19-1773; Rev 2; 2/03 KIT ATION EVALU E L B AVAILA +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier Features ♦ Ultra-Compact 4 2.06mm) CSP ♦ On-Chip Power Detector ♦ ICC < 1µA in Shutdown Mode ♦ +2.8V to +4.5V True Single-Supply Operation ♦ ±0.9dB Gain Variation from TA = -40°C to +85°C ♦ Current Adjustable with PDM or DAC Signal ♦ No External Logic Interface Circuitry Required Ordering Information Cellular-Band TDMA/AMPS Dual-Mode Phones PART 2-Way Pagers (2.06mm ✕ ♦ High Efficiency—41% at +30dBm POUT (TDMA) (typ) ________________________Applications PA Modules ✕4 TEMP RANGE PINPACKAGE TOP MARK 2251 EBE MAX2251EBE -40°C to +85°C 4 × 4 UCSP _ _ _ (LOT #) _ _ _ (DATE CODE) Cordless Phones Typical Operating Circuit appears at end of data sheet. Pin Configuration TOP VIEW MAX2251 PIN A1 INDICATOR BIAS2 GND GND GND A1 A2 A3 A4 POWER DETECTOR B1 B2 B3 B4 PD_OUT GND OUT OUT BIAS1 GND VCC GND C1 C2 C3 C4 LOGIC AND BIAS D1 D2 D3 D4 VCC IN SHDN MODE ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX2251 General Description The MAX2251 low-voltage linear power amplifier (PA) is designed for TDMA/AMPS dual-mode phone applications. The device is packaged in an ultra-compact (2.06mm ✕ 2.06mm) chip-scale package (CSP), and delivers over +30dBm of linear power in TDMA operation. An on-chip shutdown feature reduces operating current to 1µA (typ), eliminating the need for an external supply switch. The MAX2251 does not need an external reference voltage, and requires only a few external matching components and no bias circuitry. Another feature of this device is the use of external bias resistors, eliminating wasted “safety-margin” current. This feature also allows current throttleback at lower output power levels, thereby maintaining the highest possible efficiency at all power levels. MAX2251 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier ABSOLUTE MAXIMUM RATINGS VCC to GND ..........................................................-0.3V to +4.5V SHDN, MODE to GND ................................-0.3V to (VCC + 0.3V) BIAS_ to GND.............................................-0.3V to (VCC + 0.3V) RF Input Power ...............................................................+10dBm Continuous Power Dissipation (TA = +70°C) 4 ✕ 4 UCSP (derate 80mW/°C above +70°C) ....................4W Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Thermal Resistance from Junction to Backside.................1°C/W Thermal Resistance from Junction to Ambient (using MAX2251 EV kit)...............................................40°C/W Storage Temperature Range .............................-65°C to +150°C Bump Reflow Temperature .............................................+235°C Continuous Operating Lifetime ...................10 yrs ✕ 0.92(TA - 45°C) (At POUT = +32dBm, for Operating Temperature, TA ≥ 45°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. DC ELECTRICAL CHARACTERISTICS (VCC = +2.8V to +4.5V, no RF signal applied, SHDN = high, TA = -40°C to +85°C, unless otherwise noted. Typical values are measured at VCC = +3.3V and TA = +25°C.) PARAMETER Idle Supply Current CONDITIONS MIN MODE = high Logic High Threshold TYP MAX UNITS 205 255 mA 2.0 V Logic Low Threshold Shutdown Supply Current 0.8 SHDN = MODE = GND VCC = +2.8V to +4.0V 0.6 10 VCC = +4.5V 60 120 Logic High Input Current