LTC4400-1ES6

LTC4400-1/LTC4400-2 RF Power Controllers with 450kHz Loop BW and 45dB Dynamic Range FEATURES s s s DESCRIPTIO s s s s s s s s s s s s RF Power Amplifier Control in ThinSOTTM Package Internal Schottky Diode Detector with > 45dB Range Wide Input Frequency Range: 300MHz to 2.7GHz (LTC4400-1) 300MHz to 2GHz (LTC4400-2) Autozero Loop Cancels Offset Errors and Temperature Dependent Offsets Wide VCC Range: 2.7V to 6V Automatic Bandwidth Control Improves Low Power Ramp Response Allows Direct Connection to Battery RF Output Power Set by External DAC Internal Frequency Compensation Rail-to-Rail Power Control Output Power Control Signal Overvoltage Protection Low Operating Current: 1mA Low Shutdown Current: 10µA Two Pole PCTL Input Filtering Low Profile (1mm) ThinSOT (LTC4400-1) and 8-Pin MSOP (LTC4400-2) Packages The LTC®4400-1 is a SOT-23 RF power controller for fast turn-on RF power amplifiers operating in the 300MHz to 2.7GHz range. Examples include the Hitachi PF08109B, PF08122B, PF08123B, PF08107B and RF Micro Devices RF3108. For slow turn-on RF power amplifiers refer to the LTC4401-1/LTC4401-2. RF power is controlled by driving the RF amplifier power control pin and sensing the resultant RF output power via a directional coupler or capacitive tap. The RF input voltage is peak detected using an on-chip Schottky diode. This detected voltage is compared to the DAC voltage at the PCTL pin to control the output power. The RF power amplifier is protected against high power control pin voltages. Internal and external offsets are cancelled over temperature by an autozero control loop, allowing accurate low power programming. The shutdown feature disables the part and reduces the supply current to 160mV q q q 1.8 3 q q q q q 270 0.35 16 0 60 450 24 90 270 550 1.4 36 2.4 120 400 mV V µA V kΩ kHz mV q sn4400 4400fas LTC4400-1/LTC4400-2 The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3.6V, SHDN = HI, unless otherwise noted. PARAMETER RF Input Frequency Range RF Input Power Range (LTC4400-1) CONDITIONS LTC4400-1(Note 6) LTC4400-2(Note 6) RF Frequency = 900MHz (Note 6) RF Frequency = 1800MHz (Note 6) RF Frequency = 2400MHz (Note 6) RF Frequency = 2700MHz (Note 6) RF Frequency = 900MHz (Note 6) RF Frequency = 2000MHz (Note 6) Referenced to VCC q ELECTRICAL CHARACTERISTICS MIN 300 300 –28 –26 –24 –22 –28 –26 150 TYP MAX 2700 2000 18 18 16 16 18 18 UNITS MHz MHz dBm dBm dBm dBm dBm dBm Ω RF Input Power Range (LTC4400-2) RF Input Resistance 250 350 Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Specifications over the – 40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Slew rate is measured open loop. The slew time at VPCA/B is measured between 1V and 2V. Note 4: Maximum DAC zero-scale offset voltage that can be applied to PCTL. Note 5: This is the time from SHDN rising edge 50% switch point to VPCA = 0.25V. Note 6: Guaranteed by design. This parameter is not production tested. Note 7: Includes maximum DAC offset voltage and maximum control voltage. Note 8: Bandwidth is calculated using the 10% to 90% rise time: BW = 0.35/rise time Note 9: Measured 12µs after SHDN = HI. TYPICAL PERFOR A CE CHARACTERISTICS PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) LTC4400-1 Detector Characteristics at 900MHz 10000 75°C 25°C –30°C 1000 100 10 1 –28 –22 –16 –10 –4 2 8 RF INPUT POWER (dBm) UW 14 LTC4400-1 Detector Characteristics at 1800MHz 10000 75°C 25°C –30°C LTC4400-1 Detector Characteristics at 2400MHz 10000 75°C 25°C –30°C 1000 1000 100 100 10 10 1 –26 –20 –14 –8 –2 4 10 RF INPUT POWER (dBm) 16 4401 G02 1 –24 –20 –16 –12 –8 –4 0 4 8 RF INPUT POWER (dBm) 12 16 4401 G03 4401 G01 sn4400 4400fas 3 LTC4400-1/LTC4400-2 TYPICAL PERFOR A CE CHARACTERISTICS PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) 10000 PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV) LTC4400-1 Detector Characteristics at 2700MHz 75°C 25°C –30°C 1000 100 10 1 –22 –18 –14 –10 –6 –2 2 6 RF INPUT POWER (dBm) PI FU CTIO S (LTC4400-1/LTC4400-2) RF (Pins 1/8): RF Feedback Voltage. This input is referenced to VCC. The frequency range is 300MHz to 2700MHz for the LTC4400-1 and 300MHz to 2000MHz for the LTC4400-2. This pin has an internal 250Ω termination, an internal Schottky diode detector and peak detector capacitor. GND (Pins 2/4): System Ground. PCTL (Pins 3/5): Analog Input. The external power control DAC drives this input. The amplifier servos the RF power until the RF detected signal equals the DAC signal. The input impedance is typically 90kΩ. VPCB (Pin 3): (LTC4400-2 Only) Power Control Voltage Output. This pin drives an external RF power amplifier power control pin. The maximum load capacitance is 100pF. 4 UW 10 14 LTC4400-2 Detector Characteristics at 900MHz 10000 75°C 25°C –30°C LTC4400-2 Detector Characteristics at 1800MHz 10000 75°C 25°C –30°C 1000 1000 100 100 10 10 1 –28 –22 –16 –10 –4 2 8 RF INPUT POWER (dBm) 14 4400 G05 1 –26 –20 –14 –8 –2 4 10 RF INPUT POWER (dBm) 16 4400 G06 4401 G04 U U U SHDN (Pins 4/6): Shutdown Input. A logic low on the SHDN pin places the part in shutdown mode. A logic high places the part in enable mode. SHDN has an internal 150k pulldown resistor to ensure that the part is in shutdown when the drivers are in a three-state condition. VPCA (Pins 5/2): Power Control Voltage Output. This pin drives an external RF power amplifier power control pin. The maximum load capacitance is 100pF. VCC (Pins 6/1): Input Supply Voltage, 2.7V to 6V. VCC should be bypassed with 0.1µF and 100pF ceramic capacitors. Used as return for RF 250Ω termination. BSEL (Pin 7): (LTC4400-2 Only) Selects VPCA when Low and VPCB when High. This input has an internal 150k resistor to ground. sn4400 4400fas LTC4400-1/LTC4400-2 BLOCK DIAGRA 68Ω 33pF VCC 6 250Ω RF 1 28pF 30k 60µA GND 2 60µA VBG PCTL SHDN NOTE: THE DIRECTIONAL COUPLER SHOWN IN THIS FIGURE MAY BE REPLACED WITH A COUPLING CAPACITOR AND RESISTOR AS DESCRIBED IN APPLICATION NOTE 91 “LOW COST COUPLING METHODS FOR RF POWER DETECTORS REPLACE DIRECTIONAL COUPLERS” W VREF (LTC4400-1) RF IN Li-Ion RF PA 50Ω TXENB AUTOZERO – AZ + + GAIN COMPRESSION – GM + + – 30k 80mV 270kHz FILTER CLAMP + CC BUFFER 5 + RF DET 38k – 30k 30k VPCA – 22k 51k VREF + – 33.4k TXENB 10µs DELAY 6k 12Ω CONTROL 100Ω 150k 4 3 LTC4400-1 4400-1 BD sn4400 4400fas 5 LTC4400-1/LTC4400-2 BLOCK DIAGRA 50Ω VCC 1 TXENB AUTOZERO GAIN COMPRESSION 250Ω RF 8 30k 28pF 30k 60µA GND 4 60µA VBG VREF 6 W + – 150k (LTC4400-2) 0.4pF DIPLEXER 900MHz RF PA RF PA 1.8GHz/1.9GHz Li-Ion – AZ + + – GM BUF A CLAMP 2 + + – 80mV 270kHz FILTER 38k VPCA + CC MUX1 MUX2 – 30k 30k 12Ω RF DET 22k 51k VREF + – BUF B 3 VPCB 33.4k 6k 100Ω TXENB 10µs DELAY 150k CONTROL 12Ω VPCA 100Ω LTC4400-2 6 SHDN 5 PCTL 7 4400-2 BD BSEL sn4400 4400fas LTC4400-1/LTC4400-2 APPLICATIONS INFORMATION Operation The LTC4400-X RF power control amplifier integrates several functions to provide RF power control over frequencies ranging from 300MHz to 2.7GHz. This product is well suited to control RF power amplifiers that exhibit fast turn-on times. The device also prevents damage to the RF power amplifier due to overvoltage conditions. These functions include an internally compensated power control amplifier to control the RF output power, an autozero section to cancel internal and external voltage offsets, an RF Schottky diode peak detector and amplifier to convert the RF feedback signal to DC, a VPCA/B overvoltage clamp, compression and a bandgap reference. Band