RF3140 ETC1 | Alldatasheet

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RF Micro Devices, Inc.

7628 Thorndike Road

Greensboro, NC 27409, USA Tel (336) 664 1233 Fax (336) 664 0454 http://www.rfmd.com Optimum Technology Matching® Applied Si BJT GaAs MESFET GaAs HBT Si Bi-CMOS SiGe HBT Si CMOS InGaP/HBT GaN HEMT SiGe Bi-CMOS VCC OUT DCS/PCS OUT VCC2 DCS/PCS IN BAND SELECT VREG VRAMP TX ENABLE VBATT GSM850/GSM900 OUT VCC2 GSM850/GSM900 IN RF3140 QUAD-BAND GSM850/GSM900/DCS/PCS POWER AMP MODULE

  • 3V Quad-Band GSM Handsets
  • Commercial and Consumer Systems
  • Portable Battery-Powered Equipment
  • GSM850/EGSM900/DCS/PCS Products
  • GPRS Class 12 Compatible
  • Power StarTM Module The RF3140 is a high-power, high-efficiency power ampli- fier module with integrated power control. The device is self-contained with 50Ω input and output terminals. The power control function is also incorporated, eliminating the need for directional couplers, detector diodes, power control ASICs and other power control circuitry; this allows the module to be driven directly from the DAC out- put. The device is designed for use as the final RF ampli- fier in GSM850, EGSM900, DCS and PCS handheld digital cellular equipment and other applications in the 824MHz to 849MHz, 880MHz to 915MHz, 1710MHz to 1785MHz and 1850MHz to 1910MHz bands. On-board power control provides over 50dB of control range with an analog voltage input; and, power down with a logic “low” for standby operation.
  • Complete Power Control Solution
  • Single 3.0V to 5.5V Supply Voltage
  • +35dBm GSM Output Power at 3.5V
  • +33dBm DCS/PCS Output Power at 3.5V
  • 60% GSM and 55% DCS/PCS ηEFF
  • 10mmx10mm Package Size RF3140 Quad-Band GSM850/GSM900/DCS/PCS Power Amp Module RF3140 Power Amp Module 5-Piece Sample Pack RF3140 PCBA Fully Assembled Evaluation Board Rev A6 040113 10.00 ± 0.10 10.00 ± 0.10 Pin 1 1.70 1.45 0.450 ± 0.075

9.098 TYP

0.000 1.797 8.205 8.280

0.400 TYP

1.200 TYP

1.800 TYP

2.600 TYP

3.200 TYP

4.000 TYP

5.400 TYP

6.000 TYP

6.800 TYP

7.400 TYP

8.200 TYP

8.275 TYP

8.800 TYP

9.600 TYP

4.600 TYP

8.747 5.925 4.075 1.245 0.306 0.000 Pin 1 Package Style: Module (10mmx10mm)

-0.3 to +6.0 VDC Power Control Voltage (VRAMP) -0.3 to +1.8 V Input RF Power +8.5 dBm Max Duty Cycle Output Load VSWR 10:1 Operating Case Temperature -20 to +85 Storage Temperature -55 to +150 Parameter Specification Unit Condition Min. Typ. Max. Overall Power Control VRAMP Power Control “ON” 1.5 V Max. POUT, Voltage supplied to the input Power Control “OFF” 0.2 0.25 V Min. POUT, Voltage supplied to the input VRAMP Input Capacitance pF DC to 2MHz VRAMP Input Current µA VRAMP=VRAMP MAX Turn On/Off Time µs VRAMP=0.2V to VRAMP MAX Overall Power Supply Power Supply Voltage 3.5 V Specifications 3.0 5.5 V Nominal operating limits Power Supply Current µA PIN<-30dBm, TX Enable=Low, Temp=-20°C to +85°C 150 mA VRAMP=0.2V, TX Enable=High VREG Voltage 2.7 2.8 2.9 V VREG Current mA TX Enable=High µA TX Enable=Low Overall Control Signals Band Select “Low” 0.5 V Band Select “High” 1.9 2.0 3.0 V Band Select “High” Current µA TX Enable “Low” 0.5 V TX Enable “High” 1.9 2.0 3.0 V TX Enable “High” Current µA 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).

