AS1339 D a ta s h e e t 6 5 0 m A R F St e p - D o w n D C - D C f o r PA, w i t h t w o L D O s 1 General Description 2 Key Features The AS1339 is a high-frequency step-down converter optimized for dynamically powering the power amplifier (PA) in WCDMA or NCDMA handsets. The device uses a 110mΩ typical bypass FET to power the PA directly from the battery during high-power transmission. The IC integrates two 10mA low-noise, low-dropout regulators (LDOs) for PA biasing. ! Fixed Switching Frequency: 2MHz ! PA Step-Down Converter ! Low Dropout Voltage ! Low Output-Voltage Ripple ! Dynamic Output Voltage Control (0.8V to 3.75V) With a switching frequency of 2MHz, the device allows optimization for smallest solution size or highest efficiency. The AS1339 supports fast switching using small ceramic 10μF input and 4.7µF output capacitors to maintain low ripple voltage. ! 30µs Settling Time for 0.8V to 3.4V Output Voltage Change ! 650mA Output Drive Capability ! Two 10mA Low-Noise LDOs The AS1339 uses an analog input driven by an external DAC to control the output voltage linearly for continuous PA power adjustment. The gain from REFIN to OUT is 2.5V/V. At high-duty cycle, the device automatically switches to a bypass mode, connecting the input to the output through a low-impedance MOSFET. The LDOs are designed for low-noise operation, wherein each LDO in the device is individually enabled through its own logic control interface. The device is available in a 16-pin WLP (2x2mm) package. ! Low Shutdown Current ! Supply Voltage Range: 2.7V to 5.5V ! Thermal Shutdown ! 16-pin WLP (2x2mm) package 3 Applications The AS1339 is ideal for WCDMA/NCDMA cellular handsets, Wireless PDAs, and Smartphones. Figure 1. Typical Operating Circuit VIN 2.7V to 5.5V 10µF IN1A VPA 0.8V to 3.75V PAA PAB IN1B LX 2.2µH 4.7µF Analog Control REFIN PA ON/OFF PA_EN LDO1 ON/OFF EN1 LDO2 ON/OFF EN2 NC TEST PGND NC AS1339 LDO1 0.1µF VIN 2.7V to 5.5V 1µF www.austriamicrosystems.com 2.85V LDO2 IN2 AGND Revision 1.04 2.85V 0.1µF 1 - 25 AS1339 Datasheet - P i n o u t 4 Pinout Figure 2. Pin Assignments (Top View) NC AGND REFIN PGND A1 A2 A3 A4 LDO2 PA_EN EN2 LX B1 B2 B3 B4 IN2 TEST IN1B IN1A C1 C2 C3 C4 LDO1 EN1 PAB PAA D1 D2 D3 D4 Pin Description Table 1. Pin Description Pin Name Pin Number NC A1 Not Connected. Free, high impedance for normal operation. Used for internal test purpose. AGND A2 Low-Noise Analog Ground REFIN A3 DAC-Controlled Input. Reference voltage for buck converter. The output of the PA step-down converter is regulated to 2.5 x VREFIN. Bypass mode is enabled when VIN ≤ 2.69V x VREFIN. PGND A4 Power Ground for PA Step-Down Converter LDO2 B1 10mA LDO Regulator 2 Output. Connect LDO2 with a 0.1μF ceramic capacitor as close as possible to LDO2 and AGND. LDO2 is internally pulled down through a 100Ω resistor when this regulator is disabled. PA_EN B2 PA Step-Down Converter Enable Input. For normal operation, connect to logic-high. For shutdown mode, connect to logic-low. The pin is internally pulled down through a 110kΩ resistor. EN2 B3 Enable Input for LDO2. For normal operation, connect to logic-high. For shutdown mode, connect to logic-low. The pin is internally pulled down through a 110kΩ resistor. LX B4 Inductor Connection. Connect an inductor from LX to the output of the PA step-down converter. www.austriamicrosystems.com Description Revision 1.04 2 - 25 AS1339 Datasheet - P i n o u t Table 1. Pin Description Pin Name Pin Number Description IN2 C1 Supply Voltage Input for LDO1 and LDO2. Connect IN2 to a battery or supply voltage from 2.7V to 5.5V. Decouple IN2 with a 1μF ceramic capacitor as close as possible to IN2 and AGND. Connect IN2 to the same source as IN1A and IN1B. TEST C2 NC. Used for internal test purpose. The pin is internally pulled down with a 110kΩ resistor. IN1B, IN1A C3, C4 Supply Voltage Input for PA Step-Down Converter. Connect IN1A/B to a battery or supply voltage from 2.7V to 5.5V. Decouple IN1A/B with a 10μF ceramic capacitor as close as possible to IN1A/B, and PGND. IN1A and IN1B are internally connected together. Connect IN1A/B to the same source as IN2. LDO1 D1 10mA LDO Regulator 1 Output. Decouple LDO1 with a 0.1μF ceramic capacitor as close as possible to LDO1 and AGND. LDO1 is internally pulled down through a 100Ω resistor when this regulator is disabled. EN1 D2 Enable Input for LDO1. For normal operation, connect to logic-high. For shutdown mode, connect to logic-low. The pin is internally pulled down through a 110kΩ resistor. PAB, PAA D3, D4 PA Connection for Bypass