Logic Low Input Current 2 -1 _______________________________________________________________________________________ V µA 5 µA +1 µA +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier (MAX2251 EV kit, fIN = 824MHz to 849MHz, VCC = VMODE = V SHDN = +3.3V, 50Ω system, NADC modulation, duty cycle = 100%, TA = +25°C, unless otherwise noted. Typical values are at fIN = 836MHz, TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN -4.5σ Frequency Range (Note 2) VMODE = VCC or GND 824 Power Gain POUT = +30dBm 25.7 26.1 Extreme Condition Power Gain TA = -40°C to +85°C, POUT = +30dBm 24.8 25.2 Output Power VCC = +3.3V, meets ACPR specifications Adjacent/Alternate-Channel Power Ratio fOFFSET = 30/60kHz in 25kHz bandwidth TYP 4.5σ MAX UNITS 849 MHz 27.8 dB dB dBm 30 TA = +25oC -29.3/ -47.5 TA = +85°C -28/ -48 -27.4/ -45.4 -27/ -44.6 dBc AMPS Output Power VMODE = VCC, PIN = +8dBm single tone Power-Added Efficiency POUT = +30dBm AMPS Power-Added Efficiency PIN = +8dBm single tone at 836MHz 31.8 32 dBm 41.2 % 51 Turn-On Time (Note 3) Input VSWR % 2 5 1.2:1 1.76:1 µs Maximum Nonharmonic Spurious Due to Load Mismatch VCC = +2.8V to +4.5V, all input power levels, VSWR = 4:1 all phase angle, TA = -40°C to +85°C Noise Power fRF = 849MHz, noise measured at 869MHz, POUT = +30dBm -121 dBm/ Hz AMPS Noise Power fRF = 836MHz, noise measured at 881MHz, POUT = +31dBm -141 dBm/ Hz 45 dBc 29.4 dB -55 Harmonic Suppression (Note 4) Power Detector Range (Note 5) Power Detector Settling Time (Note 6) CDET = 4700pF 27 2 3 dBc µs Guaranteed by design and characterization. Operation outside the frequency range is possible, but has not been characterized. Time when V SHDN transitions to VCC until POUT is within 1dB of its final mean power. Harmonics are measured on the MAX2251 EV kit. The output matching provides some harmonic attenuation in addition to the rejection provided by the IC. The combined suppression is specified. Note 5: The range is defined by the difference between the rated linear output power and the output power that corresponds to VPD = 0.57V. Note 6: Time from when V SHDN transitions high until detector output reaches within 10% of its final value. Note 1: Note 2: Note 3: Note 4: _______________________________________________________________________________________ 3 MAX2251 AC CHARACTERISTICS, TDMA OPERATION Typical Operating Characteristics (MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.) TA = +25°C 10 5 200 150 TA = +25°C TA = -40°C 100 50 TA = -40°C 0 4.5 TA = +25°C 400 300 TA = -40°C 200 0 3.6 2.8 SUPPLY VOLTAGE (V) 4.5 2.8 GAIN vs. OUTPUT POWER 30 MAX2251-05 30 MAX2251-04 WITHOUT THROTTLEBACK 28 28 100 26 TA = +85°C TA = -40°C 24 22 50 -10 -5 0 5 15 GAIN vs. FREQUENCY MAX2251-07 30 28 28 26 26 24 20 25 30 10 15 20 GAIN vs. FREQUENCY GAIN vs. FREQUENCY AMPS VCC = VMODE = VSHDN = +2.8V POUT = +28dBm 34 TA = -40°C 24 30 POUT = +31dBm 32 GAIN (dB) GAIN (dB) TA = +25°C 25 OUTPUT POWER (dBm) VMODE = GND 30 TA = +85°C VCC = +4.5V OUTPUT POWER (dBm) OUTPUT POWER (dBm) POUT = +30dBm VCC = +3.3V 20 10 10 VCC = +2.8V 26 22 20 0 30 TA = +25°C GAIN (dB) GAIN (dB) 200 WITH THROTTLEBACK (MAINTAIN ACPR = -29dBc, ALT <-50dBc) 4.5 SUPPLY VOLTAGE (V) GAIN vs. OUTPUT POWER 300 150 3.6 SUPPLY VOLTAGE (V) SUPPLY CURRENT vs. OUTPUT POWER 250 TA = +85°C 500 100 0 3.6 2.8 SUPPLY CURRENT (mA) MAX2251-02 