FEATURES DESCRIPTIO TYPICAL APPLICATIO LT MHz to 3GHz RF Power Detector. with 60dB Dynamic Range APPLICATIO S

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1 LT4 MHz to GHz Power Detector with 6dB Dynamic Range FEATRES Frequency Range: MHz to GHz Linear Dynamic Range: 6dB Exceptional Accuracy over Temperature and Power Supply Fast Transient Response: 8ns Full-Scale Settling Time Single.7V to.v Supply Low Supply Current: 7mA Shutdown Current:.µA Tiny 6-Lead SC7 Package APPLICATIO S RSSI and ACC Power Control CATV Power Detection Optical Receiver Gain Control DESCRIPTIO The LT 4 is a MHz to GHz monolithic power detector capable of measuring signals over a 6dB dynamic range. The signal in a decibel scale is precisely converted into DC voltage on a linear scale. The 6dB input dynamic range is achieved using cascaded detectors and limiters. Their outputs are summed to generate an accurate log-linear DC voltage proportional to the input signal in db. The output is buffered with a low output impedance driver. The LT4 delivers superior temperature stability (typical output variation within ±db over the full temperature range). The output responds in less than 4ns to a large input signal., LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO MHz to GHz Power Detector Output Voltage vs Input Power.µF pf V.4. V CC = V AT 9MHz INPT 47Ω nf ENABLE LT4 EN V CC GND 4 TA T A = C TA = 4C 4 4 G 4fa

2 LT4 ABSOLTE MAXIMM RATINGS W W W (Note ) Power Supply Voltage....V Enable Voltage...V, V CC Voltage (+dbm Equivalent)... ±V Operating Ambient Temperature Range.. 4 C to 8 C Storage Temperature Range... 6 C to C Lead Temperature (Soldering, sec)... C PACKAGE/ORDER INFORMATION EN GND TOP VIEW 6 GND 4 V CC W ORDER PART NMBER LT4ESC6 SC6 PART MARKING LBGD SC6 PACKAGE 6-LEAD PLASTIC SC7 T JMAX = C, θ JA = 6 C/W Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS V CC = V, EN = V, T A = C, source impedance = Ω, unless otherwise noted. Test circuit shown in Figure. (Note ) PARAMETER CONDITIONS MIN TYP MAX NITS Input Frequency Range to MHz Input Impedance kω f = MHz Input Power Range 8 to + dbm Dynamic Range (Note ) ±db Linearity Error, T A = 4 C to 8 C 6 db Output Slope 44 mv/db Output Variation vs Temperature P IN = 48dBm to 4dBm, T A = 4 C to 8 C.7 db/ C f = 9MHz Input Power Range 6 to dbm Dynamic Range (Note ) ±db Linearity Error, T A = 4 C to 8 C 6 db Output Slope 4 mv/db Output Variation vs Temperature P IN = 48dBm to 4dBm, T A = 4 C to 8 C.8 db/ C f = 9MHz Input Power Range 6 to dbm Dynamic Range (Note ) ±db Linearity Error, T A = 4 C to 8 C 6 db Output Slope mv/db Output Variation vs Temperature P IN = 48dBm to 4dBm, T A = 4 C to 8 C. db/ C Output Intercept Ω External Termination, T A = 4 C to 8 C dbm f = MHz Input Power Range 6 to dbm Dynamic Range (Note ) ±db Linearity Error, T A = 4 C to 8 C 6 db Output Slope mv/db Output Variation vs Temperature P IN = 48dBm to 4dBm, T A = 4 C to 8 C. db/ C Output Interface Output DC Voltage No Input Signal 4 4 mv Output Impedance Ω Output Bandwidth MHz Full-Scale Setting Time Input from No Signal to dbm, to 9% 8 ns Sinking/Sourcing / ma/µa 4fa

3 LT4 ELECTRICAL CHARACTERISTICS V CC = V, EN = V, T A = C, unless otherwise noted. Test circuit shown in Figure. (Note ) PARAMETER CONDITIONS MIN TYP MAX NITS Power p/down Turn-On Time ns Turn-Off Time 8 ns EN = High (On).9 V EN = Low (Off).6 V Power Supply Supply Voltage.7. V Supply Current EN = High 7 9 ma Shutdown Current EN = Low. µa Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : Specifications over the 4 C to 8 C temperature range are assured by design, characterization and correlation with statistical process control. Note : The linearity error is calculated by the difference between the incremental slope of the output and the average output slope from 48dBm to 4dBm. The dynamic range is defined as the range over which the linearity error is within ±db. TYPICAL PEOR A CE CHARACTERISTICS VOT (V) Output Voltage vs Frequency V CC = V T A = C 9MHz MHz W.9GHz.GHz Linearity Error vs Frequency.GHz MHz 9MHz.9GHz V CC = V T A = C (Test circuit shown in Figure ) Output Voltage vs Input Power V CC = V AT MHz T A = C TA = 4C 4 4 G Variation vs Input Power V CC = V AT MHz NORMALIZED AT C.4. 4 G Output Voltage vs Input Power V CC = V AT 9MHz 4 G Variation vs Input Power V CC = V AT 9MHz NORMALIZED AT C VARIATION (db) T A = 4 C VOT (V).6..8 VARIATION (db) T A = 4 C T A = C TA = 4C G4 4 G 4 G6 4fa