Mode. Internally connected to IN1A/B using the internal bypass MOSFET during bypass mode. Connect PAA/B with a 4.7μF ceramic capacitor as close as possible to PAA/B and PGND. www.austriamicrosystems.com Revision 1.04 3 - 25 AS1339 Datasheet - A b s o l u t e M a x i m u m R a t i n g s 5 Absolute Maximum Ratings Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 5 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter Min Max Units IN1A, IN1B, IN2 to AGND -0.3 +7 V PAA, PAB, PA_EN, TEST, REFIN, NC to AGND -0.3 VIN1A/ VIN1B + 0.3 V LDO1, LDO2, EN1, EN2 to AGND -0.3 VIN2 + 0.3 V IN2 to IN1B/IN1A -0.3 +0.3 V PGND to AGND -0.3 +0.3 V LX Current 0.7 ARMS Bypass Current 1.6 ARMS +150 ºC Storage Temperature Range -65 Comments +260 ºC The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020D “Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”. 1 kV HBM MIL-Std. 883E 3015.7 methods VIN V Recommended Load Current 650 mA Continuous Power Dissipation PD-MAX 0.75 W +125 ºC Package Body Temperature ESD Rating Human Body Model Operating Ratings REFIN Common-Mode Range Junction Temperature (TJ) Range Ambient Temperature (TA) Range www.austriamicrosystems.com 0 -40 -40 +85 ºC Revision 1.04 TA = +65ºC; derate 12.5mW/ºC above +65ºC In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125ºC), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX). 4 - 25 AS1339 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VIN1A = VIN1B = VIN2 = VPA_EN = VEN1 = VEN2 = 3.6V, TA = -40ºC to +85ºC. Typical values are at TA =+25ºC, (unless otherwise specified), for external components refer to Table 5 on page 7. Table 3. Electrical Characteristics Symbol Parameter Condition Min Typ Max Unit 5.5 V Input Supply VIN ISHDN IQ Input Voltage Range 2.7 1 Shutdown Supply Current VPA_EN = VEN1 = VEN2 = 0V 0.1 1 µA DC-DC No-Load Supply Current VEN1 = VEN2 = 0V, ILOAD(DCDC) = 0mA, switching, VIN = 4.5V, VOUT = 3.4V 4.5 6 mA 3.85 V DCDC Output Voltage Output Voltage Range VOUT Output Voltage PWM Mode 0.8 VREFIN = 0.32V, VIN = 3.9V 0.75 0.8 0.85 V VREFIN = 0.84V, VIN = 3.9V 2.05 2.1 2.15 V VREFIN = 1.36V, VIN = 3.9V 3.319 3.4 3.481 V Thermal Protection Thermal Shutdown TA rising, 10ºC typical hysteresis +140 ºC Logic Control PA_EN, EN1, EN2, LogicInput High Voltage 2.7V ≤ VIN ≤ 5.5V PA_EN, EN1, EN2, LogicInput Low Voltage 2.7V ≤ VIN ≤ 5.5V VIL = 0V Logic-Input Current (PA_EN, EN1, EN2) 1.4 V -1 VIH = VIN = 5.5V 50 0.5 V +1 µA 75 µA 1.5 V REFIN REFIN Operating Common-Mode Range REFIN gain VOUT/VREFIN 0.32 2 REFIN Current VREFIN = 0.32V 2.35 2.50 2.65 V/V VREFIN = 0.84V, 1.36V 2.44 2.50 2.56 V/V +1 µA VREFIN = VIN = 5.5V -1 LX RDSONP Pin-Pin Resistance for PFET RDSONN Pin-Pin Resistance for NFET fOSC ISW = 200mA; TA = +25°C 110 ISW = 200mA 200 230 ISW = -200mA; TA = +25°C 230 ISW = -200mA 415 485 mΩ mΩ PFET Leakage Current VIN = 5.5V, VLX = 0V 0.1 3 µA NFET Leakage Current VIN = VLX = 5.5V 0.1 3 µA PFET Peak Current Limit VLX = 0V 1100 Internal Oscillator Frequency www.austriamicrosystems.com 1.8 Revision 1.04 2 mA 2.2 MHz 5 - 25 AS1339 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s Table 3. Electrical Characteristics (Continued) Symbol Parameter Condition Min Typ Max Unit 2.56 2.69 2.78 V/V 110 200 BYPASS VREFIN rising, 50mV hysteresis Bypass Activation Factor On-Resistance Bypass PFET ISW = 200mA; TA = +25°C ISW = 200mA 230 PFET Bypass Off-Leakage Current VIN = 5.5V, VPAA = VPAB = 0V Output Voltage IOUT = 0mA, 10mA; mΩ 0.1 3 µA 2.85 2.95 V 25 50 40 80 35 50 IOUT = 10mA 20 50 VEN1/2 = 0V 100 LDO1/2 one LDO enabled Quiescent Current both LDOs enabled 2.75 IOUT = 0mA Output Current 10 VOUT = 0V Current Limit Dropout Voltage ROFF 3 Shutdown Output Impedance 20 µA mA mV Ω 1. Current into supply pins without leakage of DCDC switches. 2. Limited by the 50mV output voltage accuracy for VREFIN < 0.84V 3. The dropout voltage is the input to output difference at which the output is 100mV below its nominal value. System Characteristics VIN1A = VIN1B = VIN2 = VPA_EN = VEN1 = VEN2 = 3.9V, TA = -40ºC to +85ºC. Typical values are at TA =+25ºC, (unless otherwise specified), for external components refer to Table 5 on page 7. The following parameters are verified by characterisation and are not production tested. Table 4. System Characteristics Symbol Parameter Condition Min Typ Max Unit 3 % 2.4 % ±10 50 mV VOUT = 0.8 to 3.4V, RLOAD = 8Ω, no bypass mode, no pulse-skip condition 10 25 Line_tr Line transient response VIN = 3.4 to 3.9V, VOUT = 3.0V, IOUT = 300mA, VIN increase 300mV in 10µs 30 50 Load_tr Load transient