Selection The LTC4400-2 is designed to drive two separate power control lines. The BSEL pin will select VPCA when low and VPCB when high. BSEL must be established prior to SHDN being asserted high. Control Amplifier The control amplifier supplies the power control voltage to the RF power amplifier. A portion (typically – 19dB for low frequencies and –14dB for high frequencies) of the RF output voltage is sampled, via a directional coupler or capacitive tap, to close the gain control loop. When a DAC voltage is applied to PCTL, the amplifier quickly servos VPCA/B positive until the detected feedback voltage applied to the RF pin matches the voltage at PCTL. This feedback loop provides accurate RF power control. VPCA/B is capable of driving a 6mA load current and 100pF load capacitor. Control Amplifier Compression The gain compression breakpoints are at PCTL = 80mV and PCTL = 160mV. Above 160mV the gain does not change. The compression changes the feedback attenuation these by reducing the loop gain. RF Detector The internal RF Schottky diode peak detector and amplifier converts the RF feedback voltage to a low frequency voltage. This voltage is compared to the DAC voltage at the PCTL pin by the control amplifier to close the RF power control loop. The RF pin input resistance is typically 250Ω and the frequency range of this pin is 300MHz to 2700MHz for the LTC4400-1 and 300MHz to 2000MHz for the LTC4400-2. The detector demonstrates excellent efficiency over a wide range of input power. The Schottky detector is biased at about 60µA and drives an on-chip peak detector capacitor of 28pF. Autozero An autozero system is included to improve power programming accuracy over temperature. This section cancels internal offsets associated with the Schottky diode detector and control amplifier. External offsets associated with the DAC driving the PCTL pin are also cancelled. Offset drift due to temperature is cancelled between each burst. The maximum offset voltage allowed at the DAC output is limited to 400mV. Autozeroing is performed during a 10µs period after SHDN is asserted high. An internal timer enables the VPCA/B output after 10µs. The autozero capacitors are held and the VPCA/B pin is connected to the control amplifier output. The hold droop voltage of typically < 1µV/ms provides for accurate offset cancellation. The part should be shut down between bursts or after multiple consecutive bursts. Filter There is a 270kHz two pole filter included in the PCTL path to remove DAC noise. Protection Features The RF power amplifier control voltage pin is overvoltage protected. The VPCA/B overvoltage clamp regulates VPCA/B to 2.9V when the gain and PCTL input combination attempts to exceed this voltage. Modes of Operation Shutdown: The part is in shutdown mode when SHDN is low. VPCA/B is held at ground and the power supply current is typically 10µA. Enable: When SHDN is asserted high the part will automatically calibrate out all offsets. This takes 160mV sn4400 4400fas LTC4400-1/LTC4400-2 APPLICATIO S I FOR ATIO This model (Figure 6) is being supplied to LTC users as an aid to circuit designs. While the model reflects reasonably close similarity to corresponding devices in low frequency AC performance terms, its use is not suggested as a replacement for breadboarding. Simulation should be used as a forerunner or a supplement to traditional lab testing. Users should note very carefully the following factors regarding this model: Model performance in general will reflect typical baseline specs for a given device, and certain aspects of performance may not be modeled fully. While reasonable care has been taken in the preparation, we cannot be responsible for correct