TI1 LMH2110 Logarithmic root mean square response Datasheet

LMH2110
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SNWS022C – JANUARY 2010 – REVISED MARCH 2013
LMH2110 8 GHz Logarithmic RMS Power Detector with 45 dB dynamic range
Check for Samples: LMH2110
FEATURES
DESCRIPTION
•
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•
•
•
•
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The LMH2110 is a 45 dB Logarithmic RMS power
detector particularly suited for accurate power
measurement of modulated RF signals that exhibit
large peak-to-average ratios, i.e. large variations of
the signal envelope. Such signals are encountered in
W-CDMA and LTE cell phones. The RMS
measurement topology inherently ensures a
modulation insensitive measurement.
1
2
Logarithmic Root Mean Square Response
45 dB Linear-in-dB Power Detection Range
Multi-Band Operation from 50 MHz to 8 GHz
LOG Conformance Better than ±0.5 dB
Highly Temperature Insensitive, ±0.25 dB
Modulation Independent Response, 0.08 dB
Minimal Slope and Intercept Variation
Shutdown Functionality
Wide Supply Range from 2.7V to 5V
Tiny 6-Bump DSBGA Package
APPLICATIONS
•
•
Multi Mode, Multi Band RF Power Control
– GSM/EDGE
– CDMA/CDMA2000
– W-CDMA
– OFDMA
– LTE
Infrastructure RF Power Control
The device has an RF frequency range from 50 MHz
to 8 GHz. It provides an accurate, temperature and
supply insensitive, output voltage that relates linearly
to the RF input power in dBm. The LMH2110's
excellent conformance to a logarithmic response
enables an easy integration by using slope and
intercept only, reducing calibration effort significantly.
The device operates with a single supply from 2.7V to
5V. The LMH2110 has an RF power detection range
from -40 dBm to 5 dBm and is ideally suited for use in
combination with a directional coupler. Alternatively a
resistive divider can be used as well.
The device is active for EN = High, otherwise it is in a
low power consumption shutdown mode. To save
power and prevent discharge of an external filter
capacitance, the output (OUT) is high-impedance
during shutdown.
The LMH2110 power detector is offered in a tiny 6bump DSBGA package.
Typical Application Circuit
RF
COUPLER
2.4
3
2.0
2
ANTENNA
PA
-40°C
1.6
VOUT (V)
50:
VDD
25°C
1
0
1.2
-1
0.8
A1
RFIN
85°C
OUT
B1
C2
B2, C1
-2
0.4
A2
LMH2110
EN
ERROR (dB)
Output Voltage and Log Conformance Error vs.
RF Input Power at 1900 MHz
ADC
0.0
-40
-3
-30
-20
-10
0
10
RF INPUT POWER (dBm)
GND
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010–2013, Texas Instruments Incorporated
LMH2110
SNWS022C – JANUARY 2010 – REVISED MARCH 2013
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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings
(1) (2)
Supply Voltage
VBAT - GND
5.5V
RF Input
Input power
12 dBm
DC Voltage
1V
Enable Input Voltage
ESD Tolerance
GND-0.4V <VEN and VEN< Min (VDD-0.4, 3.6V)
(3)
Human Body Model
2000V
Machine Model
200V
Charge Device Model
1000V
−65°C to 150°C
Storage Temperature Range
Junction Temperature
(4)
150°C
Maximum Lead Temperature
(Soldering,10 sec)
(1)
(2)
(3)
(4)
260°C
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
Human body model, applicable std. MIL-STD-883, Method 3015.7. Machine model, applicable std. JESD22–A115–A (ESD MM std of
JEDEC). Field-Induced Charge-Device Model, applicable std. JESD22–C101–C. (ESD FICDM std. of JEDEC)
The maximum power dissipation is a function of TJ(MAX) , θJA. The maximum allowable power dissipation at any ambient temperature is
PD = (TJ(MAX) - TA)/θJA. All numbers apply for packages soldered directly into a PC board.
Operating Ratings
(1)
Supply Voltage
2.7V to 5V
−40°C to +85°C
Temperature Range
RF Frequency Range
50 MHz to 8 GHz
−40 dBm to 5 dBm
RF Input Power Range
Package Thermal Resistance θJA (2)
(1)
(2)
2
166.7°C/W
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics.
The maximum power dissipation is a function of TJ(MAX) , θJA. The maximum allowable power dissipation at any ambient temperature is
PD = (TJ(MAX) - TA)/θJA. All numbers apply for packages soldered directly into a PC board.
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2.7V and 4.5V DC and AC Electrical Characteristics
Unless otherwise specified: all limits are ensured to; TA = 25°C, VBAT = 2.7V and 4.5V (worst of the 2 is specified), RFIN =
1900 MHz CW (Continuous Wave, unmodulated). Boldface limits apply at the temperature extremes (1).
Symbol
Parameter
Min
Typ
Max
(2)
Units
3.7
2.9
4.8
5.5
5.9
mA
VBAT= 2.7V
3.7
4.7
5
VBAT= 4.5V
4.6
5.7
6.1
VBAT= 2.7V
3.5
4.7
5
VBAT= 4.5V
4.6
5.7
6.1
Condition
(2)
(3)
Supply Interface
IBAT
Supply Current
Active mode: EN = High, no signal
present at RFIN.
Shutdown: EN = Low,
no signal present at
RFIN.
EN = Low, RFIN = 0
dBm, 1900 MHz
PSRR
Power Supply Rejection Ratio
(4)
RFIN = −10 dBm, 1900 MHz,
2.7V<VBAT<5V
45
μA
μA
56
dB
Logic Enable Interface
VLOW
EN Logic Low Input Level
(Shutdown mode)
VHIGH
EN Logic High Input Level
IEN
Current into EN Pin
0.6
V
50
nA
1.1
V
Input / Output Interface
44
50
56
Ω
0
1.5
8
mV
0.2
2
3
Ω
RIN
Input Resistance
VOUT
Minimum Output Voltage
(Pedestal)
No input Signal
ROUT
Output Impedance
EN = High, RFIN = -10 dBm, 1900 MHz,
ILOAD = 1 mA, DC measurement
IOUT
Output Short Circuit Current
Sinking, RFIN = -10 dBm, OUT
connected to 2.5V
37
32
42
Sourcing, RFIN = -10 dBm, OUT
connected to GND
40
34
46
IOUT,SD
Output Leakage Current in
Shutdown mode
EN = Low, OUT connected to 2V
en
Output Referred Noise
RFIN = −10 dBm, 1900 MHz, output
spectrum at 10 kHz
vN
Integrated Output Referred Noise
(4)
(4)
mA
50
nA
3
µV/√Hz
Integrated over frequency band
1 kHz - 6.5 kHz, RFIN = -10 dBm, 1900
MHz
210
µVRMS
Timing Characteristics
tON
Turn-on Time from shutdown
RFIN = -10 dBm, 1900 MHz, EN LowHigh transition to OUT at 90%
15
tR
Rise Time
Signal at RFIN from -20 dBm to 0 dBm,
10% to 90%, 1900 MHz
2.2
µs
tF
Fall Time
Signal at RFIN from 0 dBm to -20 dBm,
90% to 10%, 1900 MHz
31
µs
(1)
(2)
(3)
(4)
(4)
(4)
19
µs
Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very
limited self-heating of the device such that TJ = TA. No ensurance of parametric performance is indicated in the electrical tables under
conditions of internal self-heating where TJ > TA.
