19-0777; Rev 0; 4/07 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power Features The MAX8805Y/MAX8805Z high-frequency step-down converters are optimized for dynamically powering the power amplifier (PA) in WCDMA or NCDMA handsets. The devices integrate a high-efficiency PWM step-down converter for medium- and low-power transmission, and a 60mΩ typical bypass FET to power the PA directly from the battery during high-power transmission. Dual 200mA low-noise, high-PSRR low-dropout regulators (LDOs) for PA biasing are also integrated. Two switching frequency options are available—2MHz (MAX8805Y) and 4MHz (MAX8805Z)—allowing optimization for smallest solution size or highest efficiency. Fast switching allows the use of small ceramic 2.2µF input and output capacitors while maintaining low ripple voltage. The feedback network is integrated, further reducing external component count and total solution size. The MAX8805Y/MAX8805Z use an analog input driven by an external DAC to control the output voltage linearly for continuous PA power adjustment. At high duty cycle, the MAX8805Y/MAX8805Z automatically switch to the bypass mode, connecting the input to the output through a low-impedance (60mΩ typ) MOSFET. The user can also enable the bypass mode directly through a logic-control input. The LDOs in the MAX8805Y/MAX8805Z are designed for low-noise operation (35µVRMS typ). Each LDO is individually enabled through its own logic control interface. The MAX8805Y/MAX8805Z are available in a 16-bump, 2mm x 2mm WLP package (0.7mm max height). ♦ PA Step-Down Converter 7.5µs (typ) Settling Time for 0.8V to 3.4V Output Voltage Change Dynamic Output Voltage Setting from 0.4V to VBATT 60mΩ pFET and 100% Duty Cycle for Low Dropout 2MHz or 4MHz Switching Frequency Low Output-Voltage Ripple 600mA Output Drive Capability 2% Maximum Accuracy Tiny External Components Applications ♦ Dual Low-Noise LDOs Low 35µVRMS (typ) Output Noise High 70dB (typ) PSRR Guaranteed 200mA Output Drive Capability Individual ON/OFF Control ♦ Low 0.1µA Shutdown Current ♦ 2.7V to 5.5V Supply Voltage Range ♦ Thermal Shutdown ♦ Tiny 2mm x 2mm x 0.7mm WLP Package (4 x 4 Grid) Typical Operating Circuit VPA 0.4V TO VBATT BATT 2.7V TO 5.5V 2.2μF IN1A PAA IN1B PAB LX WCDMA/NCDMA Cellular Handsets 1μH Wireless PDAs PA ON/OFF Smartphones PA_EN PGND REFBP Ordering Information ANALOG CONTROL PINPACKAGE PKG CODE SWITCHING FREQUENCY (MHz) MAX8805YEWExy+T* 16 WLP-16 W162B2+1 2 MAX8805ZEWExy+T* 16 WLP-16 W162B2+1 4 REFIN HP AGND LDO1 ON/OFF EN1 LDO1 LDO2 ON/OFF EN2 VLDO1 UP TO 200mA LDO2 VLDO2 UP TO 200mA FORCED BYPASS PART 2.2μF MAX8805Z BATT 2.7V TO 5.5V IN2 +Denotes a lead-free package. T = Tape and reel package. *xy is the output voltage code (see Table 1 in the Output Voltages section). Note: All devices are specified over the -40°C to +85°C operating temperature range. Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX8805Y/MAX8805Z General Description MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power ABSOLUTE MAXIMUM RATINGS IN1A, IN1B, IN2, REFIN, EN2, REFBP to AGND ...-0.3V to +6.0V PAA, PAB, PA_EN, HP to AGND....-0.3V to (VIN1A/VIN1B + 0.3V) LDO1, LDO2, EN1 to AGND ......................-0.3V to (VIN2 + 0.3V) IN2 to IN1B/IN1A ...................................................-0.3V to +0.3V PGND to AGND .....................................................-0.3V to +0.3V LX Current ......................................................................0.7ARMS IN1A/IN1B and PAA/PAB Current .....................................2ARMS PAA and PAB Short Circuit to GND or IN...................Continuous Continuous Power Dissipation (TA = +70°C) 16-Bump WLP (derate 12.5mW/°C above +70°C).............1W Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Bump Temperature (soldering, reflow) ............................