LTC5582 40MHz to 10GHz RMS Power Detector with 57dB Dynamic Range Features n n n n n n n n n Description Frequency Range: 40MHz to 10GHz Linear Dynamic Range: Up to 57dB Accurate RMS Power Measurement of High Crest Factor Modulated Waveforms Exceptional Accuracy Over Temperature: 0.5dB (Typ) Low Linearity Error within Dynamic Range Single-Ended or Differential RF Inputs Fast Response Time: 90ns Rise Time Low Supply Current: 41.6mA at 3.3V (Typ) Small 3mm x 3mm DFN10 Applications n n n n n n RMS Power Measurement PA Power Control Receive and Transmit Gain Control LTE, WiMAX, W-CDMA, CDMA2K, TD-SCDMA, EDGE Basestations Point-to-Point Microwave Links RF Instrumentation The LTC(R)5582 is a 40MHz to 10GHz RMS responding power detector. It is capable of accurate power measurement of an AC signal with wide dynamic range, from -60dBm to 2dBm depending on frequency. The power of the AC signal in an equivalent decibel-scaled value is precisely converted into DC voltage on a linear scale, independent of the crest factor of the input signal waveforms. The LTC5582 is suitable for precision RF power measurement and level control for a wide variety of RF standards, including LTE, WiMAX, W-CDMA, CDMA2000, TD-SCDMA, and EDGE. The DC output is buffered with a low output impedance amplifier capable of driving a high capacitance load. Consult factory for more information. The part is packaged in a 10-lead 3mm x 3mm DFN. It is pin-to-pin compatible with the LT5570. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 7262661, 7317357, 7622981. Typical Application Linearity Error vs RF Input Power 2140MHz Modulated Waveforms 40MHz to 6GHz RMS Power Detector 3 TA = 25C 3.3V FLTR VCC IN+ 270pF 68 1nF 2 100nF 1nF LTC5582 EN DEC RT1 IN- RT2 GND OUT 5582 TA01a ENABLE VOUT LINEARITY ERROR (dB) 1F 1 0 -1 -2 -3 -65 4-CARRIER WCDMA CW 3-CARRIER CDMA2K -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 TAO1b 5582f LTC5582 Absolute Maximum Ratings Pin Configuration (Note 1) TOP VIEW Supply Voltage..........................................................3.8V Enable Voltage................................. -0.3V to VCC + 0.3V Input Signal Power (Single-Ended, 50)..............18dBm Input Signal Power (Differential, 50)..................24dBm TJMAX..................................................................... 150C Operating Temperature Range..................-40C to 85C Storage Temperature Range................... -65C to 125C VCC 10 FLTR 1 IN+ 2 DEC 3 IN- 4 GND 5 11 GND 9 EN 8 RT1 7 RT2 6 OUT DD PACKAGE 10-LEAD (3mm s 3mm) PLASTIC DFN TJMAX = 150C, JA = 43C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC5582IDD#PBF LTC5582IDD#TRPBF LFGZ 10-Lead 3mm x 3mm Plastic DFN -40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, EN = 3.3V. Test circuit is shown in Figure 1. (Notes 2 and 3). PARAMETER CONDITIONS MIN TYP MAX UNITS AC Input Input Frequency Range (Note 4) 40 to 10000 MHz Differential 400//0.5 //pF RF Input Power Range CW; Single-Ended, 50 -57 to 2 dBm Linear Dynamic Range 1dB Linearity Error Input Impedance fRF = 450MHz 59 Output Slope Logarithmic Intercept Output Variation vs Temperature Normalized to Output at 25C, Pin = -50dBm to 0dBm Deviation from CW Response 11dB Peak to Average Ratio (3-Carrier CDMA2K) 12dB Peak to Average Ratio (4-Carrier WCDMA) l dB 29.5 mV/dB -86.2 dBm 0.5 dB 0.1 0.1 dB dB 2nd Order Harmonic Distortion At RF Input; CW Input; PIN = 0dBm 67 dBc 3rd Order Harmonic Distortion At RF Input; CW Input; PIN = 0dBm 62 dBc 5582f LTC5582 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, EN = 3.3V. Test circuit is shown in Figure 1. (Notes 2 and 3). PARAMETER CONDITIONS MIN TYP MAX UNITS fRF = 880MHz RF Input Power Range CW; Single-Ended, 50 Linear Dynamic Range 1dB Linearity Error -57 to 2 dBm 59 Output Slope Logarithmic Intercept dB 29.3 mV/dB -86.4 dBm 0.5 dB Output Variation vs Temperature Normalized to Output at 25C, Pin = -50dBm to 0dBm Deviation from CW Response 11dB Peak to Average Ratio (3-Carrier CDMA2K) 12dB Peak to Average Ratio (4-Carrier WCDMA) 0.1 0.1 dB dB 2nd Order Harmonic Distortion At RF Input; CW Input; PIN = 0dBm 69 dBc 3rd Order Harmonic Distortion At RF Input; CW Input; PIN = 0dBm 59 dBc -56 to 1 dBm l fRF = 2140MHz RF Input Power Range