LTC5505-1

LTC5505-1/LTC5505-2 RF Power Detector with Buffered Output and >40dB Dynamic Range FEATURES s DESCRIPTIO s s s s s s s Internal Schottky Diode RF Detector with Two Input Power Ranges: LTC5505-1, –28dBm to 18dBm LTC5505-2, –32dBm to 12dBm Wide Input Frequency Range: 300MHz to 3GHz (LTC5505-1); 300MHz to 3.5GHz (LTC5505-2) Temperature Compensated Buffered Detector Output Wide VCC Range of 2.7V to 6V Low Operating Current: 0.5mA Low Shutdown Current: 16dBm, VCC minimum is 3V and an RF input series resistor of 20Ω is required to limit the input current. Note 7: Guaranteed by design. 5505f 3 LTC5505-1/LTC5505-2 TYPICAL PERFOR A CE CHARACTERISTICS LTC5505-1 Typical Detector Characteristics, 0.85GHz 10000 10000 VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C VOUT OUTPUT VOLTAGE (mV) VOUT OUTPUT VOLTAGE (mV) 1000 1000 100 0 6 –30 –24 –18 –12 –6 RF INPUT POWER (dBm) 12 5505 G01 100 –30 –24 VOUT OUTPUT VOLTAGE (mV) LTC5505-2 Typical Detector Characteristics, 0.85GHz 10000 VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 10000 VOUT OUTPUT VOLTAGE (mV) 1000 100 –32 VOUT OUTPUT VOLTAGE (mV) –26 –20 –14 –8 –2 4 RF INPUT POWER (dBm) LTC5505-2 Typical Detector Characteristics, 2.45GHz 10000 VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 10000 VOUT OUTPUT VOLTAGE (mV) 1000 VOUT OUTPUT VOLTAGE (mV) 100 –32 –26 –20 –14 –8 –2 4 RF INPUT POWER (dBm) 4 UW LTC5505-1 Typical Detector Characteristics, 1.85GHz VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 10000 LTC5505-1 Typical Detector Characteristics, 2.45GHz VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 1000 –18 –12 –6 0 6 RF INPUT POWER (dBm) 12 5505 G02 100 0 6 –30 –24 –18 –12 –6 RF INPUT POWER (dBm) 12 5505 G03 LTC5505-2 Typical Detector Characteristics, 1.85GHz VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 1000 10 5505 G04 100 –32 –26 –20 –14 –8 –2 4 RF INPUT POWER (dBm) 10 5505 G05 LTC5505-2 Typical Detector Characteristics, 3.5GHz VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C 1000 10 5505 G06 100 –32 –26 –20 –14 –8 –2 4 RF INPUT POWER (dBm) 10 5505 G07 5505f LTC5505-1/LTC5505-2 PI FU CTIO S RFIN (Pin 1): RF Input Voltage. Referenced to VCC. An external coupling capacitor to the RF source is required. The frequency range is 300MHz to 3GHz. This pin has an internal 250Ω termination, an internal Schottky diode detector and peak detector capacitor. (See Note 6 in the Electrical Characteristics.) GND (Pin 2): System Ground. SHDN (Pin 3): Shutdown Input. A logic low on the SHDN pin places the part in shutdown mode. A logic high enables the part. SHDN has an internal 150k pull down resistor to ensure that the part is in shutdown when the drivers are in a tri-state condition. VOUT (Pin 4): Buffered and Level Shifted Detector Output Voltage. VCC (Pin 5): Power Supply Voltage, 2.7V to 6V. VCC should be bypassed appropriately with ceramic capacitors. BLOCK DIAGRA RFIN 1 30k 60µA GND 2 W U U U VCC 5 GAIN COMPRESSION + BUFFER 4 VOUT – SHDN 250Ω 100Ω 30k 28pF + RF DET 130mV 100Ω – 60µA 150k 22k BIAS 3 SHDN 5505 BD 5505f 5 LTC5505-1/LTC5505-2 APPLICATIO S I FOR ATIO Operation The LTC5505-X RF detector integrates several functions to provide RF power detection over frequencies ranging from 