MAX4473ETA

19-1448; Rev 3; 8/02 Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN Features ♦ Optimized for GSM Timing Requirements ♦ 2.7V to 6.5V Single-Supply Operation ♦ 1.2mA Supply Current ♦ ≤1µA Supply Current in Shutdown Mode ♦ Guaranteed 1.5µs Enable/Disable Times ♦ Active Output Pull-Down in Shutdown Mode ♦ Rail-to-Rail Error Amplifier Output ♦ Rail-to-Rail Power Control Input ♦ Output Drive Capability—500Ω and 300pF Loads ♦ 1V to VCC Current Sense Input Common-Mode Voltage Range ♦ No Phase-Reversal for Common-Mode Voltage from 0 to VCC ♦ External Current Sensing and Gain Setting Resistors Maximize Flexibility ♦ Available in a Space-Saving 8-Pin QFN Ordering Information PART Applications GSM Cellular Phones Cordless Phones Precision Current Control High-Frequency Servo Loops TEMP RANGE PIN-PACKAGE MAX4473EUA -40°C to +85°C 8 µMAX MAX4473ETA -40°C to +85°C 8 QFN MAX4473ESA -40°C to +85°C 8 SO Pin Configuration appears at end of data sheet. Typical Operating Circuit VCC RSENSE 0.1µF RG1 8 VCC 4 PC RG2 1 SR1 2 SR2 A3 A1 BUFFER 3R V-TO-I CONVERTER R A2 OUT 7 ICCPA GC IN VCC ERROR AMPLIFIER PA Q1 MAX4473 3 SHDN GND 5 SR3 6 RG3 RFIN ICCPA = VPC · RG1 4 · RG3 · RSENSE Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. ________________________________________________________________ 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 MAX4473 General Description The MAX4473 PA power control IC is intended for closed-loop bias control of GSM power amplifiers. The device facilitates accurate control of the current delivered to the power amplifier (PA) through a control voltage. The error amplifier senses the voltage drop across an external current-sense resistor placed between the supply and the PA. The output of the error amplifier adjusts the PA gain until the current is proportional to the power control voltage applied to the MAX4473. This unique topology is useful in time-division-multipleaccess (TDMA) systems, such as GSM, where accurate transmit burst shaping and power control is required. User-selectable current sensing and gain setting resistors maximize flexibility. The MAX4473 operates from a single 2.7V to 6.5V supply and typically draws 1.2mA of supply current. The error amplifier has a common-mode range that extends from 1V to V CC . The power control input and error amplifier outputs swing Rail-to-Rail®. A low-power shutdown mode reduces supply current to less than 1µA and activates an on-board active pull-down at the error amplifier output. Fast enable/disable times of 0.9µs reduce average power consumption without compromising dynamic performance. The MAX4473 is available in a space-saving 8-pin QFN package. MAX4473 Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN ABSOLUTE MAXIMUM RATINGS VCC to GND..............................................................................7V SR1, SR2, SR3, PC, SHDN, OUT to GND ............................................-0.3V to (VCC + 0.3V) SR1 to SR3......................................................................0 to VCC OUT and SR3 Short-Circuit Duration to VCC or GND ........................................................Continuous Current into Any Pin..........................................................±50mA Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 4.10mW/°C above +70°C) ............330mW 8-Pin QFN (derate 24.4mW/°C above +70°C) ............1951mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature. .....................................................+150°C Storage Temperature Range. ............