LTC5505

LTC5505-1/LTC5505-2 - RF Power Detector with Buffered Output and >40dB Dynamic Range

Document overview

• Manufacturer or author: Linear Technology Corporation
• PDF pages: 8

Technical content

n Multimode Mobile Phone Products n PCS Devices n Wireless Data Modems n Wireless and Cable Infrastructure n RF Power Alarm n Envelope Detector n Internal Schottky Diode RF Detector with Two Input Power Ranges: LTC5505-1, –28dBm to 18dBm LTC5505-2, –32dBm to 12dBm n Wide Input Frequency Range: 300MHz to 3GHz (LTC5505-1); 300MHz to 3.5GHz (LTC5505-2) n Temperature Compensated n Buffered Detector Output n Wide VCC Range of 2.7V to 6V n Low Operating Current: 0.5mA n Low Shutdown Current: <2mA n Low Profile (1mm) ThinSOT TM Package RF Power Detector with Buffered Output and >40dB Dynamic Range The LTC 5505-X is an RF power detector for RF applica- tions operating in the 300MHz to 3.5GHz range. A tem- perature compensated Schottky diode peak detector and buffer amplifier are combined in a small 5-pin ThinSOT package. The supply voltage range is optimized for opera- tion from a single lithium-ion cell or 3xNiMH. The RF input voltage is peak detected using an on-chip Schottky diode. The detected voltage is buffered and supplied to the V OUT pin. A power saving shutdown mode reduces supply current to less than 2mA. The LTC5505-1 operates with input power levels from –28dBm to 18dBm. The LTC5505-2 operates with input power levels from –32dBm to 12dBm. , LTC and LT are registered trademarks of Linear Technology Corporation. Dual Band Mobile Phone Tx Power Control ThinSOT is a trademark of Linear Technology Corporation APPLICATIO SU

FEATURES

0.1µF Li-Ion VCC VOUT RFIN GND SHDN RF DISABLE ENABLE VPC Tx PA MODULE CELL BAND PCS BAND BSE

5505 TA01

100Ω 0.3pF

Operating Temperature Range (Note 2) .. – 40°C to 85°C ORDER PART NUMBER S5 PART MARKING TJMAX = 125°C, qJA = 250°C/W LTXV LTRW LTC5505-1ES5 LTC5505-2ES5 ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W (Note 1) ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3.6V, SHDN = VCC = HI, SHDN = 0V = LO, RF Input Signal is Off, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS VCC Operating Voltage l 2.7 6 V IVCC Shutdown Current SHDN = LO l 2 mA IVCC Operating Current SHDN = HI, I VOUT = 0mA l 0.5 0.75 mA VOUT VOL (No RF Input) R LOAD = 2k, SHDN = HI, Enabled 170 260 350 mV SHDN = LOW, Disabled 1 mV VOUT Output Current V OUT = 1.75V, VCC = 2.7V, DVOUT = 10mV l 12 m A VOUT Enable Time SHDN = HI, C LOAD = 33pF, RLOAD = 2k l 82 0 ms VOUT Bandwidth C LOAD = 33pF, RLOAD = 2k (Note 4) 4 MHz VOUT Load Capacitance (Note 7) l 33 pF VOUT Slew Rate V RFIN = 2V Step, CLOAD = 33pF, RLOAD = 2k (Note 3) 10 V/ ms VOUT Noise V CC = 3V, Noise BW = 1.5MHz, 50W RF Input Termination 1.4 mV P-P SHDN Voltage, Chip Disabled V CC = 2.7V to 6V l 0.35 V SHDN Voltage, Chip Enabled V CC = 2.7V to 6V l 1.4 V SHDN Input Current SHDN = 3.6V l 24 40 mA Consult LTC Marketing for parts specified with wider operating temperature ranges.