Min. Typ. Max. Overall (GSM850 Mode) Temp=+25 °C, VBATT=3.5V, VRAMP=VRAMP MAX, PIN=3dBm, VREG=2.8V, Freq=824MHz to 849MHz, 25% Duty Cycle, Pulse Width=1154µs Operating Frequency Range 824 to 849 MHz Maximum Output Power +34.2 +35.0 dBm Temp = 25°C, VBATT=3.5V, VRAMP=VRAMP MAX dBm Temp=+85 °C, VBATT=3.0V, VRAMP=VRAMP MAX Total Efficiency At POUT MAX, VBATT=3.5V Input Power Range dBm Maximum output power guaranteed at mini- mum drive level Output Noise Power -86 -84 dBm RBW=100kHz, 869MHz to 894MHz, POUT > +5dBm Forward Isolation 1 -35 -25 dBm TXEnable=Low, 0V, PIN=+5dBm Forward Isolation 2 -25 -10 dBm TXEnable=High, PIN=+5dBm, VRAMP=0.2V Cross Band Isolation at 2f0 -30 -20 dBm VRAMP=0.2V to VRAMP MAX Second Harmonic -15 dBm VRAMP=0.2V to VRAMP MAX Third Harmonic -30 -10 dBm VRAMP=0.2V to VRAMP MAX All Other Non-Harmonic Spurious -36 dBm VRAMP=0.2V to VRAMP MAX Input Impedance Ω Input VSWR 2.5:1 VRAMP=0.2V to VRAMP MAX Output Load VSWR Stability 8:1 Spurious<-36dBm, RBW=3MHz Output Load VSWR Ruggedness 10:1 Set VRAMP where VRAMP<34.2dBm into 50Ω load Output Load Impedance Ω Load impedance presented at RF OUT pad Power Control VRAMP Power Control Range dB VRAMP=0.2V to VRAMP MAX Note: VRAMP MAX=3/8*VBATT+0.18<1.5V

Min. Typ. Max. Overall (GSM900 Mode) Temp=+25 °C, VBATT=3.5V, VRAMP=VRAMP MAX, PIN=3dBm, VREG=2.8V, Freq=880MHz to 915MHz, 25% Duty Cycle, Pulse Width=1154µs Operating Frequency Range 880 to 915 MHz Maximum Output Power +34.2 +35.0 dBm Temp = 25°C, VBATT=3.5V, VRAMP=VRAMP MAX dBm Temp=+85 °C, VBATT=3.0V, VRAMP =VRAMP MAX Total Efficiency At POUT MAX, VBATT=3.5V Input Power Range dBm Maximum output power guaranteed at mini- mum drive level Output Noise Power -86 -82 dBm RBW=100kHz, 925MHz to 935MHz, POUT > +5dBm -88 -84 dBm RBW=100kHz, 935MHz to 960MHz, POUT > +5dBm Forward Isolation 1 -35 -25 dBm TXEnable=Low, 0V, PIN=+5dBm Forward Isolation 2 -25 -10 dBm TXEnable=High, VRAMP=0.2V, PIN=+5dBm Cross Band Isolation 2f0 -24 -20 dBm VRAMP=0.2V to VRAMP MAX Second Harmonic -15 dBm VRAMP=0.2V to VRAMP MAX Third Harmonic -30 -10 dBm VRAMP=0.2V to VRAMP MAX All Other Non-Harmonic Spurious -36 dBm VRAMP=0.2V to VRAMP MAX Input Impedance Ω Input VSWR 2.5:1 VRAMP=0.2V to VRAMP MAX Output Load VSWR Stability 8:1 Spurious<-36dBm, RBW=3MHz Output Load VSWR Ruggedness 10:1 Set VRAMP where VRAMP<34.2dBm into 50Ω load Output Load Impedance Ω Load impedance presented at RF OUT pad Power Control VRAMP Power Control Range dB VRAMP=0.2V to VRAMP MAX Note: VRAMP MAX=3/8*VBATT+0.18<1.5V