+235°C Note: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and Convection reflow. Preheating is required. Hand or wave soldering is not allowed. Stresses beyond those listed under “Absolute Maximum Ratings” 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 the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VIN1A = VIN1B = VIN2 = VPA_EN = VEN1 = VEN2 = 3.6V, VHP = 0V, VREFIN = 0.9V, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 5.5 V 2.63 2.70 V TA = +25°C 0.1 4 TA = +85°C 0.1 MAX8805Y 3500 MAX8805Z 5000 INPUT SUPPLY Input Voltage VIN1A, VIN1B, VIN2 2.7 Input Undervoltage Threshold VIN1A, VIN1B, VIN2 rising, 180mV typical hysteresis 2.52 Shutdown Supply Current VPA_EN = VEN1 = VEN2 = 0V VPA_EN = 0V, ILDO1 = ILDO2 = 0A No-Load Supply Current VEN1 = VEN2 = 0V, IPA = 0A, switching 150 VEN1 = VEN2 = 0V, VHP = 3.6V µA 250 µA 150 THERMAL PROTECTION Thermal Shutdown TA rising, 20°C typical hysteresis +160 °C LOGIC CONTROL PA_EN, EN1, EN2, HP LogicInput High Voltage 2.7V ≤ VIN1A = VIN1B = VIN2 ≤ 5.5V PA_EN, EN1, EN2, HP LogicInput Low Voltage 2.7V ≤ VIN1A = VIN1B = VIN2 ≤ 5.5V Logic-Input Current (PA_EN, EN1, EN2, HP) VIL = 0V or VIH = VIN1A = 5.5V 1.4 V 0.4 TA = +25°C 0.01 TA = +85°C 0.1 1 V µA REFIN REFIN Common-Mode Range REFIN to PA_ Gain (Falling Edge) 0.1 VREFIN = 0.4V, 0.9V, 1.7V, 2.2V 1.96 REFIN Input Resistance REFIN Dual Mode™ Threshold 2.00 V 2.04 V/V 540 VREFIN rising, 50mV hysteresis 0.45 x VIN2 0.465 x VIN2 Dual Mode is a trademark of Maxim Integrated Products, Inc. 2 2.2 _______________________________________________________________________________________ kΩ 0.48 x VIN2 V 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power (VIN1A = VIN1B = VIN2 = VPA_EN = VEN1 = VEN2 = 3.6V, VHP = 0V, VREFIN = 0.9V, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX p-channel MOSFET switch, ILX = -40mA 0.18 0.6 n-channel MOSFET rectifier, ILX = 40mA 0.15 0.6 TA = +25°C 0.1 5 TA = +85°C 1 UNITS LX On-Resistance LX Leakage Current VIN1A = VIN1B = VIN2 = 5.5V, VLX = 0V p-Channel MOSFET Peak Current Limit VLX = 0V n-Channel MOSFET Valley Current Limit µA 0.7 0.9 1.1 A 0.5 0.7 0.9 A Minimum On- and Off-Times Power-Up Delay Ω 0.1 From PA_EN rising to LX rising µs 150 250 TA = +25°C 0.060 0.1 TA = +85°C 0.1 µs BYPASS On-Resistance p-channel MOSFET bypass, IOUT = -90mA Bypass Current Limit VPA = 0 Step-Down Current Limit in Bypass VLX = 0 Total Bypass Current Limit VLX = VPA = 0 Bypass Off-Leakage Current VIN1A = VIN1B = VIN2 = 5.5V, VPAA = VPAB = 0V Ω 0.8 1.2 1.8 A 0.7 0.9 1.1 A A 2.1 2.9 TA = +25°C 1.5 0.01 10 TA = +85°C 1 µA LDO1 Output Voltage VLDO1 VIN2 = 5.5V, ILDO1 = 1mA; VIN2 = 3.4V, ILDO1 = 100mA MAX8805YEWEAA+T 1.746 1.8 1.854 MAX8805YEWEBC+T 2.425 2.5 2.575 MAX8805YEWECC+T 2.619 2.7 2.781 MAX8805YEWEDD+T 2.716 2.8 2.884 MAX8805YEWEEE+T 2.765 2.85 2.936 MAX8805YEWEGG+T 2.910 3.0 3.090 Output Current 200 V mA Current Limit VLDO1 = 0V 550 750 mA Dropout Voltage ILDO1 = 100mA, TA = +25°C (VLDO1 ≥ 2.5V) 70 200 mV Line Regulation VIN2 stepped from 3.5V to 5.5V, ILDO1 = 100mA 2.4 mV Load Regulation ILDO1 stepped from 50µA to 200mA 25 mV Power-Supply Rejection ΔVLDO1 / ΔVIN2 10Hz to 10kHz, CLDO1 = 1µF, ILDO1 = 30mA 70 dB 250 Output Noise 100Hz to 100kHz, CLDO1 = 1µF, ILDO1 = 30mA 35 µVRMS Output Capacitor for Stable Operation 0 < ILDO1 < 10mA 100 nF 0 < ILDO1 < 200mA 1 µF Shutdown Output Impedance VEN1 = 0V 1 kΩ _______________________________________________________________________________________ 3 MAX8805Y/MAX8805Z ELECTRICAL CHARACTERISTICS (continued) MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power ELECTRICAL CHARACTERISTICS (continued) (VIN1A = VIN1B = VIN2 = VPA_EN = VEN1 = VEN2 = 3.6V, VHP = 0V, VREFIN = 0.9V, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX MAX8805YEWEAA+T 1.746 1.8 1.854 MAX8805YEWEAC+T 2.619 2.7 2.781 MAX8805YEWEAD+T 2.716 2.8 2.884 MAX8805YEWEBE+T 2.765 2.85 2.936 MAX8805YEWEGG+T 2.910 3.0 3.090 550 750 200 UNITS LDO2 Output Voltage VLDO2 VIN2 = 5.5V, ILDO2 = 1mA; VIN2 = 3.4V, ILDO2 = 100mA Output Current 200 V mA Current Limit VLDO2 = 0V Dropout Voltage ILDO2 = 100mA, TA = +25°C 70 Line Regulation VIN2 stepped from 3.5V to 5.5V, ILDO2 = 100mA 2.4 mV Load Regulation ILDO2 stepped from 50µA to 200mA 25 mV Power-Supply Rejection ΔVLDO2 / ΔVIN2 10Hz to 10kHz, CLDO2 = 1µF, ILDO2 = 30mA 70 dB Output Noise 100Hz to 100kHz, CLDO2 = 1µF, ILDO2 = 30mA 35 µVRMS Output Capacitor for Stable Operation 0µA < ILDO2 < 10mA 100 nF 0µA < ILDO2 < 200mA 1 µF Shutdown Output Impedance VEN2 = 0V 1 kΩ 250 mA mV REFBP REFBP Output Voltage 0 ≤ IREFBP ≤ 1µA REFBP Supply Rejection VIN2 stepped from 2.55V to 5.5V 1.237 1.250 1.263 V 0.2 5 mV Note 1: All devices are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by design. 