HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Typical Applications Features The HMC614LP4(E) is ideal for: IPWR Output: Instantaneous Power, Crest Factor Measurement * Log -> Root-Mean-Square (RMS) Conversion RF Signal Wave shape & Crest Factor Independent * Received Signal Strength Indication (RSSI) Operates with Single-Ended or Differential Input * Transmitter Signal Strength Indication (TSSI) Supports Controller Mode [1] * RF Power Amplifier Efficiency Control 1 dB Detection Accuracy to 3.9 GHz * Receiver Automatic Gain Control Input Dynamic Range: -57 dBm to +15 dBm * Transmitter Power Control +5V Operation from -40C to +85C 11 Excellent Temperature Stability Power-Down Mode POWER DETECTORS - SMT 24 Lead 4x4mm QFN Package: 9 mm2 Functional Diagram General Description The HMC614LP4E RMS Power Detector is designed for RF power measurement, and control applications for frequencies up to 3.9 GHz. The detector provides a "true RMS" representation of any RF/IF input signal. The output is a temperature compensated, monotonic representation of real signal power, measured with a differential input sensing range of 71 dB. The HMC614LP4E is ideally suited to those wide bandwidth, wide dynamic range applications, requiring repeatable measurement of real signal power; especially where RF/IF wave shape and/or crest factor change with time. The HMC614LP4E provides an indication of the instantaneous or peak input power level normalized to the average input power level (peak to average power ratio) via the IPWR output. The capability of simultaneously measuring the instantaneous power (envelope power) and the average true RMS power provides crucial information about the RF input signal: Peak Power, Average Power, Peak to average power and RF Wave-Shape. Electrical Specifi cations, TA = +25 C, Vcc = 5V, CINT = 0.1 F [2] Parameter Typ. Typ. Typ. Typ. Typ. Typ. Typ. Typ. Units Input Frequency 100 900 1900 2200 2700 3000 3500 3900 MHz Dynamic Range ( 1 dB linearity Error) [2] 70 71 70 69 62 62 53 45 dB Differential Input Configuration Differential Input Configuration Logarithmic Slope Logarithmic Slope 37.5 37.5 37.6 38.1 39.6 41.0 44.5 50.2 mV/dB Logarithmic Intercept -69.8 -69.4 -68.8 -67.4 -63.6 -60.8 -54.8 -49.2 dBm Max. input Power at 1 dB Error 13 15 >15 >15 12 14 10 5 dBm Min. input Power at 1 dB Error -57 -56 -55 -54 -50 -48 -43 -40 dBm [1] For more information regarding controller mode operation, please contact your Hittite sales representative or email sales@hittite.com [2] Differential input drive via 1:1 balun transformer, VTGT = 2V unless otherwise noted. 11 - 76 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Electrical Specifi cations, TA = +25 C, Vcc = 5V, CINT = 0.1 F Parameter (Continued) Typ. Typ. Typ. Typ. Units Input Frequency 900 1300 2300 3300 MHz Dynamic Range ( 1 dB linearity Error) 65 66 62 58 dB mV/dB Single-Ended Input Configuration Single-Ended Input Configuration Logarithmic Slope 38.1 37.1 37.7 43.1 Logarithmic Intercept -67.3 -69.9 -67 -60.2 dBm Max. input Power at 1 dB Error >10 >10 >10 >10 dBm Min. input Power at 1 dB Error -55 -56 -58 -48 dBm Table 2: Electrical Specifi cations [1] Evaluation Kit (Diff. Input Confi g.) TA = +25 C, Vcc = 5V, CINT = 0.1 F Unless Otherwise Noted Parameter Typ. Typ. Typ. Typ. Units 3900 MHz Deviation vs. Temperature: Deviation is measured from reference, which is the same CW Input @ 25 C Differential Input Interface with 1:1 Balun Transformer (Over Full Input Frequency Range) Input Frequency 0.5 dB 900 1900 2700 1 Carrier CDMA 0.02 0.06 0.08 0.03 dB 2 Carrier CDMA 0.02 0.05 0.11 0.02 dB Average Modulation Deviation Error from CW Input [2] 3 Carrier CDMA 0.15 0.16 0.23 0.16 dB QAM256 0.01 0.03 0.05 0.01 dB IPWR/IREF Outputs IPWR Output Voltage with CW Input (average power= instantaneous power) 1.6V IREF Output Voltage Same termination resistance as IPWR 1.6V Vtgt = 2V 190 mV Vtgt = 1V 95 mV IPWR Output Slope for Input Power Change Normalized to Average Power [3] IPWR Output Slope Variation with Temperature from -40C to 85C IPWR Output Modulation BW for 3 dB voltage drop in Output Swing [1] Differential input drive via 1:1 balun transformer. [2] Modulation data taken with VTGT = 1V [3] IPWR = a(Pin(t)/Pave)+b, a is defined as IPWR Slope for input power change normalized to average power. 