Min. Typ. Max. Overall (DCS Mode) Temp=25°C, VBATT=3.5V, VRAMP=VRAMP MAX, PIN=3dBm, VREG=2.8V, Freq=1710MHz to 1785MHz, 25% Duty Cycle, pulse width=1154µs Operating Frequency Range 1710 to 1785 MHz Maximum Output Power +32 +33 dBm Temp=25°C, VBATT=3.5V, VRAMP =VRAMP MAX +29.5 +31.0 dBm Temp=+85°C, VBATT=3.0V, VRAMP=VRAMP MAX Total Efficiency At POUT MAX, VBATT=3.5V Input Power Range dBm Maximum output power guaranteed at mini- mum drive level Output Noise Power -85 -80 dBm RBW=100kHz, 1805MHz to 1880MHz, POUT > 0dBm, VBATT=3.5V Forward Isolation 1 -40 -30 dBm TXEnable=Low, 0V, PIN=+5dBm Forward Isolation 2 -20 -10 dBm TXEnable=High, VRAMP=0.2V, PIN=0dBm to +5dBm Second Harmonic -15 dBm VRAMP=0.2V to VRAMP MAX Third Harmonic -30 -15 dBm VRAMP=0.2V to VRAMP MAX All Other Non-Harmonic Spurious -36 dBm VRAMP=0.2V to VRAMP MAX Input Impedance Ω Input VSWR 2.5:1 VRAMP=0.2V to VRAMP MAX Output Load VSWR Stability 8:1 Spurious<-36dBm, RBW=3MHz Output Load VSWR Ruggedness 10:1 Set VRAMP where VRAMP<34.2dBm into 50Ω load Output Load Impedance Ω Load impedance presented at RF OUT pin Power Control VRAMP Power Control Range dB VRAMP=0.2V to VRAMP MAX, PIN=+5dBm Note: VRAMP MAX=3/8*VBATT+0.18<1.5V

Min. Typ. Max. Overall (PCS Mode) Temp=25°C, VBATT=3.5V, VRAMP =VRAMP MAX, PIN=3dBm, VREG=2.8V, Freq=1850MHz to 1910MHz, 25% Duty Cycle, pulse width=1154µs Operating Frequency Range 1850 to 1910 MHz Maximum Output Power +32 +33 dBm Temp=25°C, VBATT=3.5V, VRAMP=VRAMP MAX, 1850MHz to 1910MHz +29.5 +31.0 dBm Temp=+85°C, VBATT=3.0V, VRAMP=VRAMP MAX Total Efficiency At POUT MAX, VBATT=3.5V Input Power Range dBm Full output power guaranteed at minimum drive level Output Noise Power -85 -80 dBm RBW=100kHz, 1930MHz to 1990MHz, POUT > 0dBm, VBATT=3.5V Forward Isolation 1 -40 -30 dBm TX_ENABLE=Low, PIN=+5dBm Forward Isolation 2 -20 -10 dBm TXEnable=High, VRAMP=0.2V, PIN=+5dBm Second Harmonic -15 dBm VRAMP=0.2V to VRAMP MAX Third Harmonic -30 -15 dBm VRAMP=0.2V to VRAMP MAX All Other Non-Harmonic Spurious -36 dBm VRAMP=0.2V to VRAMP MAX Input Impedance Ω Input VSWR 2.5:1 VRAMP=0.2V to VRAMP MAX Output Load VSWR Stability 8:1 Spurious<-36dBm, VRAMP=0.2V to VRAMP MAX, RBW=3MHz Output Load VSWR Ruggedness 10:1 Set VRAMP where VRAMP<34.2dBm into 50Ω load Output Load Impedance Ω Load impedance presented at RF OUT pin Power Control VRAMP Power Control Range dB VRAMP=0.2V to VRAMP MAX, PIN=+5dBm Note: VRAMP MAX=3/8*VBATT+0.18<1.5V

