FEATURES
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LT5570
Fast Responding, 40MHz
to 2.7GHz Mean-Squared
Power Detector
DESCRIPTION
The LT
®
5570 is a 40MHz to 2.7GHz monolithic Logarithmic
Mean-Squared RF power detector. It is capable of RMS
measurement of an AC signal with wide dynamic range,
from –52dBm to 13dBm depending on frequency. The
power of the AC signal in an equivalent decibel-scaled
value is precisely converted into DC voltage on a linear
scale, independent of the crest factor of the waveforms. The
LT5570 is suitable for precision RF power measurement and
level control for a wide variety of RF standards, including
CDMA, W-CDMA, CDMA2000, TD-SCDMA and WiMAX.
The DC output is buffered with a low output impedance
amplifier capable of driving a high capacitance load.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 7262661, 7259620, 7268608.
Frequency Range: 40MHz to 2.7GHz
Accurate RMS Power Measurement of High Crest
Factor Modulated Waveforms
Linear DC Output vs Input Power in dBm
Linear Dynamic Range: Up to 60dB
Exceptional Accuracy over Temperature: ±0.3dB
Fast Response Time: 0.5μs Rise Time,
8μs Fall Time
Low Supply Current: 26.5mA
Low Impedance Output Buffer Capable of Driving
High Capacitance Load
Small 3mm
×
3mm 10-Lead DFN Package
APPLICATIONS
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RMS Power Measurement
RF Power Control
Receive and Transmit Gain Control
W-CDMA, CDMA2000, TD-SCDMA, WiMAX
RF Instrumentation
TYPICAL APPLICATION
40MHz to 2.7GHz Mean-Squared Power Detector
5V
1 F
RF
INPUT
1:4
NC
1nF
1
2
3
4
5
10
9
8
7
6
V
OUT
ENABLE
V
OUT
(V)
22nF
Output Voltage, Linearity Error vs Input Power, 25°C (2140 MHz)
2.4
2.0
1.6
1.2
0.8
0.4
0
–45
CW
4CH WCDMA
3CH CDMA2000
–35
–15
5
–25
–5
RF INPUT POWER (dBm)
15
3
2
LINEARITY ERROR (dB)
1
0
–1
–2
–3
V
CC
IN
+
DEC
IN
–
FLTR
EN
LT5570
DNC
DNC
OUT
5570 TA01a
GND
5570 TA01b
5570f
1
LT5570
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
V
CC
IN
IN
+
Supply Voltage .........................................................5.5V
Enable Voltage .................................–0.3V to V
CC
+ 0.3V
Input Signal Power (Differential) ..........................15dBm
T
JMAX
.................................................................... 125°C
Operating Temperature Range.................. –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
CAUTION: This part is sensitive to electrostatic discharge. It
is very important that proper ESD precautions be observed
when handling the LT5570.
1
2
3
4
5
10 FLTR
9 EN
8 DNC
7 DNC
6 OUT
DEC
–
GND
DD PACKAGE
10-LEAD (3mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT5570IDD#PBF
TAPE AND REEL
LT5570IDD#TRPBF
PART MARKING
LCJQ
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, EN = 5V, unless otherwise noted. Test circuits are shown in
Figures 1 and 3. (Notes 2 and 3).
PARAMETER
AC Input
Input Frequency Range (Note 4)
Input Impedance
f
RF
= 500MHz
RF Input Power Range
Linear Dynamic Range (Note 5)
Output Slope
Logarithmic Intercept
Output Variation vs Temperature
Deviation from CW Response
2
nd
Order Harmonic Distortion
3
rd
Order Harmonic Distortion
Normalized to Output at 25°C
–40°C < T
A
< 85°C; P
IN
= –50dBm to 13dBm
11dB Peak to Average Ratio (3-Carrier CDMA2K)
12dB Peak to Average Ratio (4-Carrier WCDMA)
At RF Input; CW Input; P
IN
= 10dBm
At RF Input; CW Input; P
IN
= 10dBm
CW Input; 1:4 Balun Matched into 50Ω Source
±1dB Linearity Error, T
A
= –40°C to 85°C
–52 to 13
62
36.9
–54.8
±0.5
0.4
0.3
61
66
dBm
dB
mV/dB
dBm
dB
dB
dB
dBc
dBc
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
TYP
40 to 2700
200/1
MAX
UNITS
MHz
Ω/pF
5570f
2
LT5570
ELECTRICAL CHARACTERISTICS
PARAMETER
f
RF
= 880MHz
RF Input Power Range
Linear Dynamic Range (Note 5)
Output Slope
Logarithmic Intercept
Output Variation vs Temperature
Deviation from CW Response
2
nd
Order Harmonic Distortion
3
rd
Order Harmonic Distortion
f
RF
= 2140MHz
RF Input Power Range
Linear Dynamic Range (Note 5)
Output Slope
Logarithmic Intercept
Output Variation vs Temperature
Deviation from CW Response
f
RF
= 2700MHz
RF Input Power Range
Linear Dynamic Range (Note 5)
