RF3198

RF3198 DUAL-BAND GSM900/DCS POWER AMP MODULE Package Style: LFM, 48-Pin, 7mmx7mmx0.9mm DCS IN 37 31 DCS OUT Features Integrated VREG Complete Power Control Solution +35dBm GSM Output Power at 3.5V +33dBm DCS Output Power at 3.5V 60% GSM and 55% DCS EFF 7 mmx7mmx0.9mm Package Size BAND SELECT 40 TX ENABLE 41 VBATT 42 VBATT 43 VRAMP 45 GSM IN 48 6 GSM OUT Fully Integrated Power Control Circuit Applications 3 V Dual-Band GSM Handsets Commercial and Consumer Systems Portable Battery-Powered Equipment EGSM900/DCS Products GPRS Class 10 Compatible Power StarTM Module Functional Block Diagram Product Description The RF3198 is a high-power, high-efficiency power amplifier module with integrated power control. The device is a self-contained 7mmx7mmx0.9mm lead frame module (LFM) with 50 Ω 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 output. The device is designed for use as the final RF amplifier in EGSM900 and DCS handheld digital cellular equipment and other applications in the 880MHz to 915MHz and 1710MHz to 1785MHz 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. Ordering Information RF3198 RF3198 SB RF3198PCBA-41X Dual-Band GSM900/DCS Power Amp Module Power Amp Module 5-Piece Sample Pack Fully Assembled Evaluation Board Optimum Technology Matching® Applied GaAs HBT GaAs MESFET InGaP HBT SiGe BiCMOS Si BiCMOS SiGe HBT GaAs pHEMT Si CMOS Si BJT GaN HEMT RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trademark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2006, RF Micro Devices, Inc. Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 1 of 16 RF3198 Absolute Maximum Ratings Parameter Supply Voltage Power Control Voltage (VRAMP) Input RF Power Max Duty Cycle Output Load VSWR Operating Case Temperature Storage Temperature Rating -0.3 to +6.0 -0.3 to +1.8 +10 25 10:1 -20 to +85 -55 to +150 Unit VDC V dBm % °C °C Caution! ESD sensitive device. Exceeding any one or a combination of the Absolute Maximum Rating conditions may cause permanent damage to the device. Extended application of Absolute Maximum Rating conditions to the device may reduce device reliability. Specified typical performance or functional operation of the device under Absolute Maximum Rating conditions is not implied. RoHS status based on EUDirective2002/95/EC (at time of this document revision). The information in this publication is believed to be accurate and reliable. However, no responsibility is assumed by RF Micro Devices, Inc. ("RFMD") for its use, nor for any infringement of patents, or other rights of third parties, resulting from its use. No license is granted by implication or otherwise under any patent or patent rights of RFMD. RFMD reserves the right to change component circuitry, recommended application circuitry and specifications at any time without prior notice. Parameter Overall Power Control VRAMP Power Control “ON” Power Control “OFF” VRAMP Input Capacitance VRAMP Input Current Turn On/Off Time TX Enable “ON” TX Enable “OFF” GSM Band Enable DCS/PCS Band Enable Min. Specification Typ. Max. Unit Condition 1.5 0.2 15 0.25 20 10 2 1.4 0.5 0.5 1.4 3.0 3.5 1 5.5 V V pF μA μs V V V V V V μA mA Max. POUT, Voltage supplied to the input Min. POUT, Voltage supplied to the input DC to 2MHz VRAMP =VRAMP MAX VRAMP =0.2V to VRAMP MAX Overall Power Supply Power Supply Voltage Power Supply Current Specifications Nominal operating limits PIN +5dBm TXEnable=Low, PIN =+5dBm TXEnable=High, VRAMP =0.2V, PIN =+5dBm VRAMP =0.2V to VRAMP =VRAMP_RP VRAMP =0.2V to VRAMP =VRAMP_RP VRAMP =0.2V to VRAMP =VRAMP_RP VRAMP =0.2V to VRAMP MAX Min. Specification Typ. Max. Unit Condition Temp=+25 °C, VBATT =3.5V, VRAMP =VRAMP MAX, PIN =3dBm, Freq=880MHz to 915MHz, 25% Duty Cycle, Pulse Width=1154 μs Power Control VRAMP Power Control Range Notes: VRAMP MAX =0.4*VBATT +0.06< 1.5V VRAMP_RP =VRAMP set for 34dBm at nominal conditions Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 3 of 16 RF3198 Parameter Overall (DCS Mode) Operating Frequency Range Maximum Output Power +31.5 29.5 Total Efficiency Input Power Range Output Noise Power Forward Isolation 1 Forward Isolation 2 Second Harmonic Third Harmonic All Other Non-Harmonic Spurious Input Impedance Input VSWR Output Load VSWR Stability 6:1 50 2.5:1 47 0 55 +3 -86 -44 -33 -15 -20 -35 -20 -7 -15 -36 +5 1710 to 1785 MHz dBm dBm % dBm dBm dBm dBm dBm dBm dBm Ω VRAMP =0.2V to VRAMP MAX Spurious 0 dBm, VBATT =3.5V TXEnable=Low, PIN =+5dBm TXEnable=High, VRAMP =0.2V, PIN =+5dBm VRAMP =0.2V to VRAMP =VRAMP_RP VRAMP =0.2V to VRAMP =VRAMP_RP VRAMP =0.2V to VRAMP MAX Min. Specification Typ. Max. Unit Condition Temp=25°C, VBATT =3.5V, VRAMP =VRAMP MAX, PIN =3dBm, Freq=1710MHz to 1785MHz, 25% Duty Cycle, pulse width=1154 μs Output Load VSWR Ruggedness 8:1 Output Load Impedance Power Control VRAMP Power Control Range Notes: VRAMP MAX =0.4*VBATT +0.06< 1.5V VRAMP_RP =VRAMP set for 31.5dBm at nominal conditions 4 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801 RF3198 Pin 1 2 Function NC VCC2 GSM Description Internal circuit node. Do not externally connect. Controlled voltage input to the GSM driver stage. This voltage is part of the power control function for the module. This node must be connected to VCC OUT. This pin should be externally decoupled. VCC2 Interface Schematic 3 4 5 6 NC GND GND GSM900 OUT Internal circuit node. Do not externally connect. Internally connected to the package base. Internally connected to the package base. RF output for the GSM band. This is a 50 Ω output. The output matching circuit and DC-block are internal to the package. VCC3 Output Match RF OUT 7 8 9 10 11 12 13 14 15 16 17 18 GND NC NC NC NC NC NC NC NC NC NC VCC3 GSM Internally connected to the package base. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. No internal or external connection. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Controlled voltage input to the GSM output stage. This voltage is part of the power control function for the module. This node must be connected to VCC OUT. This pin should be externally decoupled. VCC3 19 20 21 22 23 24 25 26 27 28 29 30 VCC OUT VCC OUT VCC3 DCS NC NC NC NC NC NC NC NC GND Controlled voltage output to feed VCC2 and VCC3. This voltage is part of the power control function for the module. It cannot be connected to any pins other than VCC2 and VCC3. Controlled voltage output to feed VCC2 and VCC3. This voltage is part of the power control function for the module. It cannot be connected to any pins other than VCC2 and VCC3. Controlled voltage input to the DCS output stage. This voltage is part of the power control function for the module. This node must be connected to VCC OUT. This pin should be externally decoupled. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. No internal or external connection. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internal circuit node. Do not externally connect. Internally connected to the package base. See pin 18. Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 5 of 16 RF3198 Pin 31 32 33 34 35 36 37 Function DCS OUT GND NC GND VCC2 DCS NC DCS IN Description Interface Schematic RF output for the DCS band. This is a 50 Ω output. The output matching cir- See pin 6. cuit and DC-block are internal to the package. Internally connected to the package base. Internal circuit node. Do not externally connect. Internally connected to the package base. Controlled voltage input to the DCS driver stage. This voltage is part of the power control function for the module. This node must be connected to VCC OUT. This pin should be externally decoupled. No internal connection. Connect to ground plane close to the package pin. RF input to the DCS band. This is a 50 Ω output. See pin 2. VCC1 RF IN 38 39 NC VCC1 DCS No internal connection. Connect to ground plane close to the package pin. Controlled voltage on the GSM and DCS preamplifier stages. This voltage is applied internal to the package. This pin should be externally decoupled. VCC1 40 BAND SEL Allows external control to select the GSM or DCS bands with a logic high or low. A logic low enables the GSM bands, whereas a logic high enables the DCS/PCS bands. BAND SEL TX EN GSMCTRL DCS CTRL 41 TX ENABLE This signal enables the PA module for operation with a logic high. Both bands are disabled with a logic low. VBATT TX EN TX ON 42 43 44 45 VBATT VBATT NC VRAMP Power supply for the module. This pin should be externally decoupled and connected to the battery. Power supply for the module. This pin should be externally decoupled and connected to the battery. Internal circuit node. Do not externally connect. Ramping signal from DAC. A simple RC filter may be required depending on the selected baseband. VRAM P + 46 47 48 Pkg Base VCC1 GSM GND1 GSM GSM850/ GSM900 IN GND Internally connected to VCC1 (pin 39). No external connection required. Ground connection for the GSM preamplifier stage. Connect to ground plane close to the package pin. RF input to the GSM band. This is a 50 Ω input. Connect to ground plane with multiple via holes. See recommended footprint. See pin 39. See pin 37. 