Description

RF input to the DCS/PCS band. This is a 50Ω input. BAND SELECT Allows external control to select the GSM or DCS/PCS bands with a logic high or low. A logic low enables the GSM bands, whereas a logic high enables the DCS/PCS bands. TX ENABLE This signal enables the PA module for operation with a logic high. Once TX Enable is asserted the RF output level will increase to -20dBm. VBATT Power supply for the module. This should be connected to the battery. VREG Regulated voltage input for power control function. (2.8V nom) VRAMP Ramping signal from DAC. A simple RC filter may need to be con- nected between the DAC output and the VRAMP input depending on the baseband selected. GSM850/GS M900 IN RF input to the GSM bands. This is a 50Ω input. VCC2 Controlled voltage input to driver stage for GSM bands. This voltage is part of the power control function for the module. This node must be connected to VCC out. GSM850/GS M900 OUT RF output for the GSM bands. This is a 50Ω output. The output load line matching is contained internal to the package. VCC OUT Controlled voltage output to feed VCC2. This voltage is part of the power control function for the module. It cannot be connected to anything other than VCC2, nor can any component be placed on this node (i.e., decoupling capacitor). DCS/PCS OUT RF output for the DCS/PCS bands. This is a 50Ω output. The output load line matching is contained internal to the package. VCC2 Controlled voltage input to DCS/PCS driver stage. This voltage is part of the power control function for the module. This node must be con- nected to VCC out. Pkg Base GND

PIN #1 10.0000 10.0000

The RF3140 is a quad-band GSM850, EGSM900, DCS1800, and PCS1900 power amplifier module that incorporates an indirect closed loop method of power control. This simplifies the phone design by eliminating the need for the complicated control loop design. The indirect closed loop appears as an open loop to the user and can be driven directly from the DAC output in the baseband circuit. Theory of Operation The indirect closed loop is essentially a closed loop method of power control that is invisible to the user. Most power control systems in GSM sense either for- ward power or collector/drain current. The RF3140 does not use a power detector. A high-speed control loop is incorporated to regulate the collector voltage of the amplifier while the stage are held at a constant bias. The VRAMP signal is multiplied by a factor of 2.65 and the collector voltage for the second and third stages are regulated to the multiplied VRAMP voltage. The basic circuit is shown in the following diagram. By regulating the power, the stages are held in satura- tion across all power levels. As the required output power is decreased from full power down to 0dBm, the collector voltage is also decreased. This regulation of output power is demonstrated in Equation 1 where the relationship between collector voltage and output power is shown. Although load impedance affects out- put power, supply fluctuations are the dominate mode of power variations. With the RF3140 regulating collec- tor voltage, the dominant mode of power fluctuations is eliminated. (Eq. 1) There are several key factors to consider in the imple- mentation of a transmitter solution for a mobile phone. Some of them are: Effective efficiency (ηeff) Current draw and system efficiency Power variation due to Supply Voltage Power variation due to frequency Power variation due to temperature Input impedance variation Noise power Loop stability Loop bandwidth variations across power levels Burst timing and transient spectrum trade offs Harmonics Talk time and power management are key concerns in transmitter design since the power amplifier has the highest current draw in a mobile terminal. Considering only the power amplifier’s efficiency does not provide a true picture for the total system efficiency. It is impor- tant to consider effective efficiency which is repre- sented by ηEFF. (ηEFF considers the loss between the PA and antenna and is a more accurate measurement to determine how much current will be drawn in the application). ηEFF is defined by the following relation- ship (Equation 2): (Eq. 2) Where Pn is the sum of all positive and negative RF power, PIN the input power and PDC is the delivered DC power. In dB the formula becomes (Equation 3): (Eq. 3) RF IN TX ENABLE RF OUT H(s) VRAMP TX ENABLE VBATT PdBm