3% 35 MHz For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 POWER DETECTORS - SMT Logarithmic Slope 11 - 77 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz RMSOUT vs. Pin with Different Modulations @ 1900 MHz, VTGT= 1V RMSOUT Error vs. Pin with Different Modulations @ 1900 MHz, VTGT= 1V 4 4 3.5 11 2.5 2 ERROR (dB) RMSOUT (V) 3 2 1.5 1 0 -1 1 -2 0.5 -3 0 -70 -60 -50 -40 CW 1 CARRIER CDMA 2 CARRIER CDMA 4 CARRIER CDMA QAM256 3 Ideal CW 1 CARRIER CDMA 2 CARRIER CDMA 4 CARRIER CDMA QAM256 -30 -20 -10 0 -4 -60 10 -50 -40 -20 -10 0 10 Absolute Error wrt to CW Response @ 1900 MHz for Different Modulation Schemes, VTGT= 2V Absolute Error wrt to CW Response @ 1900 MHz for Different Modulation Schemes, VTGT= 1V 0.5 2 1 Carrier CDMA 2 Carrier CDMA 4 Carrier CDMA QAM256 0.06 dB Average 0.05 dB Average 0.16 dB Average 0.11 dB Average 1 Carrier CDMA 2 Carrier CDMA 4 Carrier CDMA QAM256 1.5 ERROR (dB) 0.4 ERROR (dB) POWER DETECTORS - SMT -30 INPUT POWER (dBm) INPUT POWER (dBm) 0.3 0.2 0.20 dB Average 0.35 dB Average 0.74 dB Average 0.11 dB Average 1 0.5 0.1 0 -70 -60 -50 -40 -30 -20 -10 0 0 -70 10 INPUT POWER (dBm) -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) Table 3: Electrical Specifi cations III , HMC610LP4E Evaluation Kit (Diff. Input Confi g.), TA = +25 C, Vcc= +5V, CINT = 0.1 F, Unless Otherwise Noted. Parameter Conditions Min. Typ. Max. Units Differential Input Configuration [1] >10 Input Resistance between IN+ and IN- Between pins 3 and 4 200 Input Voltage Range VDIFFIN = VIN+ - VIN- Input Network Return Loss dB 2.25 V Single-Ended Input Configuration Input Network Return Loss Input Voltage Range [3] [4] >10 VSEin = VIN+ dB 1.4 V RMSOUT Output Output Voltage Range RL = 1k, CL = 4.7pF[2] 0.4 - 3.2 Source/Sink Current Compliance RMSOUT held at VCC/2 8 / 0.35 mA Output Slew Rate (rise / fall) With CINT = 0, Cofs = 0 100 / 5 10 6 V/s VSET Input (Negative Feedback Terminal) Input Voltage Range [2] Input Resistance 11 - 78 V 0.4 - 3.2 V 1 M For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Table 3: Electrical Specifi cations III (Continued) Parameter Conditions Min. Typ. Max. Units VREF Output (Reference Voltage) VREF Output Voltage VREF Change 2.95 V 20 mV Over Full Temperature Range V TGT Input (RMS Target Interface) Input Voltage Range 3.65 Input Resistance V 1 M ENX Logic Input (Power Down Control) Standby Mode Active Input Low Voltage Normal Operation 3.9 V Input High Current Input Low Current Input Capacitance 1.2 V 1 A 1 A 0.5 11 pF POWER DETECTORS - SMT Input High Voltage Power Supply 5 5.5 V Supply Current with Pin = -70 dBm Supply Voltage Over Full Temperature Range 4.5 65 76 mA Supply Current with Pin = 0 dBm Over Full Temperature Range 83 95 mA ENX = Hi 1 Standby Mode Supply Current mA [1] Performance of differential input configuration is limited by balun. Balun used is MACOM ETC1-1-13 good over 4.5 MHz to 3000 MHz [2] For nominal slope / intercept setting. [3] Using Wideband Single-Ended Input Interface suitable for input signal frequencies below 1000 MHz [4] Using Tuned Single-Ended Input Interface suitable for input signal frequencies above 1000 MHz RMSOUT & Error vs. Pin @ 100 MHz [1] Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 4 2 3 -2 1 4 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 2 0 2 -2 1 ERR +25C ERR +85C ERR -40C -70 ERR +25C ERR +85C ERR -40C -4 0 -60 -50 -40 -30 -20 -10 0 ERROR (dB) 0 2 ERROR (dB) RMSOUT (V) 3 4 RMSOUT (V) 4 RMSOUT & Error vs. Pin @ 900 MHz [1] 10 INPUT POWER (dBm) -4 0 -70 -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) [1] CW Input Waveform into differential input interface with 1:1 Balun. For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 79 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz RMSOUT & Error vs. Pin @ 1900 MHz [1] Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 4 2 3 -2 1 4 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 0 2 -2 1 ERR +25C ERR +85C ERR -40C 11 -4 0 -70 ERR +25C ERR +85C ERR -40C -60 -50 -40 -30 -20 -10 0 -4 0 10 -70 -60 -50 INPUT POWER (dBm) RMSOUT & Error vs. Pin @ 2700 MHz [1] -20 -10 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 4 4 2 3 0 2 -2 1 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 2 0 2 -2 1 ERR +25C ERR +85C ERR -40C -4 0 -60 -50 -40 -30 -20 -10 0 -4 0 10 -70 -60 -50 INPUT POWER (dBm) -30 -20 -10 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C RMSOUT (V) 2 0 2 -2 1 ERR +25C ERR +85C ERR -40C ERR +25C ERR +85C ERR -40C -4 0 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) -4 0 -70 -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) [1] CW Input Waveform into differential input interface with 1:1 Balun. 11 - 80 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com ERROR (dB) -2 1 4 3 ERROR (dB) 0 -60 10 4 2 2 -70 0 RMSOUT & Error vs. Pin @ 3900 MHz [1] 4 4 RMSOUT (V) -40 INPUT POWER (dBm) RMSOUT & Error vs. Pin @ 3500 MHz [1] 3 10 4 ERR +25C ERR +85C ERR -40C -70 0 ERROR (dB) RMSOUT (V) -30 RMSOUT & Error vs. Pin @ 3000 MHz [1] RMSOUT (V) 4 3 -40 INPUT POWER (dBm) ERROR (dB) POWER DETECTORS - SMT 2 ERROR (dB) 0 2 ERROR (dB) RMSOUT (V) 3 4 RMSOUT (V) 4 RMSOUT & Error vs. Pin @ 2200 MHz [1] HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Frequency vs. Intercept Over Supply Voltage [1] Frequency vs. Intercept Over Temperature [1] -40 -40 -45 4.5V 5.0V 5.5V -55 -60 -65 -55 -60 -65 -70 -70 -75 -75 -80 +25C +85C -40C -50 -80 0 500 1000 1500 2000 2500 3000 3500 4000 0 500 1000 FREQUENCY (MHz) 60 60 55 55 4.5V 5.0V 5.5V SLOPE (mV/dB) SLOPE (mV/dB) 2500 3000 3500 4000 3000 3500 4000 Frequency vs. Slope Over Temperature [1] 45 40 35 +25C +85C -40C 50 45 40 35 30 30 0 500 1000 1500 2000 2500 3000 3500 4000 0 500 1000 FREQUENCY (MHz) 2000 2500 RMSOUT vs. Pin, Intercept Adjustment [2] 4 11 4 RMSOUT @ VSET = -1.0V RMSOUT @ VSET = -0.5V RMSOUT @ VSET = 0V RMSOUT @ VSET = 0.5V RMSOUT @ VSET = 1.0V RMSOUT @ R1= 24KOhms RMSOUT @ R1= 12KOhms RMSOUT @ R1= 6.8KOhms 3 3 RMSOUT (V) 2 1500 FREQUENCY (MHz) RMSOUT vs. Pin, Slope Adjustment [1] RMSOUT (V) 2000 FREQUENCY (MHz) Frequency vs. Slope Over Supply Voltage [1] 50 1500 POWER DETECTORS - SMT -50 INTERCEPT (dBm) INTERCEPT (dBm) -45 Slope = 48mV/dB VSET = -1.0V, X Intercept = -82.2dBm VSET = -0.5V, X Intercept = -75.5dBm 2 Slope = 26mv/dB 1 1 VSET = 0V, X Intercept = -68.8dBm VSET = 0.5V, X Intercept = -62.1dBm VSET = 1.0V, X Intercept = -55.4dBm Slope = 35mV/dB 0 -70 0 -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) [1] See application circuit for location of R1 [2] See application section Log-Slope, RFBK = 12k, RSET = 24K -70 -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) [3] VTGT 1V, Average Input Power = 0 dBm [4] VTGT 2V, Average Input Power = 0 dBm For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 81 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Single-Ended RMSOUT & Error vs. Pin, Tuned @ 1300 MHz Single-Ended RMSOUT & Error vs. Pin, Tuned @ 2300 MHz 4 4 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 2 1 11 ERR +25C ERR +85C ERR -40C 0 -60 -50 -40 -30 -20 -10 0 RMSOUT (V) 0 2 -2 1 -4 0 10 ERR +25C ERR +85C ERR -40C -50 -40 -30 -20 -10 0 10 0 10 INPUT POWER (dBm) Single-Ended RMSOUT & Error vs. Pin, Tuned @ 3300 MHz 4 4 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C RMSOUT (V) 3 2 0 2 ERROR (dB) POWER DETECTORS - SMT -2 -4 -60 INPUT POWER (dBm) -2 1 ERR +25C ERR +85C ERR -40C -4 0 -60 -50 -40 -30 -20 -10 0 10 INPUT POWER (dBm) Single-Ended, Error vs. Pin, Tuned @ 900 MHz Single-Ended, Error vs. Pin, Tuned @ 1300 MHz 4 4 3 1 0 -1 1 0 -1 -2 -2 -3 -3 -4 -60 -50 -40 -30 -20 900MHz 1100MHz 1300MHz 1500MHz 1700MHz 2 ERROR (dB) ERROR (dB) 3 500MHz 700MHz 900MHz 1100MHz 1300MHz 2 -10 INPUT POWER (dBm) 11 - 82 2 0 10 -4 -60 -50 -40 -30 -20 -10 INPUT POWER (dBm) For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com ERROR (dB) 0 2 Ideal RMSOUT +25C RMSOUT +85C RMSOUT -40C 3 ERROR (dB) RMSOUT (V) 3 4 4 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Single-Ended, Error vs. Pin, Tuned @ 2300 MHz Single-Ended, Error vs. Pin, Tuned @ 3300 MHz 4 4 2 ERROR (dB) ERROR (dB) 2 1 0 -1 1 0 -1 -2 -2 -3 -3 -4 -60 -50 -40 -30 -20 2900MHz 3100MHz 3300MHz 3500MHz 3700MHz 3 1900MHz 2100MHz 2300MHz 2500MHz 2700MHz -10 0 -4 -60 10 -50 -40 INPUT POWER (dBm) IPWR Output for an Input Crest Factor of 9.03 dB over Temperature vs. Time [1] 0 11 10 +25C +85C -40C 2.2 IPWR OUTPUT (V) IPWR OUTPUT (V) -10 2.4 +25C +85C -40C 1.9 1.8 1.7 1.6 2 1.8 1.6 1.5 1.4 1.4 1 2 3 TIME (us) 4 5 0 IPWR Output & Input RF Signal Envelope vs. Time For An Input Crest Factor of 9.03 dB [2] 2 1.2 1.6 0.8 1.2 0.4 0.8 0 0.4 -0.4 Input RF Signal Envelope 0 1 2 3 TIME (s) 4 5 -0.8 2 3 4 5 TIME (us) 6 7 8 4.2 2.8 2.4 3.4 IPWR Output 2 2.6 1.6 1.8 1.2 1 0.8 0.2 -0.6 0.4 Input RF Signal Envelope 0 0 1 2 3 4 5 6 7 8 INPUT RF SIGNAL ENVELOPE (V) 1.6 IPWR Output INPUT RF SIGNAL ENVELOPE (V) 2.4 1 IPWR Output & Input RF Signal Envelope vs. Time For An Input Crest Factor of 12.04 dB [2] IPWR OUTPUT (V) 0 IPWR OUTPUT (V) -20 IPWR Output for an Input Crest Factor of 12.04 dB over Temperature vs. Time [1] 2 0 -30 INPUT POWER (dBm) POWER DETECTORS - SMT 3 -1.4 TIME (s) [1] VTGT 1V, Average Input Power = 0 dBm [2] VTGT 2V, Average Input Power = 0 dBm For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 83 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz IPWR Output vs. Instantaneous Input Power (Normalized to Average Power) [1] Peak IPWR vs Input Crest Factor [1] 3 3 IPWR(t) = (VTGT/10)x(Pin(t)/Pavg)+(1.6-(Vtgt/10)) 2.4 2.2 2 1.8 =Pin/Pav*0.2+(1.6-0.2) IPWR Output VTGT = 2V =Pin/Pav*0.1+(1.6-0.1) IPWR Output VTGT = 1V 2.6 2.4 2.2 2 1.8 1.4 1.6 0 2 4 6 8 10 INSTANTANEOUS INPUT POWER (NORMALIZED TO AVERAGE POWER) 12 RMS Error vs. Crest Factor Over VTGT [2] 3 5 7 9 11 INPUT CREST FACTOR (dB) 0.4 0 0.2 -5 25C +85C -40C 0 -0.2 -0.4 -0.6 -0.8 VTGT = 0.5V VTGT = 1.0V VTGT = 2.0V -1 -10 -15 -20 -25 -30 -1.2 Defined in large part by balun: M/A-Com balun#ETC1-1-113; -35 -1.4 4.5MHz to 3000MHz -40 -1.6 3 4 5 6 7 8 9 10 11 12 13 0 1 2 INPUT SIGNAL CREST FACTOR (dB) 3 4 FREQUENCY (GHz) Output Response Rise Time @ 1900 MHz, CINT = Open Output Response Rise Time @ 1900 MHz, CINT = 0.1 F 3.5 3.5 3 3 10 dBm 0 dBm -10 dBm -20 dBm -30 dBm 2 Input Dynamic Range to +/- 1dB Error 1.5 1 10 dBm 0 dBm -10 dBm -20 dBm -30 dBm 2.5 RMSOUT (V) 2.5 RMSOUT (V) 13 Input Return Loss RETURN LOSS (dB) RMSOUT ERROR (dB) POWER DETECTORS - SMT 2.6 1.6 11 Peak IPWR Output VTGT = 2V Peak IPWR Output VTGT = 1V 2.8 PEAK IPWR OUTPUT (V) IPWR OUTPUT (V) 2.8 2 Input Dynamic Range to +/- 1dB Error 1.5 1 0.5 0.5 0 0 0 50 100 150 200 250 300 TIME (ns) 350 400 450 500 0 200 400 600 800 1000 1200 1400 1600 1800 2000 TIME (s) [1] PIN = -20 dBm @ 1.9 GHz [2] PIN = -22 dBm @ 1.9 GHz 11 - 84 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 Output Response Fall Time @ 1900 MHz, CINT = Open RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Output Response Fall Time @ 1900 MHz, CINT = 0.1 F 3.5 3.5 3 3 Input Dynamic Range to +/- 1dB Error 2 10dBm 0dBm -10dBm -20dBm -30dBm 2.5 10 dBm 0 dBm -10 dBm -20 dBm -30 dBm 1.5 1 RMSOUT (V) 2 1.5 Input Dynamic Range to +/- 1dB Error 1 0.5 0.5 0 0 -0.5 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 TIME (ns) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 TIME (s) Absolute Maximum Ratings Supply Voltage 5.6V RF Input Power 20 dBm Max. Input Voltage 2.25 Vrms Channel / Junction Temperature 125 C Continuous Pdiss (T = 85C) (Derate 22.72 mW/C above 85C) 0.91 Watts Thermal Resistance (Rth) (junction to ground paddle) 44.02 C/W Storage Temperature -65 to +150 C Operating Temperature -40 to +85 C ESD Sensitivity (HBM) Class 1A 11 ELECTROSTATIC SENSITIVE DEVICE OBSERVE HANDLING PRECAUTIONS For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com POWER DETECTORS - SMT RMSOUT (V) 2.5 11 - 85 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Outline Drawing POWER DETECTORS - SMT 11 NOTES: 1. LEADFRAME MATERIAL: COPPER ALLOY 2. DIMENSIONS ARE IN INCHES [MILLIMETERS]. 3. LEAD SPACING TOLERANCE IS NON-CUMULATIVE 4. PAD BURR LENGTH SHALL BE 0.15mm MAXIMUM. PAD BURR HEIGHT SHALL BE 0.05mm MAXIMUM. 5. PACKAGE WARP SHALL NOT EXCEED 0.05mm. 6. ALL GROUND LEADS AND GROUND PADDLE MUST BE SOLDERED TO PCB RF GROUND. 7. REFER TO HMC APPLICATION NOTE FOR SUGGESTED PCB LAND PATTERN. Package Information Part Number Package Body Material Lead Finish MSL Rating HMC614LP4 Low Stress Injection Molded Plastic Sn/Pb Solder MSL1 HMC614LP4E RoHS-compliant Low Stress Injection Molded Plastic 100% matte Sn MSL1 [1] [2] Package Marking [3] H614 XXXX H614 XXXX [1] Max peak reflow temperature of 235 C [2] Max peak reflow temperature of 260 C [3] 4-Digit lot number XXXX Pin Descriptions 11 - 86 Pin Number Function Description 1, 6, 8, 11, 21 Vcc Bias Supply. Connect supply voltage to these pins with appropriate filtering. 2, 5, 13 GND Package bottom has an exposed metal paddle that must be connected to RF/DC ground. Interface Schematic For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Pin Descriptions (Continued) Pin Number Function Description 3, 4 IN+, IN- RF Input pins. Connect RF to IN+ and INthrough a 1:1 balun. Interface Schematic 7 ENX Disable pin. Connect to GND for normal operation. Applying voltage V>0.8 Vdd will initiate power saving mode. 9, 10 COFS Input high pass filter capacitor. Connect to common via a capacitor to determine 3 dB point of input signal high-pass filter. 12 N/C No Connection. These pins maybe be connected to RF/DC ground. Performance will not be affected. 14 VSET VSET input. Set point input for controller mode. 15 RMSOUT Logarithmic output that converts the input power to a DC level. For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com POWER DETECTORS - SMT 11 11 - 87 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Pin Descriptions (Continued) Pin Number Function Description 16 IPWR Instantaneous Power Output continuous tracking of Input Power Envelope. 17 CINT Connection for ground referenced loop filter integration capacitor. See application schematic. 18 IREF Reference DC Voltage for IPWR to replicate voltage at no envelope case. 19 VTGT This voltage input changes the logarithmic intercept point. Use of lower target voltage reduces error for complex signals with large crest factors. Normally connected to VREF. 20 VREF Reference voltage output. 22, 23 N/C These pins are not connected internally. Interface Schematic POWER DETECTORS - SMT 11 11 - 88 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Evaluation PCB - Differential Input Confi guration List of Materials for Evaluation PCB 118391 [1] Item Description J1 - J2 PC Mount SMA connector J3 - J7 DC Pins C1 - C3 1 nF Capacitor, 0402 Pkg. C4, C6, C8, C11, C17 0.1 F Capacitor, 0402 Pkg. C5, C7, C9 100 PF Capacitor, 0402 Pkg. C10 1000 PF Capacitor, 0402 Pkg. R1, R11 12K Resistor, 0402 Pkg. R2 0 Resistor, 0402 Pkg. R4 10k Resistor, 0402 Pkg. R5 68 Resistor, 0402 Pkg. R6 61.9K Resistor, 0402 Pkg. R7 3.92K Resistor, 0402 Pkg. R24 33K Resistor, 0402 Pkg. T1 1:1 Balun, M/A-COM ETC1-1-13 U1 HMC614LP4 / HMC614LP4E RMS Power Detector PCB [2] 118389 Evaluation PCB The circuit board used in the final application should use RF circuit design techniques. Signal lines should have 50 ohm impedance while the package ground leads and exposed paddle should be connected directly to the ground plane similar to that shown. A sufficient number of via holes should be used to connect the top and bottom ground planes. The evaluation circuit board shown is available from Hittite upon request. POWER DETECTORS - SMT 11 [1] Reference this number when ordering complete evaluation PCB [2] Circuit Board Material: Arlon 25FR For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 89 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Application Circuit - Differential Input Confi guration POWER DETECTORS - SMT 11 11 - 90 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Evaluation