response VIN = 3.4 to 4.2V, VOUT = 3.0V, TRISE = TFALL = 10µs, IOUT = 100 to 300mA 50 70 REFIN REFIN gain variation; relative linearity 0.32V ≤ VREFIN ≤ 1.4V 1 REFIN gain variation; absolute linearity 2 0.84V ≤ VREFIN ≤ 1.4V -2.4 0.32V ≤ VREFIN ≤ 0.84V -50 LX Ripple voltage, PWM mode www.austriamicrosystems.com 3 Revision 1.04 mVp-p 6 - 25 AS1339 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s Table 4. System Characteristics (Continued) Symbol Parameter Condition Min Typ Max Start-Up Time From PA_EN switch from 0V to 1.7V, VOUT = 3.4V, ILOAD = 0mA, within 50mV regulation error 100 150 Regulation Time; Rise Time VOUT from 0.8V to 3.4V, RLOAD = 8Ω, within 50mV regulation error 30 50 Regulation Time; Fall Time VOUT from 3.4V to 0.8V, RLOAD = 8Ω, within 50mV regulation error 30 50 Start-Up Time IOUT=10mA, within 100mV of VOUT 30 50 Shut-Down Time IOUT=0mA, within 100mV of GND 50 100 Unit µs LDO Line Regulation 4 Load Regulation 5 Ripple Rejection 6 Output Noise VIN = 4V to 3.5V; IOUT = 10mA; 10 IOUT stepped from 50µA to 10mA 25 IOUT = 4mA, VIN = 3.2V, f = 100kHz 45 IOUT = 4mA, VIN = 3.2V, f = 2MHz 45 10Hz to 100kHz, IOUT = 10mA µs mV dB 50 100 µVRMS 1. The relative linearity is defined as the difference of the minimum to the maximum gain over the entire REFIN range. 2. The absolute linearity is defined as the actual gain error (AE) of every applied VREFIN voltage between 0.32V and 1.4V. V OUT AE = ⎛ --------------------------------- – 1⎞ × 100 ⎝ 2, 5 × V REFIN ⎠ 3. The ripple voltage should measured at COUT electrode on good layout PC board and under condition using suggested inductors and capacitors. 4. For dynamic change in VOUT (Line transient response) when VIN drops 500mV from 4V (see Figure 48 on page 15); Slew rate= 40mV/µs. 5. VRIPPLE = 200mVpp; TA = +25°C; CIN1, CIN2 removed; PA_EN = 0V; 6. VIN = 3.2V; TA = +25°C; PA_EN = 3.2V; Table 5. External Components used for Characterisation Name Part Number Value Rating Type Size CIN1 GRM21BR60J106KE01 10µF 6.3V X5R 0805 CIN2 GRM155R61A105KE15 1µF 10V X5R 0402 COUT C0603C475K8PAC7867 4.7µF 10V X5R 0603 CLDO1, CLDO2 C0402C104K4RAC 100nF 16V X7R 0402 L MLP2520S3R3S 3.3µH 1A 110mΩ www.austriamicrosystems.com Revision 1.04 Manufacturer Murata www.murata.com KEMET www.kemet.com TDK 2.2x2.0x1.4mm www.coilcraft.com 7 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s 7 Typical Operation Characteristics Figure 3. DC-DC Efficiency vs. VOUT; RLOAD = 5Ω Figure 4. DC-DC Efficiency vs. VOUT; RLOAD = 7.5Ω 100 100 95 95 90 Bypass Mode 85 80 75 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 70 65 Efficiency (%) Efficiency (%) 90 Bypass Mode 85 80 75 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 70 65 60 60 0.6 1 1.4 1.8 2.2 2.6 3 3.4 3.8 0.6 1 1.4 Output Voltage (V) Figure 5. DC-DC Efficiency vs. VOUT; RLOAD = 10Ω 1.6 95 1.4 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 65 REFIN (V) Efficiency (%) 80 70 3 3.4 3.8 1 0.8 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 0.6 0.4 60 0.2 0.6 1 1.4 1.8 2.2 2.6 3 3.4 3.8 0.6 Output Voltage (V) Figure 7. DC-DC REFIN vs. VOUT; RLOAD = 7.5Ω 1.6 1.6 1.4 1.4 1.2 1.2 1 0.8 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 0.6 0.4 0.2 1 1.4 1.8 2.2 2.6 3 Output Voltage (V) 3.4 3.8 Figure 8. DC-DC REFIN vs. VOUT; RLOAD = 10Ω REFIN (V) REFIN (V) 2.6 1.2 Bypass Mode 85 75 2.2 Figure 6. DC-DC REFIN vs. VOUT; RLOAD = 5Ω 100 90 1.8 Output Voltage (V) 1 0.8 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 0.6 0.4 0.2 0.6 1 1.4 1.8 2.2 2.6 3 Output Voltage (V) www.austriamicrosystems.com 3.4 3.8 0.6 Revision 1.04 1 1.4 1.8 2.2 2.6 3 Output Voltage (V) 3.4 3.8 8 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s Figure 10. DC-DC Efficiency vs. IOUT; VOUT = 1.2V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Figure 9. DC-DC Efficiency vs. IOUT; VOUT = 0.8V 70 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 60 50 10 100 60 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 50 40 1 70 40 1000 1 Output Current (mA) 100 100 90 90 80 80 70 60 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 50 1000 70 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 60 50 40 40 1 10 100 1 1000 Figure 13. DC-DC Load Regulation, VOUT vs. IOUT; VOUT = 0.8V 0.81 1.21 Output Voltage (V) 1.22 0.8 0.79 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V 0.77 100 1000 Figure 14. DC-DC Load Regulation, VOUT vs. IOUT; VOUT = 1.2V 0.82 0.78 10 Output Current (mA) Output Current (mA) Output Voltage (V) 100 Figure 12. DC-DC Efficiency vs. IOUT; VOUT = 2.2V Efficiency (%) Efficiency (%) Figure 11. DC-DC Efficiency vs. IOUT; VOUT = 1.8V 10 Output Current (mA) 1.2 1.19 1.18 Vin = 2.7V Vin = 3.3V Vin = 3.9V 1.17 0.76 Vin = 3.0V Vin = 3.6V 1.16 1 10 100 1000 Output Current (mA) www.austriamicrosystems.com 1 10 100 1000 Output Current (mA) Revision 1.04 9 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s Figure 16. DC-DC Load Regulation, VOUT vs. IOUT; VOUT = 2.2V 1.83 2.23 1.82 2.22 Output Voltage (V) Output Voltage (V) Figure 15. DC-DC Load Regulation, VOUT vs. IOUT; VOUT = 1.8V 1.81 1.80 1.79 Vin = 2.7V Vin = 3.3V Vin = 3.9V 1.78 Vin = 3.0V Vin = 3.6V 2.21 2.20 2.19 1.77 10 100 1000 1 Output Current (mA) 100 100 95 95 Bypass PWM Mode Mode Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 100 90 Bypass PWM Mode Mode 1000 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 85 80 80 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Input Voltage (V) Input Voltage (V) Figure 19. DC-DC Efficiency vs VIN; VOUT = 2.0V Figure 20. DC-DC Efficiency vs VIN; VOUT = 1.5V 100 100 90 90 Efficiency (%) Efficiency (%) 10 Output Current (mA) Figure 18. DC-DC Efficiency vs VIN; VOUT = 3.4V Efficiency (%) Efficiency (%) Figure 17. DC-DC Efficiency vs VIN; VOUT = 3.8V 85 Vin = 3.0V Vin = 3.6V 2.17 1 90 Vin = 2.7V Vin = 3.3V Vin = 3.9V 2.18 80 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 70 80 70 60 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 60 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Input Voltage (V) Input Voltage (V) www.austriamicrosystems.com Revision 1.04 10 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s Figure 21. DC-DC Efficiency vs Input Voltage; VOUT = 1.0V Figure 22. DC-DC Line Regulation, VOUT vs. VIN; VOUT = 3.8V 100 4.5 4 Output Voltage (V) Efficiency (%) 90 80 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 70 Mode 3 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 2.7 3.05 Input Voltage (V) 4 2.02 Output Voltage (V) 2.03 3.5 PWM Mode Mode Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 2.5 2.00 1.99 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 1.97 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Input Voltage (V) Input Voltage (V) Figure 25. DC-DC Line Regulation, VOUT vs. VIN; VOUT = 1.5V Figure 26. DC-DC Line Regulation, VOUT vs. VIN; VOUT = 1.0V 1.03 1.52 1.02 Output Voltage (V) 1.53 1.51 1.50 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 1.48 5.15 5.5 2.01 1.98 2 1.49 4.1 4.45 4.8 Figure 24. DC-DC Line Regulation, VOUT vs. VIN; VOUT = 2.0V 4.5 Bypass 3.4 3.75 Input Voltage (V) Figure 23. DC-DC Line Regulation, VOUT vs. VIN; VOUT = 3.4V Output Voltage (V) PWM Mode 2 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 3 Bypass 2.5 60 Output Voltage (V) 3.5 1.01 1 0.99 0.98 1.47 Iout = 300mA Iout = 400mA Iout = 500mA Iout = 600mA 0.97 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Input Voltage (V) Input Voltage (V) www.austriamicrosystems.com Revision 1.04 11 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s Figure 27. DC-DC Output Voltage Error vs. Reference Voltage Figure 28. DC-DC Bypass Dropout Voltage vs. Output Current 100 6 Dropout Voltage (mV) Output Voltage Error (mV) 8 4 2 0 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V Vin = 3.9V -2 -4 0.25 0.5 0.75 1 1.25 80 60 40 Vin = 2.7V Vin = 3.0V Vin = 3.3V Vin = 3.6V 20 0 0 1.5 Figure 29. DC-DC No-Load Supply Current vs. VIN 100 200 300 400 500 600 700 800 900 Output Current (mA) Reference Voltage (V) Figure 30. Shutdown Supply Current vs. VIN 120 6 Mode Mode 3 2 100 80 60 40 1 20 0 0 1 2 3 4 5 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 6 Input Voltage (V) Input Voltage (V) Figure 32. DC-DC Switching; VIN=3.6V, VPA=1.2V, IOUT=500mA VLX ILX VPA 2V/Div 200mA/Div ILX VLX VPA 20mV/Div Figure 31. DC-DC Switching; VIN=3.6V, VPA=1.2V, IOUT=50mA 1µs/Div www.austriamicrosystems.com 20mV/Div PWM 2V/Div 4 Bypass 500mA/Div 5 Shutdown Current (nA) Quiescent Current (mA) Vout = 3.4V 1µs/Div Revision 1.04 12 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s Figure 33. DC-DC Soft-Start; RLOAD = 7.5Ω 2V/Div 500mA/Div 200µs/Div 2V/Div REFIN 1A/Div VPA ILX 2V/Div 1A/Div 1V/Div Figure 38. DC-DC Rectangular Wave Output in Bypass Mode; VIN = 3.6V, RLOAD = 7.5Ω 2V/Div Figure 37. DC-DC Rectangular Wave Output in PWM Mode; VIN = 4.5V, RLOAD = 7.5Ω REFIN 1V/Div REFIN ILX 500mA/Div VPA 1V/Div REFIN VPA ILX 200µs/Div VPA 1V/Div Figure 36. DC-DC Sine Wave Output in Bypass Mode; VIN = 3.6V, RLOAD = 7.5Ω 1V/Div Figure 35. DC-DC Sine Wave Output in PWM Mode; VIN = 4.5V, RLOAD = 7.5Ω ILX 200mA/Div 20µs/Div 