2 VCC

8 RLOAD 10 3

ηEFF PN PIN n m PDC ηEFF PPA PLOSS PIN VBAT IBAT 10

Where PPA is the output power from the PA, PLOSS the insertion loss, PIN the input power to the PA and PDC the delivered DC power. The RF3140 improves the effective efficiency by mini- mizing the PLOSS term in the equation. A directional coupler may introduce 0.4dB to 0.5dB loss to the tran- sit path. To demonstrate the improvement in effective efficiency consider the following example: Conventional PA Solution at F=1785MHz: RF3140 Solution: The RF3140 solution improves effective efficiency by 5%. Output power does not vary due to supply voltage under normal operating conditions if VRAMP is suffi- ciently lower than VBATT. By regulating the collector voltage to the PA the voltage sensitivity is essentially eliminated. This covers most cases where the PA will be operated. However, as the battery discharges and approaches its lower power range the maximum output power from the PA will also drop slightly. In this case it is important to also decrease VRAMP to prevent the power control from inducing switching transients. These transients occur as a result of the control loop slowing down and not regulating power in accordance with VRAMP. The switching transients due to low battery conditions are regulated by incorporating the following relation- ship limiting the maximum VRAMP voltage (Equation 2). Although no compensation is required for typical bat- tery conditions, the battery compensation required for extreme conditions is covered by the relationship in Equation 4. This should be added to the terminal soft- ware. (Eq. 4) Due to reactive output matches, there are output power variations across frequency. There are a number of components that can make the effects greater or less. Power variation straight out of the RF3140 is shown in the tables below. The components following the power amplifier often have insertion loss variation with respect to frequency. Usually, there is some length of microstrip that follows the power amplifier. There is also a frequency response found in directional couplers due to variation in the coupling factor over frequency, as well as the sensitivity of the detector diode. Since the RF3140 does not use a directional coupler with a diode detec- tor, these variations do not occur. Input impedance variation is found in most GSM power amplifiers. This is due to a device phenomena where CBE and CCB (CGS and CSG for a FET) vary over the bias voltage. The same principle used to make varac- tors is present in the power amplifiers. The junction capacitance is a function of the bias across the junc- tion. This produces input impedance variations as the Vapc voltage is swept. Although this could present a problem with frequency pulling the transmit VCO off frequency, most synthesizer designers use very wide loop bandwidths to quickly compensate for frequency variations due to the load variations presented to the VCO. The RF3140 presents a very constant load to the VCO. This is because all stages of the RF3140 are run at constant bias. As a result, there is constant reactance at the base emitter and base collector junction of the input stage to the power amplifier. Noise power in PA's where output power is controlled by changing the bias voltage is often a problem when backing off of output power. The reason is that the gain is changed in all stages and according to the noise for- mula (Equation 5), (Eq. 5) the noise figure depends on noise factor and gain in all stages. Because the bias point of the RF3140 is kept constant the gain in the first stage is always high and the overall noise power is not increased when decreas- ing output power. PPA = +33.5 dBm PIN = +3 dBm PLOSS = -0.4 dB VBAT = 3.5 V IBAT = 1.16 A ηEFF = 50.3% PPA = +33.5 dBm PIN = +3 dBm PLOSS = 0 dB VBAT = 3.5 V IBAT = 1.16 A hEFF = 55.16% VRAMP 8-- VCC 0.18 FTOT G1 G2

