LTC5531ES6#TRMPBF

LTC5531 Precision 300MHz to 7GHz RF Detector with Shutdown and Offset Adjustment U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ Temperature Compensated Internal Schottky Diode RF Detector Wide Input Frequency Range: 300MHz to 7GHz* Wide Input Power Range: –32dBm to 10dBm Buffered Detector Output Precision VOUT Offset Control Wide VCC Range of 2.7V to 6V Low Operating Current: 500µA Low Shutdown Current: 120mV, VOUT is the sum of VOS plus the detected RF signal. VOUT (Pin 5): Detector Output. VCC (Pin 6): Power Supply Voltage, 2.7V to 6V. VCC should be bypassed appropriately with ceramic capacitors. W BLOCK DIAGRA RFSOURCE VCC 6 SD + BIAS BUFFER SHUTDOWN 500Ω RFIN 1 VOUT 4 VOS 30k 500Ω 30k 180Ω 100Ω SD 31k + 25pF RF DET 24k 50µA GND 2 5 – + 80k – SD 50µA – 80k 120mV + 160k 3 5531 BD SHDN 5531f 8 LTC5531 U W U U APPLICATIO S I FOR ATIO the input range of a variety of analog-to-digital converters. VOUT will not change until VOS exceeds 120mV. The voltage at VOUT for VOS ≥120mV and with no RF signal present is: Operation The LTC5531 RF detector integrates several functions to provide RF power detection over frequencies ranging from 300MHz to 7GHz. These functions include an internal frequency compensated buffer amplifier, an RF Schottky diode peak detector and level shift amplifier to convert the RF input signal to DC and a delay circuit to avoid voltage transients at VOUT when powering up. The LTC5531 has both shutdown and voltage offset adjustment capabilities. VOUT = VOS VOUT will exactly track VOS above 120mV. 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 diode is biased at about 55µA and drives a 25pF internal peak detector capacitor. Buffer Amplifier The output buffer amplifier is capable of supplying typically 4mA into a load. The amplifier has a bandwidth of 2MHz and a fixed internal gain of two. The VOS input controls the DC input voltage to the buffer amplifier. VOS must be connected to ground if the DC output voltage is not to be changed. The buffer is initially trimmed to approximately 120mV with VOS connected to ground. Shutdown The part is in shutdown mode when SHDN is low. The supply current is reduced to < 2µA and VOUT is shorted to ground via a 280Ω resistor. When SHDN is asserted high, the part is enabled after about 8µs. The VOS pin is used to change the initial VOUT starting voltage. This function enables the LTC5531 output to span Demo Board Schematic VCC 2.7V TO 6V RFIN C4 39pF 1 R1 (OPT) 2 3 VCC SHDN 22k C1 0.1µF LTC5531ES6 RFIN VCC GND VOUT SHDN VOS C2 100pF 6 5 4 VOS VOUT C3 (OPT) 5531 DB 5531f 9 LTC5531 U W U U APPLICATIO S I FOR ATIO Applications The LTC5531 can be used as a self-standing signal strength measuring receiver for a wide range of input signals from –32dBm to 10dBm for frequencies from 300MHz to 7GHz. Operation at higher frequencies is achievable. Consult factory for more information. The LTC5531 can be used as a demodulator for AM and ASK modulated signals with data rates up to 2MHz. Depending on specific application needs, the RSSI output can be split between two branches, providing AC-coupled 0.1µF LTC5531ES6 1 2 3 DISABLE ENABLE RFIN VCC GND VOUT SHDN VOS data (or audio) output and DC-coupled RSSI output for signal strength measurements and AGC. The LTC5531 can be used for RF power detection and control. Figure 1 is an example of transmitter power control, using the LTC5531 with a capacitive tap to the power amplifier. A 0.5pF capacitor (C1) followed by a 200Ω resistor (R1) forms a coupling circuit with about 20dB loss at 900MHz referenced to the LTC5531 RF input pin. In the actual product implementation, component values for the capacitive tap may be different depending on parts placement, PCB parasitics and parameters of the antenna. Li-Ion Tx PA MODULE R1 200Ω 1% C1 0.5pF ±0.05pF CELL BAND 6 DIPLEXER 5 4 PCS BAND OFFSET ADJUSTMENT MOBILE PHONE DSP VPC BSE 5532 F01 Figure 1. Mobile Phone Tx Power Control Application with a Capacitive Tap 5531f 10 LTC5531 U PACKAGE DESCRIPTIO S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 0302 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 5531f 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. 11 LTC5531 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS Infrastructure LT5511 High Linearity Upconverting Mixer RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer LT5512 DC-3GHz High Signal Level Downconverting Mixer DC to 3GHz, 21dBm IIP3, Integrated LO Buffer LT5515 1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator 20dBm IIP3, Integrated LO Quadrature Generator LT5516 0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator 21.5dBm IIP3, Integrated LO Quadrature Generator LT5517 40MHz to 900MHz Direct Conversion Quadrature Demodulator 21dBm IIP3, Integrated LO Quadrature Generator LT5519 0.7GHz to 1.4GHz High Linearity Upconverting Mixer 17.1dBm IIP3, 50Ω Single Ended RF and LO Ports LT5520 1.3GHz to 2.3GHz High Linearity Upconverting Mixer 15.9dBm IIP3, 50Ω Single Ended RF and LO Ports LT5522 600MHz to 2.7GHz High Linearity Downconverting Mixer 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF and LO Ports RF Power Detectors LT5504 800MHz to 2.7GHz RF Measuring Receiver 80dB Dynamic Range, Temperature Compensated, 2.7V to 5.25V Supply LTC®5505 300MHz to 3GHz RF Power Detectors LTC5505-1: –28dBm to 18dBm Range, LTC5505-2: –32dBm to 12dBm Range, Temperature Compensated, 2.7V to 6V Supply LTC5507 100kHz to 1000MHz RF Power Detector –34dBm to 14dBm Range, Temperature Compensated, 2.7V to 6V Supply LTC5508 300MHz to 7GHz RF Power Detector –32dBm to 12dBm Range, Temperature Compensated, SC70 Package LTC5509 300MHz to 3GHz RF Power Detector 36dB Dynamic Range, Temperature Compensated, SC70 Package LTC5532 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Adjustable Gain and Offset RF Building Blocks LT5500 1.8GHz to 2.7GHz Receiver Front End 1.8V to 5.25V Supply, Dual-Gain LNA, Mixer, LO Buffer LT5502 400MHz Quadrature IF Demodulator with RSSI 1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain, 90dB RSSI Range LT5503 1.2GHz to 2.7GHz Direct IQ Modulator and Upconverting Mixer 1.8V to 5.25V Supply, Four-Step RF Power Control, 120MHz Modulation Bandwidth LT5506 500MHz Quadrature IF Demodulator with VGA 1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB Linear Power Gain, 8.8MHz Baseband Bandwidth LT5546 500MHz Ouadrature IF Demodulator with VGA and 17MHz Baseband Bandwidth 17MHz Baseband Bandwidth, 40MHz to 500MHz IF, 1.8V to 5.25V Supply, –7dB to 56dB Linear Power Gain RF Power Controllers LTC1757A RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC1758 RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC1957 RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC4400 SOT-23 RF PA Controller Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 450kHz Loop BW LTC4401 SOT-23 RF PA Controller Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 250kHz Loop BW LTC4403 RF Power Controller for EDGE/TDMA Multiband GSM/GPRS/EDGE Mobile Phones 5531f 12 Linear Technology Corporation LT/TP 0104 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com  LINEAR TECHNOLOGY CORPORATION 2004