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 - 76
HMC614LP4 / 614LP4E
RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
v06.1109
General Description
Features
Functional Diagram
Typical Applications
Electrical Speci cations, TA = +25 °C, Vcc = 5V, CINT = 0.1 μF [2]
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, mono-
tonic 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.
IPWR Output: Instantaneous Power,
Crest Factor Measurement
RF Signal Wave shape & Crest Factor Independent
Operates with Single-Ended or Differential Input
Supports Controller Mode [1]
±1 dB Detection Accuracy to 3.9 GHz
Input Dynamic Range: -57 dBm to +15 dBm
+5V Operation from -40°C to +85°C
Excellent Temperature Stability
Power-Down Mode
24 Lead 4x4mm QFN Package: 9 mm
The HMC614LP4(E) is ideal for:
• Log –> Root-Mean-Square (RMS) Conversion
• Received Signal Strength Indication (RSSI)
• Transmitter Signal Strength Indication (TSSI)
• RF Power Ampli er Efficiency Control
• Receiver Automatic Gain Control
• Transmitter Power Control
Parameter Typ. Typ. Typ. Typ. Typ. Typ. Typ. Typ. Units
Differential Input Con guration
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 Con guration Logarithmic Slope
Lo ga ri th m i c S lo p e 37. 5 37. 5 37.6 38 .1 39.6 41.0 4 4. 5 50. 2 mV/d B
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.
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 - 77
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
Table 2: Electrical Speci cations [1]
Evaluation Kit (Diff. Input Con g.) TA = +25 °C, Vcc = 5V, CINT = 0.1 μF Unless Otherwise Noted
Parameter Typ. Typ. Typ. Typ. Units
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) ±0.5 dB
Input Frequency 900 1900 2700 3900 MHz
Average Modulation Deviation Error from CW Input [2]
1 Carrier CDMA 0.02 0.06 0.08 0.03 dB
2 Carrier CDMA 0.02 0.05 0.11 0.02 dB
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
IPWR Output Slope for Input Power Change Normalized to Average Power [3] Vtgt = 2V 190 mV
Vtgt = 1V 95 mV
IPWR Output Slope Variation with Temperature from -40C to 85C 3%
IPWR Output Modulation BW for 3 dB voltage drop in Output Swing 35 MHz
[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 de ned as IPWR Slope for input power change normalized to average power.
Parameter Typ. Typ. Typ. Typ. Units
Single-Ended Input Con guration
Input Frequency 900 1300 2300 3300 MHz
Dynamic Range (± 1 dB linearity Error) 65 66 62 58 dB
Single-Ended Input Con guration Logarithmic Slope
Logarithmic Slope 38.1 37.1 37.7 43.1 mV/dB
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
Electrical Speci cations, TA = +25 °C, Vcc = 5V, CINT = 0.1 μF (Continued)
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 - 78
Parameter Conditions Min. Typ. Max. Units
Differential Input Con guration
Input Network Return Loss [1] >10 dB
Input Resistance between IN+ and IN- Between pins 3 and 4 200
Input Voltage Range VDIFFIN = VIN+ - VIN- 2.25 V
Single-Ended Input Con guration
Input Network Return Loss [3] [4] >10 dB
Input Voltage Range VSEin = VIN+ 1.4 V
RMSOUT Output
Output Voltage Range RL = 1k, CL = 4.7pF[2] 0.4 - 3.2 V
Source/Sink Current Compliance RMSOUT held at VCC/2 8 / 0.35 mA
Output Slew Rate (rise / fall) With CINT = 0, Cofs = 0 100 / 5 106 V/s
VSET Input (Negative Feedback Terminal)
Input Voltage Range [2] 0.4 - 3.2 V
Input Resistance 1M
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
Table 3: Electrical Speci cations III,
HMC610LP4E Evaluation Kit (Diff. Input Con g.), TA = +25 °C, Vcc= +5V, CINT = 0.1 μF, Unless Otherwise Noted.
