LT5581IDDB-PBF [Linear]
6GHz RMS Power Detector with 40dB Dynamic Range; 6GHz的RMS功率检波器与40分贝动态范围
| 型号： | LT5581IDDB-PBF |
| 厂家： | 
Linear |
| 描述： | 6GHz RMS Power Detector with 40dB Dynamic Range |
| 文件： | 总16页 (文件大小：495K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT5581
6GHz RMS Power Detector
with 40dB Dynamic Range
FEATURES
DESCRIPTION
The LT®5581 is a 10MHz to 6GHz, low power monolithic
precision RMS power detector. The RMS detector uses
a proprietary technique to accurately measure the RF
powerfrom–34dBmto+6dBm(at2.14GHz)ofmodulated
signals with a crest factor as high as 12dB. It outputs a DC
voltage in linear scale proportional to an RF input signal
power in dBm. The LT5581 is suitable for precision power
measurementandcontrolforawidevarietyofRFstandards,
including GSM/EDGE, CDMA, CDMA2000, W-CDMA, TD-
SCDMA, UMTS, LTE and WiMAX, etc. The final DC output
isconnectedinserieswithanon-chip300Ωresistor,which
enables further filtering of the output modulation ripple
with just a single off-chip capacitor.
n
Frequency Range: 10MHz to 6GHz
n
Accurate Power Measurement of High Crest Factor
(Up to 12dB) Waveforms
40dB Log Linear Dynamic Range
n
n
Exceptional Accuracy Over Temperature
n
Fast Response Time: 1μs Rise, 8μs Fall
n
Low Power: 1.4mA at 3.3V
n
Log-Linear DC Output vs Input RF Power in dBm
n
Small 3mm × 2mm 8-Pin DFN Package
Single-Ended RF Input
n
APPLICATIONS
n
GSM/EDGE, CMDA, CDMA2000, W-CDMA, LTE,
, 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 7342431.
WiMAX RF Power Control
n
Pico-Cells, Femto-Cells RF Power Control
Wireless Repeaters
CATV/DVB Transmitters
MIMO Wireless Access Points
Portable RMS Power Measurement Instrumentation
n
n
n
n
TYPICAL APPLICATION
10MHz to 6GHz Infrastructure Power
Amplifier Level Control
Linearity Error vs RF Input Power,
2140MHz Modulated Waveforms
DIRECTIONAL
COUPLER
3
2
POWER
AMP
T
= 25°C
A
RF
IN
RF
OUT
C
V
MATCH
CC
2.7V TO 5.25V
DC
DC
1
0
0.1μF
0.01μF
DIGITAL
50ꢀ
1
8
L
MATCH
C
V
POWER
SQ
CC
1000pF
CONTROL
2
7
RF
EN
IN
CW
WCDMA, UL
–1
LT5581
3
4
6
5
ADC
GND
WCDMA DL 1C
WCDMA DL 4C
LTE DL 1C
V
OUT
68ꢀ
–2
–3
GND GND GND
9
C
FILT
LTE DL 4C
0.01μF
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
5581 TA01a
5581 TA01b
5581f
1
LT5581
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Supply Voltage.........................................................5.5V
Maximum Input Signal Power—Average.............15dBm
Maximum Input Signal Power—Peak (Note 7) ....25dBm
TOP VIEW
V
1
2
3
4
8
7
6
5
C
SQ
CC
EN
RF
IN
DC Voltage at RF ....................................... –0.3V to 2V
9
IN
V
GND
GND
OUT
V
Voltage....................................–0.3V to V + 0.3V
OUT
CC
GND
Maximum Junction Temperature, T
............... 150°C
JMAX
Operating Temperature Range.................. –40°C to 85°C
DDB PACKAGE
8-LEAD (3mm s 2mm) PLASTIC DFN
= 150°C, θ = 76°C/W
Storage Temperature Range................... –65°C to 150°C
T
JMAX
JA
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
CAUTION:Thispartissensitivetoelectrostaticdischarge.It
isveryimportantthatproperESDprecautionsbeobserved
when handling the LT5581.