4 _______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power VIN1 = 3.2V 90 EFFICIENCY (%) 100 80 VIN1 = 3.6V 60 40 BYPASS MODE VIN1 = 4.2V 80 90 EFFICIENCY (%) 120 100 MAX8805Y/Z toc02 100 MAX8805Y/Z toc01 BYPASS MODE DROPOUT VOLTAGE (mV) 140 PA STEP-DOWN CONVERTER EFFICIENCY vs. OUTPUT VOLTAGE (MAX8805Y) PA STEP-DOWN CONVERTER EFFICIENCY vs. OUTPUT VOLTAGE (MAX8805Z) VIN1 = 3.6V VIN1 = 3.2V MAX8805Y/Z toc03 BYPASS MODE DROPOUT VOLTAGE vs. PA LOAD CURRENT BYPASS MODE VIN1 = 4.2V VIN1 = 3.6V 80 VIN1 = 3.2V 70 70 20 RPA = 7.5Ω 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0.5 4.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 PA LOAD CURRENT (A) OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) PA STEP-DOWN CONVERTER EFFICIENCY vs. OUTPUT VOLTAGE (MAX8805Z) PA STEP-DOWN CONVERTER EFFICIENCY vs. OUTPUT VOLTAGE (MAX8805Y) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Z) VIN1 = 3.6V VIN1 = 3.2V 70 VIN1 = 4.2V VIN1 = 3.6V 80 VIN1 = 3.2V VPA = 1.8V 90 70 2.0 2.5 3.0 3.5 4.0 VIN1 = 4.2V 70 50 60 1.5 VIN1 = 3.6V RPA = 10Ω 60 1.0 VIN1 = 3.2V 80 60 RPA = 10Ω 0.5 MAX8805Y/Z toc06 MAX8805Y/Z toc05 BYPASS MODE 100 EFFICIENCY (%) VIN1 = 4.2V 80 90 EFFICIENCY (%) BYPASS MODE 100 MAX8805Y/Z toc04 90 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 100 200 300 400 500 600 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) LOAD CURRENT (mA) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Y) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Z) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Y) VIN1 = 3.2V 80 VIN1 = 3.6V VIN1 = 4.2V 70 90 60 80 VIN1 = 3.6V 70 VIN1 = 4.2V VIN1 = 3.2V 100 200 300 400 LOAD CURRENT (mA) 500 600 90 VIN1 = 3.6V 80 VIN1 = 3.2V VIN1 = 4.2V 70 50 50 0 VPA = 1.2V 60 60 50 100 MAX8805Y/Z toc09 90 VPA = 1.2V EFFICIENCY (%) VPA = 1.8V MAX8805Y/Z toc08 100 MAX8805Y/Z toc07 100 EFFICIENCY (%) EFFICIENCY (%) 0.5 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 100 EFFICIENCY (%) RPA = 7.5Ω 60 60 0 0 100 200 300 400 LOAD CURRENT (mA) 500 600 0 100 200 300 400 500 600 LOAD CURRENT (mA) _______________________________________________________________________________________ 5 MAX8805Y/MAX8805Z Typical Operating Characteristics (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Z) VPA = 0.6V 90 EFFICIENCY (%) 90 80 70 VIN1 = 3.6V VIN1 = 4.2V 60 100 80 VIN1 = 4.2V 70 VIN1 = 3.6V VIN1 = 3.2V 60 VIN1 = 3.2V 50 50 100 200 300 400 500 600 0 100 200 300 400 500 600 LOAD CURRENT (mA) LOAD CURRENT (mA) PA STEP-DOWN CONVERTER OUTPUT VOLTAGE vs. LOAD CURRENT PA STEP-DOWN CONVERTER OUTPUT VOLTAGE vs. REFIN VOLTAGE 1.15 3.5 OUTPUT VOLTAGE (V) MAX8805Y 1.20 4.0 MAX8805Y/Z toc12 1.25 MAX8805Z MAX8805Y/Z toc13 0 OUTPUT VOLTAGE (V) MAX8805Y/Z toc11 VPA = 0.6V EFFICIENCY (%) PA STEP-DOWN CONVERTER EFFICIENCY vs. LOAD CURRENT (MAX8805Y) MAX8805Y/Z toc10 100 1.10 3.0 2.5 2.0 1.5 1.0 0.5 1.05 100 200 300 400 500 600 0 LOAD CURRENT (mA) 40 1.2 1.6 2.0 VIN1 = 4.2V, NO LOAD 20 0 -20 -40 -60 REFIN vs. REFIN TO OUT GAIN (MAX8805Y) 50 OUTPUT VOLTAGE ERROR (mV) VIN1 = 3.2V, NO LOAD 60 MAX8805Y/Z toc14 80 0.8 REFIN VOLTAGE (V) REFIN vs. REFIN TO OUT GAIN (MAX8805Z) 100 0.4 VIN1 = 3.2V, NO LOAD 30 VIN1 = 4.2V, NO LOAD MAX8805Y/Z toc15 0 OUTPUT VOLTAGE ERROR (mV) MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power 10 -10 -30 -80 -100 6 -50 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 REFIN VOLTAGE (V) REFIN VOLTAGE (V) _______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power PA STEP-DOWN CONVERTER LIGHT-LOAD SWITCHING WAVEFORMS (MAX8805Z) PA STEP-DOWN CONVERTER LIGHT-LOAD SWITCHING WAVEFORMS (MAX8805Y) MAX8805Y/Z toc16 VPA AC-COUPLED MAX8805Y/Z toc17 20mV/div VPA AC-COUPLED 20mV/div ILX 200mA/div ILX 200mA/div VLX 2V/div VLX 2V/div VPA = 1.2V, IPA = 50mA VPA = 1.2V, IPA = 50mA 400ns/div 400ns/div PA STEP-DOWN HEAVY-LOAD SWITCHING WAVEFORMS (MAX8805Z) PA STEP-DOWN HEAVY-LOAD SWITCHING WAVEFORMS (MAX8805Y) MAX8805Y/Z toc18 MAX8805Y/Z toc19 VPA AC-COUPLED 20mV/div VPA AC-COUPLED 20mV/div ILX 500mA/div ILX 500mA/div VLX 2V/div VLX 2V/div VPA = 1.2V, IPA = 500mA VPA = 1.2V, IPA = 500mA 400ns/div 400ns/div PA STEP-DOWN SOFT-START WAVEFORMS (MAX8805Y) PA STEP-DOWN