All limits are specified by test or statistical analysis.
Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not specified on shipped
production material.
This parameter is specified by design and/or characterization and is not tested in production.
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2.7V and 4.5V DC and AC Electrical Characteristics (continued)
Unless otherwise specified: all limits are ensured to; TA = 25°C, VBAT = 2.7V and 4.5V (worst of the 2 is specified), RFIN =
1900 MHz CW (Continuous Wave, unmodulated). Boldface limits apply at the temperature extremes (1).
Symbol
Parameter
RF Detector Transfer
RFIN = 50 MHz, fit range -20 dBm to -10 dBm
Condition
Min
(2)
Typ
(3)
Max
(2)
Units
(5)
PMIN
Minimum Power level, bottom end
of dynamic range
PMAX
Maximum Power level, top end of
dynamic range
VMIN
Minimum Output Voltage
At PMIN
3
mV
VMAX
Maximum Output Voltage
At PMAX
1.96
V
KSLOPE
Logarithmic Slope
42.2
44.3
46.4
mV/dB
PINT
Logarithmic Intercept
-38.6
-38.3
-38.0
dBm
DR
Dynamic Range for specified
accuracy
RFIN = 900 MHz, fit range -20 dBm to -10 dBm
Log Conformance Error within ±1 dB
-39
dBm
7
±1 dB Log Conformance Error (ELC)
46
45
±3 dB Log Conformance Error (ELC)
51
50
±0.5 dB Input referred Variation over
Temperature (EVOT), from PMIN
42
dB
(5)
PMIN
Minimum Power level, bottom end
of dynamic range
PMAX
Maximum Power level, top end of
dynamic range
VMIN
Minimum Output Voltage
At PMIN
VMAX
Maximum Output Voltage
At PMAX
KSLOPE
Logarithmic Slope
41.8
43.9
46.0
mV/dB
PINT
Logarithmic Intercept
-37.4
-37.0
-36.7
dBm
DR
Dynamic Range for specified
accuracy
EMOD
Input referred Variation due to
Modulation
Log Conformance Error within ±1 dB
-38
dBm
0
3
mV
1.58
±1 dB Log Conformance Error (ELC)
38
37
±3 dB Log Conformance Error (ELC)
45
44
±0.5 dB Input referred Variation over
Temperature (EVOT), from PMIN
44
±0.3 dB Error for a 1dB Step (E1dB STEP)
41
38
±1 dB Error for a 10dB Step (E10dB
STEP)
32
W-CDMA Release 6/7/8, -38
dBm<RFIN<-5 dBm
0.08
LTE, -38 dBm<RFIN<-5 dBm
0.19
V
dB
dB
RFIN = 1900 MHz, fit range -20 dBm to -10 dBm
(5)
PMIN
Minimum Power level, bottom end
of dynamic range
Log Conformance Error within ±1 dB
PMAX
Maximum Power level, top end of
dynamic range
VMIN
Minimum Output Voltage
At PMIN
3
VMAX
Maximum Output Voltage
At PMAX
1.5
KSLOPE
Logarithmic Slope
41.8
43.9
46.1
mV/dB
PINT
Logarithmic Intercept
-35.5
-35.1
-34.7
dBm
(5)
4
-36
dBm
0
mV
V
All limits are specified by design and measurements which are performed on a limited number of samples. Limits represent the mean
±3–sigma values. The typical value represents the statistical mean value.
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2.7V and 4.5V DC and AC Electrical Characteristics (continued)
Unless otherwise specified: all limits are ensured to; TA = 25°C, VBAT = 2.7V and 4.5V (worst of the 2 is specified), RFIN =
1900 MHz CW (Continuous Wave, unmodulated). Boldface limits apply at the temperature extremes (1).
Symbol
DR
Parameter
Condition
Dynamic Range for specified
accuracy
EMOD
Input referred Variation due to
Modulation
RFIN = 3500 MHz, fit range -15 dBm to -5 dBm
Min
Typ
(2)
(3)
±1 dB Log Conformance Error (ELC)
36
36
±3 dB Log Conformance Error (ELC)
45
43
±0.5 dB Input referred Variation over
Temperature (EVOT), from PMIN
41
±0.3 dB Error for a 1dB Step (E1dB STEP)
40
38
±1 dB Error for a 10dB Step (E10dB
STEP)
30
W-CDMA Release 6/7/8, -38
dBm<RFIN<-5 dBm
0.09
LTE, -38 dBm<RFIN<-5 dBm
0.18
Max
(2)
Units
dB
dB
(5)
PMIN
Minimum Power level, bottom end
of dynamic range
PMAX
Maximum Power level, top end of
dynamic range
VMIN
Minimum Output Voltage
At PMIN
2
VMAX
Maximum Output Voltage
At PMAX
1.52
KSLOPE
Logarithmic Slope
41.8
44.0
46.1
mV/dB
PINT
Logarithmic Intercept
-30.5
-29.7
-28.8
dBm
DR
Dynamic Range for specified
accuracy
RFIN = 5800 MHz, fit range -20 dBm to 3 dBm
Log Conformance Error within ±1 dB
-31
dBm
6
±1 dB Log Conformance Error (ELC)
37
36
±3 dB Log Conformance Error (ELC)
44
42
±0.5 dB Input referred Variation over
Temperature (EVOT), from PMIN
39
V
dB
(6)
PMIN
Minimum Power level, bottom end
of dynamic range
PMAX
Maximum Power level, top end of
dynamic range
VMIN
Minimum Output Voltage
At PMIN
3
VMAX
Maximum Output Voltage
At PMAX
1.34
KSLOPE
Logarithmic Slope
PINT
Logarithmic Intercept
DR
Dynamic Range for specified
accuracy
(6)
mV
Log Conformance Error within ±1 dB
-22
dBm
10
mV
V
42.5
44.8
47.1
mV/dB
-22.0
-21.0
-19.9
dBm
±1 dB Log Conformance Error (ELC)
32
31
±3 dB Log Conformance Error (ELC)
39
37
±0.5 dB Input referred Variation over
Temperature (EVOT), from PMIN
33
dB
All limits are specified by design and measurements which are performed on a limited number of samples. Limits represent the mean
±3–sigma values. The typical value represents the statistical mean value.