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
8-Lead (3mm × 2mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
LT5581IDDB#PBF
LT5581IDDB#TRPBF
LDKM
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C, VCC = 3.3V, EN = 3.3V, unless otherwise noted (Note 2). Test circuit is shown in Figure 1.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
AC Input
Input Frequency Range (Note 4)
Input Impedance
10-6000
205||1.6
MHz
ꢀ||pF
f
= 450MHz
RF
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–34 to 6
40
dBm
dB
Linear Dynamic Range, CW (Note 3)
Linear Dynamic Range, CDMA (Note 3)
Output Slope
1dB Linearity Errorꢁ CDMA 4-Carrier
40
dB
31
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
–42
1
Normalized to Output at 25˚C, –40°C < T < 85°Cꢁ
A
P
IN
= –34 to +6dBm
Output Variation vs Temperature
Deviation from CW Responseꢁ
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
IN
0.5
dB
A
P
= –27 to –10dBm
TETRA π/4 DQPSK
CDMA 4-Carrier 64-Channel Fwd 1.23Mcps
0.1
0.5
dB
dB
P
= –34dBm to 0dBm
IN
5581f
2
LT5581
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C, VCC = 3.3V, EN = 3.3V, unless otherwise noted (Note 2). Test circuit is shown in Figure 1.
PARAMETER
CONDITIONS
At RF Inputꢁ CW Inputꢁ P = 0dBm
MIN
TYP
–57
–52
MAX
UNITS
dBc
2nd Order Harmonic Distortion
3rd Order Harmonic Distortion
IN
At RF Inputꢁ CW Inputꢁ P = 0dBm
dBc
IN
f
RF
= 880MHz
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–34 to 6
40
dBm
dB
Linear Dynamic Range, CW (Note 3)
Linear Dynamic Range, EDGE (Note 3)
Output Slope
1dB Linearity Errorꢁ EDGE 3π/8-Shifted 8PSK
40
dB
31
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
–42
1
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
A
P
= –34 to +6dBm
IN
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
IN
0.5
0.1
dB
dB
A
P
= –27 to –10dBm
Deviation from CW Response, Pin = –34 to +6dBm EDGE 3π/8 Shifted 8PSK
= 2140MHz
f
RF
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–34 to 6
43
dBm
dB
Linear Dynamic Range, CW (Note 3)
Linear Dynamic Range, WCDMA (Note 3)
Output Slope
1dB Linearity Errorꢁ 4-Carrier WCDMA
37
dB
31
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
–42
1
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
A
P
= –34 to 6dBm
IN
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
IN
0.5
dB
A
P
= –27 to –10dBm
Maximum Deviation from CW Response
IN
WCDMA 1-Carrier Uplink
WCDMA 64-Channel 4-Carrier Downlink
0.1
0.5
dB
dB
P
= –34 to –4dBm
f
= 2600MHz
RF
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–34 to 6
dBm
dB
Linear Dynamic Range, CW (Note 3)
Output Slope
40
31
–42
1
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
A
P
= –34 to +6dBm
IN
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
IN
0.5
dB
A
P
= –27 to –10dBm
Maximum Deviation from CW Response
IN
WiMAX OFDMA Preamble
WiMAX OFDM Burst
0.1
0.5
dB
dB
P
= –34 to 2dBm
f
= 3500MHz
RF
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–30 to 6
dBm
dB
Linear Dynamic Range, CW (Note 3)
Output Slope
36
31
–41
1
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
A
P
= –30 to +6dBm
IN
5581f
3
LT5581
The l denotes the specifications which apply over the full operating temperature
ELECTRICAL CHARACTERISTICS
range, otherwise specifications are at TA = 25°C, VCC = 3.3V, EN = 3.3V, unless otherwise noted (Note 2). Test circuit is shown in Figure 1.
PARAMETER
CONDITIONS
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
MIN
TYP
MAX
UNITS
Output Variation vs Temperature
0.5
dB
A
P
= –27 to –10dBm
IN
Deviation from CW Response
IN
WiMAX OFDMA Preamble
WiMAX OFDM Burst
0.1
0.5
dB
dB
P
= –34 to –4dBm
f
= 5800MHz
RF
RF Input Power Range
Externally Matched to 50ꢀ Source
1dB Linearity Error
–25 to 6
dBm
dB
Linear Dynamic Range, CW (Note 3)
Output Slope
31
31
–33
1
mV/dB
dBm
dB
Logarithmic Intercept (Note 5)
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
A
P
= –25 to +6dBm
IN
Output Variation vs Temperature
Normalized to Output at 25°C, –40°C < T < 85°Cꢁ
IN
0.5
0.2
dB
dB
A
P
= –20 to +6dBm
Deviation from CW Response
Output
WiMAX OFDM Burstꢁ P = –25 to 6dBm
IN
Output DC Voltage
No Signal Applied to RF Input
180
300
5/5
1
mV
ꢀ
Output Impedance
Internal Series Resistor Allows for Off-Chip Filter Cap
Output Current Sourcing/Sinking
Rise Time
mA
μs
0.2V to 1.6V, 10% to 90%, f = 2140MHz
RF
Fall Time
1.6V to 0.2V, 10% to 90%, f = 2140MHz
8
μs
RF
Power Supply Rejection Ratio (Note 6)
Integrated Output Voltage Noise
Enable (EN) Low = Off, High = On
EN Input High Voltage (On)
EN Input Low Voltage (Off)
Enable Pin Input Current
Turn-On Timeꢁ CW RF input
Settling Timeꢁ RF Pulse
Power Supply
For Over Operating Input Power Range
49
dB
1kHz to 6.5kHz Integration BW, P = 0dBm CW
150
μV
RMS
IN
l
l
2
V
V
0.3
EN = 3.3V
20
1
μA
μs
μs
V
Within 10% of Final Valueꢁ P = 0dBm
IN
OUT
OUT
V
Within 10% of Final Valueꢁ P = 0dBm
1
IN
l
Supply Voltage
2.7
3.3
1.4
0.2
5.25
6
V
mA
μA
Supply Current
No RF Input Signal
EN = 0.3V, V = 3.3V
Shutdown Current
CC
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 4: An external capacitor at the C pin should be used for input
frequencies below 250MHz. Lower frequency operation results in
excessive RF ripple in the output voltage.