Absolute Error wrt to CW Response
@ 1900 MHz for Different Modulation
Schemes, VTGT= 1V
Absolute Error wrt to CW Response
@ 1900 MHz for Different Modulation
Schemes, VTGT= 2V
0
0.1
0.2
0.3
0.4
0.5
-70 -60 -50 -40 -30 -20 -10 0 10
1 Carrier CDMA 0.06 dB Average
2 Carrier CDMA 0.05 dB Average
4 Carrier CDMA 0.16 dB Average
QAM256 0.11 dB Average
ERROR (dB)
INPUT POWER (dBm)
0
0.5
1
1.5
2
-70 -60 -50 -40 -30 -20 -10 0 10
1 Carrier CDMA 0.20 dB Average
2 Carrier CDMA 0.35 dB Average
4 Carrier CDMA 0.74 dB Average
QAM256 0.11 dB Average
ERROR (dB)
INPUT POWER (dBm)
RMSOUT vs. Pin with Different
Modulations @ 1900 MHz, VTGT= 1V
RMSOUT Error vs. Pin with Different
Modulations @ 1900 MHz, VTGT= 1V
0
0.5
1
1.5
2
2.5
3
3.5
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
CW
1 CARRIER CDMA
2 CARRIER CDMA
4 CARRIER CDMA
QAM256
RMSOUT (V)
INPUT POWER (dBm)
-4
-3
-2
-1
0
1
2
3
4
-60 -50 -40 -30 -20 -10 0 10
CW
1 CARRIER CDMA
2 CARRIER CDMA
4 CARRIER CDMA
QAM256
ERROR (dB)
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
POWER DETECTORS - SMT
11
11 - 79
[1] CW Input Waveform into differential input interface with 1:1 Balun.
RMSOUT & Error vs. Pin @ 100 MHz [1] RMSOUT & Error vs. Pin @ 900 MHz [1]
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
Parameter Conditions Min. Typ. Max. Units
VREF Output (Reference Voltage)
VREF Output Voltage 2.95 V
VREF Change Over Full Temperature Range 20 mV
VTGT Input (RMS Target Interface)
Input Voltage Range 3.65 V
Input Resistance 1M
ENX Logic Input (Power Down Control)
Input High Voltage Standby Mode Active 3.9 V
Input Low Voltage Normal Operation 1.2 V
Input High Current 1A
Input Low Current 1A
Input Capacitance 0.5 pF
Power Supply
Supply Voltage 4.5 5 5.5 V
Supply Current with Pin = -70 dBm Over Full Temperature Range 65 76 mA
Supply Current with Pin = 0 dBm Over Full Temperature Range 83 95 mA
Standby Mode Supply Current ENX = Hi 1 mA
[1] Performance of differential input con guration 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
Table 3: Electrical Speci cations III (Continued)
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 - 80
[1] CW Input Waveform into differential input interface with 1:1 Balun.
RMSOUT & Error vs. Pin @ 1900 MHz [1] RMSOUT & Error vs. Pin @ 2200 MHz [1]
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
RMSOUT & Error vs. Pin @ 2700 MHz [1] RMSOUT & Error vs. Pin @ 3000 MHz [1]
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
RMSOUT & Error vs. Pin @ 3500 MHz [1] RMSOUT & Error vs. Pin @ 3900 MHz [1]
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
0
1
2
3
4
-4
-2
0
2
4
-70 -60 -50 -40 -30 -20 -10 0 10
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
ERR +25C
ERR +85C
ERR -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 81
[1] See application circuit for location of R1
[2] See application section Log-Slope, RFBK = 12k, RSET = 24K
[3] VTGT 1V, Average Input Power = 0 dBm
[4] VTGT 2V, Average Input Power = 0 dBm
Frequency vs. Intercept
Over Supply Voltage [1]
Frequency vs. Slope
Over Supply Voltage [1]
Frequency vs. Intercept
Over Temperature [1]
Frequency vs. Slope
Over Temperature [1]
-80
-75
-70
-65
-60
-55
-50
-45
-40
0 500 1000 1500 2000 2500 3000 3500 4000