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CONNECTION DIAGRAM
VDD
A1
A2
OUT
RFIN
B1
B2
GND
GND
C1
C2
EN
Figure 1. 6-Bump DSBGA
Top View
Table 1. PIN DESCRIPTIONS
Power Supply
DSBGA
Name
A1
VDD
Positive Supply Voltage.
Description
C1
GND
Power Ground.
Power Ground. May be left floating in case grounding is not feasible.
B2
GND
Logic Input
C2
EN
Analog Input
B1
RFIN
RF input signal to the detector, internally terminated with 50Ω.
Output
A2
OUT
Ground referenced detector output voltage.
6
The device is enabled for EN = High, and in shutdown mode for EN = Low. EN
should be <2.5V for having low IEN. For EN >2.5V, IEN increases slightly, while
device is still functional. Absolute maximum rating for EN = 3.6V.
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BLOCK DIAGRAM
A1
VDD
LDO
V/I
B1
Internal Supply
EXP
RFIN
OUT
A2
A
C2
EN
V/I
EXP
GND
B2, C1
Figure 2. LMH2110
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Typical Performance Characteristics
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Supply Current vs. Supply Voltage (Active)
7
Supply Current vs. Supply Voltage (Shutdown)
8
EN = HIGH
EN = LOW
5
4
3
-40°C
25°C
85°C
2
6
5
25°C
4
3
-40°C
2
1
1
0
0
1
2
3
4
5
0
0
6
1
SUPPLY VOLTAGE (V)
3
4
5
6
Figure 3.
Figure 4.
Supply Current vs. Enable Voltage (EN)
Supply Current vs. RF Input Power
7
8
7
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
2
SUPPLY VOLTAGE (V)
6
5
4
85°C
3
25°C
2
-40°C
1
6
5
4
3
-40°C
2
85°C
25°C
1
0
0.5
0.6
0.7
0.8
0.9
1.0
1.1
0
-40
1.2
-30
ENABLE VOLTAGE (V)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 5.
Figure 6.
Sourcing Output Current vs. RF Input Power
Sinking Output Current vs. RF Input Power
60
-40°C
SINKING OUTPUT CURRENT (mA)
SOURCING OUTPUT CURRENT (mA)
60
50
40
-40°C
25°C
30
85°C
20
10
0
-40
OUT = 0V
RFin = 1900 MHz
-30
-20
-10
0
10
RF INPUT POWER (dBm)
25°C
50
40
30
85°C
20
10
OUT = 2.5V
RFin = 1900 MHz
0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 7.
8
85°C
7
SUPPLY CURRENT (éA)
SUPPLY CURRENT (mA)
6
Figure 8.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
RF Input Impedance vs. Frequency,
Resistance (R) and Reactance (X)
Power Supply Rejection Ratio vs. Frequency
70
100
75
100
50
75
50
25
25
0
-25
-25
-50
60
50
PSRR (dB)
RF INPUT IMPEDANCE (Ö)
R
X
-75
-50
-100
40
30
20
10
-75
MEASURED ON BUMP
-100
10M
100M
1G
0
10
10G
100
FREQUENCY (Hz)
1k
10k
100k
FREQUENCY (Hz)
Figure 9.
Figure 10.
Output Voltage Noise vs. Frequency
Output Voltage vs. RF Input Power
2.4
2.0
5.8 GHz
3.5 GHz
VOUT (V)
1.6
1.2
1.9 GHz
900 MHz
50 MHz
0.8
0.4
8 GHz
0.0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 11.
Figure 12.
Output Voltage vs. Frequency
Log Slope vs. Frequency
2.00
48
1.75
46
RFIN = 0 dBm
LOG SLOPE (mV/dB)
1.50
VOUT (V)
RFIN = -5 dBm
1.25
1.00
RFIN = -10 dBm
RFIN = -15 dBm
0.75
RFIN = -20 dBm
0.50
RFIN = -25 dBm
-40°C
44
42
85°C
25°C
40
0.25
0.00
10M
100M
1G
38
10M
10G
FREQUENCY (Hz)
100M
1G
10G
FREQUENCY (Hz)
Figure 13.
Figure 14.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Output Voltage and Log Conformance Error vs.
RF Input Power at 50 MHz
Log Intercept vs. Frequency
-20
2
2.0
-24
LOG INTERCEPT (dBm)
3
2.4
-40°C
25°C
85°C
-32
1
ERROR (dB)
VOUT (V)
1.6
-28
0
1.2
-1
0.8
85°C
25°C
-36
-40
10M
100M
-40°C
1G
-2
0.4
-3
0.0
-40
10G
-30
FREQUENCY (Hz)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 15.
Figure 16.
Log Conformance Error (50 units) vs.
RF Input Power at 50 MHz
Temperature Variation vs.
RF Input Power at 50 MHz
2.0
3
1.5
2
-40°C
1.0
1
ERROR (dB)
0
0.5
0.0
-0.5
-1
85°C
-1.0
85°C
-2
-1.5
-3
-40
-30
-20
-10
0
-2.0
-40
10
-30
RF INPUT POWER (dBm)
0
10
Figure 18.
Temperature Variation (50 units) vs.
RF Input Power at 50 MHz
Output Voltage and Log Conformance Error vs.
RF Input Power at 900 MHz
3
2.4
1.5
-40°C
2
2.0
1.0
-40°C
25°C
1.6
VOUT (V)
0.5
0.0
-0.5
0
-1
0.8
85°C
85°C
-30
-20
-2
0.4
-1.5
-2.0
-40
1
1.2
-1.0
-10
0
0.0
-40
10
RF INPUT POWER (dBm)
-3
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 19.
10
-10
Figure 17.
2.0
ERROR (dB)
-20
RF INPUT POWER (dBm)
ERROR (dB)
ERROR (dB)
-40°C
Figure 20.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Log Conformance Error (50 units) vs.
RF Input Power at 900 MHz
Temperature Variation vs.
