4 040115 11-199 RF2942 Evaluation Board Schematic - 915MHz (Download Bill of Materials from www.rfmd.com). VCC2 C22 22nF R1 15 kΩ VCC1 J1 LO DIV2 J2 LO VCC5 J4 Q SIG- C21 22 pF C1 0.1 nF R2 10 kΩ R3 15 kΩ VCC5 J5 Q SIG+ C2 0.1 nF R4 10 kΩ L5 18 nH R5 15 kΩ C17 22 nF C19 22 pF C20 5.0 pF L4 6.8 nH C18 0.5 pF C16 22 pF VCC5 J6 I SIG- C3 0.1 nF TX EN 16 R6 10 kΩ R7 15 kΩ 15 14 13 1 12 2 11 VCC5 J7 I SIG+ C4 0.1 nF 3 10 4 9 R8 10 kΩ 1 VCC2 2 GND CON2 P3-1 P3-3 P2 P2-1 1 VCC3 2 GND 3 CON3 1 PA VCC 2 GND VCC4 P5-1 P4 P4-1 CON2 P4-3 6 7 L1 5.6 nH P3 P1 P1-1 5 1 VCC1 2 GND 3 TX EN R9 160 Ω C5 22 pF P5 1 VCC5 2 GND CON2 8 C14 22 pF C15 22 nF C11 22 pF C12 22 nF VCC3 L3 3.3 nH C10 22 pF C9 5 pF L2 56 nH J3 RF OUT R10 2Ω VCC4 C7 22 pF C8 22 nF C6 22 nF PA VCC CON3 11-200 Rev A4 040115 RF2942 Evaluation Board Layout Board Size 1.4” x 1.5” Board Thickness 0.032”, Board Material FR-4, Multi-Layer Rev A4 040115 11-201 RF2942 Graphs Unless swept, the conditions for the subsequent graphs are as follows. All cable losses accounted for in measurements. VCC=2.8V LO Frequency=1830MHz LO Amplitude=-6dBm I/Q Frequency=1MHz I/Q Amplitude=400mVP-P I/Q Phase=90° POUT versus VCC Over Temperature POUT versus LO Amplitude Over Temperature 30.0 25.0 -40.0°C 25.0°C 85.0°C 29.0 -40.0°C 25.0°C 85.0°C 24.5 28.0 27.0 24.0 26.0 23.5 24.0 POUT (dBm) POUT (dBm) 25.0 23.0 22.0 21.0 23.0 22.5 22.0 20.0 21.5 19.0 18.0 21.0 17.0 20.5 16.0 15.0 20.0 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 -15.0 POUT versus LO Frequency Over Temperature -3.0 0.0 24.0 24.0 23.5 23.5 23.0 23.0 22.5 22.0 22.5 22.0 21.5 21.5 21.0 21.0 20.5 20.5 20.0 -40.0°C 25.0°C 85.0°C 24.5 POUT (dBm) POUT (dBm) -6.0 25.0 -40.0°C 25.0°C 85.0°C 24.5 20.0 1810.0 1820.0 1830.0 1840.0 LO Frequency (MHz) 11-202 -9.0 POUT versus I/Q Amplitude Over Temperature 25.0 1800.0 -12.0 LO Amplitude (dBm) VCC (V) 1850.0 1860.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0 650.0 700.0 750.0 I/Q Amplitude (mVP-P) Rev A4 040115 RF2942 Idle Current versus VCC Over Temperature ICC versus VCC Over Temperature 350.0 350.0 -40.0°C 25.0°C 85.0°C 300.0 300.0 250.0 250.0 200.0 200.0 ICC (mA) Idle Current (mA) -40.0°C 25.0°C 85.0°C 150.0 150.0 100.0 100.0 50.0 50.0 0.0 0.0 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 2.0 2.2 2.4 2.6 VCC (V) 2.8 3.0 3.2 3.4 3.6 VCC (V) POUT 3f0 versus VCC Over Temperature POUT 2f0 versus VCC Over Temperature 0.0 -23.5 -40.0°C 25.0°C 85.0°C -40.0°C 25.0°C 85.0°C -24.0 -10.0 -24.5 -20.0 POUT 3f0 (dBc) POUT 2f0 (dBc) -25.0 -25.5 -26.0 -26.5 -27.0 -30.0 -40.0 -50.0 -27.5 -60.0 -28.0 -70.0 -28.5 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 2.0 3.6 2.2 2.4 2.6 Carrier Suppression versus VCC Over Temperature 0.0 0.0 3.0 3.2 3.4 3.6 Carrier Suppression versus LO Amplitude Over Temperature -40.0°C 25.0°C 85.0°C -40.0°C 25.0°C 85.0°C -5.0 -5.0 Carrier Suppression (dBc) -10.0 Carrier Suppression (dBc) 2.8 VCC (V) VCC (V) -15.0 -20.0 -25.0 -10.0 -15.0 -20.0 -25.0 -30.0 -30.0 -35.0 -35.0 -40.0 2.0 2.2 2.4 2.6 2.8 VCC (V) Rev A4 040115 3.0 3.2 3.4 3.6 -15.0 -12.0 -9.0 -6.0 -3.0 0.0 LO Amplitude (dBm) 11-203 RF2942 0.0 Carrier Suppression versus LO Frequency Over Temperature Carrier Suppression versus I/Q Amplitude Over Temperature 0.0 -40.0°C 25.0°C 85.0°C -40.0°C 25.0°C 85.0°C -5.0 -5.0 Carrier Suppression (dBc) Carrier Suppression (dBc) -10.0 -10.0 -15.0 -20.0 -25.0 -15.0 -20.0 -25.0 -30.0 -30.0 -35.0 -35.0 1800.0 -40.0 1810.0 1820.0 1830.0 1840.0 1850.0 1860.0 250.0 375.0 LO Frequency (MHz) 500.0 625.0 750.0 I/Q Amplitude (mVP-P) Carrier Suppression versus I/Q Phase Over Temperature Image Suppression versus VCC Over Temperature 5.0 0.0 -40.0°C 25.0°C 85.0°C -40.0°C 25.0°C 85.0°C 0.0 -5.0 -5.0 -10.0 Image Suppression (dBc) Carrier Suppression (dBc) -10.0 -15.0 -20.0 -25.0 -15.0 -20.0 -25.0 -30.0 -35.0 -40.0 -45.0 -50.0 -30.0 -55.0 -60.0 -35.0 80.0 85.0 90.0 95.0 2.0 100.0 2.2 2.4 2.6 I/Q Phase (degrees) 0.0 Image Suppression versus LO Amplitude Over Temperature 0.0 -40.0°C 25.0°C 85.0°C -5.0 Image Suppression (dBc) Image Suppression (dBc) 3.2 3.4 3.6 Image Suppression versus LO Frequency Over Temperature -40.0°C 25.0°C 85.0°C -10.0 -15.0 -20.0 -25.0 -30.0 -35.0 -15.0 -20.0 -25.0 -30.0 -35.0 -40.0 -40.0 -45.0 -45.0 -50.0 -50.0 -12.0 -9.0 -6.0 LO Amplitude (dBm) 11-204 3.0 -5.0 -10.0 -15.0 2.8 VCC (V) -3.0 0.0 1800.0 1810.0 1820.0 1830.0 1840.0 1850.0 1860.0 LO Frequency (MHz) Rev A4 040115 RF2942 Image Suppression versus I/Q Amplitude Over Temperature 0.0 Image Suppression versus I/Q Phase Over Temperature 0.0 -40.0°C 25.0°C 85.0°C -40.0°C 25.0°C -5.0 85.0°C -10.0 Image Suppression (dBc) Image Suppression (dBc) -10.0 -15.0 -20.0 -25.0 -30.0 -35.0 -20.0 -30.0 -40.0 -50.0 -40.0 -60.0 -45.0 -50.0 -70.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0 650.0 700.0 750.0 80.0 85.0 90.0 95.0 100.0 I/Q Phase (degree) I/Q Amplitude (mVP-P) LODiv2 Out versus LO Amplitude Over Temperature LODiv2 Out versus VCC Over Temperature 0.0 0.0 -40.0°C 25.0°C 85.0°C -1.0 -40.0°C 25.0°C 85.0°C -2.0 -2.0 -4.0 LODiv2 Out (dBm) LO Div2 Out (dBm) -3.0 -5.0 -6.0 -7.0 -8.0 -4.0 -6.0 -8.0 -9.0 -10.0 -10.0 -11.0 -12.0 -12.0 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 -15.0 3.6 -12.0 -9.0 -6.0 -3.0 LODiv2 Out versus LO Frequency Over Temperature LODiv2 Out versus I/Q Amplitude Over Temperature 0.0 0.0 -40.0°C 25.0°C -1.0 -40.0°C 25.0°C 85.0°C -1.0 -2.0 -2.0 -3.0 -3.0 -4.0 -4.0 LO Div2 Out (dBm) LO Div2 Out (dBm) 85.0°C -5.0 -6.0 -7.0 -8.0 -5.0 -6.0 -7.0 -8.0 -9.0 -9.0 -10.0 -10.0 -11.0 -11.0 -12.0 1800.0 0.0 LO Amplitude (dBm) VCC (V) -12.0 1810.0 1820.0 1830.0 1840.0 LO Frequency (MHz) Rev A4 040115 1850.0 1860.0 250.0 375.0 500.0 625.0 750.0 I/Q Amplitude (mVP-P) 11-205 RF2942 11-206 Rev A4 040115