CW; Single-Ended, 50 Linear Dynamic Range (Note 5) 1dB Linearity Error Output Slope Logarithmic Intercept 50 57 26 29.5 33 mV/dB -85 -72 dBm -98 Output Variation vs Temperature Normalized to Output at 25C, Pin = -47dBm to 0dBm Deviation from CW Response 11 dB Peak to Average Ratio (3-Carrier CDMA2K) 12dB Peak to Average Ratio (4-Carrier WCDMA) l dB 0.5 dB 0.1 0.1 dB dB fRF = 2700MHz RF Input Power Range CW; Single-Ended, 50 Linear Dynamic Range 1dB Linearity Error -55 to 1 56 Output Slope Logarithmic Intercept Output Variation vs Temperature Normalized to Output at 25C, Pin = -47dBm to 0dBm Deviation from CW Response 12dB Peak to Average Ratio (WiMAX OFDM) l dBm dB 29.8 mV/dB -83.8 dBm 0.5 dB 0.2 dB fRF = 3800MHz RF Input Power Range CW; Single-Ended, 50 Linear Dynamic Range 1dB Linearity Error -51 to 2 53 Output Slope Logarithmic Intercept Output Variation vs Temperature Normalized to Output at 25C, Pin = -51dBm to 2dBm Deviation from CW Response 12dB Peak to Average Ratio (WiMAX OFDM) l dBm dB 30.3 mV/dB -81 dBm 1 dB 0.2 dB fRF = 5800MHz RF Input Power Range CW; Single-Ended, 50 Linear Dynamic Range 1dB Linearity Error -46 to 3 49 dBm dB Output Slope 30.9 mV/dB Logarithmic Intercept -74.7 dBm Output Variation vs Temperature Normalized to Output at 25C, Pin = -46dBm to 2dBm Deviation from CW Response 12dB Peak to Average Ratio (WiMAX OFDM) l 1 dB 0.2 dB 5582f LTC5582 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, EN = 3.3V. Test circuit is shown in Figure 1. (Notes 2 and 3). PARAMETER CONDITIONS MIN TYP MAX UNITS Output Interface Output DC Voltage No RF Signal Present 0.69 Output Impedance V 100 Output Current Maximum 5 mA Rise Time, 10% to 90% 0.8V to 2.4V, C3 = 8nF, fRF = 100MHz 90 nS Fall Time, 90% to 10% 2.4V to 0.8V, C3 = 8nF, fRF = 100MHz 5 S Enable (EN) Low = Off, High = On EN Input High Voltage (On) l EN Input Low Voltage (Off) l 1 V 0.4 V 200 A Enable Pin Input Current EN = 3.3V 125 Turn ON Time VOUT within 10% of Final Value, C3 = 8nF 2.8 s Turn OFF Time VOUT < 0.8V, C3 = 8nF 40 s Power Supply Supply Voltage Supply Current Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC5582 is guaranteed functional over the temperature range -40C to 85C. Note 3: Logarithmic Intercept is an extrapolated input power level from the best fitted log-linear straight line, where the output voltage is 0V. Typical Performance Characteristics Output Voltage vs RF Input Power 52 mA 0.1 10 A Supply Current vs Supply Voltage 60 TA = 25C 55 2.0 1.6 450MHz 880MHz 2140MHz 2700MHz 3800MHz 5800MHz 1.2 0.8 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 1 0 -1 -2 5 5582 G01 SUPPLY CURRENT (mA) 2 LINEARITY ERROR (dB) 2.4 OUTPUT VOLTAGE (V) 41.6 VCC = 3.3V, EN = 3.3V, TA = 25C unless otherwise Linearity Error vs RF Input Power 3 TA = 25C -55 V Note 4: Operation over a wider frequency range is possible with reduced performance. Consult the factory for information and assistance. Note 5: The linearity error is calculated by the difference between the incremental slope of the output and the average output slope from -50dBm to -5dBm. The dynamic range is defined as the range over which the linearity error is within 1dB. noted. Test circuits shown in Figure 1. 0.4 -65 3.5 EN = 0V, VCC = 3.5V Shutdown Current 2.8 3.3 3.1 -3 -65 450MHz 880MHz 2140MHz 2700MHz 3800MHz 5800MHz -55 -45 -35 -25 -15 RF INPUT POWER (dBm) TA = 85C TA = 25C TA = -40C 50 45 40 35 30 25 -5 5 5582 G02 20 3.0 3.1 3.3 3.2 3.4 SUPPLY VOLTAGE (V) 3.5 3.6 5582 G27 5582f LTC5582 Typical Performance Characteristics noted. Test circuits shown in Figure 1. Output Voltage Temperature Variation from 25C, 450MHz 3 2 2 2.0 1 1.6 0 1.2 -1 0.8 0.4 -65 TA = 85C TA = 25C TA = -40C -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 2.4 3 VOUT VARIATION (dB) Rt1 = 12k Rt2 = 2k Linear Error vs RF Input Power, Modulated Waveforms, 450MHz 3 Rt1 = 12k Rt2 = 2k 1 TA = 85C 0 TA = -40C -1 -2 -2 -3 -3 -65 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 2 1 1.6 0 1.2 -1 TA = 85C TA = 25C TA = -40C -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 1 -1 -2 -3 -3 -65 3 2 2 0 1.2 -1 TA = 85C TA = 25C TA = -40C -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G09 VOUT VARIATION (dB) 3 1.6 -55 0 -1 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 -3 -65 5 4-CARRIER WCDMA CW 3-CARRIER CDMA2K -55 -45 -35 -25 -15 RF INPUT POWER (dBm) 0 3 -2 -3 -3 -65 TA = 85C TA = -40C 1 0 -1 -2 -55 TA = 25C 2 -1 -2 5 Linear Error vs RF Input Power, Modulated Waveforms, 2140MHz Rt1 = 0 Rt2 = 2k 1 -5 5582 G08 Output Voltage Temperature Variation from 25C, 2140MHz 1 0.4 -65 1 -2 -55 5 TA = 25C 5582 G07 2.0 0.8 -5 2 TA = -40C -2 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 2.4 -45 -35 -25 -15 RF INPUT POWER (dBm) 3 TA = 85C 0 Output Voltage, Linearity Error vs RF Input Power, 2140MHz Rt1 = 0 Rt2 = 2k -55 Linear Error vs RF Input Power, Modulated Waveforms, 880MHz Rt1 = 12k Rt2 = 2k 5582 G06 2.8 4-CARRIER WCDMA CW 3-CARRIER CDMA2K 5582 G05 LINEARITY ERROR (dB) -55 -3 -65 5 LINEARITY ERROR (dB) 2 VOUT VARIATION (dB) 3 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 3 2.0 0.4 -65 -1 Output Voltage Temperature Variation from 25C, 880MHz Rt1 = 12k Rt2 = 2k 0.8 0 5582 G04 Output Voltage, Linearity Error vs RF Input Power, 880MHz 2.4 1 -2 5582 G03 2.8 TA = 25C 2 LINEARITY ERROR (dB) Output Voltage, Linearity Error vs RF Input Power, 450MHz 2.8 VCC = 3.3V, EN = 3.3V, TA = 25C unless otherwise -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G10 -3 -65 4-CARRIER WCDMA CW 3-CARRIER CDMA2K -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G11 5582f LTC5582 Typical Performance Characteristics noted. Test circuits shown in Figure 1. Output Voltage Temperature Variation from 25C, 2700MHz 3 2 2 2.0 1 1.6 0 1.2 -1 0.4 -65 TA = 85C TA = 25C TA = -40C -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 3 Rt1 = 0 Rt2 = 1.6k 1 TA = -40C 0 -1 -2 -2 -3 -3 -65 2 2 1 1.6 0 1.2 -1 0.4 -65 TA = 85C TA = 25C TA = -40C -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 VOUT VARIATION (dB) 3 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 3 2.0 0.8 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 3 0 TA = 85C -1 -2 -3 -3 -65 2 1.6 0 1.2 -1 0.4 -65 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 1 5 5582 G18 CW 0 WiMAX -1 -2 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 -3 -65 5 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 Linear Error vs RF Input Power, Modulated Waveforms, 5800MHz 3 Rt1 = 0 Rt2 = 3k TA = 85C TA = -40C -1 -2 -2 -3 -3 -65 TA = 25C 2 1 0 5 5582 G17 LINEARITY ERROR (dB) 2 VOUT VARIATION (dB) 3 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 3 5 TA = 25C 5582 G16 1 TA = 85C TA = 25C TA = -40C -5 2 TA = -40C -2 2.0 0.8 -45 -35 -25 -15 RF INPUT POWER (dBm) Linear Error vs RF Input Power, Modulated Waveforms, 3800MHz Output Voltage Temperature Variation from 25C, 5800MHz Rt1 = 0 Rt2 = 3k -55 5582 G14 Rt1 = 0 Rt2 = 1.6k 1 Output Voltage, Linearity Error vs RF Input Power, 5800MHz 2.4 -3 -65 5 5582 G15 2.8 WiMAX -1 Output Voltage Temperature Variation from 25C, 3800MHz Rt1 = 0 Rt2 = 1.6k CW 0 5582 G13 Output Voltage, Linearity Error vs RF Input Power, 3800MHz 2.4 1 -2 5582 G12 2.8 TA = 25C 2 TA = 85C LINEARITY ERROR (dB) 0.8 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) 2.4 3 VOUT VARIATION (dB) Rt1 = 0 Rt2 = 1.6k Linear Error vs RF Input Power, Modulated Waveforms, 2700MHz LINEARITY ERROR (dB) Output Voltage, Linearity Error vs RF Input Power, 2700MHz 2.8 VCC = 3.3V, EN = 3.3V, TA = 25C unless otherwise 1 CW 0 WiMAX -1 -2 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G19 -3 -65 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G20 5582f LTC5582 Typical Performance Characteristics VCC = 3.3V, EN = 3.3V, TA = 25C unless otherwise noted. Test circuits shown in Figure 1. Output Voltage Temperature Variation from 25C, 8GHz Output Voltage Linearity Error vs RF Input Power, 10GHz 2.8 3 2.4 2 2 2.4 2 2.0 1 2.0 1 1.6 0 1.6 0 1.2 -1 1.2 -1 0.8 TA = 85C TA = 25C TA = -40C 0.4 -45 -35 -25 -5 -15 RF INPUT POWER (dBm) 5 10 1 OUTPUT VOLTAGE (V) 3 VOUT VARIATION (dB) 3 TA = 85C 0 TA = -40C -1 -2 -2 0.8 -3 -3 -45 -35 -25 -15 -5 RF INPUT POWER (dBm) 5 10 5582 G30 31.0 2 30.5 TA = 85C -1 -45 -35 -25 -15 -5 RF INPUT POWER (dBm) 5 10 29.5 29.0 28.0 -81 -84 -87 0 1 2 4 3 FREQUENCY (GHz) 5 -90 6 25 25 20 15 10 5 2 4 3 FREQUENCY (GHz) 1 5 4.8 TA = 85C TA = 25C TA = -40C 20 4.0 10 5 fRF = 100MHz RF PULSE ON 4.4 15 6 Output Transient Response, C3 = 8nF OUTPUT VOLTAGE (V) TA = 85C TA = 25C TA = -40C 0 5582 G22 Logarithmic Intercept Distribution vs Temperature, 2140MHz PERCENTAGE DISTRIBUTION (%) PERCENTAGE DISTRIBUTION (%) 30 -78 5582 G21 Slope Distribution vs Temperature, 2140MHz -3 TA = 85C TA = 25C TA = -40C -75 30.0 5582 G33 35 -72 TA = 85C TA = 25C TA = -40C 28.5 -2 5 10 Logarithmic Intercept vs Frequency INTERCEPT (dBm) SLOPE (mV/dB) VOUT VARIATION (dB) 3 0 -25 -15 -5 RF INPUT POWER (dBm) 5582 G32 Slope vs Frequency TA = -40C -35 5582 G31 Output Voltage Temperature Variation from 25C, 10GHz 1 -2 TA = 85C TA = 25C TA = -40C 0.4 -45 LINEARITY ERROR (dB) 2.8 LINEARITY ERROR (dB) OUTPUT VOLTAGE (V) Output Voltage, Linearity Error vs RF Input Power, 8GHz RF PULSE OFF 3.6 RF PULSE OFF 3.2 PIN = 0dBm PIN = -10dBm PIN = -20dBm PIN = -30dBm PIN = -40dBm PIN = -50dBm 2.8 2.4 2.0 1.6 1.2 0.8 0 27.9 28.5 29.1 29.7 SLOPE (mV/dB) 30.3 5582 G23 0 -90 -88 -86 -84 -82 -80 LOGRITHMIC INTERCEPT (dBm) 5582 G24 0.4 0 1 2 3 4 5 6 TIME (s) 7 8 9 10 5582 G25 5582f LTC5582 Typical Performance Characteristics noted. Test circuits shown in Figure 1. Output Transient Response, C3 = 1F OUTPUT VOLTAGE (V) RF PULSE OFF 3.6 RF PULSE OFF 3.2 2.8 2.4 2.0 1.6 PIN = 0dBm PIN = -10dBm PIN = -20dBm PIN = -30dBm PIN = -40dBm PIN = -50dBm 1.2 SUPPLY CURRENT (mA) 55 4.0 0 TA = 85C TA = 25C TA = -40C -5 50 45 40 35 30 -10 -15 -20 25 0.8 0.4 60 fRF = 100MHz RF PULSE ON 4.4 RF Input Return Loss vs Frequency Supply Current vs RF Input Power RETURN LOSS (dB) 4.8 VCC = 3.3V, EN = 3.3V, TA = 25C unless otherwise 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 TIME (ms) 5582 G26 20 -65 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 G28 -25 0 1 3 2 4 FREQUENCY (GHz) 5 6 5582 G22 Pin Functions VCC (Pin 1): Power Supply Pin. Typical current consumption is 41.6mA at room temperature. This pin should be externally bypassed with 1nF and 1F chip capacitors. IN+, IN- (Pins 2, 4): Differential Input Signal Pins. Either one can be driven with a single-ended signal while the other is AC-coupled to ground. These pins can also be driven with a differential signal. The pins are internally biased to 1.585V and should be DC blocked externally. The differential impedance is typically 400. The impedance of each pin to the DEC pin is 200. RT2 (Pin 7): Optional Control Pin for 2nd-Order Output Temperature Compensation. Connect this pin to ground to disable it. The output voltage will decrease with respect to the room temperature (25C) by connecting it to ground via an off-chip resistor when the ambient temperature is either higher or lower. RT1 (Pin 8): Optional Control Pin for 1st-Order Output Temperature Compensation. Connect this pin to ground to disable it. The output voltage will increase inversely proportional to ambient temperature. DEC (Pin 3): Input Common Mode Decoupling Pin. This pin is internally biased to 1.585V and connected to an onchip 50pF capacitor to ground. The impedance between DEC and IN+ (or IN-) is 200. The pin can be connected to the center tap of an external balun when terminated differentially. The pin can be floating or connected to ground via an AC-decoupling capacitor when driven either in single-ended or differential input configuration. EN (Pin 9): Enable Pin. An applied voltage above 1V will activate the bias for the IC. For an applied voltage below 0.4V, the circuits will be shut down (disabled) with a reduction in power supply current. If the enable function is not required, then this pin can be connected to VCC. Typical enable pin input current is 100A for EN = 3.3V. Note that at no time should the Enable pin voltage be allowed to exceed VCC by more than 0.3V. GND (Pin 5, Exposed Pad Pin 11): Circuit Ground Return for the Entire IC. This must be soldered to the printed circuit board ground plane. FLTR (Pin 10): Connection for an External Filtering Capacitor C3. A minimum of 8nF capacitance is required for stable AC average power measurement. This capacitor should be connected to VCC. OUT (Pin 6): DC Output Pin. The output impedance is mainly determined by an internal 100 series resistance which provides protection if the output is shorted to ground. 