RF Input Power at 900 MHz
2.0
3
1.5
2
-40°C
1.0
1
ERROR (dB)
ERROR (dB)
-40°C
0
0.5
0.0
-0.5
-1
85°C
-1.0
85°C
-2
-1.5
-3
-40
-30
-20
-10
0
-2.0
-40
10
-30
RF INPUT POWER (dBm)
-10
0
Figure 21.
Figure 22.
Temperature Variation (50 units) vs.
RF Input Power at 900 MHz
1 dB Power Step Error vs.
RF Input Power at 900 MHz
10
2.0
2.0
1.5
1.5
-40°C
25°C
1.0
1.0
85°C
ERROR (dB)
ERROR (dB)
-20
RF INPUT POWER (dBm)
0.5
0.0
-0.5
0.5
0.0
-0.5
-40°C
-1.0
-1.0
85°C
-1.5
-1.5
-2.0
-40
-30
-20
-10
0
-2.0
-40
10
-30
RF INPUT POWER (dBm)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 23.
Figure 24.
10 dB Power Step Error vs.
RF Input Power at 900 MHz
W-CDMA Variation vs.
RF Input Power at 900 MHz
1.5
2.0
1.5
1.0
85°C
ERROR (dB)
ERROR (dB)
1.0
0.5
0.0
-0.5
0.5
0.0
-0.5
-40°C
W-CDMA, REL8
W-CDMA, REL6
W-CDMA, REL7
-1.0
-1.0
-1.5
-2.0
-40 -35 -30 -25 -20 -15 -10
-5
-1.5
-40
0
RF INPUT POWER (dBm)
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 25.
Figure 26.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Output Voltage and Log Conformance Error vs.
RF Input Power at 1900 MHz
1.5
20MHz, 100RB
1.0
3
2.0
2
-40°C
0.5
LTE, QPSK
0.0
25°C
1.6
VOUT (V)
ERROR (dB)
2.4
1
0
1.2
-0.5
-1
0.8
LTE, 16QAM
ERROR (dB)
LTE Variation vs.
RF Input Power at 900 MHz
85°C
-1.0
-2
0.4
LTE, 64QAM
-1.5
-40
-30
-20
-10
0
-3
0.0
-40
10
-30
RF INPUT POWER (dBm)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 27.
Figure 28.
Log Conformance Error (50 units) vs.
RF Input Power at 1900 MHz
Temperature Variation vs.
RF Input Power at 1900 MHz
2.0
3
1.5
2
1.0
ERROR (dB)
ERROR (dB)
-40°C
1
0
-40°C
0.5
0.0
-0.5
-1
85°C
-1.0
85°C
-2
-1.5
-3
-40
-30
-20
-10
0
-2.0
-40
10
-30
RF INPUT POWER (dBm)
0
Figure 30.
Temperature Variation (50 units) vs.
RF Input Power at 1900 MHz
1 dB Power Step Error vs.
RF Input Power at 1900 MHz
1.5
-40°C
25°C
1.0
1.0
ERROR (dB)
85°C
0.5
0.0
-0.5
0.5
0.0
-0.5
-40°C
-1.0
-1.0
85°C
-1.5
-1.5
-2.0
-40
10
2.0
1.5
ERROR (dB)
-10
Figure 29.
2.0
-30
-20
-10
0
-2.0
-40
10
RF INPUT POWER (dBm)
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 31.
12
-20
RF INPUT POWER (dBm)
Figure 32.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
10 dB Power Step Error vs.
RF Input Power at 1900 MHz
W-CDMA Variation vs.
RF Input Power at 1900 MHz
1.5
2.0
1.5
1.0
1.0
W-CDMA, REL8
0.5
ERROR (dB)
ERROR (dB)
85°C
0.5
0.0
-0.5
0.0
W-CDMA, REL6
-0.5
-40°C
-1.0
W-CDMA, REL7
-1.0
-1.5
-2.0
-40 -35 -30 -25 -20 -15 -10
-5
-1.5
-40
0
-30
RF INPUT POWER (dBm)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 33.
Figure 34.
LTE Input referred Variation vs.
RF Input Power at 1900 MHz
Output Voltage and Log Conformance Error vs.
RF Input Power at 3500 MHz
1.5
3
2.4
20MHz, 100RB
1.0
2
2.0
-40°C
0.0
1.6
1
25°C
0
1.2
-0.5
-1
0.8
LTE, 16QAM
ERROR (dB)
LTE, QPSK
VOUT (V)
ERROR (dB)
0.5
85°C
-1.0
-2
0.4
LTE, 64QAM
-1.5
-40
-30
-20
-10
0
0.0
-40
10
RF INPUT POWER (dBm)
-3
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 35.
Figure 36.
Log Conformance Error (50 units) vs.
RF Input Power at 3500 MHz
Temperature Variation vs.
RF Input Power at 3500 MHz
2.0
3
1.5
2
1.0
ERROR (dB)
ERROR (dB)
-40°C
1
0
-40°C
0.5
0.0
-0.5
-1
-3
-40
85°C
-1.0
85°C
-2
-1.5
-30
-20
-10
0
-2.0
-40
10
RF INPUT POWER (dBm)
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 37.
Figure 38.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Output Voltage and Log Conformance Error vs.
RF Input Power at 5800 MHz
2.0
3
2.4
1.5
2
2.0
-40°C
1.0
-40°C
VOUT (V)
ERROR (dB)
0.5
0.0
-0.5
25°C
1.6
1
1.2
0
0.8
-1
ERROR (dB)
Temperature Variation (50 units) vs.
RF Input Power at 3500 MHz
-1.0
85°C
0.4
-1.5
-2.0
-40
-30
-20
-10
0
-3
0.0
-40
10
-2
85°C
-30
RF INPUT POWER (dBm)
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 39.
Figure 40.
Log Conformance Error (50 units) vs.
RF Input Power at 5800 MHz
Temperature Variation vs.
RF Input Power at 5800 MHz
2.0
3
1.5
-40°C
-40°C
1.0
1
ERROR (dB)
0
0.5
0.0
-0.5
-1
-1.0
85°C
-2
85°C
-1.5
-3
-40
-30
-20
-10
0
-2.0
-40
10
-30
RF INPUT POWER (dBm)
-20
10
Figure 42.
Temperature Variation (50 units) vs.
RF Input Power at 5800 MHz
Output Voltage and Log Conformance Error vs.
RF Input Power at 8000 MHz
1.5
3
2.4
-40°C
2
2.0
1.0
-40°C
0.5
VOUT (V)
ERROR (dB)
0
Figure 41.