SQ
Note 5: Logarithmic intercept is an extrapolated input power level from the
Note 2: The LT5581 is guaranteed to meet specified performance from
best fitted log-linear straight line, where the output voltage is 0V.
–40°C to 85°C.
Note 6: PSRR is determined as the dB value of the change in V
voltage
OUT
Note 3: The linearity error is calculated by the difference between the
incremental slope of the output and the average output slope from
–20dBm to 0dBm. The dynamic range is defined as the range over which
the linearity error is within 1dB.
over the change in V supply voltage.
Note 7: Not production tested. Guaranteed by design and correlation to
production tested parameters.
CC
5581f
4
LT5581
TYPICAL PERFORMANCE CHARACTERISTICS
Performance characteristics taken at VCC = 3.3V,
EN = 3.3V and TA = 25°C, unless otherwise noted. (Test circuit shown in Figure 1)
Output Voltage vs Frequency
Output Voltage vs Frequency
Linearity Error vs Frequency
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
3
T
= 25°C
T
= 25°C
T = 25°C
A
A
A
10MHz
880MHz
2
450MHz
880MHz
2.14GHz
2.6GHz
3.5GHz
5.8GHz
2.14GHz
2.6GHz
3.5GHz
1
0
10MHz
450MHz
880MHz
2.14GHz
2.6GHz
3.5GHz
5.8GHz
–1
–2
–3
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–40
–35
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–35
5581 G01
5581 G02
5581 G03
Output Voltage and Linearity Error
at 450MHz
Linearity Error Temperature
Linearity Error vs RF Input Power,
450MHz Modulated Waveforms
Variation from 25°C at 450MHz
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
3
2
3
T
= 25°C
25°C
A
2.0
85°C
CW
TETRA
CDMA 4C
2
–40°C
1.5
1.0
85°C
1
1
0
0.5
0
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
–1
–1
–2
–3
–2
–3
5
10
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
–35
–35
–35
5581 G05
5581 G06
5581 G04
Linearity Error Temperature
Variation from 25°C at 880MHz
Linearity Error vs RF Input Power,
880MHz Modulated Waveforms
Output Voltage and Linearity Error
at 880MHz
3
2
3
2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
T
= 25°C
25°C
A
2.0
85°C
CW
EDGE
–40°C
1.5
1.0
85°C
1
0
1
0
0.5
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
–1
–1
–2
–3
–2
–3
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–35
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
5581 G08
5581 G09
5581 G07
5581f
5
LT5581
TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage and Linearity Error
at 2140MHz
Linearity Error Temperature
Linearity Error vs RF Input Power,
2140MHz Modulated Waveforms
Variation from 25°C at 2140MHz
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
3
2
3
2
T
= 25°C
25°C
A
2.0
85°C
–40°C
1.5
1.0
85°C
1
0
1
0
0.5
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
CW
WCDMA, UL
–1
–1
WCDMA DL 1C
WCDMA DL 4C
LTE DL 1C
–2
–3
–2
–3
LTE DL 4C
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–20
5
10
–35
–40
–30 –25
–15 –10 –5
0
–35
RF INPUT POWER (dBm)
5581 G10
5581 G12
5581 G11
Output Voltage and Linearity Error
at 2600MHz
Linearity Error Temperature
Linearity Error vs RF Input Power,
2.6GHz Modulated Waveforms
Variation from 25°C at 2600MHz
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
3
2
3
2
25°C
T
= 25°C
A
2.0
85°C
–40°C
1.5
1.0
85°C
1
0
1
0
0.5
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
–1
–1
CW
–2
–3
–2
–3
WiMax OFDM PREAMBLE
WiMax OFDM BURST
WiMax OFDMA PREAMBLE
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–35
–20
5
10
–30 –25
–15 –10 –5
0
–35
RF INPUT POWER (dBm)
5581 G13
5581 G14
5581 G15