5 VCC

4 VOUT

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: The rise time at VOUT is measured between 0.5V and 1.5V. Note 4: Bandwidth is calculated using the 10% to 90% rise time equation: BW = 0.35/rise time. Note 5: RF performance is tested at: 1800MHz, 14dBm, –14dBm (LTC5505-1) 1800MHz, 12dBm, –14dBm (LTC5505-2) Note 6: For input RF power levels >16dBm, VCC minimum is 3V and an RF input series resistor of 20W is required to limit the input current. Note 7: Guaranteed by design. ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3.6V, SHDN = VCC = HI, SHDN = 0V = LO, RF Input Signal is Off, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS RFIN Input Frequency Range (LTC5505-1) 300 to 3000 MHz (LTC5505-2) 300 to 3500 MHz RFIN Input Power Range (LTC5505-1) RF Frequency = 900MHz (Note 5, 6, 7) V CC = 2.7V to 6V –28 to 18 dBm RF Frequency = 1800MHz (Note 5, 6, 7)VCC = 2.7V to 6V –26 to 18 dBm RF Frequency = 2400MHz (Note 5, 7)VCC = 2.7V to 6V –24 to 16 dBm RF Frequency = 2700MHz (Note 5, 7)VCC = 2.7V to 6V –22 to 16 dBm RFIN Input Power Range (LTC5505-2) RF Frequency = 900MHz (Note 5) –32 to 12 dBm RF Frequency = 1800MHz (Note 5) –32 to 12 dBm RF Frequency = 2400MHz (Note 5) –32 to 12 dBm RF Frequency = 2700MHz (Note 5) –30 to 12 dBm RFIN AC Input Resistance (LTC5505-1) F = 850MHz 165 W F = 1850MHz 20 W RFIN Input Shunt Capacitance (LTC5505-1) 2p F RFIN AC Input Resistance (LTC5505-2) F = 850MHz 165 W F = 1850MHz 59 W RFIN Input Shunt Capacitance (LTC5505-2) 1.3 pF

TYPICAL PERFOR A CE CHARACTERISTICSUW LTC5505-1 Typical Detector Characteristics, 0.85GHz LTC5505-2 Typical Detector Characteristics, 0.85GHz LTC5505-1 Typical Detector Characteristics, 2.45GHz LTC5505-1 Typical Detector Characteristics, 1.85GHz RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G01

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G02

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G03

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G04

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C LTC5505-2 Typical Detector Characteristics, 2.45GHz LTC5505-2 Typical Detector Characteristics, 1.85GHz RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G05

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G06

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C LTC5505-2 Typical Detector Characteristics, 3.5GHz RF INPUT POWER (dBm) VOUT OUTPUT VOLTAGE (mV) 10000

5505 G07

VCC = 2.7V TO 6V 0Ω SERIES TERMINATION –40°C 25°C 85°C

RFIN (Pin 1): RF Input Voltage. Referenced to V CC. An external coupling capacitor to the RF source is required. The frequency range is 300MHz to 3GHz. This pin has an internal 250 W 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. V OUT (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. 5505 BD GAIN COMPRESSION SHDN 28pF VOUT SHDN GND 2 BUFFER 250Ω RF DET 30k 30k 60µA6 0 µA 150k 22k 130mV BIAS 100Ω 100Ω RFIN VCC

APPLICATIO S I FOR ATIOWU UU 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 V OUT when coming out of shutdown and a gain compres- sion 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 60mA 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 voltage gain is reduced to 0.7. The compression expands the low power detector range due to higher gain. Modes of Operation MODE SHDN OPERATION Shutdown Low Disabled Enable High Power Detect

Applications

The LTC5505-1 and LTC5505-2 can be used as self- standing signal strength measuring receivers for a wide range of input signals from –32dBm to 18dBm for fre- quencies from 300MHz to 3.5GHz. The LTC5505-1 and LTC5505-2 can be used as demodu- lators 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 100W 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.) Example of LTC5505-X GSM/DCS Power Control Timing Diagram 5505 TD t1: PART COMES OUT OF SHUTDOWN 20µs MAXIMUM PRIOR TO BURST. t2: CIRCUITS POWER UP AND SETTLE. t3: BASEBAND CONTROLLER STARTS RF POWER RAMP UP AT 22µs AFTER SHDN IS ASSERTED HIGH. t2 t3 t4 t5 t6 20µs2 µs2 8 µs 543 µs2 8 µs SHDN VOUT RF INPUT POWER t4: BASEBAND CONTROLLER COMPLETES RAMP UP. t5: BASEBAND CONTROLLER STARTS RF POWER RAMP DOWN AT END OF BURST. t6: LTC5505-X RETURNS TO SHUTDOWN MODE BETWEEN BURSTS

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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 1.50 – 1.75 (NOTE 4)2.80 BCS 0.30 – 0.45 TYP

5 PLCS (NOTE 3)

DATUM ‘A’ 0.09 – 0.20 (NOTE 3) S5 TSOT-23 0801 PIN ONE

2.90 BSC

(NOTE 4)

0.95 BSC

1.90 BSC

0.80 – 0.90

1.00 MAX

0.01 – 0.100.20 BSC 0.35 – 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 3.254 0.754 0.854 – 0.127 RECOMMENDED SOLDER PAD LAYOUT