2.0
0.0
-0.5
-1.5
-2.0
-40
25°C
1.6
1
1.2
0
-1
0.8
-1.0
85°C
-30
-20
-10
0
RF INPUT POWER (dBm)
-2
0.4
85°C
0.0
-40
10
-3
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 43.
14
-10
RF INPUT POWER (dBm)
ERROR (dB)
ERROR (dB)
2
Figure 44.
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Typical Performance Characteristics (continued)
Unless otherwise specified: TA = 25°C, VBAT = 2.7V, RFin = 1900 MHz CW (Continuous Wave, unmodulated). Specified errors
are input referred.
Temperature Variation vs.
RF Input Power at 8000 MHz
2.0
1.5
ERROR (dB)
1.0
-40°C
0.5
0.0
-0.5
-1.0
85°C
-1.5
-2.0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 45.
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APPLICATION INFORMATION
The LMH2110 is a 45 dB Logarithmic RMS power detector particularly suited for accurate power measurements
of modulated RF signals that exhibit large peak-to-average ratios (PAR’s). The RMS detector implements the
exact definition of power resulting in a power measurement insensitive to high PAR’s. Such signals are
encountered e.g. in LTE and W-CDMA applications. The LMH2110 has an RF frequency range from 50 MHz to 8
GHz. It provides an output voltage that relates linearly to the RF input power in dBm. Its output voltage is highly
insensitive to temperature and supply variations.
Typical Application
The LMH2110 can be used in a wide variety of applications like LTE, W-CDMA, CDMA, GSM. This section
discusses the LMH2110 in a typical transmit power control loop for such applications.
Transmit-power-control-loop circuits make the transmit power level insensitive to power amplifier (PA)
inaccuracy. This is desired, since power amplifiers are non-linear devices and temperature dependent, making it
hard to estimate the exact transmit power level. If a control loop is used, the inaccuracy of the PA is eliminated
from the overall accuracy of the transmit power level. The accuracy of the transmit power level now depends on
the RF detector accuracy instead. The LMH2110 is especially suited for transmit power control applications,
since it accurately measures transmit power and is insensitive to temperature, supply voltage and modulation
variations.
Figure 46 shows a simplified schematic of a typical transmit power control system. The output power of the PA is
measured by the LMH2110 through a directional coupler. The measured output voltage of the LMH2110 is
digitized by the ADC inside the baseband chip. Accordingly, the baseband controls the PA output power level by
changing the gain control signal of the RF VGA. Although the output ripple of the LMH2110 is typically low
enough, an optional low-pass filter can be placed in between the LMH2110 and the ADC to further reduce the
ripple.
COUPLER
RF
PA
VGA
ANTENNA
B
A
S
E
B
A
N
D
50:
GAIN
VDD
OPTIONAL
RS
ADC
A2
CS
EN
A1
OUT
RFIN
B1
LMH2110
EN
C2
B2, C1
GND
Figure 46. Transmit Power Control System
Accurate Power Measurement
Detectors have evolved over the years along with the communication standards. Newer communication
standards like LTE and W-CDMA raise the need for more advanced accurate power detectors. To be able to
distinguish the various detector types it is important to understand what the ideal power measurement should
look like and how a power measurement is implemented.
Power is a metric for the average energy content of a signal. By definition it is not a function of the signal shape
over time. In other words, the power content of a 0 dBm sine wave is identical to the power content of a 0 dBm
square wave or a 0 dBm W-CDMA signal; all these signals have the same average power content.
The average power can be described by the following formula:
16
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1
P=
T
T
³0
2
VRMS
v(t)
dt =
R
R
2
where
•
•
•
•
T is the time interval over which is averaged
v(t) is the instantaneous voltage at time t
R is the resistance in which the power is dissipated
VRMS is the equivalent RMS voltage
(1)
According to aforementioned formula for power, an exact power measurement can be done via measuring the
RMS voltage (VRMS) of a signal. The RMS voltage is described by:
VRMS =
2
1
v(t) dt
T³
(2)
Implementing the exact formula for RMS can be difficult though. A simplification can be made in determining the
average power when information about the waveform is available. If the signal shape is known, the relationship
between RMS value and, for instance, the peak value of the RF signal is also known. It thus enables a
measurement based on measuring peak voltage rather than measuring the RMS voltage. To calculate the RMS
value (and therewith the average power), the measured peak voltage is translated into an RMS voltage based on
the waveform characteristics. A few examples:
• Sine wave: VRMS = VPEAK/ √2
• Square wave: VRMS = VPEAK
• Saw-tooth wave: VRMS = VPEAK/ √3
For more complex waveforms it is not always easy to determine the exact relationship between RMS value and
peak value. A peak measurement can then become impractical. An approximation can be used for the VRMS to
VPEAK relationship but it can result in a less accurate average power estimate.
Depending on the detection mechanism, power detectors may produce a slightly different output signal in
response to the earlier mentioned waveforms, even though the average power level of these signals are the
same. This error is due to the fact that not all power detectors strictly implement the definition for signal power,
being the root mean square (RMS) of the signal. To cover for the systematic error in the output response of a
detector, calibration can be used. After calibration a look-up table corrects for the error. Multiple look-up tables
can be created for different modulation schemes.
Types of RF Detectors
This section provides an overview of detectors based on their detection principle. Detectors that will be discussed
are:
• Peak Detectors
• LOG Amp Detectors
• RMS Detectors
Peak Detectors
A peak detector is one of the simplest types of detectors. According to the naming, the peak detector “stores” the
highest value arising in a certain time window. However, usually a peak detector is used with a relative long
holding time when compared to the carrier frequency and a relative short holding time with respect to the
envelope frequency. In this way a peak detector is used as AM demodulator or envelope tracker (Figure 47).
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PEAK
ENVELOPE
CARRIER
Figure 47. Peak detection vs. envelope tracking
A peak detector usually has a linear response. An example of this is a diode detector (Figure 48). The diode
rectifies the RF input voltage and subsequently the RC filter determines the averaging (holding) time. The
selection of the holding time configures the diode detector for its particular application. For envelope tracking a
relatively small RC time constant is chosen, such that the output voltage tracks the envelope nicely. A
configuration with a relatively large time constant can be used for supply regulation of the power amplifier (PA).
Controlling the supply voltage of the PA can reduce power consumption significantly. The optimal mode of
operation is to set the supply voltage such that it is just above the maximum output voltage of the PA. A diode
detector with relative large RC time constant measures this maximum (peak) voltage.