5582f LTC5582 Test Circuits R1 1.5 1 C4 270pF J1 RF INPUT C5 0.4pF 2 R4 68 C8 1nF NC 3 4 C9 100pF 5 FLTR VCC IN+ LTC5582 EN DEC RT1 IN- RT2 GND OUT EXPOSED PAD 11 REF DES 5582 F01 10 C3 100nF C2 1nF C1 1F 9 3.3V EN R3 100k 8 7 6 OUT C10 OPTIONAL R5 2k R6 0 VALUE SIZE PART NUMBER C1 1uF 0402 MURATA GRM155R60J105KE19 C2, C8 1nF 0402 MURATA GRM155R71H102KA01 C3 100nF 0402 TDK CID05X7R1C104K C4 270pF 0402 MURATA GRM155CIH271JA01 C5 0.4pF 0402 MURATA GJM1555C1HR40BB01 C9 100pF 0402 AVX 0402YC101KAT R1 1.5 0603 VISHAY CRCW06031R50JNEA R3 100K 0402 VISHAY CRCW0402100KFKED R4 68 0402 VISHAY CRCW040268R1FKED R5 2k 0402 VISHAY CRCW04022K00FKEA R6 0 0402 VISHAY CRCW0402020000Z0ED Figure 1. Test Schematic Optimized for 40MHz to 5500MHz in Single-Ended Input Configuration Figure 2. Top Side of Evaluation Board 5582f LTC5582 Applications Information The LTC5582 is a true RMS RF power detector, capable of measuring an RF signal over the frequency range from 40MHz to 10GHz, independent of input waveforms with different crest factors such as CW, CDMA2K, WCDMA, LTE and WiMAX signals. Up to 60dB dynamic range is achieved with a very stable output within the full temperature range from -40C to 85C. Its sensitivity can be as low as -57dBm up to 2.7GHz even with single-ended 50 input termination. RF Inputs The differential RF inputs are internally biased at 1.585V. The differential impedance is 400. These pins should be DC blocked when connected to ground or other matching components. The LTC5582 can be driven in a single-ended configuration as illustrated in Figure 3. The single-ended input impedance vs frequency is detailed in Table 1. The DEC Pin can be either left floating or AC-coupled to ground via an external capacitor. While the RF signal is applied to the IN+ (or IN-) Pin, the other pin IN- (or IN+) should be AC-coupled to ground. By simply terminating a 68 resistor between the IN+ and IN- Pins and coupling the non-signal side to ground using a 1nF capacitor, broadband 50 input matching can be achieved with typical return loss better than 10dB from 40MHz to 5.5GHz. At higher RF frequencies, additional matching components may be needed. J1 RF INPUT LTC5582 C4 1nF 2 C5 3 R4 68 C9 OPTIONAL VCC IN+ DEC 200 50pF C8 1nF 4 IN- 200 5582 F03 Figure 3. Single-Ended Input Configuration Table 1. Single-Ended Input Impedance (DEC Floating) S11 FREQUENCY (MHZ) INPUT IMPEDANCE () MAG ANGLE () 40 220.7-j63.0 0.655 -7.0 100 195.2-j47.3 0.611 -7.1 200 175.1-j37.6 0.571 -7.3 400 200.9-j42.2 0.618 -6.3 600 159.8-j52.9 0.563 -11.5 800 154.8-j52.4 0.554 -12.2 1000 158.6-j57.1 0.568 -12.4 1200 164.1-j81.1 0.612 -14.7 1400 138.1-j110.5 0.650 -21.0 1600 102.7-j113.3 0.659 -28.5 1800 80.1-j103.1 0.647 -35.3 2000 67.1-j92.0 0.628 -41.3 2200 58.4-j82.3 0.607 -46.7 2400 52.9-j74.5 0.586 -52.0 2600 48.5-j67.6 0.566 -57.0 2800 44.8-j61.5 0.546 -62.0 3000 41.8-j56.1 0.526 -66.9 3200 41.8-j56.3 0.508 -72.0 3400 37.3-j47.0 0.490 -77.1 3600 35.4-j42.9 0.473 -80.2 3800 33.9-j39.1 0.457 -87.7 4000 32.4-j35.5 0.445 -93.1 4200 31.1-j32.3 0.429 -98.8 4400 29.9-j29.1 0.416 -104.7 4600 28.9-j26.2 0.405 -110.7 4800 27.9-j23.3 0.395 -117.0 5000 27.0-j20.5 0.388 -123.5 5200 26.2-j17.8 0.382 -130.2 5400 25.4-j15.2 0.376 -136.9 5600 24.7-j12.6 0.376 -144.1 5800 24.0-j10.0 0.377 -151.3 6000 23.3-j7.5 0.377 -158.4 The LTC5582 differential inputs can also be driven from a fully balanced source as shown in Figure 4. When the signal source is a single-ended 50, conversion to a differential signal can be achieved using a 1:8 balun to match the internal 400 input impedance to the 50 source. This impedance transformation results in 9dB voltage gain, thus 9dB improvement in sensitivity is obtained 5582f 10 LTC5582 Applications Information while the overall dynamic range remains the same. At high frequency, additional LC elements may be needed for the input impedance matching due to the parasitics of the transformer and PCB traces. LTC5582 J1 RF INPUT 2 3 MATCHING NETWORK CS1 6.8pF VCC TO IN- IN+ DEC 5582 F05 Figure 5. Single-Ended-to-Differential Conversion 200 0 200 -5 5582 F04 Figure 4. Differential Input Configuration Due to the high input impedance of the LTC5582, a narrow band L-C matching network can be also used to convert a single-ended input to differential signal as shown in Figure 5. By this means, the sensitivity and overall linear