SOFT-START WAVEFORMS (MAX8805Z) MAX8805Y/Z toc21 MAX8805Y/Z toc20 VPA_EN 2V/div VPA_EN 2V/div VPA 1V/div VPA 1V/div ILX 500mA/div 20μs/div ILX 200mA/div 20μs/div _______________________________________________________________________________________ 7 MAX8805Y/MAX8805Z Typical Operating Characteristics (continued) (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power Typical Operating Characteristics (continued) (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) PA STEP-DOWN CONVERTER LINE TRANSIENT RESPONSE (MAX8805Y) PA STEP-DOWN CONVERTER LINE TRANSIENT RESPONSE (MAX8805Z) MAX8805Y/Z toc23 MAX8805Y/Z toc22 VIN1 500mV/div 3.5V VPA AC-COUPLED 50mV/div ILX 200mA/div VIN1 500mV/div 3.5V VPA AC-COUPLED 50mV/div ILX 200mA/div 10μs/div 10μs/div PA STEP-DOWN CONVERTER LOAD TRANSIENT RESPONSE (MAX8805Z) PA STEP-DOWN CONVERTER LOAD TRANSIENT RESPONSE (MAX8805Y) MAX8805Y/Z toc24 MAX8805Y/Z toc25 500mA IPA 4.0V 4.0V 4.0V 4.0V 500mA 500mA/div IPA ILX 500mA/div ILX 500mA/div VPA AC-COUPLED 100mV/div VPA AC-COUPLED 100mV/div 0mA 0mA 500mA/div 0mA 0mA 10μs/div 10μs/div PA STEP-DOWN CONVERTER OUTPUT VOLTAGE TRANSIENT RESPONSE PA STEP-DOWN CONVERTER FORCED BYPASS-FET TRANSIENT RESPONSE MAX8805Y/Z toc27 MAX8805Y/Z toc26 0.5V VREFIN 500mV/div VHP 0V 1V VPA 500mV/div 500mA/div ILX 10μs/div 8 3.6V 0.5V 0.5V 2V/div 0V VPA 2V/div 1.2V 1.2V 500mA/div ILX 20μs/div _______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power PA STEP-DOWN CONVERTER AUTOMATIC BYPASS-FET TRANSIENT RESPONSE PA STEP-DOWN CONVERTER AUTOMATIC BYPASS-FET TRANSIENT RESPONSE MAX8805Y/Z toc28 MAX8805Y/Z toc29 1.8V VREFIN 1V/div VREFIN IS A 0.4V TO 2V SINUSOIDAL VREFIN SIGNAL 0.6V 0.6V 1V/div 3.6V 3.6V 2V/div VPA 1.2V 1V/div 1.2V VPA 500mA/div ILX ILX 500mA/div 10μs/div 200μs/div PA STEP-DOWN CONVERTER SHUTDOWN RESPONSE (MAX8805Y) PA STEP-DOWN CONVERTER SHUTDOWN RESPONSE (MAX8805Z) MAX8805Y/Z toc31 MAX8805Y/Z toc30 2V 2V VPA_EN 2V/div 0V VPA_EN 2V/div 0V 1.2V 1.2V VPA 2V/div 1V/div VPA ILX ILX 100mA/div 100mA/div 10μs/div 10μs/div LDO1, LDO2 SUPPLY CURRENT vs. SUPPLY VOLTAGE LDO1, LDO2 DROPOUT VOLTAGE vs. LOAD CURRENT 100 50 MAX8805Y/Z toc33 150 150 LDO1, LDO2 DROPOUT VOLTAGE (mV) MAX8805Y/Z toc32 NO-LOAD SUPPLY CURRENT (μA) 200 120 90 60 30 0 0 2.0 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 0 50 100 150 200 LOAD CURRENT (mA) _______________________________________________________________________________________ 9 MAX8805Y/MAX8805Z Typical Operating Characteristics (continued) (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VIN1A = VIN1B = VIN2 = 3.6V, VPA = 1.2V, VLDO1 = 2.85V, VLDO2 = 2.85V, RPA = 7.5Ω, circuit of Figure 5, TA = +25°C, unless otherwise noted.) LDO OUTPUT NOISE SPECTRAL DENSITY vs. FREQUENCY LDO PSRR vs. FREQUENCY 60 50 40 30 20 ILDO = 30mA 10 MAX8805Y/Z toc35 70 1.0E+04 OUTPUT NOISE DENSITY NOISE (nV/√Hz) MAX8805Y/Z toc34 80 PSRR (dB) MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power 1.0E+03 1.0E+02 1.0E+01 0.01 0.1 1 10 100 1000 0.01 0.1 FREQUENCY (kHz) 1 10 100 1000 FREQUENCY (kHz) LDO LINE TRANSIENT RESPONSE LDO1, LDO2 OUTPUT NOISE WAVEFORM MAX8805Y/Z toc37 MAX8805Y/Z toc36 VIN2 4.0V 4.0V 500mV/div 3.5V 50mV/div VLDO_ 5mV/div ILDO_ = 80mA 400μs/div 20μs/div LDO1, LDO2 LOAD TRANSIENT RESPONSE NEAR DROPOUT LDO1, LDO2 TURN ON AND SHUTDOWN RESPONSE MAX8805Y/Z toc39 MAX8805Y/Z toc38 80mA ILDO1 0mA 0mA VLDO1 100mA/div 50mV/div VEN1,2 2V/div VLDO1 2V/div VLDO2 2V/div 80mA ILDO2 0mA 0mA 100mA/div 50mV/div VLDO2 VIN2 = VLDO1,2 + 200mV 20μs/div 10 1ms/div ______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power PIN NAME FUNCTION A1 REFBP Reference Noise Bypass. Bypass REFBP to AGND with a 0.22µF ceramic capacitor to reduce noise on the LDO outputs. REFBP is internally pulled down through a 1kΩ resistor during shutdown. A2 AGND Low-Noise Analog Ground A3 REFIN DAC-Controlled Input. The output of the PA step-down converter is regulated to 2 x VREFIN. When VREFIN reaches 0.465 x VIN2, bypass mode is enabled. A4 PGND Power Ground for PA Step-Down Converter B1 LDO2 200mA LDO Regulator 2 Output. Bypass LDO2 with a 1µF ceramic capacitor as close as possible to LDO2 and AGND. LDO2 is internally pulled down through a 1kΩ resistor when this regulator is disabled. B2 PA_EN PA