4 LT4 TYPICAL PEOR A CE CHARACTERISTICS W (Test circuit shown in Figure ).4. Output Voltage vs Input Power Variation vs Input Power Output Voltage vs Input Power V CC = V AT.9GHz V CC = V AT.9GHz NORMALIZED AT C.4. V CC = V AT.GHz.6..8 VARIATION (db) T A = 4 C T A = C TA = 4C T A = C TA = 4C 4 4 G7 4 G8 4 G9 VOT VARIATION (db) Variation vs Input Power V CC = V AT.GHz NORMALIZED AT C T A = 4 C VOT (V) Output Voltage vs Input Power at V CC = V and V T A = C MHz V CC = V, V.9GHz V CC = V, V PERCENTAGE DISTRIBTION (%) Output Voltage Distribution vs Temperature P IN = 48dBm AT.9GHz V CC = V T A = C T A = 4 C G 4 G 4 G Output Voltage Distribution vs Temperature Supply Voltage vs Supply Current PERCENTAGE DISTRIBTION (%) 4 P IN = 4dBm AT.9GHz V CC = V T A = C T A = 4 C SPPLY CRRENT (ma) T A = C T A = 4 C SPPLY VOLTAGE (V). 4 G G4 4 4fa

5 LT4 TYPICAL PEOR A CE CHARACTERISTICS W (Test circuit shown in Figure ) Input Return Loss vs Frequency Output Transient Response V/DIV RETRN LOSS (db) INPT PLSED dbm AT MHz... INPT FREQENCY (GHz) ns/div 4 G 4 G6 PI F CTIO S EN (Pin ): Enable. When the input voltage is higher than.9v, the circuit is completely turned on. When the input voltage is less than.6v, the circuit is turned off. GND (Pins, ): Ground. (Pin ): Detector Output. V CC (Pin 4): Power Supply. This pin should be decoupled using pf and.µf capacitors. (Pin 6): input. This pin is internally biased to V CC.8V. A coupling capacitor must be used to connect to the signal source. BLOCK DIAGRA W 4 V CC 6 LIMITER LIMITER LIMITER LIMITER + V REF OFFSET COMP BIAS GND EN 4 BD 4fa

6 LT4 TEST CIRCIT EN R Ω C EN LT4 GND GND V CC 6 4 C nf C pf R 47Ω C.µF J V CC 4 F REF DES C C C C R R VALE nf.µf pf 47Ω Ω SIZE PART NMBER AVX 4CJATA TAIYO YDEN TMK7BJ4KA AVX 6CKATA Figure. Evaluation Circuit Schematic Figure. Component Side Silkscreen of Evaluation Board Figure. Component Side Layout of Evaluation Board APPLICATIO S I FOR ATIO 6 W The LT4 is a logarithmic-based detector, capable of measuring an signal over the frequency range from MHz to GHz. The 6dB linear dynamic range is achieved with very stable output over the full temperature range from 4 C to 8 C. The absolute variation over temperature is typically within ±db over a 47dB dynamic range at.9ghz. Input Port The port is internally biased at V CC -.8V. The pin should be DC blocked when connected to ground or other matching components. A 47Ω resistor (R) connected to ground will provide better than db input return loss up to.ghz. An additional nh inductance in series with R will provide improved input matching up to GHz. The impedance vs frequency of the input is detailed in Table. The approximate linear input power range of the LT4 is from 6dBm to dbm with a Ω source impedance. However, this range can be adjusted either upward or downward to tailor for a particular application 4fa