250 600 MAX2251-06 15 TA = +85°C MAX2251-09 20 300 VMODE = GND NO INPUT DRIVE 700 QUIESCENT CURRENT (mA) TA = +85°C 25 800 MAX2251-08 SHUTDOWN CURRENT (nA) 30 NO INPUT DRIVE 350 QUIESCENT CURRENT (mA) VSHDN = VMODE = GND NO INPUT DRIVE 35 400 MAX2251-01 40 QUIESCENT CURRENT vs. SUPPLY VOLTAGE MAX2251-03 QUIESCENT CURRENT vs. SUPPLY VOLTAGE SHUTDOWN vs. SUPPLY VOLTAGE GAIN (dB) MAX2251 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier 24 28 26 VMODE = VCC 24 22 22 22 20 20 824 829 834 839 FREQUENCY (MHz) 4 844 849 20 824 829 834 839 FREQUENCY (MHz) 844 849 824 829 834 839 FREQUENCY (MHz) _______________________________________________________________________________________ 844 849 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier 44 30 42 25 20 TA = +85°C 34 5 32 VCC = +2.8V PO = +28dBm TA = +25°C 26 28 30 30 824 829 OUTPUT POWER (dBm) 839 844 824 849 50 -30 ACPR/ALT (dBc) 40 30 20 POUT = +30dBm 10 ACPR TA = +25°C -35 -40 ALT TA = +85°C -45 ACPR TA = +85°C ALT TA = +25°C 28 30 32 829 OUTPUT POWER (dBm) -100 MAX2251-16 fIN = 836MHz -25 -110 NOISE POWER (dBm/Hz) -30 -35 ACPR -45 ALT 834 839 844 24 26 OUTPUT POWER (dBm) ALT 824 829 POUT = +30dBm TA = -40°C fIN = 849MHz -130 -140 fIN = 824MHz -150 28 30 839 844 849 NOISE POWER vs. FREQUENCY AMPS fIN = 836MHz -120 834 FREQUENCY (MHz) -100 -110 POUT = +32dBm TA = -40°C -120 fIN = 849MHz -130 -140 fIN = 836MHz fIN = 824MHz -150 -160 -170 -60 22 -45 849 -160 -55 20 ACPR -40 NOISE POWER vs. FREQUENCY ACPR/ALT vs. OUTPUT POWER -50 -35 FREQUENCY (MHz) -20 -40 VSHDN = VCC = +2.8V POUT = +28dBm -55 824 NOISE POWER (dBm/Hz) 26 849 -50 MAX2251-17 24 844 -30 -55 22 839 ACPR/ALT vs. FREQUENCY -25 -50 0 834 FREQUENCY (MHz) ACPR/ALT vs. FREQUENCY -25 MAX2251-13 VMODE = VCC 20 829 FREQUENCY (MHz) POWER-ADDED EFFICIENCY vs. OUTPUT POWER, AMPS 60 834 ACPR/ALT (dBc) 24 38 32 MAX2251-14 22 40 34 30 20 VMODE = GND 42 36 36 0 PAE (%) 44 40 10 VMODE = VCC 46 TA = +25°C 38 15 ACPR/ALT (dBc) TA = -40°C POUT = +31dBm 48 MAX2251-15 35 50 MAX2251-18 46 PAE (%) 40 POUT = +30dBm PAE (%) 48 MAX2251-11 45 PAE (%) 50 MAX2251-10 50 POWER-ADDED EFFICIENCY vs. FREQUENCY, AMPS POWER-ADDED EFFICIENCY vs. FREQUENCY MAX2251-12 POWER-ADDED EFFICIENCY vs. OUTPUT POWER -170 869 874 879 884 FREQUENCY (MHz) 889 894 869 874 879 884 889 894 FREQUENCY (MHz) _______________________________________________________________________________________ 5 MAX2251 Typical Operating Characteristics (continued) (MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.) EVM vs. FREQUENCY EVM (% RMS) 4 3 2 3 TA = +85°C TA = +25°C 2 1 1 0 0 20 22 24 26 28 30 829 834 839 MAX2251-21 TA = +25°C 1.5 1.0 TA = +85°C 0.5 844 0 849 5 TA = -40°C TA = +25°C 1.5 1.0 TA = +85°C 0.5 0 3.0 POWER DETECTOR VOLTAGE (V) 2.0 10 fIN = 836MHz SINGLE-TONE SINE WAVE VSHDN = VCC = +3.3V VMODE = VCC 2.5 2.0 TA = -40°C 1.5 TA = +25°C 1.0 TA = +85°C 0.5 0 0 5 10 15 20 OUTPUT POWER (dBm) 25 30 15 20 OUTPUT POWER (dBm) POWER DETECTOR vs. OUTPUT POWER MAX2251-22 POWER DETECTOR VOLTAGE (V) VMODE = GND fIN = 836MHz SINGLE-TONE SINE WAVE 2.5 TA = -40°C 2.0 FREQUENCY (MHz) POWER DETECTOR vs. OUTPUT POWER 3.0 2.5 0 824 OUTPUT POWER (dBm) 6 3.0 MAX2251-23 4 POWER DETECTOR vs. OUTPUT POWER POUT = +30dBm VSHDN = VMODE = VCC = +3.3V POWER DETECTOR VOLTAGE (V) MAX2251-19 5 MAX2251-20 EVM vs. OUTPUT POWER 5 EVM (% RMS) MAX2251 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier 0 5 10 15 20 25 30 OUTPUT POWER (dBm) _______________________________________________________________________________________ 25 30 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier PIN NAME FUNCTION A1 BIAS2 Second Stage Bias Control. Connect an 11kΩ resistor to GND to set the bias current for the second stage of the PA. A2, A3, A4, B2, C2, C4 GND Ground. Connect to the PC board ground plane with as low an inductance path as possible. B1 PD_OUT B3, B4 OUT C1 BIAS1 First Stage Bias Control. Connect an external 47.5kΩ resistor to ground to set the bias current for the driver stage. C3 VCC Driver Stage Supply Voltage. Connect a pullup inductor to VCC. The pullup inductor can be a PC board trace. D1 VCC Supply Voltage. Bypass to ground with 100pF and 0.01µF capacitors. D2 IN D3 SHDN Shutdown Input. Drive logic low to place the device in shutdown mode. Drive logic high for normal operation. D4 MODE Mode Selection Input. Drive logic high for TDMA/AMPS mode. Drive logic low for higher gain AMPS operation. Power Detector Output. This output is a DC voltage indicating the PA output power. Connect a capacitor to set time constant. The settling time is typically 2µs with a 4700pF capacitor. RF Output. Connect a pullup high-Q inductor to VCC. Requires matching network. Connect B3 and B4 together. RF Input. Requires a highpass L-section impedance matching network. Detailed Description The MAX2251 is a linear PA intended for TDMA/AMPS dual-mode applications. The PA is fully characterized in the 824MHz to 849MHz U.S. cellular band. The PA consists of a driver stage and an output stage; both are independently biased using external resistors. The MAX2251 also features an integrated power detector. Bias Control External resistors connected to C1 and A1 independently set the bias currents of the driver and output stages, respectively. An internal bandgap reference fixes the voltages at C1 and A1. RBIAS1 is typically 47.5kΩ and RBIAS2 is typically 11kΩ. The bias current can be dynamically adjusted by summing a current into the bias pin of interest with an external source such as a DAC. See the Typical Operating Circuit. The Typical Operating Characteristics graph, Supply Current vs. Output Power, demonstrates the current saving with throttleback at low-output power levels. Power Detector The on-chip power detector monitors the output power. The power detector outputs a voltage proportional to the output power. Connect a filter capacitor from PD_OUT to GND to set the power detector time con- stant. The integrated power detector eliminates the need for an external detector circuit. Applications Information External Matching The MAX2251 requires input, interstage, and output matching circuits for proper operation. See the Typical Operating Circuit for suggested component values. Use high-quality components for L2 and C12 in the output-matching circuit for highest efficiency. The MAX2251 EV kit uses a trace as a pullup inductor (approximately 2nH) for the interstage matching. Mode Selection MAX2251 features two modes of operation: high-linear mode and high-gain mode. For TDMA operation, drive MODE high or connect to VCC. For AMPS operation, drive MODE high for best PAE, or drive MODE low for best gain. Layout and Thermal