4.5V
5.0V
5.5V
INTERCEPT (dBm)
FREQUENCY (MHz)
-80
-75
-70
-65
-60
-55
-50
-45
-40
0 500 1000 1500 2000 2500 3000 3500 4000
+25C
+85C
-40C
INTERCEPT (dBm)
FREQUENCY (MHz)
30
35
40
45
50
55
60
0 500 1000 1500 2000 2500 3000 3500 4000
4.5V
5.0V
5.5V
SLOPE (mV/dB)
FREQUENCY (MHz)
30
35
40
45
50
55
60
0 500 1000 1500 2000 2500 3000 3500 4000
+25C
+85C
-40C
SLOPE (mV/dB)
FREQUENCY (MHz)
RMSOUT vs. Pin, Slope Adjustment [1] RMSOUT vs. Pin, Intercept Adjustment [2]
0
1
2
3
4
-70 -60 -50 -40 -30 -20 -10 0 10
RMSOUT @ R1= 24KOhms
RMSOUT @ R1= 12KOhms
RMSOUT @ R1= 6.8KOhms
RMSOUT (V)
INPUT POWER (dBm)
Slope = 48mV/dB
Slope = 26mv/dB
Slope = 35mV/dB
0
1
2
3
4
-70 -60 -50 -40 -30 -20 -10 0 10
RMSOUT @ VSET = -1.0V
RMSOUT @ VSET = -0.5V
RMSOUT @ VSET = 0V
RMSOUT @ VSET = 0.5V
RMSOUT @ VSET = 1.0V
RMSOUT (V)
INPUT POWER (dBm)
VSET = -1.0V, X Intercept = -82.2dBm
VSET = -0.5V, X Intercept = -75.5dBm
VSET = 0V, X Intercept = -68.8dBm
VSET = 0.5V, X Intercept = -62.1dBm
VSET = 1.0V, X Intercept = -55.4dBm
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 82
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
0
1
2
3
4
-4
-2
0
2
4
-60 -50 -40 -30 -20 -10 0 10
ERR +25C
ERR +85C
ERR -40C
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
-4
-3
-2
-1
0
1
2
3
4
-60 -50 -40 -30 -20 -10 0 10
500MHz
700MHz
900MHz
1100MHz
1300MHz
INPUT POWER (dBm)
ERROR (dB)
0
1
2
3
4
-4
-2
0
2
4
-60 -50 -40 -30 -20 -10 0 10
ERR +25C
ERR +85C
ERR -40C
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
0
1
2
3
4
-4
-2
0
2
4
-60 -50 -40 -30 -20 -10 0 10
ERR +25C
ERR +85C
ERR -40C
Ideal
RMSOUT +25C
RMSOUT +85C
RMSOUT -40C
RMSOUT (V)
ERROR (dB)
INPUT POWER (dBm)
-4
-3
-2
-1
0
1
2
3
4
-60 -50 -40 -30 -20 -10 0 10
900MHz
1100MHz
1300MHz
1500MHz
1700MHz
INPUT POWER (dBm)
ERROR (dB)
Single-Ended RMSOUT &
Error vs. Pin, Tuned @ 1300 MHz
Single-Ended,
Error vs. Pin, Tuned @ 900 MHz
Single-Ended RMSOUT &
Error vs. Pin, Tuned @ 2300 MHz
Single-Ended,
Error vs. Pin, Tuned @ 1300 MHz
Single-Ended RMSOUT &
Error vs. Pin, Tuned @ 3300 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
POWER DETECTORS - SMT
11
11 - 83
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
IPWR Output for an Input Crest Factor
of 9.03 dB over Temperature vs. Time [1]
1.4
1.5
1.6
1.7
1.8
1.9
2
012345
+25C
+85C
-40C
IPWR OUTPUT (V)
TIME (us)
IPWR Output & Input RF Signal Envelope vs.
Time For An Input Crest Factor of 9.03 dB [2]
IPWR Output & Input RF Signal Envelope vs.
Time For An Input Crest Factor of 12.04 dB [2]
IPWR Output for an Input Crest Factor
of 12.04 dB over Temperature vs. Time [1]
1.4
1.6
1.8
2
2.2
2.4
012345678
+25C
+85C
-40C
IPWR OUTPUT (V)
TIME (us)
0
0.4
0.8
1.2
1.6
2
2.4
2.8
-1.4
-0.6
0.2
1
1.8
2.6
3.4
4.2
012345678
IPWR OUTPUT (V)
INPUT RF SIGNAL ENVELOPE (V)
TIME (μs)
IPWR Output
Input RF Signal Envelope
0
0.4
0.8
1.2
1.6
2
2.4
-0.8
-0.4
0
0.4
0.8
1.2
1.6
012345
IPWR OUTPUT (V)
INPUT RF SIGNAL ENVELOPE (V)
TIME (μs)
IPWR Output
Input RF Signal Envelope
[1] VTGT 1V, Average Input Power = 0 dBm
[2] VTGT 2V, Average Input Power = 0 dBm
-4
-3
-2
-1
0
1
2
3
4
-60 -50 -40 -30 -20 -10 0 10
1900MHz
2100MHz
2300MHz
2500MHz
2700MHz
INPUT POWER (dBm)
ERROR (dB)
-4
-3
-2
-1
0
1
2