application on any and all computer systems. Model users are hereby notified that these models are supplied “as is”, with no direct or implied responsibility on the part of LTC for their operation within a customer circuit or system. Further, Linear Technology Corporation reserves the right to change these models without prior notice. In all cases, the current data sheet information is your final design guideline, and is the only performance guarantee. For further technical information, refer to individual device data sheets. Your feedback and suggestions on this model is appreciated. CONTROL AMPLIFER VOLTAGE GAIN (dB) RF POWER AMP VPC G2 CONTROLLED RF OUTPUT POWER + PCTL G1 – IFB LTC4400-X H1 RF H2 4400 F04 RF DETECTOR RF COUPLER 14dB to 20dB LOSS Figure 4. Closed-Loop Block Diagram U Linear Technology Corporation hereby grants the users of this model a nonexclusive, nontransferable license to use this model under the following conditions: The user agrees that this model is licensed from Linear Technology and agrees that the model may be used, loaned, given away or included in other model libraries as long as this notice and the model in its entirety and unchanged is included. No right to make derivative works or modifications to the model is granted hereby. All such rights are reserved. This model is provided as is. Linear Technology makes no warranty, either expressed or implied about the suitability or fitness of this model for any particular purpose. In no event will Linear Technology be liable for special, collateral, incidental or consequential damages in connection with or arising out of the use of this model. It should be remembered that models are a simplification of the actual circuit. 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40 –50 –60 100 180 RLOAD = 2k 160 CLOAD = 33pF 140 120 PHASE 100 80 60 GAIN 40 20 0 –20 –40 –60 –80 –100 10k 100k 1M 10M FREQUENCY (Hz) 4400 F05 W UU PHASE (DEG) 1k Figure 5. SPICE Model Open-Loop Gain and Phase Characteristics from RF to VPCA, PCTL < 80mV sn4400 4400fas 11 LTC4400-1/LTC4400-2 APPLICATIO S I FOR ATIO *LTC4400-X Low Frequency AC Spice Model* *July 11, 2001 *Main Network Description GGIN1 ND3 0 ND2 IFB 86E-6 GGXFB IFB 0 0 ND12 33E-6 GGX5 ND11 0 0 ND10 1E-6 GGX6 ND12 0 0 ND11 1E-6 GGX1 ND4 0 0 ND3 1E-6 GGX2 ND6 0 0 ND4 1E-6 GGX3 ND7 0 0 ND6 1E-6 GGX4 ND8 0 0 ND7 1E-6 EEX1 ND9 0 0 ND8 2 CCC1 ND3 0 44E-12 CCPCTL2 ND2 0 7E-12 CCPCTL1 ND1 0 13E-12 CCLINT VPCA 0 5E-12 CCLOAD VPCA 0 33E-12 CCFB1 IFB 0 2.4E-12 CCX5 ND11 0 16E-15 CCX6 ND12 0 1.2E-15 CCP ND10 0 28E-12 CCX2 ND6 0 8E-15 CCX3 ND7 0 32E-15 LLX1 ND5 0 80E-3 RR01 ND3 0 20E6 RRFILT ND2 ND1 44E3 RRPCTL1 PCTL ND1 51E3 RRPCTL2 ND1 0 38E3 RR9 VPCA ND9 50 RRLOAD VPCA 0 2E3 RRFB1 IFB 0 22E3 RRT RF 0 250 RRX5 ND11 0 1E6 RRX6 ND12 0 1E6 RRSDRF ND10 500 RRX1 ND4 ND5 1E6 RRX2 ND6 0 1E6 RRX3 ND7 0 1E6 RRX4 ND8 0 1E6 **Closed-loop feedback, comment-out VPCTLO, VRF, Adjust EFB gain to reflect external gain, currently set at 3X** *EFB RF 0 VPCA VIN 3 *VIN VIN 0 DC 0 AC 1 *VPCTLO PCTL 0 DC 0 **Open-loop connections, comment-out EFB, VIN and VPCTLO****** VPCTLO PCTL 0 DC 0 VRF RF 0 DC 0 AC 1 ******Add AC statement and print statement as required*** .AC DEC 50 100 1E7 *****for PSPICE only***** .OP .PROBE ************************* .END Figure 6. LTC4400-X Low Frequency AC SPICE Model 12 U sn4400 4400fas W UU LTC4400-1/LTC4400-2 APPLICATIO S I FOR ATIO PCTL RPCTL1 51E3 ND1 RFILT 44E3 ND2 ND3 + GM GIN1 RO1 20E6 86E-6 CC1 44E-12 + GM CPCTL1 13E-12 RPCTL2 38E3 C PCTL2 7E-12 – – RF RT 250Ω RSD 500Ω ND10 CP 28E-12 ND11 + GM GX5 RX5 1E6 1E-6 CX5 16E-15 + GM GX6 RX6 1E6 1E-6 CX6 1.2E-15 – – Figure 7. LTC4400-X Low Frequency AC Model U ND4 GX1 RX1 1E6 ND5 LX1 80E-3 ND6 ND7 ND8 W