Linearity Error Temperature
Variation from 25°C at 3500MHz
Linearity Error vs RF Input Power,
3.5GHz Modulated Waveforms
Output Voltage and Linearity Error
at 3500MHz
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
3
2
3
2
T
= 25°C
25°C
A
2.0
85°C
–40°C
1.5
1.0
85°C
1
0
1
0
0.5
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
–1
–1
CW
WiMax OFDMA PREAMBLE
WiMax OFDM BURST
–2
–3
–2
–3
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–20
5
10
–35
–40
–30 –25
–15 –10 –5
0
–35
RF INPUT POWER (dBm)
5581 G16
5581 G18
5581 G17
5581f
6
LT5581
TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage and Linearity Error
at 5800MHz
Linearity Error Temperature
Linearity Error vs RF Input Power,
5.8GHz Modulated Waveforms
Variation from 25°C at 5800MHz
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
3
2
3
2
T
= 25°C
25°C
A
2.0
85°C
–40°C
1.5
1.0
1
0
1
0
85°C
0.5
0
–40°C
–0.5
–1.0
–1.5
–2.0
–2.5
–1
–1
–2
–3
–2
–3
CW
WiMax OFDM BURST
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–40
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–35
–35
–35
5581 G19
5581 G20
5581 G21
Slope vs Frequency
Supply Current vs Supply Voltage
Slope Distribution vs Temperature
2.0
1.8
1.6
1.4
1.2
1.0
0.8
50
40
30
34
32
30
28
26
T
T
T
= –40°C
= 25°C
= 85°C
T
= 25°C
A
A
A
A
85°C
25°C
–40°C
20
10
0
3.4 3.8 4.2 4.6
SUPPLY VOLTAGE (V)
5
5.4
2.6
3
0
1
2
3
4
5
6
28
29
30
31
32
33
34
FREQUENCY (GHz)
SLOPE (mV/dB)
5581 G23
5581 G24
5581 G22
Logarithmic Intercept
vs Frequency
Logarithmic Intercept Distribution
vs Temperature
50
40
30
–30
–35
–40
–45
–50
T
T
T
= –40°C
= 25°C
= 85°C
T
= 25°C
A
A
A
A
20
10
0
–48 –47 –46 –45 –44 –43 –42 –41
0
1
2
3
4
5
6
FREQUENCY (GHz)
LOGARITHMIC INTERCEPT (dBm)
5581 G26
5581 G25
5581f
7
LT5581
TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage and Linearity Error
vs VCC at 2140MHz
Supply Current vs RF Input Power
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5
16
14
12
10
8
T
= 25°C
T
= 25°C
A
A
2.0
3.3V
5V
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
6
4
2
0
–40
–35
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
0
5
10
–25 –20
–10 –5
0
5
10 15
–15
RF INPUT POWER (dBm)
5581 G28
5581 G27
Output Transient Response with
RF and EN Pulse
Return Loss vs Frequency
Reference in Figure 1 Test Circuit
0
–5
3.0
2.5
10
5
T
= 25°C, V = 5V
CC
T
= 25°C
A
A
RF&EN
PULSE
OFF
RF&EN
PULSE
OFF
RF & EN PULSE ON
2.0
0
–10
–15
–20
–25
–30
P
= 10dBm
= 0dBm
IN
P
1.5
1.0
0.5
0
–5
IN
P
= –10dBm
IN
–10
–15
–20
P
P
= –20dBm
= –30dBm
IN
IN
–0.5
–25
0
2
3
4
5
6
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
TIME (ms)
1
1
FREQUENCY (GHz)
5581 G30
L1, C1 = 2.2nH, 1.5pF
L1, C1 = 1nH, 1.5pF
L1, C1 = 0nH, 1pF
L1, C1 = 0nH, 0.5pF
L1, C1 = 0nH, 0pF
5581 G29
Output Transient Response with
CW RF and EN Pulse
Output Transient Response
3.0
2.5
4
2
3.0
2.5
2.0
1.5
1.0
0.5
0
10
5
T
= 25°C
T
= 25°C, V = 5V
CC
A
A
EN PULSE ON
RF PULSE ON
EN
PULSE
OFF
EN
PULSE
OFF
RF
RF
PULSE
OFF
PULSE
OFF
2.0
0
0
P
= 10dBm
= 0dBm
IN
1.5
1.0
0.5
0
–2
–4
–6
–8
P
= 10dBm
= 0dBm
IN
P
IN
–5
–10
–15
–20
P
P
= –10dBm
= –20dBm
= –30dBm
IN
IN
IN
IN
P
P
P
= –10dBm
IN
P
P
= –20dBm
= –30dBm
IN
IN
–0.5
–10
0.2 0.3 0.4 0.5 0.6
TIME (ms)
1
0
0.1
0.7 0.8 0.9
20 30 40 50 60
TIME (μs)
100
0
10
70 80 90
5581 G32
5581 G31
5581f
8
LT5581
PIN FUNCTIONS
V
(Pin 1): Power Supply, 2.7V to 5.25V. V
C (Pin 8): Optional Low Frequency Range Extension
SQ
Capacitor. This pin is for frequencies below 250MHz. Use
0.01μF from pin to ground for 10MHz operation.