3
4
-60 -50 -40 -30 -20 -10 0 10
2900MHz
3100MHz
3300MHz
3500MHz
3700MHz
INPUT POWER (dBm)
ERROR (dB)
Single-Ended,
Error vs. Pin, Tuned @ 2300 MHz
Single-Ended,
Error vs. Pin, Tuned @ 3300 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
POWER DETECTORS - SMT
11
11 - 84
[1] PIN = -20 dBm @ 1.9 GHz
[2] PIN = -22 dBm @ 1.9 GHz
IPWR Output vs. Instantaneous Input
Power (Normalized to Average Power) [1] Peak IPWR vs Input Crest Factor [1]
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
024681012
=Pin/Pav*0.2+(1.6-0.2)
IPWR Output VTGT = 2V
=Pin/Pav*0.1+(1.6-0.1)
IPWR Output VTGT = 1V
IPWR OUTPUT (V)
INSTANTANEOUS INPUT POWER
(NORMALIZED TO AVERAGE POWER)
IPWR(t) = (VTGT/10)x(Pin(t)/Pavg)+(1.6-(Vtgt/10))
1.6
1.8
2
2.2
2.4
2.6
2.8
3
35791113
Peak IPWR Output VTGT = 2V
Peak IPWR Output VTGT = 1V
PEAK IPWR OUTPUT (V)
INPUT CREST FACTOR (dB)
Output Response
Rise Time @ 1900 MHz, CINT = Open
Output Response
Rise Time @ 1900 MHz, CINT = 0.1 μF
0
0.5
1
1.5
2
2.5
3
3.5
0 50 100 150 200 250 300 350 400 450 500
10 dBm
0 dBm
-10 dBm
-20 dBm
-30 dBm
RMSOUT (V)
TIME (ns)
Input
Dynamic
Range to
+/- 1dB Error
0
0.5
1
1.5
2
2.5
3
3.5
0 200 400 600 800 1000 1200 1400 1600 1800 2000
10 dBm
0 dBm
-10 dBm
-20 dBm
-30 dBm
RMSOUT (V)
TIME (μs)
Input
Dynamic
Range to
+/- 1dB Error
RMS Error vs. Crest Factor Over VTGT [2] Input Return Loss
-1.6
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
345 678 910111213
VTGT = 0.5V
VTGT = 1.0V
VTGT = 2.0V
RMSOUT ERROR (dB)
INPUT SIGNAL CREST FACTOR (dB)
-40
-35
-30
-25
-20
-15
-10
-5
0
01234
+85C
RETURN LOSS (dB)
FREQUENCY (GHz)
Defined in large part by balun:
4.5MHz to 3000MHz
M/A-Com balun#ETC1-1-113;
-40C
25C
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 85
Output Response
Fall Time @ 1900 MHz, CINT = Open
Output Response
Fall Time @ 1900 MHz, CINT = 0.1 μF
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
10 dBm
0 dBm
-10 dBm
-20 dBm
-30 dBm
RMSOUT (V)
TIME (ns)
Input
Dynamic
Range to
+/- 1dB Error
0
0.5
1
1.5
2
2.5
3
3.5
0 200 400 600 800 1000 1200 1400 1600 1800 2000
10dBm
0dBm
-10dBm
-20dBm
-30dBm
RMSOUT (V)
TIME (μs)
Input
Dynamic
Range to
+/- 1dB Error
Absolute Maximum Ratings
ELECTROSTATIC SENSITIVE DEVICE
OBSERVE HANDLING PRECAUTIONS
Supply Voltage 5.6V
RF Input Power 20 dBm
Max. Input Voltage 2.25 Vrms
Channel / Junction Temperature 125 °C
Continuous Pdiss (T = 85°C)
(Derate 22.72 mW/°C above 85°C) 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
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 86
Outline Drawing
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.
Part Number Package Body Material Lead Finish MSL Rating Package Marking [3]
HMC614LP4 Low Stress Injection Molded Plastic Sn/Pb Solder MSL1 [1] H614
XXXX
HMC614LP4E RoHS-compliant Low Stress Injection Molded Plastic 100% matte Sn MSL1 [2] H614
XXXX
[1] Max peak re ow temperature of 235 °C
[2] Max peak re ow temperature of 260 °C
[3] 4-Digit lot number XXXX
Package Information
Pin Number Function Description Interface Schematic
1, 6, 8, 11, 21 Vcc Bias Supply. Connect supply voltage to these pins
with appropriate  ltering.
2, 5, 13 GND Package bottom has an exposed metal paddle that
must be connected to RF/DC ground.