UU + GM GX2 RX2 1E6 1E-6 CX2 8E-15 + GM GX3 RX3 1E6 1E-6 CX3 32E-15 + GM GX4 RX4 1E6 1E-6 1E-6 – – – IFB ND8 2X BUFFER ND12 GXFB GM RFB1 22E3 33E-6 CFB1 2.4E-12 EX1 VAMP + – + – 2 R9 50Ω CLINT 5E-12 ND9 RLOAD 2E3 VPCA CLOAD 33E-12 4400 F07 sn4400 4400fas 13 LTC4400-1/LTC4400-2 PACKAGE DESCRIPTIO U S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID 0.95 BSC 0.30 – 0.45 6 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 1.00 MAX DATUM ‘A’ 0.01 – 0.10 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 0302 0.62 MAX 0.95 REF 3.85 MAX 2.62 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 sn4400 4400fas 14 LTC4400-1/LTC4400-2 PACKAGE DESCRIPTIO 5.23 (.206) MIN 0.42 ± 0.04 (.0165 ± .0015) TYP RECOMMENDED SOLDER PAD LAYOUT DETAIL “A” 0° – 6° TYP 4.90 ± 0.15 (1.93 ± .006) 3.00 ± 0.102 (.118 ± .004) NOTE 4 0.254 (.010) GAUGE PLANE 0.18 (.077) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.13 ± 0.076 (.005 ± .003) MSOP (MS8) 0802 NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. U MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 0.889 ± 0.127 (.035 ± .005) 3.2 – 3.45 (.126 – .136) 0.65 (.0256) BSC 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 8 7 65 0.52 (.206) REF 0.53 ± 0.015 (.021 ± .006) DETAIL “A” 1 1.10 (.043) MAX 23 4 0.86 (.034) REF 0.65 (.0256) BSC sn4400 4400fas 15 LTC4400-1/LTC4400-2 TYPICAL APPLICATION LTC4400-2 Dual Band Cellular Telephone Transmitter 68Ω 33pF RF VPCA VPCB PCTL 50Ω DAC 1.8GHz/ 1.9GHz RF PA 900MHz RF PA DIRECTIONAL COUPLER VIN Li-Ion SHDN BSEL 0.1µF RELATED PARTS PART NUMBER LTC1261 LTC1732 LTC1734/LTC1734L LTC1754 LTC1757A LTC1758 LTC1957 LTC4052 LTC4401 LT 5500 LT5502 LT5503 LT5504 LTC5505 LTC5507 LTC5508 LT5511 LT5512 ® DESCRIPTION Regulated Inductorless Voltage Inverter Li-Ion Linear Charger ThinSOT Li-Ion Battery Charger ThinSOT Charge Pump RF Power Controller RF Power Controller RF Power Controller Li-Ion Pulse Charger SOT-23 RF PA Controller 1.8GHz to 2.7GHz Receiver Front End 400MHz Quadrature IF Demodulator with RSSI 1.2GHz to 2.7GHz Direct IQ Modulator with Mixer 800MHz to 2.7GHz RF Measuring Receiver 300MHz to 3.5GHz RF Power Detector 100kHz to 1GHz RF Power Detector 300MHz to 7GHz RF Power Detector High Signal Level Up Converting Mixer High Signal Level Down Converting Mixer 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q U LTC4400-2 VCC SHDN BSEL GND DIPLEXER 4400 TA03 COMMENTS Regulated –5V from 3V, REG Pin Indicates Regulation, Up to 15mA, Micropower Complete Linear Charger for 1- and 2-Cell Li-Ion Battery Only Two External Components, No Reverse Current Protection Diode Required, No Sense Resistor Required, PROG Voltage for Charge Termination 2V ≤ VIN ≤ 4V, IOUT = 40mA, No Inductors for White LED Backlight Single/Dual Band GSM/DCS/GPRS Mobile Phones Single/Dual Band GSM/DCS/GPRS Mobile Phones Single/Dual Band GSM/DCS/GPRS Mobile Phones Complete Pulse Charger for 1-Cell Li-Ion Battery Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 250kHz Loop BW Dual LNA Gain Setting +13.5dB/–14dB at 2.5GHz, Double-Balanced Mixer, 1.8V ≤ VSUPPLY ≤ 5.25V 70MHz to 400MHz IF, 1.8V ≤ VSUPPLY ≤ 5.25V, 84dBm Limiting Gain, 90dB RSSI Range Direct IQ Modulator with Integrated 90° Phase Shifter, 4-Step RF Power Control, 1.8V ≤ VSUPPLY ≤ 5.25V 80dB Dynamic Range, Temperature Compensated, 2.7V to 5.5V Supply >40dB Dynamic Range, Temperature Compensated, 2.7V to 6V Supply 40dB Dynamic Range, Temperature Compensated, 2.7V to 6V Supply 40dB Dynamic Range, 2.7V to 6V Supply, SC70 Package RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer DC-3GHz RF Input, 20dBm IIP3, Integrated LO Buffer sn4400 4400fas LT/TP 0403 1K REV A • PRINTED IN THE USA www.linear.com © LINEAR TECHNOLOGY CORPORATION 2001