Management Issues The MAX2251 EV kit serves as a layout guide. Use controlled impedance lines on all high-frequency inputs and outputs. Connect GND to the PC board ground plane with as low inductance path as possible. The GND pins also serve as heat sinks. Connect all GND _______________________________________________________________________________________ 7 MAX2251 Pin Description MAX2251 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier pins directly to the topside RF ground. On boards where the ground plane is not on the component side, connect all GND pins to the ground plane with plated through holes, close to the package. PC board traces connecting the GND pins also serve as heat sinks. Make sure that the traces are sufficiently wide. UCSP Reliability The ultra-chip-scale package (UCSP) represents a unique packaging form factor that may not perform equally to a packaged product through traditional mechanical reliability tests. CSP reliability is integrally linked to the user’s assembly methods, circuit board material, and usage environment. The user should closely review these areas when considering use of a CSP. Performance through Operating Life Test and Moisture Resistance remains uncompromised as it is primarily determined by the wafer-fabrication process. 8 Mechanical stress performance is a greater consideration for a CSP. CSPs are attached through direct solder contact to the user’s PC board, foregoing the inherent stress relief of a packaged-product lead frame. Solder joint contact integrity must be considered. Testing done to characterize the CSP reliability performance shows that it is capable of performing reliably through environmental stresses. Users should also be aware that, as with any interconnect system there are electro-migration-based current limits that, in this case, apply to the maximum allowable current in the bumps. Reliability is a function of this current, the duty cycle, lifetime, and bump temperature. See the Absolute Maximum Ratings section of the data sheet for any specific limitations, listed under Continuous Operating Lifetime. Results of environmental stress tests and additional usage data and recommendations are detailed in the UCSP application note, which can be found on Maxim’s website at www.maxim-ic.com. _______________________________________________________________________________________ +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier TOP VIEW OPTIONAL BIAS CURRENT THROTTLEBACK CONTROL DAC RTB1 RTB2 MAX2251 PIN A1 INDICATOR VCC R4 11k BIAS2 GND GND GND A1 A2 A3 A4 L2 7.15nH POWER DETECTOR W = 85 L = 315 GND B1 C9 4700pF C7 0.01µF B2 PD_OUT B3 B4 OUT OUT BIAS1 GND VCC GND C1 C2 C3 C4 C14 4.7pF C13 220pF RFOUT C12 10pF W = 12 L = 125 FERRITE BEAD R3 47.5k VCC C10 0.01µF C11 100pF LOGIC AND BIAS VCC IN D1 D2 C6 100pF MODE D3 D4 W=3 L = 76 W = 35 L = 187 VCC C5 100pF C4 0.01µF SHDN C3 9pF RFIN L1 4.7nH W = 18 L = 80 W = 18 L = 150 SHUTDOWN LOGIC INPUT MODE SELECT INPUT ALL TRANSMISSION LINE UNITS ARE IN MILS. _______________________________________________________________________________________ 9 MAX2251 Typical Operating Circuit 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.) 16L,UCSP.EPS MAX2251 +2.8V, Single-Supply, Cellular-Band Linear Power Amplifier 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.