Pin Descriptions
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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
Pin Number Function Description Interface Schematic
3, 4 IN+, IN- RF Input pins. Connect RF to IN+ and IN-
through a 1:1 balun.
7ENX
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  lter capacitor. Connect to common
via a capacitor to determine 3 dB point of input signal
high-pass  lter.
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.
Pin Descriptions (Continued)
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 88
Pin Number Function Description Interface Schematic
16 IPWR Instantaneous Power Output continuous tracking of
Input Power Envelope.
17 CINT Connection for ground referenced loop  lter
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.
Pin Descriptions (Continued)
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 89
Evaluation PCB - Differential Input Con guration
The circuit board used in the  nal 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.
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 µF Capacitor, 0402 Pkg.
C5, C7, C9 100 PF Capacitor, 0402 Pkg.
C10 1000 PF Capacitor, 0402 Pkg.
R1, R11 12K Ω Resistor, 0402 Pkg.
R2 0 Ω Resistor, 0402 Pkg.
R4 10k Ω Resistor, 0402 Pkg.
R5 68 Ω Resistor, 0402 Pkg.
R6 61.9K Ω Resistor, 0402 Pkg.
R7 3.92K Ω Resistor, 0402 Pkg.
R24 33K Ω Resistor, 0402 Pkg.
T1 1:1 Balun, M/A-COM ETC1-1-13
U1 HMC614LP4 / HMC614LP4E
RMS Power Detector
PCB [2] 118389 Evaluation PCB
[1] Reference this number when ordering complete evaluation PCB
[2] Circuit Board Material: Arlon 25FR
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 90
Application Circuit - Differential Input Con guration
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 91
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
Evaluation PCB - Single-Ended Input Con guration
The circuit board used in the  nal 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.
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 µF Capacitor, 0402 Pkg.
C5, C7, C9 100 pF Capacitor, 0402 Pkg.
C14 2.2 pF Capacitor, 0402 Pkg.
R1, R11 12K Ω Resistor, 0402 Pkg.
R2, R8 0 Ω Resistor, 0402 Pkg.
R3 10k Ω Resistor, 0402 Pkg.
R4 82 Ω Resistor, 0402 Pkg.
R5 27 Ω Resistor, 0402 Pkg.
R6 61.9K Ω Resistor, 0402 Pkg.
R7 3.92K Ω Resistor, 0402 Pkg.
R24 33K Ω Resistor, 0402 Pkg.
U1 HMC614LP4(E) RMS Power Detector
PCB [2] 121404 Evaluation PCB
[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
POWER DETECTORS - SMT
11
11 - 92
Application Circuit - Single-Ended Input Con guration
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 93
Application Information
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 recti er, 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.
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, peak-
to-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.
Principle of Operation
0
1
2
3
4
-65 -55 -45 -35 -25 -15 -5 5 15
Measured
Ideal
RMS OUTPUT VOLTAGE (V)
INPUT POWER (dBm)
VRMS vs. PIN
0
0.4
0.8
1.2
1.6
2
2.4
2.8
-1.4
-0.6
0.2
1
1.8
2.6
3.4
4.2
012345678
IPWR OUTPUT (V)
INPUT RF SIGNAL ENVELOPE (V)
TIME (μs)
Corresponding IPWR Output
Envelope of RF Input Signal
iPWR Output
Where ß is op-amp gain set via resistors on the VSET pin.
PIN = VRMS/[log-slope]+[log-intercept], dBm
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 94
Con guration For The Typical Application
The RF input can be connected in either a differential or single-ended con guration: see “RF Input Interface” section
for details on each input con guration.
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 speci c 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.
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 con gured 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:
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 = 27Ω, R4 = 82Ω,
C2 = 100 pF, R2 = 0Ω, L1, C3 - see graph.
Wideband SE-interface: for signal frequencies < 900MHz
R5 = 27Ω, R4 = 82Ω,
C2, C3 are 1nF decoupling caps.
R2 is 0Ω, and R5 is open
The value of RD depends on the balun used; if the
balun is 50Ω on both sides of the SE-Diff conversion,
then
RM = the desired power match impedance in ohms
For RM = 50, RD = 64.7 ~ ~ 68
RD =
220 * RM , , where
220 - RM
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
R5 on
Eval Board
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 - 95
~ ~ 1
π x ƒL x 3.2
For wideband (un-tuned) input interfaces, choose the input decoupling capacitor values by  rst determining the lowest
spectral component the power detector is required to sense, ƒL.
