FAN5904: Multi-mode Buck Converter for GSM/EDGE, CDMA, 3G & 4G PAs September 2011

Introduction Smartphones and most mobile handsets in market today are not only 3G and 4G-enabled but also backwards compatible to 2G technologies – GSM/GPRS/EDGE Consumers are demanding that handsets have longer talk/usage times and don’t want to re-charge them frequently Current power management solutions to support PAs are for 3G technologies However there is a need to have DC-DC converter that can also support GSM, GPRS and EDGE Key difference is that it needs to be able to handle up to 2.3A of continuous current

RF Power Mgmt for Today, Tomorrow and Yesterday FAN5904 GSM 2G GPRS 2.5G EDGE 2.75G WCDMA 3G HSPA+ 3.5G LTE 4G FAN5903

FAN5904 Buck Converter for GSM/EDGE, 3G & 4G PAs Features High Power Mode: GSM/EDGE PAMs Up to 95% efficiency Enables 35dBm output power 5µs VOUT step response to allow early GSM Tx power loop settling 3MHz PWM Mode Low Power Mode: 3G/4G PAs Supports 29dBm output power 10µs VOUT step response to allow early power loop settling 6MHz PWM for high POUT and PFM for low POUT PA operation Bypass Mode 3A of load current 35mΩ integrated bypass FET 2.7V to 5.5V Input Voltage Range VOUT range: 0.4V to 3.4V Small Form Factor Inductor (470nH) and Capacitors Pkg: 1.71x1.71mm WLCSP-16 Status Samples & EVBs: Available Now Production: Now

FAN5904 Optimization (1) FAN5904 offers flexibility to trade efficiency for cost and solution size. Current EVBs offer good efficiency in the smallest form factors. 3MHz/6MHz switching frequencies enable excellent regulation, low ripple, and fast transient response with small inductor size. If efficiency is most important, inductor size may be increased at the cost of increased board space. FAN5904 Exceeds GSM performance requirements with 2010 size 470nH inductor. Smallest available inductor package that can handle large current requirements mandated by 2G applications.

FAN5904 Optimization (2) Efficiency Optimization Smallest solution yields lowest cost. Larger inductor may be used with FAN5904 to maximize efficiency. Ripple voltage decreases with increasing inductor value, while larger inductor dimensions yields lower ESR. Low ripple and low ESR increase efficiency. 1µH 3030 inductor (DCR=43mW, Isat > 2.3A) improves efficiency at cost of increased board space. Efficiency improvement typically 3-5%. More at low power

FAN5904 Implementation Options Smallest Board Space – 470nH Inductor 3MHz/6MHz architecture allows small 2520 470nH inductor to be used for both 2G and 3G applications. TDK VLS252010 470nH DCR=40mW. Supports DC currents up to 2.5A. Board Area w/ 2520 package 4.06mm x 5.11mm Board Area w/ 2010 package 3.45mm x 5.11mm 2016 package also available with area less than 15mm2. Optimal Efficiency – 1µH Inductor Decreased ripple achieved with larger inductor reduces loss and improves efficiency. Coilcraft XFL3010-102, 1µH, DCR=43mW. Size 3mm x 3mm x 1mm Efficiency is improved by 3-5% typically. Even more at low power. Board Area w/ 3030 Inductor 3.42 mm x 6.80mm FAN5904 Evaluation Board Footprint w/ 470nH 2520 Inductor FAN5904 Evaluation Board Footprint w/ 1µH 3030 Inductor

FAN5904 Application Diagram

FAN5904 Lower Heat Dissipation 20C 40C 25C 50C 30C 65C POUT=28dBm @ VPA=2.37V POUT=28dBm @ VBAT=3.7V POUT=28dBm @ VBAT=4.2V (Battery Charging) 3G PA w/ FAN5904 Thermal Profile 3G PA Only Thermal Profile

2G/3G/4G PA Thermal Issues Common issue facing smartphones today is heat generated by PAs which causes these issues: “Hot” or very warm mobile handset during voice calls and heavy data transmit functions Thermal vias cannot dissipate all of the heat resulting in hotter PAs Parameters 3G PA Only 3G PA + FAN5904 POUT = 17dBm POUT = 0dBm VPA (V) 3.700 0.984 0.718 IBATT (A) 0.167 0.015 0.058 0.004 Power Dissipation (W) 0.618 0.056 0.057 0.003 JC @ >16dBm (C/W) 16.0 - Rise in Temperature (C) 9.9 0.9

FAN5904: Low Power Mode WCDMA/HSPA PAs

DC Efficiency Low Power Mode, VIN = 3.7V

DC Efficiency Low Power Mode, VIN = 3.7V

FAN5904 + 3G PA in WCDMA Mode Battery Current vs. Output Power

FAN5904: Extending Connection Time for Mobile Devices Voice Calls Data Transmit Usage curve from GSMA’s “Battery Life Measurement Technique, v4.7 Assumes System Current Consumption = 100mA