PCB - Single-Ended Input Confi guration List of Materials for Evaluation PCB 121406 [1] Item Description J1 - J4 PCB Mount SMA Connector J5 - J10 DC Pin C2, C3, C10 1 nF Capacitor, 0402 Pkg. C4, C6, C8, C11, C17 0.1 F Capacitor, 0402 Pkg. C5, C7, C9 100 pF Capacitor, 0402 Pkg. C14 2.2 pF Capacitor, 0402 Pkg. R1, R11 12K Resistor, 0402 Pkg. R2, R8 0 Resistor, 0402 Pkg. R3 10k Resistor, 0402 Pkg. R4 82 Resistor, 0402 Pkg. R5 27 Resistor, 0402 Pkg. R6 61.9K Resistor, 0402 Pkg. R7 3.92K Resistor, 0402 Pkg. R24 33K Resistor, 0402 Pkg. U1 HMC614LP4(E) RMS Power Detector PCB [2] 121404 Evaluation PCB The circuit board used in the final application should use RF circuit design techniques. Signal lines should have 50 ohm impedance while the package ground leads and exposed paddle should be connected directly to the ground plane similar to that shown. A sufficient number of via holes should be used to connect the top and bottom ground planes. The evaluation circuit board shown is available from Hittite upon request. POWER DETECTORS - SMT 11 [1] Reference this number when ordering complete evaluation PCB [2] Circuit Board Material: Arlon 25FR For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 91 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Application Circuit - Single-Ended Input Confi guration POWER DETECTORS - SMT 11 11 - 92 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Application Information Principle of Operation 11 RMS OUTPUT VOLTAGE (V) Measured Ideal 3 2 1 0 -65 Where is op-amp gain set via resistors on the VSET pin. PIN = VRMS/[log-slope]+[log-intercept], dBm -55 -45 -35 -25 -15 -5 5 15 INPUT POWER (dBm) Monolithic true-RMS detectors are in-effect analog calculators, calculating the RMS value of the input signal, unlike other types of power detectors which are designed to respond to the RF signal envelope. At the core of an RMS detector is a full-wave rectifier, log/antilog circuit, and an integrator. The RMS output signal is directly proportional to the logarithm of the time-averaged VIN2. The bias block also contains temperature compensation circuits which stabilize output accuracy over the entire operating temperature range. The DC offset cancellation circuit actively cancels internal offsets so that even very small input signals can be measured accurately. iPWR Output IPWR OUTPUT (V) 2.8 4.2 Corresponding IPWR Output 2.4 3.4 2 2.6 1.6 1.8 1.2 1 0.8 0.2 -0.6 0.4 0 Envelope of RF Input Signal 0 1 2 3 4 5 6 7 8 INPUT RF SIGNAL ENVELOPE (V) The iPWR feature tracks the RF envelope and provides a signal which is directly proportional to instantaneous signal power, normalized to average real power calculated by the RMS circuitry. Reading both the iPWR and RMS output voltage signals provides a very informative picture of the RF input signal: peak power, average power, peakto-average power, and RF wave-shape. Simultaneous measurement of instantaneous signal power and average power is essential for taking full advantage of a receive signal chain's available dynamic range, while avoiding saturation, or to maximize transmitter efficiency. POWER DETECTORS - SMT VRMS vs. PIN 4 -1.4 TIME (s) For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 93 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Confi guration For The Typical Application The RF input can be connected in either a differential or single-ended configuration: see "RF Input Interface" section for details on each input configuration. The RMS output signal is typically connected to VSET, providing a Pin -> VRMS transfer characteristic slope of 36.5mV/dBm, however the RMS output can be re-scaled to "magnify" a specific portion of the input sensing range, and to fully utilize the dynamic range of the RMS output. Refer to the section under the "log-slope and intercept" heading for details. The iPWR output voltage signal can be processed directly for measurement of the input RF envelope, or a peak-hold circuit can be applied for measuring crest factor. See the section under "iPWR - Instantaneous Power" for application information. POWER DETECTORS - SMT 11 VTGT is also typically connected directly to VREF, however the VTGT voltage can be adjusted to optimize measurement accuracy, especially when measurement at higher crest factors is important: see "Adjusting VTGT for greater precision" section for technical details. Due to part-to-part variations in log-slope and log-intercept, a system-level calibration is recommended to satisfy absolute accuracy requirements: refer to the "System Calibration" section for more details. RF Input Interface The IN+ and IN- pins are differential RF inputs, which can be externally configured with differential or single-ended input. Power match components are placed at these input terminals, along with DC blocking capacitors. The coupling capacitor values also set the lower spectral boundary of the input signal bandwidth. The inputs can be reactively matched (refer to input return loss graphs), but a resistor network should be sufficient for