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 (VCC = 2.7V to 6.5V, SHDN > 2.4V, MAX4473 test circuit, RG1 = RG2 = 1kΩ ±1%, RG3 = 2.5kΩ ±1%, RSENSE = 100Ω ±1%, RL = 10kΩ, CL = 300pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 6.0V, VPC = 1.0V, TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 6.5 V 1.2 2 mA 0.03 1 µA GENERAL Supply Voltage 2.7 Supply Current VPC = 0 Shutdown Supply Current SHDN < 0.4V, RL = 10kΩ SHDN Input High Voltage 2.4 V SHDN Input Low Voltage SHDN Input Current SHDN = 0 to VCC 0.4 V ±0.5 µA ERROR AMPLIFIER SR1, SR2 Input Offset Voltage ±0.5 ±2 1V < VSR1, VSR2 < VCC at +25°C ±0.5 ±1 SR1, SR2 Input Offset Voltage Drift 1V < VSR1, VSR2 < VCC SR1, SR2 Input Common-Mode Voltage Range Inferred from CMRR test; VPC = GND (Note 2) SR1, SR2 Input Bias Current 1V < VSR1, VSR2 < VCC, VPC = GND, SR3 = unconnected SR1, SR2 Input Bias Offset Current 1V < VSR1, VSR2 < VCC, VPC = GND, SR3 = unconnected SR1, SR2 Shutdown Leakage Current SHDN < 0.4V, VSR1 = VSR2 = VCC µV/°C 10 1 VCC V ±0.04 ±1 µA ±0.001 ±0.2 µA ±0.001 ±0.5 µA Output Current Limit 20 mA Gain-Bandwidth Product RL = 10kΩ, CL = 300pF, fo = 10kHz 2 MHz Phase Margin RL = 10kΩ, CL = 300pF 60 degrees Slew Rate Measured from 30% to 70% of VOUT, RL = 10kΩ, CL = 300pF 1.8 V/µs Power-Supply Rejection Ratio Large-Signal Gain Output Voltage Swing 65 75 80 80 80 80 80 0.15 0.5 mV VCC = 2.7V 1V < VSR1, VSR2 < VCC, VPC = GND VCC = 6.5V 2.7V < VCC < 6.5V, VPC = GND VCC = 6.5V, 0.3V < VOUT < 6V RL = 10kΩ to VCC / 2 VCC = 2.7V, 0.3V < VOUT < 2.4V VCC = 6.5V, 0.7V < VOUT < 5.5V RL = 500Ω to VCC / 2 VCC = 2.7V, 0.7V < VOUT < 2.2V RL = 10kΩ to VCC / 2 RL = 500Ω to VCC / 2 VOUT = VCC / 2 Common-Mode Rejection Ratio 2 1V < VSR1, VSR2 < VCC 85 95 90 130 125 130 120 dB dB dB VCC - 0.15 VCC - 0.5 _______________________________________________________________________________________ V Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN (VCC = 2.7V to 6.5V, SHDN > 2.4V, MAX4473 test circuit, RG1 = RG2 = 1kΩ ±1%, RG3 = 2.5kΩ ±1%, RSENSE = 100Ω ±1%, RL = 10kΩ, CL = 300pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 6.0V, VPC = 1.0V, TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN Capacitive-Load Stability No sustained oscillations (Note 3) Enable/Disable Time From 50% of SHDN edge to VOUT = 1V, VPC = 2V TYP MAX UNITS 300 pF 0.9 1.5 µs ±0.04 ±1 µA 0 GAIN CONTROL BUFFER AND V-TO-I CONVERTER PC Input Bias Current GND < VPC < VCC - 0.15V SR3 Output Current Limit VPC = 2.55V, SR1 = SR2 = VCC 0.750 4 VPC to VRG1 Ratio Measure voltage across RG1, 0.3V < VPC < 2.55V (Note 4) 0.095 0.1 PC Input Bandwidth Bandwidth from VPC to VRG1 mA 0.105 2 V/V MHz Note 1: Limits over temperature are guaranteed by design. Note 2: No output phase-reversal for input common-mode voltage range from GND to VCC. Common-mode range limited by voltage drop across Q1 and RG3. Note 3: Guaranteed by design. Note 4: Error dependent on tolerance of RG1, RG2, and RG3. Specified with 0.1% tolerance resistors. Typical Operating Characteristics (See Test Circuit, TA = +25°C, unless otherwise noted.) VRG1 / VPC RATIO vs. VPC RESPONSE 50 40 0.1025 GAIN (dB) VRG1 / VPC (V/V) 0.8 0 AVCL = 1000 -18 VCC = 6.5V VCM = VCC / 2 -36 VPC = 0 -54 GAIN -72 60 0.1050 TA = +85°C 1.0 0.1075 0.1000 0.0975 PHASE 30 20 -90 ERROR AMPLIFIER 10 -108 0 0.0950 3.0 3.5 4.0 4.5 5.0 5.5 6.0 -20 0.0900 -30 0 6.5 1 2 3 4 5 -144 300pF 100Ω 10 6 10kΩ -162 100 1k 10k 100k 1M -180 10M SUPPLY VOLTAGE (V) VPC (V) FREQUENCY (Hz) ENABLE/DISABLE TIME ERROR-AMPLIFIER OUTPUT LOW VOLTAGE vs. TEMPERATURE ERROR-AMPLIFIER OUTPUT HIGH VOLTAGE vs. TEMPERATURE 0.30 SHDN 2V/div VCC = 6.5V, RL = 500Ω to VCC / 2 0.45 0.25 0.40 VOL (V) 0.20 0.15 VCC = 2.7V, RL = 500Ω to VCC / 2 GND 500ns/div 0.05 0 -40 0.30 0.25 VCC = 2.7V, RL = 500Ω to VCC / 2 0.20 0.15 0.10 OUT 500mV/div VCC = 6.5V, RL = 500Ω to VCC / 2 0.35 GND VCC = 6.5V VPC = 2V MAX4473 toc06 2.5 0.0925 MAX4473 toc05 0.4 SHDN = VCC PC = GND -126 100kΩ -10 VCC - VOH (V) 0.6 MAX4473 toc04 SUPPLY CURRENT (mA) TA = +25°C VCC = 6.0V MAX4473 toc03 70 MAX4473 toc02 MAX4473 