20µs/Div 10µs/Div www.austriamicrosystems.com 1V/Div PA_EN VPA ILX ILX 200mA/Div VPA 1V/Div PA_EN 2V/Div Figure 34. DC-DC Shutdown 10µs/Div Revision 1.04 13 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s VPA 500mA/Div 500mA/Div ILX 200mA/Div IOUT 500mV/Div VPA VIN ILX 100mV/Div Figure 40. DC-DC Load Transient; IOUT = 0mA to 500mA, VIN = 3.6V, VOUT = 2.5V 50mV/Div Figure 39. DC-DC Line Transient; VIN = 4.0V to 3.5V, VOUT = 1.2V, RLOAD = 10Ω 50µs/Div 50µs/Div Figure 41. LDO Quiescent Current vs. VIN Figure 42. LDO Line Regulation, VOUT vs. VIN 2.9 80 2.88 2.86 60 Output Voltage (V) Quiescent Current (µA) 70 50 40 30 20 2.82 2.8 2.78 2.76 Iout = 0mA Iout = 1mA Iout = 10mA Iout = 20mA 2.74 both LDO's one LDO 10 2.72 2.7 0 1 2 3 4 5 Input Voltage (V) 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 6 Figure 43. LDO PSRR vs. Freq.; VIN = 3.2V, VOUT = 2.85V, VRIPPLE = 200mVPP, COUT =100nF Input Voltage (V) Figure 44. LDO Output Noise vs. Freq.; VIN = 3.2V, VOUT = 2.85V, COUT =100nF 10 0 4mA no Load -10 10mA no Load Noise (µV / Hz) -20 PSRR (dB) 2.84 -30 -40 -50 1 0.1 -60 -70 0.01 -80 10 100 1000 10000 100000 Frequency (Hz) www.austriamicrosystems.com 10 100 1000 10000 100000 Frequency (Hz) Revision 1.04 14 - 25 AS1339 Datasheet - Ty p i c a l O p e r a t i o n C h a r a c t e r i s t i c s 20µs/Div 20mV/Div VLDO VIN 50µs/Div 1V/Div 20mV/Div Figure 48. LDO Line Transient; VIN = 4.0V to 3.5V, IOUT = 10mA 2V/Div VIN VLDO Figure 47. LDO Line Transient; VIN = 5.5V to 3.5V, IOUT = 10mA www.austriamicrosystems.com 20mV/Div VLDO IOUT 50µs/Div 5mA/Div 2V/Div Figure 46. LDO Load Transient; IOUT = 0mA to 10mA, VIN = 3.6V 2V/Div EN2 VLDO Figure 45. LDO Turn ON / OFF Response; VIN = 3.6V, no load 50µs/Div Revision 1.04 15 - 25 AS1339 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS1339 is designed to dynamically power the PA in WCDMA and NCDMA handsets. The device is empowered with a high-frequency, high-efficiency step-down converter, and two LDOs. The step-down converters are capable of delivering 650mA. The PWM control scheme provides fast transient response, while 2MHz switching frequency allows the trade-off between efficiency and small external components. A 110mΩ bypass FET connects the PA directly to the battery during high-power transmission. Figure 49. Block Diagram Li+ Battery IN1A Bypass FET 10µF + PFET IN1B LX 2MHz BUCK REFIN NFET 4.7µF PGND 2.85V LDO1 BASEBAND PROCESSOR GPIO GPIO GPIO 2.5x REFIN PAB PAA DAC 2.2µH PA_EN EN1 EN2 TEST Not Connected LDO1 Control Logic 1µF REF 2.85V LDO2 LDO2 IN2 0.1µF ROFF AS1339 0.1µF ROFF NC AGND Operating the AS1339 The AS1339’s control block turns on the internal PFET (P-channel MOSFET) switch during the first part of each switching cycle, thus allowing current to flow from the input through the inductor to the output filter capacitor and load. The inductor limits the current to a ramp with a slope of (VIN - VOUT) / L, by storing energy in a magnetic field. During the second part of each cycle, the controller turns the PFET switch off, blocking current flow from the input, and then turns the NFET (N-channel MOSFET) synchronous rectifier on. As a result, the inductor’s magnetic field collapses, generating a voltage that forces current from ground through the synchronous rectifier to the output filter capacitor and load. While the stored energy is transferred back into the circuit and depleted, the inductor current ramps down with a slope of VOUT / L. The output filter capacitor stores charge when the inductor current is high, and releases it when low, smoothing the voltage across the load. The output voltage is regulated by modulating the PFET switch on-time to control the average current sent to the load. The output voltage is equal to the average voltage at the LX pin. While in operation, the output voltage is regulated by switching at a constant frequency and then modulating the energy per cycle to control the power to the load. Energy per cycle is set by modulating the PFET switch on-time pulse width to control the peak inductor current. This is done by comparing the signal from the current-sense amplifier with a slope compensated error signal from the voltage-feedback error amplifier. At the beginning of each cycle, the clock turns on the PFET switch, causing the inductor current to ramp up. When the current sense signal ramps past the error amplifier signal, the PWM comparator turns off the PFET switch and turns on the NFET synchronous rectifier, ending the first part of the cycle. If an increase in load pulls the