7 LT4 APPLICATIO S I FOR ATIO Table. Input Impedance W FREQENCY INPT S (MHz) IMPEDANCE (Ω) MAG ANGLE (DEG) 49-j j j j j j j j j j j j j j j j j need. By simply inserting an attenuator in front of the input, the power range is shifted higher by the amount of the attenuation. Moreover, due to the high input impedance of the LT4, the detecting range can be moved downward for better detection sensitivity by using a narrow band L-C matching network. By this means, the sensitivity of the detector can be extended to as low as 7dBm. By changing the value of resistor R, the sensitivity of the detector can be fine-tuned within the range from 7dBm to 6dBm. Though the range is adjustable, the overall linear dynamic range remains the same. Output Interface The output interface of the LT4 is shown in Figure 4. The output currents from the detectors are summed and converted into an output voltage,. The maximum charging current available to the output load is about µa. The internal compensation capacitor C C is used to guarantee stable operation for a large capacitive output load. The slew rate is V/µs, and the small-signal output bandwidth is approximately MHz when the output is resistively V CC + OTPT CRRENTS FROM ECTORS Figure 4. Simplified Circuit Schematic of the Output Interface terminated or open. The fastest output transient response is achieved when a large signal is applied to the input port. See the output transient response plot in the Typical Performance Characteristics section. When the output is terminated with a load capacitance C L, the slew rate is then limited to µa/(c L +.pf). For example, the slew rate is reduced to 7.4V/µs when C L = pf. A capacitive load may result in output voltage overshoot, which can be minimized with a series compensation resistor R as shown in Figure. The suggested resistor values for various capacitive loads are listed in Table. Table. Resistor Value for Capacitive Output C (pf) R (kω). 4. The optional RC network at the output (R and C on the demo board) can also provide further output filtering, if needed. The output bandwidth is primarily dictated by the RC constant of this lowpass filter when its corner frequency is less than MHz. When a large signal (e.g., dbm) is present at the input port, the output voltage swing can be as high as.4v. To assure proper operation of the chip, the minimum resistive load at the output termination should be greater than 8kΩ. C C + µa 4 F4 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. 4fa 7

8 LT4 PACKAGE DESCRIPTIO SC6 Package 6-Lead Plastic SC7 (Reference LTC DWG # -8-68).47 MAX.6 REF.8. (NOTE 4).6 REF.6 MAX. REF.96 MIN (NOTE 4) INDEX AREA (NOTE 6) PIN RECOMMENDED SOLDER PAD LAYOT PER IPC CALCLATOR..4. MAX.6 BSC PLCS (NOTE ).. REF....8 (NOTE ) NOTE:. DIMENSIONS ARE IN MILLIMETERS. DRAWING NOT TO SCALE. DIMENSIONS ARE INCLSIVE OF PLATING 4. DIMENSIONS ARE EXCLSIVE OF MOLD FLASH AND METAL BRR. MOLD FLASH SHALL NOT EXCEED.4mm 6. AILS OF THE PIN INDENTIFIER ARE, BT MST BE LOCATED WITHIN THE INDEX AREA 7. EIAJ PACKAGE REFERENCE IS EIAJ SC-7 SC6 SC7 8 RELATED PARTS PART NMBER DESCRIPTION COMMENTS LT4 8MHz to.7ghz Measuring Receiver 8dB Dynamic Range, Temperature Compensated,.7V to.v Supply LT6 MHz Quadrature IF Demodulator with VGA.8V to.v Supply, 4MHz to MHz IF, 4dB to 7dB Linear Power Gain, 8.8MHz Baseband Bandwidth LT High Linearity pconverting Mixer Output to GHz, 7dBm IIP, Integrated LO Buffer LT DC-GHz High Signal Level Downconverting Mixer DC to GHz, dbm IIP, Integrated LO Buffer LT.GHz to.ghz Direct Conversion Quadrature Demodulator dbm IIP, Integrated LO Quadrature Generator LT6.8GHz to.ghz Direct Conversion Quadrature Demodulator.dBm IIP, Integrated LO Quadrature Generator LT7 4MHz to 9MHz Direct Conversion Quadrature Demodulator dbm IIP, Integrated LO Quadrature Generator LT9.7GHz to.4ghz High Linearity pconverting Mixer 7.dBm IIP, Ω Single Ended and LO Ports LT.GHz to.ghz High Linearity pconverting Mixer.9dBm IIP, Ω Single Ended and LO Ports LT 6MHz to.7ghz High Linearity Downconverting Mixer 4.V to.v Supply, dbm IIP at 9MHz, NF =.db, Ω Single Ended and LO Ports LTC MHz to 7GHz Precision Power Detector Precision Offset Control, Adjustable Gain and Offset LT46 MHz Quadrature IF Demodulator with VGA and 7MHz 7MHz Baseband Bandwidth, 4MHz to MHz IF,.8V to.v Baseband Bandwidth Supply, 7dB to 6dB Linear Power Gain 8 Linear Technology Corporation 6 McCarthy Blvd., Milpitas, CA (48) 4-9 FAX: (48) fa LT/LT 9 REV A PRINTED IN THE SA LINEAR TECHNOLOGY CORPORATION 4

FEATURES TYPICAL APPLICATIO LTC MHz to 3GHz RF Power Detector. in SC70 Package DESCRIPTIO APPLICATIO S

FEATURES TYPICAL APPLICATIO LTC MHz to 3GHz RF Power Detector. in SC70 Package DESCRIPTIO APPLICATIO S 300MHz to 3GHz RF Power Detector in SC70 Package FEATRES Temperature Compensated Internal Schottky Diode RF Detector Wide Input Frequency Range: 300MHz to 3GHz Wide Input Power Range: 30dBm to 6dBm Buffered