Power control loop stability often presents many chal- lenges to transmitter design. Designing a proper power control loop involves trade-offs affecting stability, tran- sient spectrum and burst timing. In conventional architectures the PA gain (dB/ V) varies across different power levels, and as a result the loop bandwidth also varies. With some power amplifiers it is possible for the PA gain (control slope) to change from 100dB/V to as high as 1000dB/V. The challenge in this scenario is keeping the loop bandwidth wide enough to meet the burst mask at low slope regions which often causes instability at high slope regions. The RF3140 loop bandwidth is determined by internal bandwidth and the RF output load and does not change with respect to power levels. This makes it eas- ier to maintain loop stability with a high bandwidth loop since the bias voltage and collector voltage do not vary. An often overlooked problem in PA control loops is that a delay not only decreases loop stability it also affects the burst timing when, for instance the input power from the VCO decreases (or increases) with respect to temperature or supply voltage. The burst timing then appears to shift to the right especially at low power lev- els. The RF3140 is insensitive to a change in input power and the burst timing is constant and requires no software compensation. Switching transients occur when the up and down ramp of the burst is not smooth enough or suddenly changes shape. If the control slope of a PA has an inflection point within the output power range or if the slope is simply too steep it is difficult to prevent switch- ing transients. Controlling the output power by chang- ing the collector voltage is as earlier described based on the physical relationship between voltage swing and output power. Furthermore all stages are kept con- stantly biased so inflection points are nonexistent. Harmonics are natural products of high efficiency power amplifier design. An ideal class “E” saturated power amplifier will produce a perfect square wave. Looking at the Fourier transform of a square wave reveals high harmonic content. Although this is com- mon to all power amplifiers, there are other factors that contribute to conducted harmonic content as well. With most power control methods a peak power diode detector is used to rectify and sense forward power. Through the rectification process there is additional squaring of the waveform resulting in higher harmon- ics. The RF3140 address this by eliminating the need for the detector diode. Therefore the harmonics coming out of the PA should represent the maximum power of the harmonics throughout the transmit chain. This is based upon proper harmonic termination of the trans- mit port. The receive port termination on the T/R switch as well as the harmonic impedance from the switch itself will have an impact on harmonics. Should a prob- lem arise, these terminations should be explored. The RF3140 incorporates many circuits that had previ- ously been required external to the power amplifier. The shaded area of the diagram below illustrates those components and the following table itemizes a compar- ison between the RF3140 Bill of Materials and a con- ventional solution: Component Conventional Solution RF3140 Power Control ASIC $0.80 N/A Directional Coupler $0.20 N/A Buffer $0.05 N/A Attenuator $0.05 N/A Various Passives $0.05 N/A Mounting Yield (other than PA) $0.12 N/A Total $1.27 $0.00

*Shaded area eliminated with Indirect Closed Loop using RF3140

Evaluation Board Schematic (Download Bill of Materials from www.rfmd.com.) 50 Ω µstrip 50 Ω µstrip 50 Ω µstrip 50 Ω µstrip DCS/PCS IN BAND SELECT TX ENABLE VBATT VREG VRAMP GSM850/GSM900 IN DCS/PCS OUT GSM850/GSM900 OUT 15 kΩ Used to filter noise and spurious from base band. 50 Ω µstrip 50 Ω µstrip 50 Ω µstrip 50 Ω µstrip BAND SELECT TX ENABLE VBATT VREG VRAMP 22 µF* 1 nF* *Not required in most applications. GND CON1 DCS/PCS IN GSM850/GSM900 IN DCS/PCS OUT GSM850/GSM900 OUT Used to filter noise and spurious from base band. 15 kΩ VCC CON1 P2-1 Note 1: All the PA output measurements are referenced to the PA output pad (Pin 11 and 9). Note 2: The 50 Ω microstrip between the PA output pad and the SMA connector has an approximate insertion loss of 0.1 dB for GSM850/EGSM900 and 0.2 dB for DCS1800/PCS1900 bands. 6.8 pF

Board Size 2.0” x 2.0” Board Thickness 0.032”, Board Material FR-4, Multi-Layer

3µinch to 8µinch gold over 180µinch nickel. assembly processes. The PCB land pattern has been developed to accommodate lead and package tolerances. Figure 1. PCB Metal Land and Solder Mask Pattern (Top View)

increased by a 4:1 ratio to achieve similar results. . Figure 2. Thermal Pad and Via Design (RFMD qualification)