dynamic range of the detector will be very similar to the one using 1:8 RF input balun. The conversion gain is strongly dependent on the loss (or Q) of the matching network, particularly at high frequency. The lower the Q, the lower the conversion gain. However, the matching bandwidth is correspondingly wider. The following formulas are provided to calculate the input matching network for single-ended-to-differential conversion at low RF frequency (i.e., below 1GHz). CS1 = CS2 = 1 2.25 * 10 = fc fc 50RIN 50RIN 2.25 * 1010 LM = = 2fc fc 9 (pF ) RETURN LOSS (dB) IN- -10 -15 -20 -25 -30 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) 5582 F06 Figure 6. RF Input Return Loss 2.8 2.4 OUTPUT VOLTAGE (V) 4 LM 66nH CS2 6.8pF 50pF T1 1:8 TO IN+ RF INPUT SINGLE-ENDED-TODIFFERENTIAL INPUTS 2.0 1.6 SINGLE-ENDED 1.2 0.8 (nH) where RIN is the differential input resistance (400) and fc is the center RF operating frequency. As an example, Figure 6 shows that good input return loss is achieved from 300MHz to 400MHz when Cs1= Cs2 = 6.8pF and LM = 66nH. Figure 7 show the sensitivity is also improved by 8dB at 350MHz while the dynamic range remains the same. 0.4 -75 -65 -55 -45 -35 -25 -15 RF INPUT POWER (dBm) -5 5 5582 F07 Figure 7. Output Voltage vs RF Input Power Although these equations give a good starting point, it is usually necessary to adjust the component values after building and testing the circuit. As the RF operating frequency increases, the real values of CS1, CS2, LM will deviate from the above equations due to parasitics of the components, device and PCB layout. For a 50 input termination, the approximate RF input power range of the LTC5582 is from -60dBm to 2dBm, 5582f 11 LTC5582 The sensitivity of LTC5582 is dictated by the broadband input noise power that also determines the output DC offset voltage. When the inputs are terminated differently, the DC output voltage may vary slightly. When the input noise power is minimized, the DC offset voltage is also reduced to the minimum. And the detector's sensitivity and dynamic range will be improved accordingly. External Filtering (FLTR) Capacitor This pin is internally biased at VCC - 0.43V via a 1.2k resistor from the voltage supply, VCC. To assure stable operation of the LTC5582, an external capacitor C3 with a value of 8nF or higher is required to connect from the FLTR Pin to VCC to avoid an abnormal start-up condition. Don't connect this filtering capacitor to ground or any other low voltage reference at any time. This external capacitor value has a dominant effect on the output transient response. The lower the capacitance, the faster the output rise and fall times. For signals with AM content such as W-CDMA, significant ripple can be observed when the loop bandwidth set by C3 is close to the modulation bandwidth of the signal. A 4-carrier WCDMA RF signal is used as an example in this case. The trade-offs of the residual ripple vs the output transient times are as shown in Figure 8. In general, the LTC5582 output ripple remains relatively constant regardless of the RF input power level for a fixed C3 and modulation format of the RF signal. Typically, C3 must be selected to smooth out the ripple to achieve the desired accuracy of RF power measurement. Output Interface The output buffer amplifier of the LTC5582 is shown in Figure 9. This Class AB buffer amplifier can source and sink 5mA current to and from the load. The output impedance is determined primarily by the 100 series resistor 12 500 50 450 45 400 40 350 35 300 30 RIPPLE 250 25 FALL TIME 200 20 150 15 100 10 50 0 RISE TIME 0 200 400 600 800 FILTERNING CAPACITOR C3 (nF) RISE TIME (s) even with high crest factor signals such as a 4-carrier WCDMA waveform, and the minimum detectable RF power level varies as the input RF frequency increases. The linear dynamic range can also be shifted to suit a particular application need. By simply inserting an attenuator in front of the RF input, the power range is shifted higher by the amount of the attenuation. RIPPLE (mVP-P), FALL TIME (s) Applications Information 5 0 1000 5582 F08 Figure 8. Residual Ripple, Output Transient Times vs Filtering Capacitor C3 LTC5582 VCC INPUT 100 OUT RSS VOUT CLOAD 5582 F09 Figure 9. Simplified