good wideband performance. Differential Input Interface: The value of RD depends on the balun used; if the balun is 50 on both sides of the SE-Diff conversion, then RD = 220 * RM , , where 220 - RM RM = the desired power match impedance in ohms For RM = 50, RD = 64.7 ~ 68 Single-Ended Input Interface: Tuned SE-interface: for signal frequencies > 900 MHz Choose L and C elements from the following graph for narrowband tuning of the SE-interface: R5 = 27, R4 = 82, C2 = 100 pF, R2 = 0, L1, C3 - see graph. R5 on Eval Board Wideband SE-interface: for signal frequencies < 900MHz R5 = 27, R4 = 82, C2, C3 are 1nF decoupling caps. R2 is 0, and R5 is open 11 - 94 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz 5 8 4 6 3 4 2 2 1 0 0 0.9 1.4 1.9 2.4 2.9 3.4 3.9 CENTER FREQUENCY, Fc, (GHz) For wideband (un-tuned) input interfaces, choose the input decoupling capacitor values by first determining the lowest spectral component the power detector is required to sense, L. Choose the input decoupling capacitor values (C2, C3) by first determining the lowest spectral component the power detector is required to sense, L. C2 = C3 = Input decoupling capacitor value ~ Example: 1 Farads, where L is in Hertz. x L x 3.2 If the power detector needs to sense down to 10 MHz, the decoupling capacitor value should be 1/(*10E6*3.2) = 10nF A DC bias (Vcc-0.7V) is present on the IN+ and IN- pins, and should not be overridden. RMS Output Interface and Transient Response Output transient response is determined by the integration capacitance (CINT), and output load conditions. Using larger values of CINT will narrow the operating bandwidth of the integrator, resulting in a longer averaging time-interval and a more filtered output signal; however it will also slow the power detector's transient response. A larger CINT value favors output accuracy over speed. For the fastest possible transient settling times, leave the CINT pin free of any external capacitance. This configuration will operate the integrator at its widest possible bandwidth, resulting in short averaging time-interval and an output signal with little filtering. Most applications will choose to have some external integration capacitance, maintaining a balance between speed and accuracy. Furthermore, error performance over crest factor is degraded when CINT is very small (for CINT<100pF). 11 POWER DETECTORS - SMT 10 TUNING CAPACITANCE, C3, (pF) TUNING INDUCTACE, L1 (nH) Tuning SE Input Interface: C 300 MHz Modulation & Deviation in Electrical Spec Table 2 are given for CINT= 0.1 F Start by selecting CINT using the following expression, and then adjust the value as needed, based on the application's preference for faster transient settling or output accuracy. , in Farads, where LAM =lowest amplitude-modulation component frequency in Hertz Example: when LAM =10kHz, CINT = 1500F/(2**1E4) = 24E-9 Farads ~ 22nF For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 95 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Table: Transient Response vs. CINT Capacitance with COFS = 0 POWER DETECTORS - SMT 11 CINT Rise Time (0 dBm) Fall Time (-30 dBm) Fall Time (-10 dBm) Fall Time (0 dBm) 0 34 nsec 140 nsec 620 nsec 820 nsec 100 pF 120 nsec 550 nsec 920 nsec 1.2 sec 1 nF 890 nsec 4.1 sec 6.7 sec 7.9 sec 10 nF 9.6 sec 43 sec 70 sec 83 sec 100 nF 80 sec 360 sec 625 sec 720 sec Input signal is 1900 MHz CW-tone switched on and off RMS is loaded wtih 1k, 4pF, and VTGT = 2V, D.R. is input dynamic range to 1 dB error. Transient response can also be slewed by the RMS output if it is excessively loaded: keep load resistance above 375. An optimal load resistance of approximately 500 to 1k will allow the output to change as quickly as it is can. For increased load drive capability, consider a buffer amplifier on the RMS output. Using an integrating amplifier on the RMS output allows for an alternative treatment for faster settling times. An external amplifier optimized for transient settling can also provide additional RMS filtering, when operating HMC614LP4 with a lower CINT capacitance value. LOG-Slope and Intercept The HMC614LP4 provides for an adjustment of output scale with the use of an integrated operational amplifier. Logslope and intercept can be adjusted to "magnify" a specific portion of the input sensing range, and to fully utilize the dynamic range of the RMS output. A log-slope of 36.5mV/dBm is set by connecting RMS Output to VSET through resistor network for = 1 (see schematic). The log-slope is adjusted by applying the appropriate resistors on the RMS and VSET pins. Log-intercept is adjusted by applying a DC voltage to the VSET pin. Optimized_slope = ( + 1) * log_slope / 2 Optimized_intercept = log_intercept - * VZC 2 = (RFBK / RSET) x 2 When RFBK = RSET , and VZC = 0V: = 1 2 Note: Apply a capacitor across RFBK for additional stability. 