6 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801 RF3198 Package Drawing -A- 7.00 TYP 6.75 TYP 0.10 C A 2 PLCS 0.08 C 0.70 0.65 0.10 C B 2 PLCS 0.90 0.85 0.05 0.00 2 PLCS 0.10 C B -B2 PLCS 0.10 C A 3.37 TYP 3.50 TYP Dimensions in mm. -C- SEATING PLANE 0.10M C A B 0.60 TYP 0.24 0.60 TYP 0.24 Shaded lead is pin 1. 0.30 0.18 0.50 2.20 1.90 0.30 0.50 TYP 0.30 5.25 4.95 Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 7 of 16 RF3198 Pin Out TX ENABLE GND1 GSM GSM900 IN VCC1 DCS BAND SEL vcc1 GSM VRAMP DCS IN 37 36 NC 35 VCC2 DCS 34 GND 33 NC 32 GND 31 DCS OUT 30 GND 29 NC 28 NC 27 NC 26 NC 25 NC 13 NC 14 NC 15 NC 16 NC 17 NC 18 VCC3 GSM 19 VCC OUT 20 VCC OUT 21 VCC3 DCS 22 NC 23 NC 24 NC VBATT VBATT NC 48 NC 1 VCC2 GSM 2 NC 3 GND 4 GND 5 GSM900 OUT 6 GND 7 NC 8 NC 9 NC 10 NC 11 NC 12 47 46 45 44 43 42 41 40 39 38 8 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. NC Rev A0 DS070801 RF3198 Application Schematic TX EN VBATT VRAMP GSM900 IN 48 1 2 10 nF 3 4 5 GSM900 OUT 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Fully Integrated Power Control Circuit From VCC1 BAND SEL VCC1 1 nF DCS IN 47 46 45 44 43 42 41 40 39 38 37 36 VCC 15 kΩ 4.7 μF 35 34 33 32 31 30 29 28 27 26 25 DCS OUT 1 nF 27 Ω 47 pF 10 nF Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 9 of 16 RF3198 Evaluation Board Schematic TX EN R3 100 kΩ VRAMP VBATT VCC1 R2 100 kΩ BAND SEL 50 Ω μstrip GSM900 IN 48 1 2 C9 10 nF 3 4 5 50 Ω μstrip GSM900 OUT 6 7 8 9 10 11 12 13 From VCC1 R4 100 kΩ R1 15 kΩ C2 4.7 μF 44 43 42 41 40 39 C6 1 nF 38 37 36 VCC 50 Ω μstrip DCS IN 47 46 45 35 34 33 32 50 Ω μstrip 31 30 29 28 27 26 25 14 15 16 17 18 19 20 21 22 23 24 DCS OUT C8 1 nF 27 Ω C13 47 pF C10 10 nF 10 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801 RF3198 Theory of Operation Overview The RF3198 is a dual-band EGSM900 and DCS1800 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 forward power or collector/drain current. The RF3198 does not use a power detector. A highspeed 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. VBATT TX ENABLE VRAMP H(s) RF IN TX ENABLE RF OUT By regulating the power, the stages are held in saturation 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 output power, supply fluctuations are the dominate mode of power variations. With the RF3198 regulating collector voltage, the dominant mode of power fluctuations is eliminated. P dBm ( 2 ⋅ V CC – V SAT ) = 10 ⋅ log ------------------------------------------–3 8 ⋅ R LOAD ⋅ 10 2 (Eq. 1) There are several key factors to consider in the implementation of a transmitter solution for a mobile phone. Some of them are: • • • • • • • • • • 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 Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 11 of 16 RF3198 Output power does not vary due to supply voltage under normal operating conditions if VRAMP is sufficiently 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 relationship limiting the maximum VRAMP voltage (Equation 2). Although no compensation is required for typical battery conditions, the battery compensation required for extreme conditions is covered by the relationship in Equation 2. This should be added to the terminal software. V RAMPMAX = 0.4 ⋅ V BATT + 0.06 ≤ 1.5 V (Eq. 2) 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. 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 RF3198 does not use a directional coupler with a diode detector, 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 varactors is present in the power amplifiers. The junction capacitance is a function of the bias across the junction. 