Z0
D
VREF
C
R
VOUT
Figure 48. Diode Detector
Since peak detectors measure a peak voltage, their response is inherently depended on the signal shape or
modulation form as discussed in the previous section. Knowledge about the signal shape is required to
determine an RMS value. For complex systems having various modulation schemes, the amount of calibration
and look-up tables can become unmanageable.
LOG Amp Detectors
LOG Amp detectors are widely used RF power detectors for GSM and the early W-CDMA systems. The transfer
function of a LOG amp detector has a linear-in-dB response, which means that the output in volts changes
linearly with the RF power in dBm. This is convenient since most communication standards specify transmit
power levels in dBm as well. LOG amp detectors implement the logarithmic function by a piecewise linear
approximation. Consequently, the LOG amp detector does not implement an exact power measurement, which
implies a dependency on the signal shape. In systems using various modulation schemes calibration and lookup
tables might be required.
RMS Detectors
An RMS detector has a response that is insensitive to the signal shape and modulation form. This is because its
operation is based on exact determination of the average power, i.e. it implements:
VRMS =
18
2
1
v(t) dt
T³
(3)
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RMS detectors are in particular suited for the newer communication standards like W-CDMA and LTE that exhibit
large peak-to-average ratios and different modulation schemes (signal shapes). This is a key advantage
compared to other types of detectors in applications that employ signals with high peak-to-average power
variations or different modulation schemes. For example, the RMS detector response to a 0 dBm modulated WCDMA signal and a 0 dBm unmodulated carrier is essentially equal. This eliminates the need for long calibration
procedures and large calibration tables in the baseband due to different applied modulation schemes.
LMH2110 RF Power Detector
For optimal performance of the LMH2110, it needs to be configured correctly in the application. The detector will
be discussed by means of its block diagram (Figure 49). Subsequently, the details of the electrical interfacing are
separately discussed for each pin.
A1
VDD
LDO
V/I
EXP
i1
RFIN
B1
Internal Supply
OUT
iOUT
A
A2
VOUT
i2
C2
EN
V/I
EXP
GND
B2, C1
Figure 49. Block Diagram
For measuring the RMS (power) level of a signal, the time average of the squared signal needs to be measured
as described in section Accurate Power Measurement. This is implemented in the LMH2110 by means of a
multiplier and a low-pass filter in a negative-feedback loop. A simplified block diagram of the LMH2110 is
depicted in Figure 49. The core of the loop is a multiplier. The two inputs of the multiplier are fed by (i1, i2):
i1 = iLF + iRF
i2 = iLF - iRF
(4)
(5)
in which iLF is a current depending on the DC output voltage of the RF detector and iRF is a current depending on
the RF input signal. The output of the multiplier (iOUT) is the product of these two current and equals:
2
2
iout =
iRF
iLF
I0
(6)
in which I0 is a normalizing current. By a low-pass filter at the output of the multiplier the DC term of this current
is isolated and integrated. The input of the amplifier A acts as the nulling point of the negative feedback loop,
yielding:
³ iLF dt = ³ iRF dt
2
2
(7)
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which implies that the average power content of the current related to the output voltage of the LMH2110 is
made equal to the average power content of the current related to the RF input signal.
For a negative-feedback system, the transfer function is given by the inverse function of the feedback block.
Therefore, to have a logarithmic transfer for this RF detector, the feedback network implements an exponential
function resulting in an overall transfer function for the LMH2110 of:
§ 1 V 2dt ·
³ RF ¸
© Vx
¹
Vout = V0 log ¨
(8)
in which V0 and VX are normalizing voltages. Note that as a result of the feedback loop also a square-root is
implemented yielding the RMS function.
Given this architecture for the RF detector, the high-performance of the LMH2110 can be understood. In theory
the accuracy of the logarithmic transfer is set by:
• The exponential feedback network, which basically needs to process a DC signal only.
• A high loop gain for the feedback loop, which is specified by the amplifier gain A.
The RMS functionality is inherent to the feedback loop and the use of a multiplier. So, a very accurate LOG-RMS
RF power detector is obtained.
To ensure a low dependency on the supply voltage, the internal detector circuitry is supplied via a low drop-out
(LDO) regulator. This enables the usage of a wide range of supply voltage (2.7V to 5V) in combination with a low
sensitivity of the output signal for the external supply voltage.
RF Input
RF systems typically use a characteristic impedance of 50Ω. The LMH2110 is no exception to this. The RF input
pin of the LMH2110 has an input impedance of 50Ω. It enables an easy, direct connection to a directional
coupler without the need for additional components (Figure 46). For an accurate power measurement the input
power range of the LMH2110 needs to be aligned with the output power range of the power amplifier. This can
be done by selecting a directional coupler with the correct coupling factor.
Since the LMH2110 has a constant input impedance, a resistive divider can also be used in stead of a directional
coupler (Figure 50).
RF
ANTENNA
PA
R1
VDD
A1
RFIN
B1
A2
OUT
LMH2110
EN
ADC
C2
B2, C1
GND
Figure 50. Application with Resistive Divider
Resistor R1 implements an attenuator together with the detector input impedance to match the output range of
the PA to the input range of the LMH2110. The attenuation (AdB) realized by R1 and the effective input
impedance of the LMH2110 equals:
20
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R1 º
ª
AdB = 20LOG «1 +
»
RIN ¼
¬
(9)
Solving this expression for R1 yields:
A
ª dB º
20
R1 = «¬10
- 1»¼ RIN
(10)
Suppose the desired attenuation is 30 dB with a given LMH2110 input impedance of 50Ω, the resistor R1 needs
to be 1531Ω. A practical value is 1.5 kΩ. Although this is a cheaper solution than the application with directional
coupler, it also comes with a disadvantage. After calculating the resistor value it is possible that the realized
attenuation is less then expected. This is because of the parasitic capacitance of resistor R1 which results in a
lower actual realized attenuation. Whether the attenuation will be reduced depends on the frequency of the RF
signal and the parasitic capacitance of resistor R1. Since the parasitic capacitance varies from resistor to resistor,
exact determination of the realized attenuation can be difficult. A way to reduce the parasitic capacitance of
resistor R1 is to realize it as a series connection of several separate resistors.
Enable
To save power, the LMH2110 can be brought into a low-power shutdown mode by means of the enable pin (EN).
