FAN5902 800mA Buck Converter for 3G RFPAs Features Description 92% Efficient Synchronous Operation The FAN5902 is a high-efficiency, low-noise, synchronous, step-down DC-to-DC converter designed for powering the radio frequency power amplifiers (RFPA) in 3G mobile handsets and other mobile applications. It provides up to 800mA of output current over an input voltage range of 2.7V to 5.5V. The output voltage can be dynamically adjusted from 0.4V up to 3.4V, proportional to an analog input voltage ranging from 0.2V to 1.7V provided by an external DAC. This allows supplying the RFPA with the voltage level that provides optimum Power Added Efficiency (PAE). 6MHz PWM Operation Allows 470nH Small Form Factor Inductor 100% Duty Cycle for Low Dropout Operation 2.7V to 5.5V Input Voltage Range VOUT Range from 0.4V to 3.4V (or VIN) Up to 800mA Output Current 20µs Step Response 30µs Bypass Transition Time 50mΩ Integrated Bypass FET with Controlled Slew Rate for Low Battery Voltage Operation Thermal Shutdown FAN5902 — 800mA Buck Converter for 3G RFPAs May 2009 An integrated bypass FET automatically switches on when the battery voltage drops too close to the output voltage (when VOUT=VBAT-250mV). The bypass transition is controlled by a slew rate controller to limit the inrush current and reduce the RFPA gain deviation. The FAN5902 offers fast transition times, allowing changes to the output voltage in less than 20µs. Input Under-Voltage Lockout 12-Lead MLP (0.8mm Maximum) The FAN5902 operates at 6MHz, enabling the use of a small, low-value inductor of 470nH. A current-mode control loop with fast transient response ensures excellent line and load regulation. 12-Bump WLCSP Applications Battery-Powered 3G RFPAs The FAN5902 improves the RFPA power efficiency and increases the talk/connection time in 3G handsets. Multiband/Multimode WCDMA/CDMA Handset RF Transceivers The FAN5902 is available in a 12-lead MLP package and 12-bump WLCSP. RF PC Cards Pocket PC and PDAs with Communication Capabilities Important For complete performance specifications and datasheet, please contact a Fairchild Semiconductor sales representative. Ordering Information Part Number Operating Temperature Range Package FAN5902MPX -40 to +85°C 12-Lead, 3x3.5mm, Molded Leadless Package (MLP) RoHS Tape and Reel FAN5902UCX -40 to +85°C 12-Bump, Wafer-Level Chip-Scale Package (WLCSP) RoHS Tape and Reel Eco Status Packing Method For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 10μF PVIN VOUTSNS PVIN VOUTSNS 0.4V < VOUT < VBAT 20mA < IOUT < 800mA AVIN 470nH FAN5902 VBAT 2.7V to 5.5V VOUT SW 2.2μF From Processor BPE N SYNC EN From External DAC VCON PGND AGND Figure 1. FAN5902 Circuit FAN5902 — 800mA Buck Converter for 3G RFPAs Application Diagrams DCDC 10 F 0603 V OUT_SNS 50m PV IN PV IN V OUT_SNS Bypass Slew Controller VBATT 2.7V up to 5.5V AV IN Switcher SW 470nH Controller BPE N 2.2 F 0603 PGND SY NC VOUT EN Reference 0.4V up to VIN Up to 800mA VCON AGND Bandgap VOUT Dynamic Scaling 3 Supply VMO D E G P I O D A C Bias R FO U T RFIN Base Process or Duplexer PDET Power Detector RX R FPA Figure 2. © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short Typical Application www.fairchildsemi.com 2 FAN5902 — 800mA Buck Converter for 3G RFPAs Pin Configurations Figure 3. 12-Lead MLP (Top View) Figure 4. 12-Bump WLCSP (Top View) Pin Definitions MLP Pin # WLCSP Pin # Name (*) (*) AGND Analog ground, reference ground for the IC. Follow PCB routing notes for connecting this pin. VOUTSNS Output voltage sense pin. Connect to VOUT to establish feedback path for regulation. EN VCON Description Enables switcher when HIGH, shutdown mode when LOW. This pin should not be left floating. Analog control input from an external D-to-A converter. AVIN Analog bias supply voltage input. Connect to PVIN. AGND Connect to analog ground. BPEN Force bypass transistor when HIGH; auto-bypass when LOW. This pin should not be left floating SYNC External clock synchronization input and PFM lockout. When SYNC remains HIGH, the DC-to-DC does not allow PFM mode. Tie SYNC to AGND if not used. PGND Power ground of the internal MOSFET switches. Follow routing notes for connections between PGND and AGND. SW Switching node of the internal MOSFET switches. Connect to