Step-Down Converter Enable Input. Connect to IN_ or logic-high for normal operation. Connect to GND or logic-low for shutdown mode. B3 EN2 B4 LX Inductor Connection. Connect an inductor from LX to the output of the PA step-down converter. C1 IN2 Supply Voltage Input for LDO1, LDO2, and Internal Reference. Connect IN2 to a battery or supply voltage from 2.7V to 5.5V. Bypass IN2 with a 2.2µF ceramic capacitor as close as possible to IN2 and AGND. Connect IN2 to the same source as IN1A and IN1B. C2 HP High-Power Mode Set Input. Drive HP high to invoke forced bypass mode. Bypass mode connects the input of the PA step-down converter directly to its output through the internal bypass MOSFET. Drive HP low to disable the forced bypass mode. C3, C4 IN1B, IN1A Supply Voltage Input for PA Step-Down Converter. Connect IN1_ to a battery or supply voltage from 2.7V to 5.5V. Bypass the connection of IN1_ with a 2.2µF ceramic capacitor as close as possible to IN1_, and PGND. IN1A and IN1B are internally connected together. Connect IN1_ to the same source as IN2. D1 LDO1 200mA LDO Regulator 1 Output. Bypass LDO1 with a 1µF ceramic capacitor as close as possible to LDO1 and AGND. LDO1 is internally pulled down through a 1kΩ resistor when this regulator is disabled. D2 EN1 D3, D4 LDO2 Enable Input. Connect to IN2 or logic-high for normal operation. Connect to AGND or logic-low for shutdown mode. LDO1 Enable Input. Connect to IN2 or logic-high for normal operation. Connect to AGND or logic-low for shutdown mode. PA Connection for Bypass Mode. Internally connected to IN1_ using the internal bypass MOSFET during PAB, PAA bypass mode. PA_ is connected to the internal feedback network. Bypass PA_ with a 2.2µF ceramic capacitor as close as possible to PA_ and PGND. ______________________________________________________________________________________ 11 MAX8805Y/MAX8805Z Pin Description MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power IN1A IN1B R4 BYPASS FET R5 PAA C1 R3 PAB CURRENT-LIMIT CONTROL HP PWM ERROR COMPARATOR R7 REFIN LX PWM LOGIC R6 C2 PGND STEP-DOWN CURRENT LIMIT R2 R1 IN2 BANDGAP REFBP 1.25V REFERENCE AGND LDO1 CURRENT LIMIT LDO1 ERROR AMP BANDGAP R9 EN1 EN2 CONTROL LOGIC R8 PA_EN R7 BANDGAP LDO2 CURRENT LIMIT LDO2 ERROR AMP R12 R11 R10 Figure 1. Block Diagram 12 ______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power Voltage-Positioning Load Regulation The MAX8805Y/MAX8805Z step-down converters utilize a unique feedback network. By taking DC feedback from the LX node through R1 in Figure 1, the usual phase lag due to the output capacitor is removed, making the loop exceedingly stable and allowing the use of very small ceramic output capacitors. To improve the load regulation, resistor R3 is included in the feedback. This configuration yields load regulation equal to half of the inductor’s series resistance multiplied by the load current. This voltage-positioning load regulation greatly reduces overshoot during load transients or when changing the output voltage from one level to another. However, when calculating the required REFIN voltage, the load regulation should be considered. Because inductor resistance is typically well specified and the typical PA is a resistive load, the MAX8805Y/MAX8805Z VREFIN to VOUT gain is slightly less than 2V/V. Step-Down Converter Bypass Mode During high-power transmission, the bypass mode connects IN1A and IN1B directly to PAA and PAB with the 2.5 5.0 4.5 2.0 4.0 3.5 1.5 3.0 2.5 1.0 2.0 1.5 1.0 0.5 IN2 PA_ REFIN 0.5 REFIN VOLTAGE (V) Step-Down Converter Control Scheme A hysteretic PWM control scheme ensures high efficiency, fast switching, fast transient response, low-output ripple, and physically tiny external components. The control scheme is simple: when the output voltage is below the regulation threshold, the error comparator begins a switching cycle by turning on the high-side switch. This high-side switch remains on until the minimum on-time expires and the output voltage is within regulation, or the inductor current is above the currentlimit threshold. Once off, the high-side switch remains off until the minimum off-time expires and the output voltage falls again below the regulation threshold. During the off period, the low-side