The device is active for EN = HIGH (VEN>1.1V) and in the low-power shutdown mode for EN = LOW (VEN <
0.6V). In this state the output of the LMH2110 is switched to a high impedance mode. This high impedance mode
prevents the discharge of the optional low-pass filter which is good for the power efficiency. Using the shutdown
function, care must be taken not to exceed the absolute maximum ratings. Since the device has an internal
operating voltage of 2.5V, the voltage level on the enable should not be higher than 3V to prevent damage to the
device. Also enable voltage levels lower than 400 mV below GND should be prevented. In both cases the ESD
devices start to conduct when the enable voltage range is exceeded and excessive current will be drawn. A
correct operation is not ensured then. The absolute maximum ratings are also exceeded when the enable (EN) is
switched to HIGH (from shutdown to active mode) while the supply voltage is switched off. This situation should
be prevented at all times. A possible solution to protect the device is to add a resistor of 1 kΩ in series with the
enable input to limit the current.
Output
The output of the LMH2110 provides a DC voltage that is a measure for the applied RF power to the input pin.
The output voltage has a linear-in-dB response for an applied RF signal.
RF power detectors can have some residual ripple on the output due to the modulation of the applied RF signal.
The residual ripple on the LMH2110’s output is small though and therefore additional filtering is usually not
needed. This is because its internal averaging mechanism reduces the ripple significantly. For some modulation
types however, having very high peak-to-average ratios, additional filtering might be useful.
Filtering can be applied by an external low-pass filter. It should be realized that filtering reduces not only the
ripple, but also increases the response time. In other words, it takes longer before the output reaches its final
value. A trade-off should be made between allowed ripple and allowed response time. The filtering technique is
depicted in Figure 51. The filtering of the low pass output filter is realized by resistor RS and capacitor CS. The -3
dB bandwidth of this filter can be calculated by:
f−3
dB
= 1 / (2πRSCS)
(11)
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VDD
RFIN
B1
A1
A2
OUT
RS
LMH2110
EN
+
CS
C2
B2,C1
ADC
GND
Figure 51. Low-Pass Output Filter for Residual Ripple Reduction
The output impedance of the LMH2110 is HIGH in shutdown. This is especially beneficial in pulsed mode
systems. It ensures a fast settling time when the device returns from shutdown into active mode and reduces
power consumption.
In pulse mode systems, the device is active only during a fraction of the time. During the remaining time the
device is in low-power shutdown. Pulsed mode system applications usually require that the output value is
available at all times. This can be realized by a capacitor connected between the output and GND that “stores”
the output voltage level. To apply this principle it should be ensured that discharging of the capacitor is
minimized in shutdown mode. The connected ADC input should thus have a high input impedance to prevent a
possible discharge path through the ADC. When an additional filter is applied at the output, the capacitor of the
RC-filter can be used to store the output value. An LMH2110 with a high impedance shutdown mode save power
in pulse mode systems. This is because the capacitor CS doesn’t need to be fully re-charged each cycle.
Supply
The LMH2110 has an internal LDO to handle supply voltages between 2.7V to 5V. This enables a direct
connection to the battery in cell phone applications. The high PSRR of the LMH2110 ensures that the
performance is constant over its power supply range.
Specifying Detector Performance
The performance of the LMH2110 can be expressed by a variety of parameters. This section discusses the key
parameters.
Dynamic Range
The LMH2110 is designed to have a predictable and accurate response over a certain input power range. This is
called the dynamic range (DR) of a detector. For determining the dynamic range a couple of different criteria can
be used. The most commonly used ones are:
• Log conformance error, ELC
• Variation over temperature error, EVOT
• 1 dB step error, E1 dB
• 10 dB step error, E10 dB
• Variation due to modulation, EMOD
The specified dynamic range is the range in which the specified error metric is within a predefined window. An
explanation of these errors is given in the following paragraphs.
Log Conformance error
The LMH2110 implements a logarithmic function. In order to describe how close the transfer is to an ideal
logarithmic function the log conformance error is used. To calculate the log conformance error the detector
transfer function is modeled as a linear-in-dB relationship between the input power and the output voltage.
The ideal linear-in-dB transfer is modeled by 2 parameters:
• Slope
• Intercept
22
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and is described by:
VOUT = KSLOPE (PIN – PINT)
where
•
•
•
KSLOPE is the slope of the line in mV/dB
PIN the input power level
PINT is the power level in dBm at which the line intercepts VOUT = 0V (See Figure 52).
(12)
2.4
Ideal
LOG function
2.0
VOUT (V)
1.6
Detector
response
1.2
0.8
KSLOPE
PINT
0.4
0.0
-50
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 52. Ideal Logarithmic Response
To determine the log conformance error two steps are required:
1. Determine the best fitted line at 25°C.
2. Determine the difference between the actual data and the best fitted line.
The best fit can be determined by standard routines. A careful selection of the fit range is important. The fit range
should be within the normal range of operation of the device. Outcome of the fit is KSLOPE and PINT.
Subsequently, the difference between the actual data and the best fitted line is determined. The log conformance
is specified as an input referred error. The output referred error is therefore divided by the KSLOPE to obtain the
input referred error. The log conformance error is calculated by the following equation:
ELC =
VOUT
KSLOPE 25qC (PIN
PINT 25qC)
KSLOPE 25qC
where
•
•
VOUT is the measured output voltage at a power level at PIN at a temperature. KSLOPE 25°C (mV/dB)
PINT 25°C (dBm) are the parameters of the best fitted line of the 25°C transfer
(13)
In Figure 53 it can be seen that both the error with respect to the ideal LOG response as well as the error due to
temperature variation are included in this error metric. This is because the measured data for all temperatures is
compared to the fitted line at 25°C. The measurement result of a typical LMH2110 in Figure 53 shows a dynamic
range of 36 dB for ELC= ±1dB.
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2.4
3
2.0
2
VOUT (V)
25°C
1
ERROR (dB)
-40°C
1.6
1.2
0
0.8
-1
85°C
-2
0.4
-3
0.0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 53. VOUT and ELC vs. RF input Power at 1900 MHz
Variation over Temperature Error
In contrast to the log conformance error, the variation over temperature error (EVOT) purely measures the error
due to temperature variation. The measured output voltage at 25°C is subtracted from the output voltage at
another temperature. Subsequently, it is translated into an input referred error by dividing it by KSLOPE at 25°C.
The equation for variation over temperature is given by:
EVOT = (VOUT_TEMP – VOUT 25°C) / KSLOPE 25°C
(14)
The variation over temperature is shown in Figure 54, where a dynamic range of 41 dB is obtained (from PMIN = 36 dBm) for EVOT = ±0.5 dB.