FAN5904: Usage Time Summary WCDMA Mode Type Parameters FAN5904 (minutes) No FAN5904 Improvement Absolute (minutes) Percentage Voice Tx Time using 3 PA Power Modes 528 462 65 14% Tx Time with PA in High Power Mode 515 297 218 73.2% Data 436 348 88 25.4% 394 253 141 55.6%

Determining 3G PA VCC vs. POUT Determine PA VCC for a Range of POUT Determine acceptable Adjacent Channel Power Ratio 3GPP limit: -33dBc @ 5MHz. Add margin for component and voltage tolerances and manufacturing margins. Limit of -39dBc used here. Measure PA VCC vs. RF POUT for desired ACPR Use a signal analyzer to measure ACPR Start with PA VCC = 3.4V, then reduce VCC until ACPR = desired value ACPR Measurement -39.0 29.0 dBm -39.2 PA VCC vs. POUT Results Embedded Look Up Table POUT TX_AGC VCON 29 256 1.300 27 244 1.160 25 198 0.944 23 176 0.780 22 150 0.560 POUT (dBm) PIN PA VCC (V) IBATT (mA) VBATT -5 MHz OFFSET (dB) + 5 MHz OFFSET 29.0 3.4 3.25 518.40 3.7 -39.0 -39.2 28.2 2.2 465.12 -38.5 -40.3 27.0 1.2 2.90 369.34 -38.9 -40.7 26.1 0.4 2.61 300.05 -38.8 -40.6 25.0 -0.4 2.36 243.84 -40.4 23.9 -1.2 2.13 198.68 23.0 -1.9 1.95 165.11 -40.5 NEW Fixed values added to calibration table. Not part of factory calibration. Factory calibration values.

Transmit Spurs Far Below WCDMA Modulation Spurs << Mask for Low & High Power WCDMA PA Output: 26.9dBm (PWM mode) Modulation On Modulation Off High Output Power DCDC in High Power mode (PWM) Frequency automatically decreases for longer duty cycle (to provide more current) Low Output Power DCDC in Low Power mode PFM mode Frequency automatically decreases to increase efficiency Modulation On Modulation Off WCDMA PA Output: 5dBm (PFM mode) No Spurs for Mid Power Spurs < -87dBc 8dBm < POUT < 25dBm (FSW = 3MHz or 6 MHz)

Transmit EVM: Almost No Change W-CDMA EVM increased by 0.6% with FAN5904, but still far below limit. RF POUT MEASURED EVMRMS EVM LIMIT Lab Supply FAN5904 W-CDMA Specification 29dBm 1.4% (VCC = 3.4V) 1.9% (VCC = 3.25V) 17.5% 16dBm 1.2% 1.8% (VCC = 2.275V) 5dBm 1.3% (VCC = 1.764V)

Rx Band Output Noise: No change FAN5904 adds no noise in the receive bands. 2G POUT [dBm] PA VCC [V] PA MODE Rx Noise [dBm/Hz] FAN5904 Lab Supply 34.0 3.315 GSM -133 -134.5 30.5 2.236 -148.4 -148.5 5.0 0.487 3G POUT [dBm] PA VCC [V] W-CDMA PA MODE Rx Noise [dBm/Hz] FAN5904 Lab Supply 29.0 3.25 High Power -135.1 -135.2 16.0 2.275 Med. Power -148.5 5.0 1.764 Low Power -6dB N9010A Signal Analyzer E4438C Signal Generator VBIAS VCC Rx BAND Tx PA

FAN5904 Voltage Transition WCDMA transition time High POUT = 20µs Low POUT = 5µs Start-up transition time 20µs WCDMA Specification for slot transition time 30µs

FAN5904: High Power Mode GSM/EDGE PAs

DC Efficiency High Power Mode, VIN = 3.7V

DC Efficiency High Power Mode, VIN = 5.0V

FAN5904 + GSM/EDGE PA in EDGE Mode Battery Current vs FAN5904 + GSM/EDGE PA in EDGE Mode Battery Current vs. Output Power (GSM850)

FAN5904 + GSM/EDGE PA in EDGE Mode Battery Current vs FAN5904 + GSM/EDGE PA in EDGE Mode Battery Current vs. Output Power (PCS1900)

FAN5904 + GSM/EDGE PA in GSM Mode Battery Current vs FAN5904 + GSM/EDGE PA in GSM Mode Battery Current vs. Output Power (GSM850)

FAN5904 + GSM/EDGE PA in GSM Mode Battery Current vs FAN5904 + GSM/EDGE PA in GSM Mode Battery Current vs. Output Power (PCS1900)

FAN5904: Extending Connection Time for Mobile Devices Voice Calls @ 850MHz Data Transmit @ 850MHz *Usage curve from Microwave Journal article: Intelligent Power Management: A method to Improve 2G/3G Handset Talk Time, July 2007. **Assumes System Current Consumption = 100mA