Choose the input decoupling capacitor values (C2, C3) by  rst determining the lowest spectral component the power
detector is required to sense, ƒL.
C2 = C3 = Input decoupling capacitor value Farads, where ƒL is in Hertz.
Example:
If the power detector needs to sense down to 10 MHz, the decoupling capacitor value should be
1/(π*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  ltered 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 con guration will operate the integrator at its widest possible bandwidth, resulting in short
averaging time-interval and an output signal with little ltering. 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).
Modulation & Deviation in Electrical Spec Table 2 are given for CINT= 0.1 µF
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 ƒLAM=lowest amplitude-modulation component frequency in Hertz
Example: when ƒLAM=10kHz, CINT = 1500F/(2*π*1E4) = 24E-9 Farads ~ 22nF
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
0
2
4
6
8
10
0
1
2
3
4
5
0.9 1.4 1.9 2.4 2.9 3.4 3.9
TUNING INDUCTACE, L1 (nH)
TUNING CAPACITANCE, C3, (pF)
CENTER FREQUENCY, Fc, (GHz)
Tuning SE Input Interface: ƒC ±300 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
POWER DETECTORS - SMT
11
11 - 96
Table: Transient Response vs. CINT Capacitance with COFS= 0
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 µsec
1 nF 890 nsec 4.1 µsec 6.7 µsec 7.9 µsec
10 nF 9.6 µsec 43 µsec 70 µsec 83 µsec
100 nF 80 µsec 360 µsec 625 µsec 720 µsec
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
375Ω. An optimal load resistance of approximately 500Ω to 1kΩ will allow the output to change as quickly as it is can.
For increased load drive capability, consider a buffer ampli er on the RMS output.
Using an integrating ampli er on the RMS output allows for an alternative treatment for faster settling times. An external
ampli er optimized for transient settling can also provide additional RMS  ltering, 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 ampli er. Log-
slope and intercept can be adjusted to “magnify” a speci c 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 ß = 1 (see sc-
hematic). 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.
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 Speci cations 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
ß = optimal_slope x 2 -1 = 80.0 x 2 -1 = 3.38 = 2RFBK ~ 51k , at 900 MHz
log_slope 36.5 RSET 15k
Optimized_slope = (ß + 1) * log_slope / 2
Optimized_intercept = log_intercept – ß * VZC
ß = (RFBK / RSET) x 2
When RFBK = RSET, and VZC = 0V: ß = 1
Note: Apply a capacitor across RFBK for additional stability.
Note: Avoid excessive loading of the RMS output: RLOAD > 375Ω
2
2
0V < VSET < 3.2V
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 97
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) / -ß = 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
• Both the iPWR and RMS detectors share the same temperature compensation mechanisms.
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.
1.6
1.9
2.2
2.5
2.8
3 5.7 8.5 11.2 14
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)
INPUT RF SIGNAL CREST FACTOR (dB) =20Log(Vpeak/Vrms)
IPWR, Peak Power Output Normalized
to Average Power
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 98
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
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 de ned 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.
DC Offset Cancellation Loop ≈ Bandwidth , Hz
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  t 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  nd 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
VTGT in uence on DC offset compensation
VTGT 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
-40
-36
-32
-28
-24
-20
-16
-12
-8
-4
0
4
2 4 6 8 10 12 14 16
VTGT= 0.5V
VTGT= 1.25V
VTGT= 2.0V
VTGT= 2.75V
VTGT= 3.50V
RMSOUT ERROR (dB)
CREST FACTOR (dB)
RMS Output Error vs. Crest Factor
**Worst Case Conditions** using circuit described in
“ Application & Evaluation PCB Schematic” section
1
π(5000)(COFS+20x10-12)
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz
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 - 99
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.
VTGT should be referenced to VREF for best performance. It is recommended to use a temperature stable DC ampli er
between VTGT and VREF to create VTGT > VREF. The VREF pin is a temperature compensated voltage reference output,
only intended for use with VTGT.
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:
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.
• 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.
De nitions:
• Log-slope: slope of PIN –> VRMS best- t 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- t line.
[measured_PIN] = [measured_VRMS] / [best- t-slope] + [best- t-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 speci c error tolerance.
• Crest Factor: Peak power to average power ratio for time-varying signals.
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
HMC614LP4 / 614LP4E
v06.1109 RMS & PEAK TO AVERAGE
POWER DETECTOR 0.1 - 3.9 GHz