CC
CC
should be bypassed with a 0.1μF ceramic capacitor.
EN (Pin 2): Chip Enable. A logic low or no-connect on the
enable pin shuts down the part. A logic high enables the
part.Aninternal500kpull-downresistorensuresthepartis
off when the enable driver is in a three-state condition.
Exposed Pad (Pin 9): Ground. The Exposed Pad must
be soldered to the PCB. For high frequency oper-
ation, the backside ground connection should have a low
inductance connection to the PCB ground, using many
through-hole vias. See the layout information in the Ap-
plications Information section.
V
(Pin 3): Detector Output.
OUT
GND (Pins 4, 5, 6): Ground.
RF (Pin7):RFInput.ShouldbeDC-blockedwithcoupling
IN
capacitorꢁ 1000pF recommended. This pin has an internal
200ꢀ termination.
BLOCK DIAGRAM
9
LT5581
EXPOSED
PAD
OUTPUT
BUFFER
150kHz LPF
300ꢀ
RF
V
OUT
IN
RMS
DETECTOR
7
3
BIAS
EN
GND
C
V
CC
SQ
8
2
1
4
5
6
5581 BD
5581f
9
LT5581
TEST CIRCUIT
C7
0.1μF
V
CC
C6
100pF
C3
0.01μF
1
8
7
6
5
EN
C
V
SQ
CC
C5
OPT
C2
1000pF
L1
2.2nH
RF
IN
2
3
4
RF
EN
IN
LT5581
R3
0ꢀ
C1
1.5pF
R2
68ꢀ
V
OUT
NC
NC
GND
V
OUT
C4
OPT
NC
GND GND GND
9
PINS 4, 5, 6: OPTIONAL GROUND
5581 F01
RF
GND
0.018" EE = 4.4
0.018"
0.062"
DC
GND
REF DES
C6
VALUE
SIZE
0603
0603
0603
0603
0603
PART NUMBER
RF MATCH
IN
FREQUENCY
RANGE
L1
C1
1.5pF
1.5pF
1pF
100pF
0.1μF
AVX 06033A101KAT2A
AVX 06033C104KAT2A
AVX 06033C103KAT2A
AVX 06033C102KAT2A
1GHz to 2.2GHz
2GHz to 2.6GHz
2.6GHz to 3.4GHz
3.8GHz to 5.5GHz
4.6GHz to 6GHz
2.2nH
C7
1.2nH
C3
0.01μF
1000pF
68ꢀ
0
0
0
C2
0.5pF
0
R2
Figure 1. Evaluation Circuit Schematic
5581f
10
LT5581
APPLICATIONS INFORMATION
OPERATION
Table 1. RF Input Impedance
INPUT
S11
To achieve an accurate average power measurement of
the high crest factor modulated RF signals, the LT5581
combines a proprietary high speed power measurement
subsystem with an internal 150kHz low pass averag-
ing filter and an output voltage buffer in a completely
integrated solution with minimal off-chip components.
The resulting output voltage is directly proportional to
the average RF input power in dBm. Figure 1 shows the
evaluation circuit schematic, and Figures 2 and 3 show
the associated board artwork. For best high frequency
performance, it is important to place many ground vias
directly under the package.
FREQUENCY
(MHz)
IMPEDANCE
(Ω)
MAG
0.606
0.603
0.601
0.601
0.608
0.613
0.631
0.638
0.645
0.679
0.710
0.716
0.737
0.759
0.774
0.783
0.709
0.774
ANGLE (°)
–0.8
10
203.6-j5.5
199.5-j22.4
191.7-j40.3
171.1-j68.5
121.8-j95.4
100.2-j97.5
56.8-j86.5
48-j81.2
50
–3.4
100
–6.4
200
–12.3
–24
400
500
–29.8
–46.5
–51.8
–56.8
–79.5
–97.9
–101.2
–112.9
–125.7
–136.9
–147.1
–157.6
–179.9
800
900
1000
1500
2000
2100
2500
3000
3500
4000
5000
6000
41.1-j76
22.2-j55
RF Input Matching
14.6-j41.4
13.6-j39.2
10.8-j32.1
8.6-j25
The input resistance is about 205ꢀ. Input capacitance
is 1.6pF. The impedance vs frequency of the RF input is
detailed in Table 1.