FAN5904: Extending Connection Time for Mobile Devices Voice Calls @ 1900MHz Data Transmit @ 1900MHz *Usage curve from Microwave Journal article: Intelligent Power Management: A method to Improve 2G/3G Handset Talk Time, July 2007. **Assumes System Current Consumption = 100mA

FAN5904: Usage Time Summary GSM/GPRS Mode Type Parameters FAN5904 (minutes) No FAN5904 Improvement Absolute (minutes) Percentage Voice Tx Time with PA @ 12.5% Duty Cycle in GSM Mode in Low Band 402 336 66 20% Tx Time with PA @ 12.5% Duty Cycle in GSM Mode in High Band 494 416 78 19% Data Tx Time with PA @ 25% Duty Cycle in GPRS Mode in Low Band 279 234 45 Tx Time with PA @ 25% Duty Cycle in GPRS Mode in High Band 376 292 84 29%

ORFS with FAN5904 EGSM900 (900MHz) Procedure Reduce VDCDC for POUT slightly greater than target Reduce VRAMP to fine-tune POUT Spectrum Analyzer set to EGSM limits PIN = 0.7dBm, VBAT = 3.5V, Unmodified SKY77604 (Quad-band GSM/EDGE PAM)

ORFS with FAN5904 PCS1900 (1880MHz) Procedure Reduce VDCDC for POUT slightly greater than target Reduce VRAMP to fine-tune POUT Spectrum Analyzer set to PCS limits PIN = 0.7dBm, VBAT = 3.5V, Unmodified SKY77604 (Quad-band GSM/EDGE PAM)

Original factory calibration table. Determining 2G PA VCC vs. POUT Determine PA VCC for a Range of POUT Determine acceptable ORFS margin Customer consensus is 6dB of margin is sufficient For example, -63dBc becomes -69dBc limit Measure PA VCC vs. RF POUT for desired ORFS Use a spectrum analyzer to measure ORFS (at fSW) Start with PA VCC = 3.4V, then reduce VCC until POUT = Target POUT + 1dB (measured at the DCDC switching frequency). Next, reduce VRAMP until POUT = Target POUT. ORFS Measurement PA VCC vs. POUT Results Embedded Look Up Table POUT TX_AGC VRAMP VCON 34.0 256 1.740 1.326 32.0 244 1.300 1.111 30.5 198 1.200 0.894 28.0 176 1.062 0.728 26.0 150 1.000 0.585 POUT (dBm) PIN PA VCC (V) IBATT (mA) VBATT VRAMP 34.0 5.0 3.315 1350 3.7 1.740 32.0 2.778 932 1.300 30.5 2.236 650 1.200 28.0 1.82 450 1.062 26.0 1.462 324 1.000 24.0 1.205 236 0.920 NEW New VRAMP and fixed VCON values added to calibration table. Not part of factory calibration. Original factory calibration table.

Bill of Materials & Evaluation Board Part Type Case Size Value Vendor Part Number FAN5904 Inductor 2520 470nH TDK VLS252010T-R47N Input Capacitor 0603 10µF Panasonic ECJ-1VB1A106M Output Capacitor 0402 2* x 4.7µF Murata GRM155R60J475ME87D FAN5904 Evaluation Board Connect to PA evaluation boards. * One of the 4.7µF is replaced by the PA decoupling capacitor in most applications. ** C6 is for evaluation only and not needed for the actual application.

Pricing & Availability Fairchild Part Number Package Unit Price @ 1ku Availability FAN5904UC00X WLCSP-16 $0.950 Now FAN5904UC01X

Summary Best in-class power management solutions to support all cellular standards Meets specifications outlined in cellular standards FAN5904 is a compact, high efficiency buck converter that provides these benefits: More than 60 minutes of increased talk/usage time in 3G mode More than 45 minutes of increased talk/usage time in 2G mode Lowers heat dissipation by 40% Smallest solution footprint Smaller passive components due to 6MHz switching frequency Lowers total cost of ownership Reduce battery size, weight and cost

Technical Materials FAN5904 Datasheet http://www.fairchildsemi.com/ds/FA/FAN5904.pdf FAN5904 Product Overview http://www.fairchildsemi.com/pf/FA/FAN5904.html Evaluation Boards Request via Sales Center Samples

Marketing & Apps Contacts Marketing Contact Wayne Seto wayne.seto@fairchildsemi.com +1-408-822-2197 Applications Support Paul Finkel paul.finkel@fairchildsemi.com +1-408-822-2543

Appendix

FAN5904 Timing Diagrams GSM/EDGE WCDMA

Test Configuration VCC VBATT IBATT FAN5904 -10dB PA VRAMP VBIAS Power Mode Control VRAMP E4438C Signal Generator VBIAS VCC N9010A Signal Analyzer VCC VRAMP and Peak Current for GSM PA VCON FAN5904 VBATT Function Generator Peak Current IBATT Power Supply

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