Output Slope
Logarithmic Intercept
Output Variation vs Temperature
Deviation from CW Response
Output
Output DC Voltage
Output Impedance
Sourcing/Sinking
Rise Time
Fall Time
0.2V to 1.6V, 10% to 90%, C1 = 22nF f
RF
= 2140MHz
,
1.6V to 0.2V, 90% to 10%, C1 = 22nF f
RF
= 2140MHz
,
No RF Signal Present
0.1
100
5/2.5
0.5
8
V
Ω
mA
μS
μS
Normalized to Output at 25°C
–40°C < T
A
< 85°C; P
IN
= –31dBm to 13dBm
11dB Peak to Average Ratio (3-Carrier CDMA2K)
12dB Peak to Average Ratio (4-Carrier WCDMA)
CW Input; 1:4 Balun Matched into 50Ω Source
±1dB Linearity Error, T
A
= –40°C to 85°C
–35 to 13
48
36.4
–38.5
±0.2
0.1
0.5
dBm
dB
mV/dB
dBm
dB
dB
Normalized to Output at 25°C
–40°C < T
A
< 85°C; P
IN
= –36dBm to 13dBm
11dB Peak to Average Ratio (3-Carrier CDMA2K)
12dB Peak to Average Ratio (4-Carrier WCDMA)
CW Input; 1:4 Balun Matched into 50Ω Source
±1dB Linearity Error, T
A
= –40°C to 85°C
47
34.8
–43.6
–38 to 13
51
36.5
–40.6
±0.3
0.1
0.2
39.0
–37.6
dBm
dB
mV/dB
dBm
dB
dB
dB
Normalized to Output at 25°C
–40°C < T
A
< 85°C; P
IN
= –47dBm to 13dBm
11dB Peak to Average Ratio (3-Carrier CDMA2K)
12dB Peak to Average Ratio (4-Carrier WCDMA)
At RF Input; CW Input; P
IN
= 10dBm
At RF Input; CW Input; P
IN
= 10dBm
CW Input; 1:4 Balun Matched into 50Ω Source
±1dB Linearity Error, T
A
= –40°C to 85°C
–48 to 13
61
37.7
–51.9
±0.4
0.3
0.2
60
61
dBm
dB
mV/dB
dBm
dB
dB
dBc
dBc
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, EN = 5V, unless otherwise noted. Test circuits are shown in
Figures 1 and 3. (Notes 2 and 3).
MIN
TYP
MAX
UNITS
5570f
3
LT5570
ELECTRICAL CHARACTERISTICS
PARAMETER
Enable (EN) Low = Off, High = On
EN Input High Voltage (On)
EN Input Low Voltage (Off)
Enable Pin Input Current
Turn ON Time
Turn OFF Time
Power Supply
Supply Voltage
Supply Current
Shutdown Current
EN = 0V, V
CC
= 5V
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, EN = 5V, unless otherwise noted. Test circuits are shown in
Figures 1 and 3. (Notes 2 and 3).
CONDITIONS
MIN
2
1
68
1
5
4.75
5
26.5
0.1
5.25
32.5
100
TYP
MAX
UNITS
V
V
μA
μs
μs
V
mA
μA
EN = 5V
V
OUT
within 10% of Final Value, C1 = 22nF
V
OUT
< 0.1V, C1 = 22nF
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Specifications over the –40ºC to +85ºC temperature range are
assured by design, characterization and correlation with statistical process
controls.
Note 3:
A 1:4 input transformer is used for the input matching to 50Ω
source.
Note 4:
Operation over a wider frequency range is possible with reduced
performance. Consult the factory for information and assistance.
Note 5:
The linearity error is calculated by the difference between the
incremental slope of the output and the average output slope from
–30dBm to 2dBm. The dynamic range is defined as the range over which
the linearity error is within ±1dB.
5570f
4
LT5570
TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage vs Frequency
2.4
2.0
1.6
V
OUT
(V)
1.2
0.8
0.4
0
–55 –45
500MHz
880MHz
2140MHz
2700MHz
–35 –25 –15 –5
RF INPUT POWER (dBm)
5
15
LINEARITY ERROR (dB)
T
A
= 25°C
3
2
1
0
–1
–2
–3
–55 –45
500MHz
880MHz
2140MHz
2700MHz
–35 –25 –15 –5
RF INPUT POWER (dBm)
5
15
(Test Circuits Shown in Figures 1 and 3)
Linearity Error vs Frequency
T
A
= 25°C
5570 G01
5570 G02
Output Voltage, Linearity Error vs
RF Input Power, 500MHz
2.4
2.0
1.6
V
OUT
(V)
1.2
0.8
0.4
0
–55 –45
T
A
= –40°C
T
A
= 25°C
T
A
= 85°C
–35 –25 –15 –5
RF INPUT POWER (dBm)
5
15
3
2
LINEARITY ERROR (dB)
LINEARITY ERROR (dB)
1
0
–1
–2
–3
3
2
1
0
–1
–2
Linearity Error vs RF Input Power,
500MHz Modulated Waveforms
T
A
= 25°C
–3
–55 –45
CW
4CH WCDMA
3CH CDMA2000
–35 –25 –15 –5
RF INPUT POWER (dBm)
5
15
5570 G03
5570 G04
Output Voltage, Linearity Error vs
RF Input Power, 880MHz
2.4
2.0
1.6
V
OUT
(V)
1.2
0.8
0.4
0
–55 –45
T
A
= –40°C
T
A
= 25°C
T
A
= 85°C
–35 –25 –15 –5
RF INPUT POWER (dBm)
5
15
3
2
1
0
–1
–2
–3
LINEARITY ERROR (dB)
LINEARITY ERROR (dB)
3
2
1
0
–1
–2
Linearity Error vs RF Input Power,
880MHz Modulated Waveforms
T
A
= 25°C
–3
–55 –45
CW
4CH WCDMA
3CH CDMA2000
–5
–35 –25 –15
RF INPUT POWER (dBm)
5
15
5570 G05
5570 G06
5570f
5
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