7.3-j19.4
6.6-j14.5
8.8-j9.6
6.4-j0
5581 F02
5581 F03
Figure 2. Top Side of Evaluation Board
Figure 3. Bottom Side of Evaluation Board
5581f
11
LT5581
APPLICATIONS INFORMATION
A shunt 68ꢀ resistor can be used to provide a broadband
impedance match at low frequencies up to 1.3GHz, and
from 4.5GHz to 6GHz. As shown in Figure 4, a nominal
broadband input match can be achieved up to 2.2GHz by
using an LC matching circuit consisting of a series 2.2nH
inductor (L1) and a shunt 1.5pF capacitor (C1). This
match will maintain a return loss of about 10dB across
the band. For matching at higher frequencies, values for
L1 and C1 are listed in the table of Figure 1. The input
reflection coefficient referenced to the RF input pin (with
no external components) is shown on the Smith Chart
in Figure 5. Alternatively, it is possible to match using
an impedance transformation network by omitting R1
and transforming the 205ꢀ load to 50ꢀ. The resulting
match, over a narrow band of frequencies, will improve
sensitivity up to about 6dB maximumꢁ the dynamic range
remains the same. For example, by omitting R1 and set-
ting L1 = 1.8nH and C1 = 3pF, a 2:1 VSWR match can
be obtained from 1.95GHz to 2.36GHz, with a sensitivity
improvement of 5dB.
frequencyoperation.Forinputfrequenciesdownto10MHz,
0.01μF is needed at C . For frequencies above 250MHz,
SQ
the on-chip 20pF decoupling capacitor is sufficient, and
C
SQ
may be eliminated as desired. The DC-blocking ca-
pacitor can be as large as 2200pF for 10MHz operation, or
100pF for 2GHz operation. A DC-blocking capacitor larger
than 2200pF results in an undesirable RF pulse response
on the falling edge. Therefore, for general applications,
the recommended value for C2, is conservatively set at
1000pF.
Output Interface
The output buffer of the LT5581 is shown in Figure 6. It
includes a push-pull stage with a series 300ꢀ resistor.
The output stage is capable of sourcing and sinking 5mA
of current. The output pin can be shorted to GND or V
CC
without damage, but going beyond V + 0.5V or GND
CC
–0.5Vmayresultindamage,astheinternalESDprotection
diodes will start to conduct excessive current.
The residual ripple, due to RF modulation, can be reduced
The RF input DC blocking capacitor (C2) and the C
by adding external components R and C
(R3 and
IN
SQ
SS
LOAD
bias decoupling capacitor (C3), can be adjusted for low
C4 on the Evaluation Circuit Schematic in Figure 1) to
V
LT5581
CC
C3
0.01μF
C
SQ
8
7
20pF
205ꢀ
RF
C2
1000pF
IN
(MATCHED)
L1
RF
IN
R1
68ꢀ
C1
5581 F04
Figure 4. Simplified Circuit Schematic of the RF Input Interface
Figure 5. Input Reflection Coefficient
5581f
12
LT5581
APPLICATIONS INFORMATION
the output pin, to form an RC lowpass filter. The internal
of 3, using a 0.047μF external filter capacitor. The aver-
age power in the preamble section is –10dBm, while the
burst section has a 3dB lower average power. With the
capacitor, therippleinthepreamblesectionisabout0.5dB
peak-to-peak. The modulation used was OFDM (WiMAX
802.16-2004) MMDS band, 1.5MHz BW, with 256 size FFT
300ꢀ resistor in series with the output pin enables filter-
ing of the output signal with just the addition of C
.
LOAD
Figure 7 shows the effect of the external filter capacitor
on the residual ripple level for a 4-carrier WCDMA signal
at 2.14GHz with –10dBm. Adding a 10nF capacitor to the
output decreases the peak-to-peak output ripple from
3
and 1 burst at QPSK /4.