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 RF3198 presents a very constant load to the VCO. This is because all stages of the RF3198 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 formula (Equation 3), F2 – 1 F3 – 1 F TOT = F 1 + --------------- + ------------------G1 G1 ⋅ G2 (Eq. 3) the noise figure depends on noise factor and gain in all stages. Because the bias point of the RF3198 is kept constant the gain in the first stage is always high and the overall noise power is not increased when decreasing output power. Power control loop stability often presents many challenges to transmitter design. Designing a proper power control loop involves trade-offs affecting stability, transient 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 RF3198 loop bandwidth is determined by internal bandwidth and the RF output load and does not change with respect to power levels. This makes it easier to maintain loop stability with a high bandwidth loop since the bias voltage and collector voltage do not vary. 12 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801 RF3198 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 levels. The RF3198 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 switching transients. Controlling the output power by changing the collector voltage is as earlier described based on the physical relationship between voltage swing and output power. Furthermore all stages are kept constantly 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 common 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 harmonics. The RF3198 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 transmit 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 problem arise, these terminations should be explored. The RF3198 incorporates many circuits that had previously been required external to the power amplifier. The shaded area of the diagram below illustrates those components and the following table itemizes a comparison between the RF3198 Bill of Materials and a conventional solution. Component Power Control ASIC Directional Coupler Buffer Attenuator Various Passives Mounting Yield (other than PA) Total Conventional Solution $0.80 $0.20 $0.05 $0.05 $0.05 $0.12 $1.27 RF3198 N/A N/A N/A N/A N/A N/A $0.00 1 2 3 4 5 6 7 14 13 12 11 10 9 8 From DAC *Shaded area eliminated with Indirect Closed Loop using RF3198 Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 13 of 16 RF3198 Evaluation Board Layout Board Size 2.0” x 2.0” Board Thickness 0.032”, Board Material FR-4 14 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801 RF3198 PCB Design Requirements PCB Surface Finish The PCB surface finish used for RFMD’s qualification process is electroless nickel, immersion gold. Typical thickness is 3 μinch to 8 μinch gold over 180 μinch nickel. PCB Land Pattern Recommendation PCB land patterns are based on IPC-SM-782 standards when possible. The pad pattern shown has been developed and tested for optimized assembly at RFMD; however, it may require some modifications to address company specific assembly processes. The PCB land pattern has been developed to accommodate lead and package tolerances. PCB Metal Land Pattern A = 0.64 x 0.28 (mm) Typ. B = 0.28 x 0.64 (mm) Typ. C = 5.65 (mm) Sq. 5.50 Typ. 0.50 Typ. Pin 48 Dimensions in mm. BBBBBBBBBBBB Pin 1 0.50 Typ. A A A A A A A A A A A A A A A A A A A A A A A BBBBBBBBBBBB Pin 36 2.75 C 5.50 Typ. 0.55 Typ. 0.55 Typ. A Pin 24 2.75 Figure 1. PCB Metal Land Pattern (Top View) Rev A0 DS070801 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. 15 of 16 RF3198 PCB Solder Mask Pattern Liquid Photo-Imageable (LPI) solder mask is recommended. The solder mask footprint will match what is shown for the PCB metal land pattern with a 2mil to 3mil expansion to accommodate solder mask registration clearance around all pads. The center-grounding pad shall also have a solder mask clearance. Expansion of the pads to create solder mask clearance can be provided in the master data or requested from the PCB fabrication supplier. A = 0.74 x 0.38 (mm) Typ. B = 0.38 x 0.74 (mm) Typ. C = 5.25 x 2.20 (mm) 5.50 Typ. Dimensions in mm. 0.50 Typ. Pin 48 BBBBBBBBBBBB Pin 1 Pin 36 0.50 Typ. 0.55 Typ. A A A A A A A A A A A A C A A A A A A A A A A A A Pin 24 1.95 5.50 Typ. BBBBBBBBBBBB 0.55 Typ. 2.75 Figure 2. PCB Solder Mask Pattern (Top View) Thermal Pad and Via Design Thermal vias are required in the PCB layout to effectively conduct heat away from the package. The via pattern has been designed to address thermal, power dissipation and electrical requirements of the device as well as accommodating routing strategies. The via pattern used for the RFMD qualification is based on thru-hole vias with 0.203mm to 0.330mm finished hole size on a 0.5mm to 1.2mm grid pattern with 0.025mm plating on via walls. If micro vias are used in a design, it is suggested that the quantity of vias be increased by a 4:1 ratio to achieve similar results. 16 of 16 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com. Rev A0 DS070801