toc01 TA = -40°C 1.2 ERROR-AMPLIFIER RESPONSE 0.1100 PHASE (degrees) SUPPLY CURRENT vs. SUPPLY VOLTAGE 1.4 VCC = 2.7V, RL = 10kΩ to VCC / 2 VCC = 6.5V, RL = 10kΩ to VCC / 2 -15 10 35 TEMPERATURE (°C) 60 85 0.10 0.05 0 -40 VCC = 6.5V, RL = 10kΩ to VCC / 2 VCC = 2.7V, RL = 10kΩ to VCC / 2 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX4473 ELECTRICAL CHARACTERISTICS (continued) Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN MAX4473 Pin Description PIN NAME FUNCTION 1 SR1 Inverting Input of Error Amplifier and Drain of V-to-I FET, Q1. Connect to supply side of current-sense resistor, RSENSE, through gain resistor RG1. 2 SR2 Noninverting Input of Error Amplifier. Connect to load side of current-sense resistor, RSENSE, through gain resistor RG2. Set RG2 equal to RG1. 3 SHDN Shutdown Input. Drive SHDN low to disable all amplifiers, pull OUT to GND, set the gate-to-source voltage of the V-to-I FET (Q1) to 0, and reduce supply current to less than 1µA. Drive high or connect to VCC for normal operation. 4 PC Power Control Input. Apply a voltage to PC to set a DC current through the sense resistor to control PA bias. 5 GND Ground 6 SR3 Inverting Input of V-to-I Converter and Source of V-to-I FET, Q1. Connect to ground through gain resistor RG3. 7 OUT Output of Error Amplifier. Connect to gain control pin of power amplifier in bias control applications. 8 VCC +2.7V to +6.5V Voltage Supply Input. Bypass to ground with a 0.1µF capacitor. Detailed Description The MAX4473 is a voltage-controlled, unidirectional, high-side current setting amplifier for applications where accurate control of PA supply current is desired. This device is intended for wireless TDMA based systems (GSM, DECT), where tight restrictions over the PA’s transmit burst and output power require closedloop control over the PA’s output power. When used with a PA, the MAX4473 functions as a voltage-controlled constant current source, accurately setting PA supply current by varying the gain of the PA. If you know the output power versus supply current profile for the PA, you can set the PA’s output power by controlling the amount of supply current delivered to the PA. The MAX4473 is composed of an input buffer (A1), a voltage-to-current converting amplifier (A2), and a railto-rail output error amplifier (A3) (see Typical Operating Circuit). External gain and sense resistors allow programmability for a wide range of applications. In the Typical Operating Circuit, PA supply current flows from the system supply, through the external current-sense resistor (RSENSE), to the PA. The rail-to-rail outputs of the error amplifier, A3, adjust the gain of the PA until the voltage drop across RSENSE equals the voltage drop across external gain resistor, RG1. The voltage drop across RG1 sets the voltage drop across RSENSE, with a larger voltage drop resulting in more current delivered to the PA. The voltage drop across RG1 is set by A1, A2, and the V-to-I FET, Q1. A voltage applied to the PC input of the input buffer is divided by 4 four by a resistor-divider network. A2 forces its inverting input and the source of Q1 to VPC / 4, thus setting a voltage across RG3. The resulting current through RG3 sets the current through RG1. This unique architecture allows the supply current to be set independent of supply voltage. Set PA supply current according to the following equation: ICCPA = ( VPC · RG1 ) / ( 4 · RSENSE · RG3 ) Shutdown Mode When SHDN is a logic-level low (SHDN < 0.4V), amplifiers A1, A2, and A3 are off, Q1 is turned off, and the output of A3 is actively pulled to ground with an Nchannel FET. Supply current is reduced to less than 1µA in shutdown mode. Typical power-up time is 0.9µs and typical power-down time is 0.3µs, using the MAX4473 test circuit. Applications Information Gain Resistor