135mV to 50mV . The filter –3dB corner frequency
P-P
P-P
Figure9showshowthepeak-to-peakrippledecreaseswith
increasing external filter capacitance value. Also shown is
how the RF pulse response will have longer rise and fall
times with the addition of this lowpass filter cap.
can be calculated with the following equation:
1
fC =
2π CLOAD(300 + RSS)
Figure8showsthetransientresponsefora2.6GHzWiMAX
signal, with preamble and burst ripple reduced by a factor
1.4
1.2
1.25
1.20
T
= 25°C
A
LT5581
INPUT
V
CC
NO CAP
0.01μF
1.0
1.15
40μA
0.8
0.6
0.4
0.2
1.10
1.05
1.00
0.95
V
OUT
300ꢀ
R
SS
V
3
OUT
(FILTERED)
C
LOAD
0
0.90
20 30 40 50 60
TIME (μs)
100
70 80 90
0
10
5581 F07
Figure 6. Simplified Circuit Schematic of the Output Interface
Figure 7. Residual Ripple, Output Transient Response
for RF Pulse with WCDMA 4-Carrier Modulation
9
8
7
6
5
4
3
2
1
1000
100
10
1.4
RIPPLE
RISE
FALL
T
= 25°C
T
= 25°C
A
NO CAP
0.047μF
A
1.2
1.0
0.8
0.6
0.4
0.2
0
1
0
0.01
0.1
1
0.001
0.4 0.6 0.8
1
1.2
2
0
0.2
1.4 1.6 1.8
EXTERNAL CAPACITOR (μF)
TIME (ms)
5581 F09
5581 F08
Figure 8. Residual Ripple for 2.6GHz WiMAX OFDM 802.16-2004
Figure 9. Residual Ripple, Output Transient Times for RF Pulse
with WCDMA 4-Carrier Modulation vs External Filter Capacitor C4
5581f
13
LT5581
APPLICATIONS INFORMATION
Figure 10 shows that rise time and fall time are strong
functions of RF input power. Data is taken without the
output filter capacitor.
peak envelope, divided by the total number of periodic
measurements in the measurement period). It is impor-
tant to note that the CF refers to the 150kHz low pass
filtered envelope of the signal. The error will depend on
the statistics and bandwidth of the modulation signal in
relation to the internal 150kHz filter. For example, in the
case of WCDMA, simulations prove that it is possible to
set the external filter capacitor corner frequency at 15kHz
and only introduce an error less than 0.1dB.
For a given RF modulation type—WCDMA, for exam-
ple—the internal 150kHz filter provides nominal filtering
of the residual ripple level. Additional external filtering
occurs in the log domain, which introduces a systematic
log error in relation to the signal’s crest factor, as shown
1
in the following equation in dB.
Figure 11 depicts the output AM modulation ripple as a
function of modulation difference frequency for a 2-tone
input signal at 2140MHz with –10dBm input power. The
–CF/10
Error|dB = 10 • log (r + (1 – r)10
) – CF • (r-1)
10
Where CF is the crest factor and r is the duty cycle of the
measurement (or number of measurements made at the
1
Steve Murray, “Beware of Spectrum Analyzer Power Averaging Techniques,” Microwaves
& RF, Dec. 2006.
9
30
25
20
15
10
5
0
T
= 25°C
A
T
= 25°C
A
8
7
6
5
4
3
2
1
0
FALL TIME
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
RISE TIME
0
–20 –15 –10 –5
INPUT POWER (dBm)
0
5
–30 –25
0.01
0.1
10
0.001
1
2-TONE FREQUENCY SEPARATION (MHz)
5581 F10
5581 F11
Figure 10. RF Pulse Response Rise Time
and Fall Time vs RF Input Power
Figure 11. Output DC Voltage Deviation and Residual
Ripple vs 2-Tone Separation Frequency
2.0
4.0
T
= 25°C
T
= 25°C
A
A
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0dBm
–10dBm
–20dBm
–30dBm
NO RF INPUT
0dBm
–10dBm
–20dBm
–30dBm
NO RF INPUT
0.1
10
FREQUENCY (kHz)
100
1000
1
0.1
10
FREQUENCY (kHz)
100
1000
1
5581 F13
5581 F12
Figure 12. Output Voltage Noise Density
Figure 13. Integrated Output Voltage Noise
5581f
14
LT5581
APPLICATIONS INFORMATION
resulting deviation in the output voltage of the detector
shows the effect of the internal 150kHz filter.
It is important that the voltage applied to the EN pin never
exceeds V by more than 0.5V, otherwise, the supply
CC
current may be sourced through the upper ESD protection
diode connected at the EN pin.
The output voltage noise density and integrated noise are
showninFigures12and13, respectively, forvariousinput
powerlevels.Noiseisastrongfunctionofinputlevel.There
is roughly a 10dB reduction in the output noise level for
an input level of 0dBm versus no input.
V
LT5581
EN
CC
2
Enable Pin
500k
300k
300k
A simplified schematic of the EN pin is shown in Figure
14. To enable the LT5581, it is necessary to put greater
than 1V on this pin. To disable or turn off the chip, this
voltage should be below 0.3V. At an enable voltage of
3.3V, the pin draws roughly 20μA. If the EN pin is not
connected, the chip is disabled through an internal 500k
pull-down resistor.