output down, the error amplifier output increases, which allows the inductor current to ramp higher before the comparator turns off the PFET. This increases the average current sent to the output and www.austriamicrosystems.com Revision 1.04 16 - 25 AS1339 Datasheet - D e t a i l e d D e s c r i p t i o n adjusts for the increase in the load. Before appearing at the PWM comparator, a slope compensation ramp from the oscillator is subtracted from the error signal for stability of the current feedback loop. Internal Synchronous Rectifier To reduce the rectifier forward voltage drop and the associated power loss, the AS1339 uses an internal NFET as a synchronous rectifier. The big advantage of a synchronous rectification is the higher efficiency in a condition where the output voltage is low compared to the voltage drop across an ordinary rectifier diode. During the inductor current down slope in the second part of each cycle the synchronous rectifier is turned on. Before the next cycle the synchronous rectifier is turned off. There is no need for an external diode because the NFET is conducting through its intrinsic body diode during the transient intervals before it turns on. Bypass Mode This mode connects IN1A and IN1B directly to PAA and PAB with the internal 110mΩ (typ) bypass FET, while the stepdown converter is forced into 100% duty-cycle operation during high-power transmission. Due to the low on-resistance in this mode, the result is low dropout, high efficiency and a high output current capability. The AS1339 enters bypass mode automatically when VIN ≤ 2.69 x VREFIN and thus prevents excessive output ripple as the step-down converter approaches dropout. Due to an internal limitation of VREFIN ≤ 1.5V the maximum output voltage is limited to 2.78 x 1.5V = 4.17V in Bypass Mode. Shutdown Mode To put the PA step-down converter in shutdown mode, connect PA_EN to GND or disconnect PA_EN (NC =>logic-low). During shutdown mode, the control circuitry, internal switching MOSFET, and synchronous rectifier are turned off and LX becomes high impedance. For normal operation, connect PA_EN to IN1A/B or logic-high. To place LDO1 or LDO2 in shutdown mode, connect EN1 or EN2 to GND or disconnect EN1 or EN2 (NC => logic-low). The outputs of the LDOs are pulled to ground through an internal 100Ω resistor during shutdown. When the PA stepdown and LDOs are all in shutdown, the AS1339 enters a very low power state, where the input current drops to 0.8μA (typ). Note: All enable Pins (PA_EN, EN1 and EN2) have an internal 110kΩ pull-down resistance. Soft-Start The internal soft-start circuitry of the PA step-down converter limits inrush current at startup, reducing transients on the input source. Soft-start is favorable for supplies with high output impedance such as Li+ and alkaline cells. The DC-DC can start-up with full output load of 7.5Ω. Analog REFIN Control The PA step-down converter uses REFIN to set the output voltage, which enables the converter to operate in applications requiring dynamic voltage control. The output voltage is limited to an upper level of 3.85V, when operating in PWM mode. In Bypass mode the output voltage is limited to VIN. Notes: 1. VOUT = 2.5 x VREFIN 2. If REFIN is left floating the output voltage of the step-down converter can assume any value between 0.6V and VIN. Thermal Overload Protection To prevent the AS1339 from short-term misuse and overload conditions the chip includes a thermal overload protection. To block the normal operation mode the device is turning off the PFET and the NFET in PWM and bypass mode as soon as the junction temperature exceeds 140°C. To resume the normal operation the temperature has to drop below 130°C. Note: Continuing operation in thermal overload conditions may damage the device and is considered bad practice. www.austriamicrosystems.com Revision 1.04 17 - 25 AS1339 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9 Application Information The AS1339 is designed to supply power amplifiers for RF applications. The output power of the PA can directly be controlled via the output voltage of the AS1339. Figure 50 shows a typical application. Figure 50. Typical Application Diagram Li+ Battery IN1A CIN1 + 2.2µH LX IN1B PAB COUT PAA REFIN DAC PGND LDO1 BASEBAND PROCESSOR PA_EN GPIO CLDO1 AS1339 BIAS EN1 EN2 TEST Not Connected GPIO GPIO RFIN IN LDO2 RFOUT PA1 CLDO2 NC IN2 BIAS AGND CIN2 RFIN IN RFOUT PA2 Capacitor Selection for Step-Down Converter Input Capacitor To reduce the current peaks drawn from the battery or power source and