0V < VSET < 3.2V Note: Avoid excessive loading of the RMS output: RLOAD > 375 Example: An application only requires the power detector to measure input signal power levels ranging from -40 dBm to 0 dBm at 900 MHz. To optimize the full output voltage range of RMS, we re-map PIN(MIN) = -40 dBm to RMS(MIN) = 0V and PIN(MAX) = 0dBm to RMS(MAX) =3.2V. log_slope = 36.5 mV/dB, log_intercept = -72 dBm at 900 MHz (see Electrical Specifications table 3) Input signal power range = 0 dBm - (-40 dBm) = 40 dB Output voltage range = 3200 mV Optimal_slope = 3200 mV/40 dB = 80 mV/dB Then we should apply VZC to shift RMS down for PIN(MIN) = -40 dBm to map to RMS(MIN) = 0V = 11 - 96 optimal_slope x 2 log_slope -1 = 80.0 x 2 36.5 -1 = 3.38 = 2RFBK ~ 51k , at 900 MHz RSET 15k For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz RMS = (PIN - log_intercept) * optimal_slope, with VZC = 0V And with Pin = -40 dBm: RMS = 2.56V = [(-40 dBm) - (-72 dBm)] * 80 mV/dBm, at 900 MHz So we must shift RMS down 2.56V by applying VZC =2x (-2.56V) / - = 2x (-2.56V) / -3.38 = 1.506 iPWR - Envelope Power Normalized To Average Power The iPWR is an envelope detector output which provides a measurement of instantaneous signal power normalized to average power. The iPWR output makes peak-to-average power comparisons immediately obvious. This simultaneous measurement of envelope power and average power in HMC614LP4 has two fundamental advantages over traditional methods of which employ two different power detectors working in parallel. * Both the iPWR and RMS detectors share the same measurement structures, and 11 With traditional implementation of peak-to-average power detection, the dominant source of errors is due to the uncorrelated measurement deviations between the two separate detectors. Both detectors in the HMC614LP4 share the same circuits, so any deviations, however small, are fully correlated. HMC614LP4 provides a reference voltage, iREF (pin 18), which when used with the iPWR output allows cancellation of temperature and supply related variations of the iPWR DC offset. iPWR DC offset is equal to the iREF reference voltage, and this level corresponds to the peak-to-average ratio of an unmodulated carrier (CW-tone crest factor = 3dB). For the best cancellation of the effects of temperature and supply voltage on iPWR DC offset, load both the iPWR and iREF outputs with an equivalent resistance. To measure peak power, a peak-hold mechanism is required at the iPWR output. The peak-hold circuit can be as simple as an RC combination on the iPWR pin. The graph below describes the iPWR peak-hold levels as a function of input crest factor. Note that the voltage applied at VTGT has an effect of the iPWR reading. The VTGT signal optimizes internal bias points for measurement accuracy at higher crest factors: refer to the section under "Adjusting VTGT for greater precision" for a full description on crest factor optimization. IPWR, Peak Power Output Normalized to Average Power Vpeak, Vtgt=2V, R=30k, C=10nF Vpeak, Vtgt=1V, R=30k, C=10nF Vpeak, , Vtgt,=2V, R=100k, C=10nF Vpeak, Vtgt=1V, R=100k, C=10nF IPWR OUTPUT (V) 2.8 POWER DETECTORS - SMT * Both the iPWR and RMS detectors share the same temperature compensation mechanisms. 2.5 2.2 1.9 1.6 3 5.7 8.5 11.2 14 INPUT RF SIGNAL CREST FACTOR (dB) =20Log(Vpeak/Vrms) For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 97 HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Standby Mode The ENX can be used to force the power detector into a low-power standby mode. In this mode, the entire power detector is powered-down. As ENX is deactivated, power is restored to all of the circuits. There is no memory of previous conditions. Coming-out of stand-by, CINT and COFS capacitors will require recharging, so if large capacitor values have been chosen, the wake-up time will be lengthened. DC Offset Compensation Loop POWER DETECTORS - SMT 11 Internal DC offsets, which are input signal dependant, require continuous cancellation. Offset cancellation is a critical function needed for maintenance of measurement accuracy and sensitivity. The DC offset cancellation loop performs this function, and its response is largely defined by the capacitance off the COFS pin. Setting DC offset cancellation, loop bandwidth strives to strike a balance between offset cancellation accuracy, and loop response time. A larger value of COFS results in a more precise offset cancellation, but at the expense of a slower offset cancellation response. A smaller value of COFS tilts the performance trade-off towards a faster offset cancellation response. The optimal loop bandwidth setting will allow internal offsets to be cancelled at a minimally acceptable speed. 