Schematic of the Output Interface connected to the output of the buffer amplifier inside the chip. This will prevent overstress on internal devices in the event that the output is shorted to ground. The -3dB small-signal bandwidth of the buffer amplifier is about 22.4MHz and the full-scale rise/fall time can be as fast as 80ns, limited by the slew rate of the internal circuit instead. When the output is resistively terminated or open, the fastest output transient response is achieved when a large signal is applied to the RF input. The rise time of the LTC5582 is about 90ns and the fall time is 5s, respectively, for full-scale pulsed RF input power when C3 = 8nF. The speed of the output transient response is dictated mainly by the filtering capacitor C3 (at least 8nF) at the FLTR Pin. See the detailed output transient response in the Typical Performance Characteristics section. When the RF input has AM content, residual ripple may be present at the output depending upon the low frequency content of the modulated RF signal. This ripple can be reduced with a larger filtering capacitor C3 at the expense of a slower transient response. 5582f LTC5582 Applications Information CLOAD 5mA * 5mA * allowable additional time = 1.7 V 0.25s = 735pF 1.7 V Once CLOAD is determined, RSS can be chosen properly to form a RC low-pass filter with a corner frequency of 1/[2(RSS + 100) * CLOAD]. Temperature Compensation of Logarithmic Intercept The simplified interface schematic of the intercept temperature compensation is shown in Figure 10. The adjustment of the output voltage can be described by the following equation with respect to the ambient temperature: VOUT = -TC1 * (TA - TNOM) - TC2 * (TA - TNOM)2- detV1 - detV2 where TC1 and TC2 are the 1st-order and 2nd-order temperature compensation coefficients, respectively; TA is the actual ambient temperature; and TNOM is the reference room temperature; detV1 and detV2 are the output voltage variations when RT1 and RT2 are not set to zero at room temperature. The temperature coefficients TC1 and LTC5582 VCC RT1 OR RT2 250 RT1 OR RT2 5582 F10 Figure 10. Simplified Interface Circuit Schematic of the Control Pins RT1 and RT2 When Pins RT1 and RT2 are shorted to ground, the temperature compensation circuit is disabled automatically. Table 2 lists the suggested RT1 and RT2 values at various RF frequencies for the best output performance over temperature. 1.2 120 1.0 100 TC1 0.8 80 0.6 60 0.4 40 0.2 0 20 detV1 5 10 15 20 25 RT1 (k) detV1 (mV) In general, the rise time of the LTC5582 is much shorter than the fall time. However, when the output RC filter is used, the rise time can be dominated by the time constant of this filter. Accordingly, the rise time becomes very similar to the fall time. Although the maximum sinking capability of the LTC5582 is 5mA, it is recommended that the output load resistance should be greater than 1.2k in order to achieve the full output voltage swing. TC2 are shown as functions of the tuning resistors RT1 and RT2 in Figures 11 and 12, respectively. TC1 (mV/C) Since the output buffer amplifier of the LTC5582 is capable of driving an arbitrary capacitive load, the residual ripple can be further filtered at the output with a series resistor RSS and a large shunt capacitor CLOAD. See Figure 9. This lowpass filter also reduces the output noise by limiting the output noise bandwidth. When this RC network is designed properly, a fast output transient response can be maintained with a reduced residual ripple. For example, we can estimate CLOAD with an output voltage swing of 1.7V at 2140MHz. In order not to allow the maximum 5mA souring current to limit the fall time (about 5s), the maximum value of CLOAD can be chosen as follows: 30 35 0 40 5582 F11 Figure 11. 1st-Order Temperature Compensation Coefficient TC1 vs RT1 Value Table 2. Suggested RT1 and RT2 Values for Optimal Temperature Performance vs RF Frequency FREQUENCY (MHz) RT1 (k) RT2 (k) 450 12 2 880 12 2 2140 0 2 2700 0 1.6 3600 0 1.6 5800 0 3 5582f 13 LTC5582 20 200 16 160 12 120 TC2 8 80 4 0 40 detV2 0 1 2 3 4 5 RT2 (k) Enable Interface detV2 (mV) TC2 (V/C) Applications Information 6 7 8 0 5582 F12 Figure 12. 