to reduce the switching noise in the device an input capacitor is highly recommended. At the switching frequency the impedance of the capacitor should be very low. It’s recommended to use a X5R or X7R dielectric multilayer ceramic capacitor due to their small size, low ESR and small temperature coefficients. For most applications a 4.7µF capacitor is sufficient. To decrease the interfering noise and to lower the input ripple the capacitor value can be set higher (e.g. 10µF). Output Capacitor To ensure a stable loop regulation and a small output voltage ripple a low impedance capacitor should be used. It’s recommended to use a X5R or X7R dielectric multilayer ceramic capacitor due to their small size, low ESR and small temperature coefficients. For most applications a 4.7µF capacitor is sufficient. To achieve a better load-transient performance and to decrease the output ripple the capacitor value can be set higher (e.g. 10µF). Table 6. Recommended Capacitors for the Step-Down Converter Name CIN1, COUT Part Number C Voltage Type Size GRM21BR60J106KE01 10µF 6.3V X5R 0805 GRM21BR61C475KA88 4.7µF 16V X5R 0805 C0603C475K8PAC7867 4.7µF 10V X5R 0603 www.austriamicrosystems.com Revision 1.04 Manufacturer Murata www.murata.com KEMET www.kemet.com 18 - 25 AS1339 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Capacitor Selection for LDO’s Input Capacitor The capacitor for the LDO Input should have at least a value of the sum of the output capacitors of LDO1 and LDO2. With a larger input capacitance and lower ESR a better noise rejection and line transient response can be achieved. Output Capacitor For the LDO outputs the capacitor value depends on the needed load current. For a stable operation with rated maximum load currents a minimum output capacitor of 1µF is recommended. At light loads of 10mA or less a 0.1µF capacitor is sufficient. With larger output capacitance a reduced output noise, improved load-transient response, better stability and power-supply rejection can be achieved. Table 7. Recommended Capacitors for the LDO’s Name CIN2, CLDO1, CLDO2 Part Number C Voltage Type Size C0402C104K4RAC 100nF 16V X7R 0402 GRM155R61A105KE15 1µF 10V X5R 0402 Manufacturer KEMET www.kemet.com Murata www.murata.com Inductor Selection For most applications the value of the external inductor should be in the range of 1.5µH to 4.7µH as the inductor value has a direct effect on the ripple current. The selected inductor must be rated for its DC resistance and saturation current. The inductor ripple current (ΔIL) decreases with higher inductance and increases with higher VIN to VOUT. In Equation (EQ 3) the maximum inductor current in PWM mode under static load conditions is calculated. The saturation current of the inductor should be rated higher than the maximum inductor current as calculated with Equation (EQ 4). This is recommended because the inductor current will rise above the calculated value during heavy load transients. The inductor current ripple ΔIL (see EQ 3) is defined by the slope of the current (dI / dt) (see EQ 1) multiplied by the PFET on-time tON (see EQ 2). Figure 51. Ripple Current Diagram IL ILmax ΔIL IOUTmax dI dt t tON 1/f V IN – V OUT dI ----- = ---------------------------dt L 1 t ON = DutyCycle × --f www.austriamicrosystems.com V OUT DutyCycle = ------------V IN Revision 1.04 (EQ 1) (EQ 2) 19 - 25 AS1339 Datasheet - A p p l i c a t i o n I n f o r m a t i o n V OUT × ( V IN – V OUT ) ΔI L = -----------------------------------------------------V IN × f × L (EQ 3) ΔI L I LMAX = I OUTMAX + -------2 (EQ 4) f .... Switching Frequency (2.0MHz typical) L .... Inductor Value ILMAX .... Maximum Inductor current ΔIL .... Peak to Peak inductor ripple current IOUTMAX .... Applied load current Accepting larger values of ripple current allows the use of low inductance values, but results in higher output voltage ripple, greater core losses, and lower output current capability. The total losses of the coil have a strong impact on the efficiency of the dc/dc conversion and consist of both the losses in the dc resistance and the following frequencydependent components: 1. 2. 3. 