300MHz to 3.5GHz. These functions include an internally compensated buffer amplifier, an RF Schottky diode peak detector and level shift amplifier to convert the RF feedback signal to DC, a delay circuit to avoid voltage transients at VOUT when coming out of shutdown and a gain compression circuit to extend the detector dynamic range. Buffer Amplifier The buffer amplifier has a gain of two and is capable of driving a 2mA load. The buffer amplifier typically has an output voltage range of 0.25V to 1.75V. RF Detector The internal RF Schottky diode peak detector and level shift amplifier converts the RF input signal to a low frequency signal. The detector demonstrates excellent efficiency and linearity over a wide range of input power. The Schottky detector is biased at about 60µA and drives a peak detector capacitor of 28pF. Gain Compression The gain compression circuit changes the feedback ratio as the RF peak-detected input voltage increases above 100mV. Below 100mV, the voltage gain from the peak detector to the buffer output is 1.5. Above 200mV, the Example of LTC5505-X GSM/DCS Power Control Timing Diagram 20µs SHDN 2µs 28µs 543µs 28µs VOUT RF INPUT POWER 5505 TD t1 t2 t3 t 1: PART COMES OUT OF SHUTDOWN 20µs MAXIMUM PRIOR TO BURST. t 2: CIRCUITS POWER UP AND SETTLE. t 3: BASEBAND CONTROLLER STARTS RF POWER RAMP UP AT 22µs AFTER SHDN IS ASSERTED HIGH. 6 U voltage gain is reduced to 0.7. The compression expands the low power detector range due to higher gain. Modes of Operation MODE Shutdown Enable SHDN Low High OPERATION Disabled Power Detect W U U Applications The LTC5505-1 and LTC5505-2 can be used as selfstanding signal strength measuring receivers for a wide range of input signals from –32dBm to 18dBm for frequencies from 300MHz to 3.5GHz. The LTC5505-1 and LTC5505-2 can be used as demodulators for AM and ASK modulated signals with data rates up to 5MHz. Depending on specific application needs, the RSSI output can be split into two branches, providing AC-coupled data (or audio) output and DC-coupled, RSSI output for signal strength measurements and AGC. The LTC5505-1 and LTC5505-2 can be used for dual band mobile phone transmitter power control (refer to Typical Application schematic on first page). The circuit uses a capacitive tap at the Tx PA outputs. For example, a 0.3pF capacitor (C1) followed by a 100Ω resistor (R1) forms a coupling circuit with about a 20dB loss at the cellular band and 18dB loss at the PCS band, referenced to the LTC5505-2 IC RF input pin. For improved coupling accuracy, the C1 capacitor should be a high tolerance component (±0.05pF.) t4 t5 t6 t 4: BASEBAND CONTROLLER COMPLETES RAMP UP. t 5: BASEBAND CONTROLLER STARTS RF POWER RAMP DOWN AT END OF BURST. t 6: LTC5505-X RETURNS TO SHUTDOWN MODE BETWEEN BURSTS 5505f LTC5505-1/LTC5505-2 TYPICAL APPLICATIO U 0Ω TO 20Ω 33pF 1 2 DISABLE ENABLE 3 LTC5505-X VCC 5 RFIN GND SHDN VOUT 4 0.1µF Li-Ion BSEL Tx PA MODULE 900MHz OUTPUT 1.8GHz OUTPUT 50Ω 5505 TA02 Dual Band Mobile Phone Tx Power Control with Directional Coupler 900MHz INPUT 1.8GHz INPUT DIRECTIONAL COUPLER DIPLEXER MOBILE PHONE DSP VPC PACKAGE DESCRIPTIO 0.754 0.854 ± 0.127 3.254 0.95 BSC 1.9 BSC RECOMMENDED SOLDER PAD LAYOUT 0.20 BSC 1.00 MAX DATUM ‘A’ 0.35 – 0.50 REF 0.09 – 0.20 (NOTE 3) 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 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 S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 2.90 BSC (NOTE 4) 2.80 BCS 1.50 – 1.75 (NOTE 4) PIN ONE 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.01 – 0.10 1.90 BSC S5 TSOT-23 0801 5505f 7 LTC5505-1/LTC5505-2 RELATED PARTS PART NUMBER DESCRIPTION LT1618 LTC1733 LTC1734/ LTC1734L LTC1878 LT1932 LT1937 LTC3200 LTC3200-5 LTC3201 LTC3202 LTC3404 LTC3405/ LTC3405A LTC3406/ LTC3406B LTC3412 LTC3411 LTC3440 LTC4052 LTC4053 LTC4412 Constant Current/Constant Voltage, 1.4MHz, High Efficiency Boost Regulator Standalone Li-Ion Linear Battery Charger Li-Ion Linear Battery Charger in ThinSOT 600mA IOUT, 550kHz, Synchronous Step-Down DC/DC Converter Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator Low Noise, 2MHz, Regulated Charge Pump White LED Driver Low Noise, 2MHz, Regulated Charge Pump White LED Driver Low Noise, 1.7MHz, Regulated Charge Pump White LED Driver Low Noise, 1.5MHz, Regulated Charge Pump White LED Driver 600mA IOUT, 1.4MHz, Synchronous Step-Down DC/DC Converter 300mA IOUT, 1.5MHz, Synchronous Step-Down DC/DC Converter 600mA IOUT, 1.5MHz, Synchronous Step-Down DC/DC Converter 2.5A IOUT, 4MHz, Synchronous Step-Down DC/DC Converter 1.25A IOUT, 4MHz, Synchronous Step-Down DC/DC Converter 600mA IOUT, 2MHz, Synchronous Buck-Boost DC/DC Converter Li-Ion Battery Pulse Charger USB Compatible Li-Ion Charger Low Loss PowerPath Controller TM COMMENTS Up to 16 White LEDs, VIN = 1.6V to 18V, VOUT Max = 34V, IQ = 1.8mA, ISD = < 1µA, MS10 Monolithic Charger, Thermal Rejection Prevents Overheating, Small Design, Up to 1.5A Charge Current 50mA to 700mA Charge Current, Only Three Components for Complete Solution 95% Efficiency, VIN = 2.7V to 6V, VOUT Min = 0.8V, IQ = 10µA, ISD = < 1µA, MS8 Up to 8 White LEDs, VIN = 1V to 10V, VOUT Max = 34V, IQ = 1.2mA, ISD = < 1µA, ThinSOT Up to 4 White LEDs, VIN = 2.5V to 10V, VOUT Max = 34V, IQ = 1.9mA, ISD = < 1µA, ThinSOT, SC70 Up to 6 White LEDs, VIN = 2.7V to 4.5V, IQ = 8mA, ISD = < 1µA, MS10 Up to 6 White LEDs, VIN = 2.7V to 4.5V, IQ = 6.5mA, ISD = < 1µA, ThinSOT Up to 6 White LEDs, VIN = 2.7V to 4.5V, IQ = 6.5mA, ISD = < 1µA, MS10 Up to 8 White LEDs, VIN = 2.7V to 4.5V, IQ = 5mA, ISD = < 1µA, MS10 95% Efficiency, VIN = 2.7V to 6V, VOUT Min = 0.8V, IQ = 10µA, ISD = < 1µA, MS8 95% Efficiency, VIN = 2.7V to 6V, VOUT Min = 0.8V, IQ = 20µA, ISD = < 1µA, ThinSOT 95% Efficiency, VIN = 2.5V to 5.5V, VOUT Min = 0.6V, IQ = 20µA, ISD = < 1µA, ThinSOT 95% Efficiency, VIN = 2.5V to 5.5V, VOUT Min = 0.8V, IQ = 60µA, ISD = < 1µA, TSSOP-16E 95% Efficiency, VIN = 2.5V to 5.5V, VOUT Min = 0.8V, IQ = 60µA, ISD = < 1µA, MS10 95% Efficiency, VIN = 2.5V to 5.5V, VOUT Min = 2.5V, IQ = 25µA, ISD = < 1µA, MS10 Minimum Heat Dissipation, Current Limit for Safety, Standalone Charger, Monolithic Standalone, Monolithic, 100mA/500mA or Up to 2A from Wall Adapter Replaces Power Supply ORing Diodes, High Efficiency PowerPath is a trademark of Linear Technology Corporation. 5505f 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q LT/TP 1102 2K • PRINTED IN USA www.linear.com © LINEAR TECHNOLOGY CORPORATION 2001