synchronous rectifier turns on and remains on until the high-side switch turns on again. The internal synchronous rectifier eliminates the need for an external Schottky diode. Forced and Automatic Bypass Mode Invoke forced bypass mode by driving HP high or invoke automatic bypass mode by applying a high voltage to REFIN. To prevent excessive output ripple as the step-down converter approaches dropout, the MAX8805Y/MAX8805Z enter bypass mode automatically when VREFIN > 0.465 x VIN2 (see Figure 2). Note that IN2 is used instead of IN1 to prevent switching noise from causing false enagement of automatic bypass mode. For this reason, IN2 must be connected to the same source as IN1. IN2 AND PA_ VOLTAGE (V) The MAX8805Y/MAX8805Z are designed to dynamically power the PA in WCDMA and NCDMA handsets. The devices contain a high-frequency, high-efficiency stepdown converter, and two LDOs. The step-down converter delivers over 600mA. The hysteretic PWM control scheme provides extremely fast transient response, while 2MHz and 4MHz switching-frequency options allow the trade-off between efficiency and the smallest external components. A 60mΩ bypass FET connects the PA directly to the battery during high-power transmission. internal 60mΩ (typ) bypass FET, while the step-down converter is forced into 100% duty-cycle operation. The low on-resistance in this mode provides low dropout, long battery life, and high output current capability. 0 0 0 5 10 15 20 25 30 35 40 45 50 TIME (ms) Figure 2. VIN2 and VPA_ with Automatic Entry/Exit into Bypass Mode Shutdown Mode Connect PA_EN to GND or logic-low to place the MAX8805Y/MAX8805Z PA step-down converter in shutdown mode. In shutdown, the control circuitry, internal switching MOSFET, and synchronous rectifier turn off and LX becomes high impedance. Connect PA_EN to IN1_ or logic-high for normal operation. Connect EN1 or EN2 to GND or logic-low to place LDO1 or LDO2, respectively, in shutdown mode. In shutdown, the outputs of the LDOs are pulled to ground through an internal 1kΩ resistor. When the PA step-down and LDOs are all in shutdown, the MAX8805Y/MAX8805Z enter a very low power state, where the input current drops to 0.1µA (typ). ______________________________________________________________________________________ 13 MAX8805Y/MAX8805Z Detailed Description MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power Step-Down Converter Soft-Start The MAX8805Y/MAX8805Z PA step-down converter has internal soft-start circuitry that limits inrush current at startup, reducing transients on the input source. Softstart is particularly useful for supplies with high output impedance such as Li+ and alkaline cells. See the SoftStart Waveforms in the Typical Operating Characteristics. Analog REFIN Control The MAX8805Y/MAX8805Z PA step-down converter uses REFIN to set the output voltage. The output voltage is regulated at twice the voltage applied at REFIN minus the load regulation. This allows the converter to operate in applications where dynamic voltage control is required. Table 1. LDO1 and LDO2 Output Voltage Selection PART FREQUENCY (MHz) LDO1 (V) LDO2 (V) MAX8805YEWEAA+T 2 1.80 1.80 MAX8805YEWEAE+T 2 1.80 2.85 MAX8805YEWEEE+T 2 2.85 2.85 MAX8805ZEWEAA+T 4 1.80 1.80 MAX8805ZEWEAE+T 4 1.80 2.85 MAX8805ZEWEEE+T 4 2.85 2.85 Note: Contact the factory for other output-voltage options. Thermal Shutdown Thermal shutdown limits total power dissipation in the MAX8805Y/MAX8805Z. If the junction temperature exceeds +160°C, thermal-shutdown circuitry turns off the IC, allowing it to cool. The IC turns on and begins soft-start after the junction temperature cools by 20°C. This results in a pulsed output during continuous thermal-overload conditions. Applications Information Output Voltages The MAX8805Y/MAX8805Z PA step-down converters set the PA_ output voltage to twice the voltage applied to REFIN. LDO1 and LDO2 output voltages are determined by the part number suffix, as shown in Table 1. LDO Dropout Voltage The regulator’s minimum input/output differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the MAX8805Y/MAX8805Z LDOs use a p-channel MOSFET pass transistor, their dropout voltages are a function of drain-to-source on-resistance (RDS(ON)) multiplied by the