4. The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies) Additional losses in the conductor from the skin effect (current displacement at high frequencies) Magnetic field losses of the neighboring windings (proximity effect) Radiation losses Note: For highest efficiency, a low DC-resistance inductor is recommended. Table 8. Recommended Inductors Part Number L DCR MLP2520S1R5S 1.5µH 80mΩ Current Rating Dimensions (L/W/T) 1.5A 2.5x2.0x1.2mm MLP2520S2R2S 2.2µH 110mΩ 1.2A 2.5x2.0x1.2mm MLP2520S3R3S 3.3µH 110mΩ 1.0A 2.5x2.0x1.2mm EPL2014-222MLC 2.2µH 120mΩ 0.98A 2.2x2.0x1.4mm EPL2014-332MLC 3.3µH 152mΩ 0.8A 2.2x2.0x1.4mm EPL2014-472MLC 4.7µH 231mΩ 0.65A 2.2x2.0x1.4mm XPL2010-222ML 2.2µH 156mΩ 1.2A 2.0x1.9x1.0mm XPL2010-332ML 3.3µH 207mΩ 0.925A 2.0x1.9x1.0mm www.austriamicrosystems.com Revision 1.04 Manufacturer TDK www.tdk.com Coilcraft www.coilcraft.com 20 - 25 AS1339 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Figure 53. Efficiency Comparison of different Inductors; VIN = 3.9V, VOUT = 1.5V 100 100 90 90 80 80 70 70 Efficiency (%) . Efficiency (%) . Figure 52. Efficiency Comparison of different Inductors; VIN = 3.9V, VOUT = 1.0V 60 50 40 30 MLP2520S1R5S 20 MLP2520S3R3S 10 EPL2014-332 MLP2520S2R2S EPL2014-222 EPL2014-472 0 60 50 40 30 MLP2520S1R5S 20 MLP2520S3R3S 10 EPL2014-332 MLP2520S2R2S EPL2014-222 EPL2014-472 0 10 100 1000 10 Output Current (mA) 100 1000 Output Current (mA) Example The following system should be designed: - A supply with a Lithium-Ion Battery = 4.5V - VOUT = 3.0V - IOUTMAX = 500mA For the first step VREF is calculated as shown in Equation (EQ 5). V OUT V REF = ------------- = 1, 2V 2, 5 V IN ≤ 2, 69 × V REF (EQ 5) (EQ 6) Due to Equation (EQ 6): VIN = 3.23V If VIN is falling below 3.23V the device is going into Bypass mode (see Bypass Mode on page 17). Hence a 2.2µH coil is used, ΔIL can be calculated with Equation (EQ 3): ΔIL= 227mA With this result IMAX can be calculated with Equation (EQ 4): IMAX = 614mA. The saturation current of the coil should be chosen slightly higher than IMAX because heavy load transients could increase the peak current. For a short period of time (~50µs) the peak inductor current can rise up to a value of approximately 1.1A (p-channel MOSFET peak current limit). In this case a coil with a rated saturation current of ~800mA can be chosen. www.austriamicrosystems.com Revision 1.04 21 - 25 AS1339 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Layout Considerations High peak currents of up to 1.1A and a high switching frequency makes the PCB layout important. Following rules should be considered: - The power traces (IN1A, IN1B, IN2, LX, PAA, PAB, PGND) should be kept as short, direct and wide as practical. All capacitors should be placed as close as possible near the device. Try to keep the serial resistance (ESR) of CLDO1 and CLDO2 as low as possible. The negative terminations of the capacitors COUT and CIN should be kept as close to each other as possible. A starpoint to PGND is recommended. As shown in Figure 54 the current path between the pins IN1A/IN1B (C3/C4) and pin PGND (A4) via CIN1 is kept as short as possible. Also the current path between the pins PAB/PAA (D3/D4) and pin PGND (A4) via COUT is very close. The negative terminals of CIN1 and COUT are connected to pin PGND (A4) as a starpoint. In order to keep noise emissions suppressed the connection between pin LX (B4) and the pins PAB/PAA (D3/D4) via the coil is kept very short. A shielded coil is recommended. To keep the influence of the DC-DC on the LDOs in terms of supply ripple and noise quite low the IN1, IN2 and AGND, PGND path are separated in the layout. These power paths should be connected via a starpoint directly at the supply. Figure 54. Layout for Space Limited Applications www.austriamicrosystems.com Revision 1.04 22 - 25 AS1339 Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s 10 Package Drawings and Markings The devices are available in a 16-pin WLP (2x2mm) package. Figure 55. 16-pin WLP (2x2mm) Package 2015±20 257.5±20 257.5±20 2015±20 www.austriamicrosystems.com Revision 1.04 23 - 25 AS1339 Datasheet - O r d e r i n g I n f o r m a t i o n 11 Ordering Information The devices are available as the standard products shown in Table 9. Table 9. Ordering Information Part Number AS1339-BWLT Marking Description Delivery Form Package AS1339 650mA RF Step-Down DC-DC for PA, with two LDOs Tape and Reel 16-pin WLP (2x2mm) All devices are RoHS compliant and free of halogene substances. www.austriamicrosystems.com Revision 1.04 24 - 25 AS1339 Datasheet Copyrights Copyright © 1997-2009, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. 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No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG Tobelbaderstrasse 30 A-8141 Unterpremstaetten - Graz, Austria Tel: +43 (0) 3136 500 0 Fax: +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact-us www.austriamicrosystems.com Revision 1.04 25 - 25