1 DC Offset Cancellation Loop Bandwidth , Hz (5000)(COFS+20x10 -12) For example: loop bandwidth for DC cancellation with COFS = 1nF, bandwidth is ~62 kHz Note: The measurement error produced by internal DC offsets cannot be measured at any single operating point, in terms of input signal frequency and level, with repeatability. Measurement error must be calculated to a best fit line, over the entire operating range (again, in terms of signal level and frequency). Adjusting VTGT for greater precision There are two competing aspects of performance, for which VTGT can be used to set a preference. Depending on which aspect of precision is more important to the application, the VTGT pin can be used to find a compromise between two sources of RMS output error: internal DC offset cancellation error and deviation at high crest factors (>10 dB). * Increasing VTGT input voltage will improve internal DC offset cancellation, but deviation at high crest factors will increase slightly. A 50% increase in VTGT should produce an 18% improvement in RMS precision due to improved DC offset cancellation performance. * Decreasing VTGT input voltage will reduce errors at high crest factors, but DC offset cancellation performance will be slightly degraded. See "RMS Output Error vs. Crest Factor" graph. * DC Offsets are observed as a random ripple in the logarithmic characteristics RMS Output Error vs. Crest Factor **Worst Case Conditions** using circuit described in " Application & Evaluation PCB Schematic" section VTGT infl uence on DC offset compensation 4 0 RMSOUT ERROR (dB) -4 -8 -12 -16 V = 0.5V TGT V = 1.25V TGT V = 2.0V TGT V = 2.75V TGT V = 3.50V -20 -24 -28 V TGT Logarithmic Linearity Error due to Internal DC Offsets 1.0V Nominal +0.2 dB 1.5V Nominal +0.1 dB 2.0V Nominal 3.0V Nominal -0.06 dB 3.5V Nominal -0.1 dB TGT -32 -36 -40 2 4 6 8 10 12 14 16 CREST FACTOR (dB) 11 - 98 For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com HMC614LP4 / 614LP4E v06.1109 RMS & PEAK TO AVERAGE POWER DETECTOR 0.1 - 3.9 GHz Adjusting VTGT for greater precision (Continued) If input signal crest factor is not expected to exceed 10 dB, you can improve RMS precision by increasing VTGT voltage. Keep in mind that changing VTGT also adjusts the log-intercept point, which shifts the "input dynamic range". The best set-point for VTGT will be the lowest voltage that still maintains the "input dynamic range" over the required range of input power. This new VTGT set-point should optimize DC offset correction performance. If error performance for crest factors >10 dB requires optimization, set VTGT for the maximum tolerable error at the highest expected crest factor. Increasing VTGT beyond that point will unnecessarily compromise internal DC offset cancellation performance. After changing VTGT, re-verify that the "input dynamic range" still covers the required range of input power. System Calibration Due to part-to-part variations in log-slope and log-intercept, a system-level calibration is recommended to satisfy absolute accuracy requirements. When performing this calibration, choose at least two test points: near the top-end and bottom-end of the measurement range. It is best to measure the calibration points in the regions (of frequency and amplitude) where accuracy is most important. Derive the log-slope and log-intercept, and store them in non-volatile memory. Calibrate iPWR scaling by measuring the peak-to-average ratio of a known signal. For example if the following two calibration points were measured at 2.35 GHz: With Vrms = 2.34V at Pin = -7 dBm, Now performing a power measurement: and Vrms=1.84V at Pin = -16 dBm Vrms measures 2.13V slope calibration constant = SCC [Measured Pin] = [Measured Vrms]*SCC + ICC SCC = (-16+7)/(1.84-2.34) = 18 dB/V [Measured Pin] = 2.13*18.0 - 49.12 = -10.78 dBm intercept calibration constant = ICC An error of only 0.22 dB ICC = Pin - SCC*Vrms = -7 - 18.0 * 2.34 = -49.12 dBm Factory system calibration measurements should be made using an input signal representative of the application. If the power detector will operate over a wide range of frequencies, choose a central frequency for calibration. Layout Considerations * Mount RF input coupling capacitors close to the IN+ and IN- pins. 11 POWER DETECTORS - SMT VTGT should be referenced to VREF for best performance. It is recommended to use a temperature stable DC amplifier between VTGT and VREF to create VTGT > VREF. The VREF pin is a temperature compensated voltage reference output, only intended for use with VTGT. * Solder the heat slug on the package underside to a grounded island which can draw heat away from the die with low thermal impedance. The grounded island should be at RF ground potential. * Connect power detector ground to the RF ground plane, and mount the supply decoupling capacitors close to the supply pins. Defi nitions: * Log-slope: slope of PIN -> VRMS best-fit line, when RMS is connected directly to VSET in units of mV/dB * Log-intercept: x-axis intercept of PIN -> VRMS transfer characteristic. In units of dBm. * RMS Output Error: The difference between the measured PIN and the best-fit line. [measured_PIN] = [measured_VRMS] / [best-fit-slope] + [best-fit-intercept], dBm * Input Dynamic Range: the range of average input power for which there is a corresponding RMS output voltage with "RMS Output Error" falling within a specific error tolerance. * Crest Factor: Peak power to average power ratio for time-varying signals. For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com Application Support: Phone: 978-250-3343 or apps@hittite.com 11 - 99