load current (see the Typical Operating Characteristics). Inductor Selection The MAX8805Y operates with a switching frequency of 2MHz and utilizes a 2.2µH inductor. The MAX8805Z operates with a switching frequency of 4MHz and utilizes a 1µH inductor. The higher switching frequency of the MAX8805Z allows the use of physically smaller inductors at the cost of slightly lower efficiency. The lower switching frequency of the MAX8805Y results in greater efficiency at the cost of a physically larger inductor. See the Typical Operating Characteristics for efficiency graphs for both the MAX8805Y and MAX8805Z. 14 The inductor’s DC current rating only needs to match the maximum load of the application because the MAX8805Y/MAX8805Z feature zero current overshoot during startup and load transients. For optimum transient response and high efficiency, choose an inductor with DC series resistance in the 50mΩ to 150mΩ range. See Table 2 for suggested inductors and manufacturers. Output Capacitor Selection For the PA step-down converter, the output capacitor (CPA) is required to keep the output voltage ripple small and ensure regulation loop stability. CPA must have low impedance at the switching frequency. Ceramic capacitors with X5R or X7R dielectric are highly recommended due to their small size, low ESR, and small temperature coefficients. Due to the unique feedback network, the output capacitance can be very low. A 2.2µF capacitor is recommended for most applications. For optimum load-transient performance and very low output ripple, the output capacitor value can be increased. For LDO1 and LDO2, the minimum output capacitance required is dependent on the load currents. For loads less than 10mA, it is sufficient to use a 0.1µF capacitor for stable operation over the full temperature range. With rated maximum load currents, a minimum of 1µF is recommended. Reduce output noise and improve loadtransient response, stability, and power-supply rejection by using larger output capacitors. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. With dielectrics such as Z5U and Y5V, it is necessary to use 2.2µF or larger to ensure stability at temperatures below -10°C. With X7R or X5R dielectrics, 1µF is sufficient at all operating temperatures. These regulators are optimized for ceramic capacitors. Tantalum capacitors are not recommended. ______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power SERIES INDUCTANCE (µH) ESR (Ω) CURRENT RATING (mA) DIMENSIONS (mm) LPO3310 1.0 1.5 2.2 0.07 0.10 0.13 1600 1400 1100 3.3 x 3.3 x 1.0 = 11mm3 MIPF2520 1.0 1.5 2.2 0.05 0.07 0.08 1500 1500 1300 2.5 x 2.0 x 1.0 = 5mm3 MIPS2520 1.3 2.0 0.09 0.11 1500 1200 2.5 x 2.0 x 1.0 = 5mm3 MIPF2016 1.0 2.2 0.11 1100 2.0 x 1.6 x 1.0 = 3.2mm3 Hitachi KSLI-252010 1.5 2.2 0.115 0.080 — 2.5 x 2.0 x 1.0 = 5mm3 Murata LQH32C_53 1.0 2.2 0.06 0.10 1000 790 3.2 x 2.5 x 1.7 = 14mm3 Sumida CDRH2D09 1.2 1.5 2.2 0.08 0.09 0.12 590 520 440 3.0 x 3.0 x 1.0 = 9mm3 CDRH2D11 1.5 2.2 3.3 0.05 0.08 0.10 680 580 450 3.2 x 3.2 x 1.2 = 12mm3 CB2518T 2.2 4.7 0.09 0.13 510 340 2.5 x 1.8 x 2.0 = 9mm3 D3010FB 1.0 0.20 1170 3.0 x 3.0 x 1.0 = 9mm3 D2812C 1.2 2.2 0.09 0.15 860 640 3.0 x 3.0 x 1.2 = 11mm3 D310F 1.5 2.2 0.13 0.17 1230 1080 3.6 x 3.6 x 1.0 = 13mm3 D312C 1.5 2.2 0.10 0.12 1290 1140 3.6 x 3.6 x 1.2 = 16mm3 MANUFACTURER Coilcraft FDK Taiyo Yuden TOKO Input Capacitor Selection The input capacitor (CIN1) of the PA converter reduces the current peaks drawn from the battery or input power source and reduces switching noise in the MAX8805Y/MAX8805Z. The impedance of CIN1 at the switching frequency should be kept very low. Ceramic capacitors with X5R or X7R dielectric are highly recommended due to their small size, low ESR, and small temperature coefficients. A 2.2µF capacitor is recommended for most applications. For optimum noise immunity and low input ripple, the input capacitor value can be increased. For the LDOs, use an input capacitance equal to the value of the sum of the output capacitance of LDO1 and LDO2. Larger input capacitor values and lower ESR provide better noise rejection and line transient response. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. With dielectrics such as Z5U and Y5V, it may be necessary to use two times the sum of the output capacitor values of LDO1 and LDO2 (or larger) to ensure stability at temperatures below -10°C. With X7R or X5R dielectrics, a capacitance equal to the sum is sufficient at all operating temperatures. ______________________________________________________________________________________ 15 MAX8805Y/MAX8805Z Table 2. Suggested Inductors MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power Thermal Considerations In most applications, the MAX8805Y/MAX8805Z do not dissipate much heat due to their high efficiency. However, in applications where the MAX8805Y/ MAX8805Z run at high ambient temperature with heavy loads, the heat dissipated may exceed the maximum junction temperature of the IC. If the junction temperature reaches approximately +160°C, all power switches are turned off and LX and PA_ become high impedance, and LDO1 and LDO2 are pulled down to ground through an internal 1kΩ pulldown resistor. The MAX8805Y/MAX8805Z maximum power dissipation depends on the thermal resistance of the IC package and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. The power dissipated in the device is: PDISS = PPA x (1/ηPA - 1) + ILDO1 x (VIN2 - VLDO1) + ILDO2 x (VIN2 -VLDO2) where ηPA is the efficiency of the PA step-down converter and PPA is the output power of the PA step-down converter. The maximum allowed power dissipation is: where (T JMAX - T A ) is the temperature difference between the MAX8805Y/MAX8805Z die junction and the surrounding air; θJA is the thermal resistance of the junction through the PCB, copper traces, and other materials to the surrounding air. PCB Layout High switching frequencies and relatively large peak currents make the PCB layout a very important part of design. Good design minimizes excessive EMI on the feedback paths and voltage gradients in the ground plane, resulting in a stable and well-regulated output. Connect CIN1 close to IN1A/IN1B and PGND. Connect the inductor and output capacitor as close as possible to the IC and keep their traces short, direct, and wide. Keep noisy traces, such as the LX node, as short as possible. Figure 3 illustrates an example PCB layout and routing scheme. PMAX = (TJMAX - TA) / θJA 16 ______________________________________________________________________________________ EN2 REFIN HP PA_EN MAX8805Y/MAX8805Z EN1 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power PGND AGND CBYP CIN1 CPA CLDO2 3.8mm CIN2 VPA CLDO1 LDO1 LDO2 VIN LPA 5.5mm Figure 3. Recommended PCB Layout ______________________________________________________________________________________ 17 MAX8805Y/MAX8805Z 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power IN1A Li+ BATTERY MAX8805Y/MAX8805Z 2.2μF IN1B REFIN DAC LX 2MHz OR 4MHz BUCK 1μH OR 2.2μH* PBA PBB BASEBAND PROCESSOR 2.2μF PGND PA_EN GPIO HP GPIO EN1 GPIO IN PA1 CONTROL EN2 GPIO EN/BIAS REFBP IN2 REF 1μF AGND 0.22μF LDO1 0.1μF LDO1 LDO2 LDO2 0.1μF EN/BIAS IN PA2 *1μH FDK MIPS 2520D1R0 2.2μH FDK MIPF 2520D2R2 Figure 4. Typical Application Circuit Using LDOs for PA Enable/Bias 18 ______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power MAX8805Y/MAX8805Z IN1A Li+ BATTERY MAX8805Y/MAX8805Z 2.2μF IN1B REFIN DAC LX 2MHz OR 4MHz BUCK 1μH OR 2.2μH* PBA PBB BASEBAND PROCESSOR 2.2μF PGND GPIO PA_EN HP GPIO EN1 GPIO IN PA CONTROL EN2 GPIO REFBP IN2 REF 2.2μF AGND 0.22μF LDO1 IN 1μF RF RECEIVER LDO1 LDO2 LDO2 IN 1μF RF TRANSMITTER *1μH FDK MIPS 2520D1R0 2.2μH FDK MIPF 2520D2R2 Figure 5. Typical Application Circuit Using LDOs for RF Power ______________________________________________________________________________________ 19 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power MAX8805Y/MAX8805Z Pin Configuration Chip Information PROCESS: BiCMOS TOP VIEW REFBP AGND REFIN PGND A1 A2 A3 A4 LDO2 PA_EN EN2 LX B1 B2 B3 B4 IN2 HP IN1B IN1A C1 C2 C3 C4 LDO1 EN1 PAB PAA D1 D2 D3 D4 (BUMP IN BOTTOM) 16-Bump, 2mm × 2mm WLP 20 ______________________________________________________________________________________ 600mA PWM Step-Down Converters in 2mm x 2mm WLP for WCDMA PA Power 16L WLP.EPS Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 21 © 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. MAX8805Y/MAX8805Z Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)