5581 F14
Figure 14. Enable Pin Simplified Schematic
PACKAGE DESCRIPTION
DDB Package
8-Lead Plastic DFN (3mm × 2mm)
(Reference LTC DWG # 05-08-1702 Rev B)
0.61 ±0.05
(2 SIDES)
R = 0.115
0.40 ± 0.10
3.00 ±0.10
(2 SIDES)
TYP
5
R = 0.05
TYP
8
0.70 ±0.05
2.55 ±0.05
1.15 ±0.05
2.00 ±0.10
PIN 1 BAR
TOP MARK
PIN 1
(2 SIDES)
R = 0.20 OR
(SEE NOTE 6)
0.25 × 45°
PACKAGE
OUTLINE
0.56 ± 0.05
(2 SIDES)
CHAMFER
4
1
(DDB8) DFN 0905 REV B
0.25 ± 0.05
0.25 ± 0.05
0.75 ±0.05
0.200 REF
0.50 BSC
2.20 ±0.05
(2 SIDES)
0.50 BSC
2.15 ±0.05
(2 SIDES)
0 – 0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
5581f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT5581
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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OUT
OUT
OUT
LT5534
50MHz to 3GHz Log RF Power Detector with
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Precision 600MHz to 7GHz RF Power Detector 25ns Response Time, Comparator Reference Input, Latch Enable Input,
with Fast Comparator Output
–26dBm to +12dBm Input Range
LT5537
LT5538
Wide Dynamic Range Log RF/IF Detector
75dB Dynamic Range 3.8GHz Log RF Power
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Low Frequency to 1GHz, 83dB Log Linear Dynamic Range
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LT5570
60dB Dynamic Range RMS Detector
40MHz to 2.7GHz, 0.5dB Accuracy Over Temperature
Infrastructure
LT5514
Ultralow Distortion, IF Amplifier/ADC Driver
with Digitally Controlled Gain
40MHz to 900MHz Quadrature Demodulator
1.5GHz to 2.4GHz High Linearity Direct
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850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range
21dBm IIP3, Integrated LO Quadrature Generator
LT5517
LT5518
22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended RF and LO
Ports, 4-Channel W-CDMA ACPR = –64dBc at 2.14GHz
LT5519
LT5520
LT5521
LT5522
LT5525
LT5526
LT5527
LT5528
LT5557
0.7GHz to 1.4GHz High Linearity Upconverting
Mixer
17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω Matching,
Single-Ended LO and RF Ports Operation
1.3GHz to 2.3GHz High Linearity Upconverting
Mixer
15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω Matching,
Single-Ended LO and RF Ports Operation
24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO
Port Operation
10MHz to 3700MHz High Linearity
Upconverting Mixer
600MHz to 2.7GHz High Signal Level
Downconverting Mixer
4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF
and LO Ports
High Linearity, Low Power Downconverting
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High Linearity, Low Power Downconverting
Mixer
400MHz to 3.7GHz High Signal Level
Downconverting Mixer
1.5GHz to 2.4GHz High Linearity Direct
Quadrature Modulator
Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, I = 28mA
CC
3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, I = 28mA,
CC
–65dBm LO-RF Leakage
IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, I = 78mA,
CC
Conversion Gain = 2dB
21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5V Baseband
DC
Interface, 4-Channel W-CDMA ACPR = –66dBc at 2.14GHz
400MHz to 3.8GHz, 3.3V High Signal Level
Downconverting Mixer
IIP3 = 23.7dBm at 2600MHz, 23.5dBm at 3600MHz, I = 82mA at 3.3V
CC
LT5560
LT5568
Ultralow Power Active Mixer
700MHz to 1050MHz High Linearity Direct
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10mA Supply Current, 10dBm IIP3, 10dB NF, Usable as Up- or Down-Converter.
22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5V Baseband
DC
Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz
LT5572
LT5575
1.5GHz to 2.5GHz High Linearity Direct
Quadrature Modulator
800MHz to 2.7GHz High Linearity Direct
Conversion I/Q Demodulator
21.6dBm OIP3 at 2GHz, –158.6dBm/Hz Noise Floor, High-Ohmic 0.5V Baseband
DC
Interface, 4-Ch W-CDMA ACPR = –67.7dBc at 2.14GHz
50ꢀ, Single-Ended RF and LO Inputs. 28dBm IIP3 at 900MHz, 13.2dBm P1dB,
0.04dB I/Q Gain Mismatch, 0.4° I/Q Phase Mismatch
5581f
LT 0708 • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
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●
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