output inductor. PVIN Supply voltage input to the internal MOSFET switches. Connect to input power source. (*) Pinout available upon request © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 3 Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol Parameter Min. Max. Unit AVIN, PVIN -0.3 6.0 Voltage On Any Other Pin -0.3 AVIN+0.3 TJ Junction Temperature -40 +125 °C TSTG Storage Temperature -65 +150 °C VIN TL Lead Soldering Temperature (10 Seconds) θJC Thermal Resistance, Junction to Tab (1) θJC Thermal Resistance, Junction to Case 1. Refer to θJA data below. (1) V +260 °C MLP Package 5 °C/W WLCSP Package 30 °C/W Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol Parameter Min. Typ. Max. Unit VCC Supply Voltage Range 2.7 5.5 V VOUT Output Voltage Range 0.4 VIN V Output Current 20 800 mA IOUT L CIN COUT Inductor Input Capacitor 0.47 (2) Output Capacitor µH 10 (2) 2.2 FAN5902 — 800mA Buck Converter for 3G RFPAs Absolute Maximum Ratings µF 4.7 10.0 µF TA Operating Ambient Temperature Range -40 +85 °C TJ Operating Junction Temperature Range -40 +125 °C Notes: 2. A high input capacitor value is required for limiting input voltage drop during bypass transitions or during large output voltage transitions. Ensure the input capacitor value is greater than the output capacitor’s. See the inrush current specifications below. 3. Refer to application note AN-6087 for more details. Dissipation Ratings(4) Package Molded Leadless Package (MLP) Wafer-Level Chip-Scale Package (WLCSP) (4) θJA 49ºC/W (5) 110ºC/W (5) Power Rating (5) at TA ≤ 25°C Derating Factor > TA=25ºC 2050mW 21mW/ºC 900mW 9mW/ºC Notes: 4. Thermal Resistance, Junction-to-Ambient, measured according to JEDEC 2S2P PCB (and zero air flow). θJA for JEDEC 1S0P PCB (and zero air flow) = 210°C/W. 5. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD=[TJ(max) - TA ] / θJA. © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 4 Typical performance at 25°C. 30 PAE [%] IBAT [mA] 500 250 IBAT without FAN5902 PAE with FAN5902 15 PAE without FAN5902 IBAT with FAN5902 0 0 15 POUT [dBm] 0 0 30 15 POUT [dBm] 30 Figure 5. Comparison of RF PA Current Consumption with and without FAN5902 Figure 6. Comparison of RFPA Power Added Efficiency with and without FAN5902 Figure 7. Rise Times for 300mV, 500mV, and 2V ΔVOUT COUT = 2.2µF (VIN=3.7V) Figure 8. Rise Times for 300mV, 500mV, and 2V ΔVOUT COUT = 2.2µF (VIN=3.7V) © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short FAN5902 — 800mA Buck Converter for 3G RFPAs Typical Performance Characteristics www.fairchildsemi.com 5 2X 0.10 A A 3.50 2.60 B 2.65 0.85 PIN#1 IDENT 3.00 2.84 0.10 B TOP VIEW 2X 1.85 1.05 0.85 0.8 MAX 0.10 C (0.2) 0.08 C LAND PATTERN RECOMMENDATION FAN5902 — 800mA Buck Converter for 3G RFPAs Physical Dimensions SIDE VIEW 0.05 0.00 C 2.60+/-0.05 SEATING PLANE (0.38) PIN#1 IDENT 1 6 1.60+/-0.05 0.25+/-0.05 0.45+/-0.05 (12X) 12 7 0.25+/-0.05 (12X) 0.50 BOTTOM VIEW 0.10 0.05 NOTES: A. CONFORMS TO JEDEC MO-229 VARIATION WFED-2. B. DIMENSIONS ARE IN MILLIMETERS C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 D. LANDPATTERN RECOMMENDATION IS BASED ON IPC 7351 DESIGN GUIDELINES E. LANDPATTERN EXTENSION TO INCLUDE CENTER PAD TABS IS OPTIONAL F. FILENAME AND REV: MKT-MLP12DREV1 C A B C Figure 9: 3x3.5mm 12-Lead MLP Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 6 BALL A1 INDEX AREA A E (Ø0.25) Cu PAD B 0.03 C 2X 0.50 A1 0.50 D 1.00 (Ø0.35) SOLDER MASK OPENING 0.03 C TOP VIEW RECOMMENDED LAND PATTERN (NSMD) 2X 0.06 C D 0.332±0.018 0.625 0.539 0.05 C 0.250±0.025 SEATING PLANE C SIDE VIEWS FAN5902 — 800mA Buck Converter for 3G RFPAs Physical Dimensions (Continued) (X)+/-.018 0.005 0.50 C A B 12 X Ø0.315 +/- .025 D C 0.50 B A (Y)+/-.018 A. NO JEDEC REGISTRATION APPLIES B. DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 D DATUM C, THE SEATING PLANE, IS DEFINED BY THE SPHERICAL CROWNS OF THE BALLS. F FOR DIMENSIONS D, E, X, AND Y SEE 1 2 3 BOTTOM VIEW PRODUCT DATASHEET. F. BALL COMPOSITION: Sn95.5Ag3.9Cu0.6 SAC405 ALLOY G. DRAWING FILENAME: MKT-UC012AArev2 Figure 10. 12-Bump WLCSP Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 7 FAN5902 — 800mA Buck Converter for 3G RFPAs © 2009 Fairchild Semiconductor Corporation FAN5902 • Rev. 1.0.2.short www.fairchildsemi.com 8