Selection (RG1, RG2, RG3) For proper operation, do not make the value of external gain resistors RG1 and RG2 larger than twice the value of RG3. In most practical applications, choose RG1 smaller than RG3 to limit the voltage drop over RG1 and RSENSE. A large voltage drop over RSENSE substantially reduces the voltage applied to the PA, thus reducing PA output power. Set RG2 equal to RG1 to compensate for the input bias currents of A3. Recommended values for RG3 are between 1kΩ and 10kΩ. _______________________________________________________________________________________ Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN • Efficiency and Power Dissipation: At high current levels, the I2R losses in RSENSE are significant. Take this into consideration when choosing the resistor value and its power dissipation (wattage) rating. Also, the sense resistor’s value may drift if it is allowed to heat up excessively. _________________________Test Circuit Pin Configuration RSENSE TOP VIEW VCC 100Ω 0.1% RG1 1kΩ 1% 0.1µF VCC PC SHDN GND SR1 RG2 1kΩ 1% SR2 MAX4473 2N3904 OUT RL 10kΩ SR3 RG3 2.5kΩ 1% CL 300pF RE 750Ω SR1 1 8 VCC SR2 2 7 OUT 3 6 SR3 PC 4 5 GND MAX4473 SHDN QFN/µMAX/SO Chip Information TRANSISTOR COUNT: 348 _______________________________________________________________________________________ 5 MAX4473 Sense Resistor Selection (RSENSE) Choose RSENSE based on the following criteria: • Voltage Loss: A high R SENSE value causes the power-source voltage to degrade through IR loss. For minimal voltage loss, use low RSENSE values. • Accuracy: A high RSENSE value allows lower currents to be measured more accurately because input offset voltages become less significant when the sense voltage is larger. For best performance, select RSENSE to provide approximately 100mV of sense voltage for the full-scale current in each application. Package Information 4X S 8 E ÿ 0.50±0.1 8 INCHES DIM A A1 A2 b H c D e E H 0.6±0.1 1 L 1 α 0.6±0.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.010 0.014 0.005 0.007 0.116 0.120 0.0256 BSC 0.116 0.120 0.188 0.198 0.016 0.026 6∞ 0∞ 0.0207 BSC 8LUMAXD.EPS (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.) MILLIMETERS MAX MIN 0.05 0.75 1.10 0.15 0.95 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0∞ 6∞ 0.5250 BSC TOP VIEW A1 A2 A α c e L b SIDE VIEW FRONT VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0036 DIM A A1 B C e E H L N E H INCHES MILLIMETERS MAX MIN 0.053 0.069 0.004 0.010 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.050 0.016 MAX MIN 1.75 1.35 0.25 0.10 0.49 0.35 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 REV. J 1 1 SOICN .EPS MAX4473 Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC D A B e C 0∞-8∞ A1 L FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, .150" SOIC APPROVAL DOCUMENT CONTROL NO. 21-0041 REV. B 1 1 6 _________________________________________________________________________________________ Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications in 8-Pin QFN 6, 8, &10L, QFN THIN.EPS PACKAGE OUTLINE, 6, 8 & 10L, QFN THIN (DUAL), EXPOSED PAD, 3x3x0.80 mm 21-0137 C COMMON DIMENSIONS SYMBOL A MIN. 0.70 MAX. 0.80 D 2.90 3.10 E 2.90 3.10 A1 0.00 0.05 L k 0.20 0.40 0.25 MIN A2 0.20 REF. PACKAGE VARIATIONS PKG. CODE N D2 E2 e JEDEC SPEC b T633-1 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF T833-1 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF T1033-1 10 1.50±0.10 2.30±0.10 0.50 BSC MO229 / WEED-3 0.25±0.05 2.00 REF [(N/2)-1] x e PACKAGE OUTLINE, 6, 8 & 10L, QFN THIN (DUAL), EXPOSED PAD, 3x3x0.80 mm 21-0137 C 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 ______________________7 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX4473 Package Information (continued) (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.)