1.9 BSC

Dual Band Mobile Phone Tx Power Control with Directional Coupler LTC5505-X1 MOBILE PHONE DSP 0.1µF Li-Ion VCC VOUT RFIN GND SHDNDISABLE ENABLE 33pF 900MHz INPUT 1.8GHz INPUT 900MHz OUTPUT 1.8GHz OUTPUTVPC Tx PA MODULE BSEL 50Ω

5505 TA02

0Ω TO 20Ω TYPICAL APPLICATIO U

LT/TP 1102 2K • PRINTED IN USA Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com ª LINEAR TECHNOLOGY CORPORATION 2001 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1618 Constant Current/Constant Voltage, 1.4MHz, Up to 16 White LEDs, V IN = 1.6V to 18V, VOUT Max = 34V, High Efficiency Boost Regulator I Q = 1.8mA, ISD = <1mA, MS10 LTC1733 Standalone Li-Ion Linear Battery Charger Monolithic Charger, Thermal Rejection Prevents Overheating, Small Design, Up to 1.5A Charge Current LTC1734/ Li-Ion Linear Battery Charger in ThinSOT 50mA to 700mA Charge Current, Only Three Components for Complete Solution LTC1734L LTC1878 600mA I OUT, 550kHz, Synchronous Step-Down 95% Efficiency, V IN = 2.7V to 6V, VOUT Min = 0.8V, DC/DC Converter I Q = 10mA, ISD = <1mA, MS8 LT1932 Constant Current, 1.2MHz, High Efficiency Up to 8 White LEDs, V IN = 1V to 10V, VOUT Max = 34V, White LED Boost Regulator I Q = 1.2mA, ISD = <1mA, ThinSOT LT1937 Constant Current, 1.2MHz, High Efficiency Up to 4 White LEDs, V IN = 2.5V to 10V, VOUT Max = 34V, White LED Boost Regulator I Q = 1.9mA, ISD = <1mA, ThinSOT, SC70 LTC3200 Low Noise, 2MHz, Regulated Charge Pump Up to 6 White LEDs, V IN = 2.7V to 4.5V, White LED Driver I Q = 8mA, ISD = <1mA, MS10 LTC3200-5 Low Noise, 2MHz, Regulated Charge Pump Up to 6 White LEDs, V IN = 2.7V to 4.5V, White LED Driver I Q = 6.5mA, ISD = <1mA, ThinSOT LTC3201 Low Noise, 1.7MHz, Regulated Charge Pump Up to 6 White LEDs, V IN = 2.7V to 4.5V, White LED Driver I Q = 6.5mA, ISD = <1mA, MS10 LTC3202 Low Noise, 1.5MHz, Regulated Charge Pump Up to 8 White LEDs, V IN = 2.7V to 4.5V, White LED Driver I Q = 5mA, ISD = <1mA, MS10 LTC3404 600mA I OUT, 1.4MHz, Synchronous Step-Down 95% Efficiency, V IN = 2.7V to 6V, VOUT Min = 0.8V, DC/DC Converter I Q = 10mA, ISD = <1mA, MS8 LTC3405/ 300mA I OUT, 1.5MHz, Synchronous Step-Down 95% Efficiency, V IN = 2.7V to 6V, VOUT Min = 0.8V, LTC3405A DC/DC Converter I Q = 20mA, ISD = <1mA, ThinSOT LTC3406/ 600mA I OUT, 1.5MHz, Synchronous Step-Down 95% Efficiency, V IN = 2.5V to 5.5V, VOUT Min = 0.6V, LTC3406B DC/DC Converter I Q = 20mA, ISD = <1mA, ThinSOT LTC3412 2.5A I OUT, 4MHz, Synchronous Step-Down 95% Efficiency, V IN = 2.5V to 5.5V, VOUT Min = 0.8V, DC/DC Converter I Q = 60mA, ISD = <1mA, TSSOP-16E LTC3411 1.25A I OUT, 4MHz, Synchronous Step-Down 95% Efficiency, V IN = 2.5V to 5.5V, VOUT Min = 0.8V, DC/DC Converter I Q = 60mA, ISD = <1mA, MS10 LTC3440 600mA I OUT, 2MHz, Synchronous Buck-Boost 95% Efficiency, V IN = 2.5V to 5.5V, VOUT Min = 2.5V, DC/DC Converter I Q = 25mA, ISD = <1mA, MS10 LTC4052 Li-Ion Battery Pulse Charger Minimum Heat Dissipation, Current Limit for Safety, Standalone Charger, Monolithic LTC4053 USB Compatible Li-Ion Charger Standalone, Monolithic, 100mA/500mA or Up to 2A from Wall Adapter LTC4412 Low Loss PowerPath TM Controller Replaces Power Supply ORing Diodes, High Efficiency PowerPath is a trademark of Linear Technology Corporation.