2nd-Order Temperature Compensation Coefficient TC2 vs RT2 Value VCC EN 52k 52k 5582 F13 Figure 13. Enable Pin Simplified Circuit A simplified schematic of the EN Pin interface is shown in Figure 13. The enable voltage necessary to turn on the LTC5582 is 1V. To disable or turn off the chip, this voltage should be below 0.4V. It is important that the voltage applied to the EN pin should never exceed VCC by more than 0.3V. Otherwise, the supply current may be sourced through the upper ESD protection diode connected at the EN pin. Under no circumstances should voltage be applied to the EN Pin before the supply voltage is applied to the VCC pin. If this occurs, damage to the IC may result. Supply Voltage Ramping Fast ramping of the supply voltage can cause a current glitch in the internal ESD protection circuits. Depending on the supply inductance, this could result in a supply voltage overshooting at the initial transient that exceeds the maximum rating. A supply voltage ramp time of greater than 1ms is recommended. In case this voltage ramp time is not controllable, a small (i.e., 1.5) series resistor should be inserted in-between VCC Pin and the supply voltage source to mitigate the problem and self-protect the IC. The R1 shown in Figure 1 is served for this purpose. 5582f 14 LTC5582 Package Description DD Package 10-Lead Plastic DFN (3mm x 3mm) (Reference LTC DWG # 05-08-1699 Rev B) 0.70 p0.05 3.55 p0.05 1.65 p0.05 2.15 p0.05 (2 SIDES) PACKAGE OUTLINE 0.25 p 0.05 0.50 BSC 2.38 p0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 p0.10 (4 SIDES) R = 0.125 TYP 6 0.40 p 0.10 10 1.65 p 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF 0.75 p0.05 0.00 - 0.05 5 1 (DD) DFN REV B 0309 0.25 p 0.05 0.50 BSC 2.38 p0.10 (2 SIDES) BOTTOM VIEW--EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 5582f 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. 15 LTC5582 Typical Application 40MHz to 6GHz Infrastructure Power Amplifier Level Control DIRECTIONAL COUPLER PA RFIN 3.3V 100nF 1 50 270pF 68 2 3 4 1nF 5 FLTR VCC IN+ LTC5582 EN DEC RT1 IN- RT2 GND OUT EXPOSED PAD 11 1F 10 DIGITAL POWER CONTROL 9 8 7 6 1nF OUT ADC 5582 TA02 Related Parts PART NUMBER DESCRIPTION RF Power Detectors LTC5505 RF Power Detectors with >40dB Dynamic Range LTC5507 100kHz to 1000MHz RF Power Detector LTC5508 300MHz to 7GHz RF Power Detector LTC5509 300MHz to 3GHz RF Power Detector LTC5530 300MHz to 7GHz Precision RF Power Detector LTC5531 300MHz to 7GHz Precision RF Power Detector LTC5532 300MHz to 7GHz Precision RF Power Detector LT5534 50MHz to 3GHz Log RF Power Detector with 60dB Dynamic Range LTC5536 Precision 600MHz to 7GHz RF Power Detector with Fast Comparator Output LT5537 Wide Dynamic Range Log RF/IF Detector LT5538 75dB Dynamic Range 3.8GHz Log RF Power Detector LT5570 60dB Dynamic Range RMS Detector LT5581 6GHz RMS Power Detector with 40dB Dynamic Range Infrastructure LTC5540/LTC5541/ 600MHz to 4GHz High Dynamic Range LTC5542/LTC5543 Downconverting Mixer LT5579 1.5GHz to 3.8GHz High Linearity Upconverting Mixer LTC5598 5MHz to 1600MHz High Linearity Direct Quadrature Modulator COMMENTS 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply 100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply 44dB Dynamic Range, Temperature Compensated, SC70 Package 36dB Dynamic Range, Low Power Consumption, SC70 Package Precision VOUT Offset Control, Shutdown, Adjustable Gain Precision VOUT Offset Control, Shutdown, Adjustable Offset Precision VOUT Offset Control, Adjustable Gain and Offset 1dB Output Variation over Temperature, 38ns Response Time, Log Linear Response 25ns Response Time, Comparator Reference Input, Latch Enable Input, -26dBm to +12dBm Input Range Low Frequency to 1GHz, 83dB Log Linear Dynamic Range 0.8dB Accuracy Over Temperature 40MHz to 2.7GHz, 0.5dB Accuracy Over Temperature 1dB Accuracy Over Temperature, Log Linear Response, 1.4mA at 3.3V IIP3 = 26dBm, 8dB Conversion Gain, <10dB NF, 3.3V, 190mA Supply Operation 27.3dBm OIP3 at 2.14GHz, 9.9dB NF, 2.6dB Conversion Gain, -35dBm LO Leakage 27.7dBm OIP3 at 140MHz, -161.2dBm/Hz Noise Floor, 0.5VDC Baseband Interface, -55dBm LO Leakage and 50.4dBc Image Rejection at 140MHz 5582f 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LT 0510 * PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2010