2.0
1.5
ERROR (dB)
1.0
-40°C
0.5
0.0
-0.5
85°C
-1.0
-1.5
-2.0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 54. EVOT vs. RF Input Power at 1900 MHz
1 dB step error
This parameter is a measure for the error for an 1 dB power step. According to a 3GPP specification, the error
should be less than ±0.3 dB. Often, this condition is used to define a useful dynamic range of the detector.
The 1 dB step error is calculated in 3 steps:
1. Determine the maximum sensitivity.
2. Determine average sensitivity.
3. Calculate the 1 dB step error.
24
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First the maximum sensitivity (SMAX) is calculated per temperature by determining the maximum difference
between two output voltages for a 1 dB step within the power range:
SMAX = VOUT P+1 – VOUT P
(15)
For calculating the 1 dB step error an average sensitivity (SAVG) is used which is the average of the maximum
sensitivity and an allowed minimum sensitivity (SMIN). The allowed minimum sensitivity is determined by the
application. In this datasheet SMIN = 30 mV/dB is used. Subsequently, the average sensitivity can be calculated
by:
SAVG = (SMAX + SMIN) / 2
(16)
The 1dB error is than calculated by:
E1
dB
= (SACTUAL - SAVG) / SAVG
where
•
SACTUAL (actual sensitivity) is the difference between two output voltages for a 1 dB step at a given power
level
(17)
Figure 55 shows the typical 1 dB step error at 1900 MHz, where a dynamic range of 38 dB over temperature is
obtained for E1dB = ±0.3 dB.
2.0
1.5
25°C
1.0
ERROR (dB)
85°C
0.5
0.0
-0.5
-40°C
-1.0
-1.5
-2.0
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 55. 1 dB Step Error vs. RF Input Power at 1900 MHz
10 dB step error
This error is defined in a different manner than the 1 dB step error. This parameter shows the input power error
over temperature when a 10 dB power step is made. The 10 dB step at 25°C is taken as a reference.
To determine the 10 dB step error first the output voltage levels (V1 and V2) for power levels “P” and “P+10dB”
at the 25°C are determined (Figure 56). Subsequently these 2 output voltages are used to determine the
corresponding power levels at temperature T (PT and PT+X). The difference between those two power levels
subtracted by 10 results in the 10 dB step error.
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VOUT (V)
SNWS022C – JANUARY 2010 – REVISED MARCH 2013
25°C response
V2
Temp (T)
response
V1
RFIN (dBm)
P
P+10 dB
PT
PT+X
Figure 56. Graphical Representation of 10 dB Step calculations
Figure 57 shows the typical 10 dB step error at 1900 MHz, where a dynamic range of 30 dB is obtained for E10dB
= ±1 dB.
2.0
1.5
ERROR (dB)
1.0
85°C
0.5
0.0
-0.5
-40°C
-1.0
-1.5
-2.0
-40 -35 -30 -25 -20 -15 -10
-5
0
RF INPUT POWER (dBm)
Figure 57. 10 dB Step Error vs. RF Input Power at 1900 MHz
Variation due to Modulation
The response of an RF detector may vary due to different modulation schemes. How much it will vary depends
on the modulation form and the type of detector. Modulation forms with high peak-to-average ratios (PAR) can
cause significant variation, especially with traditional RF detectors. This is because the measurement is not an
actual RMS measurement and is therefore waveform dependent.
To calculate the variation due to modulation (EMOD), the measurement result for an un-modulated RF carrier is
subtracted from the measurement result of a modulated RF carrier. The calculations are similar to those for
variation over temperature. The variation due to modulation can be calculated by:
EMOD = (VOUT_MOD – VOUT_CW) / KSLOPE
where
•
•
VOUT_MOD is the measured output voltage for an applied power level of a modulated signal
VOUT_CW is the output voltage as a result of an applied un-modulated signal having the same power level
(18)
Figure 58 shows the variation due to modulation for W-CDMA, where a EMOD of 0.09 dB in obtained for a
dynamic range from -38 dBm to –5 dBm.
26
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1.5
1.0
ERROR (dB)
W-CDMA, REL8
0.5
0.0
-0.5
W-CDMA, REL6
W-CDMA, REL7
-1.0
-1.5
-40
-30
-20
-10
0
10
RF INPUT POWER (dBm)
Figure 58. Variation due to Modulation for W-CDMA
Layout Recommendations
As with any other RF device, careful attention must me paid to the board layout. If the board layout isn’t properly
designed, performance might be less then can be expected for the application.
The LMH2110 is designed to be used in RF applications, having a characteristic impedance of 50Ω. To achieve
this impedance, the input of the LMH2110 needs to be connected via a 50Ω transmission line. Transmission lines
can be created on PCBs using microstrip or (grounded) coplanar waveguide (GCPW) configurations.
In order to minimize injection of RF interference into the LMH2110 through the supply lines, the PCB traces for
VDD and GND should be minimized for RF signals. This can be done by placing a small decoupling capacitor
between the VDD and GND. It should be placed as close as possible to the VDD and GND pins of the LMH2110.
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REVISION HISTORY
Changes from Revision B (March 2013) to Revision C
•
28
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 27
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PACKAGE OPTION ADDENDUM
www.ti.com
11-Apr-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Top-Side Markings
(3)
(4)
LMH2110TM/NOPB
ACTIVE
DSBGA
YFQ
6
250
Green (RoHS
& no Sb/Br)
SNAGCU
Level-1-260C-UNLIM
-40 to 85
P
LMH2110TMX/NOPB
ACTIVE
DSBGA
YFQ
6
3000
Green (RoHS
& no Sb/Br)
SNAGCU
Level-1-260C-UNLIM
-40 to 85
P
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a
continuation of the previous line and the two combined represent the entire Top-Side Marking for that device.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
Samples
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jun-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
LMH2110TM/NOPB
DSBGA
YFQ
6
250
178.0
8.4
LMH2110TMX/NOPB
DSBGA
YFQ
6
3000
178.0
8.4
Pack Materials-Page 1
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
0.89
1.3
0.7
4.0
8.0
Q1
0.89
1.3
0.7
4.0
8.0
Q1
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jun-2013
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LMH2110TM/NOPB
DSBGA
YFQ
LMH2110TMX/NOPB
DSBGA
YFQ
6
250
210.0
185.0
35.0
6
3000
210.0
185.0
35.0
Pack Materials-Page 2
MECHANICAL DATA
YFQ0006xxx
D
0.600±0.075
E
TMD06XXX (Rev B)
D: Max = 1.27 mm, Min = 1.21 mm
E: Max = 0.87 mm, Min = 0.81 mm
4215075/A
NOTES:
A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.
B. This drawing is subject to change without notice.
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12/12
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