LT5538IDD-PBF [Linear]
40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range; 40MHz至3.8GHz的RF功率检波器与75分贝动态范围
| 型号： | LT5538IDD-PBF |
| 厂家： | 
Linear |
| 描述： | 40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range |
| 文件： | 总12页 (文件大小：233K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT5538
40MHz to 3.8GHz
RF Power Detector with
75dB Dynamic Range
FEATURES
DESCRIPTION
The LT®5538 is a 40MHz to 3800MHz monolithic logarith-
mic RF power detector, capable of measuring RF signals
over a wide dynamic range, from –75dBm to 10dBm. The
RF signal in an equivalent decibel-scaled value is precisely
convertedintoDCvoltageonalinearscale. Thewidelinear
dynamic range is achieved by measuring the RF signal us-
ing cascaded RF limiters and RF detectors. Their outputs
are summed to generate an accurate linear DC voltage
proportional to the input RF signal in dBm. The LT5538
delivers superior temperature stable output (within 1dB
over full temperature range) from 40MHz to 3.8GHz. The
output is buffered with a low impedance driver.
■
Frequency Range: 40MHz to 3.8GHz
■
75dB Log Linear Dynamic Range
■
Exceptional Accuracy over Temperature
■
Linear DC Output vs. Input Power in dBm
■
–72dBm Detection Sensitivity
■
Single-ended RF Input
■
Low Supply Current: 29mA
■
Supply Voltage: 3V to 5.25V
■
8-lead DFN 3mm × 3mm package
APPLICATIONS
■
Received Signal Strength Indication (RSSI)
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
RF Power Measurement and Control
■
RF/IF Power Detection
Receiver RF/IF Gain Control
Envelope Detection
ASK Receiver
■
■
■
TYPICAL APPLICATION
Output Voltage and Linearity Error
vs Input Power
40MHz - 3.8GHz Logarithmic RF Detector
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
V
= 5V AT 880 MHz
CC
LT5538
EN
V
OUT
ENBL
OUT
2
RF
INPUT
+
+
IN
CAP
–
–
1nF
1nF
IN
CAP
1
56
5V
GND
V
CC
0
5538 TA01
9
0.1μF
100pF
–1
–2
–3
T
T
T
= –40°C
= 25°C
= 85°C
A
A
A
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
5538 TA02
5538f
1
LT5538
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
TOP VIEW
Power Supply Voltage..............................................5.5V
Enable Voltage .....................................–0.3V, V + 0.3V
CC
ENBL
1
2
3
4
8
7
6
5
OUT
RF Input Power....................................................15dBm
Operating Ambient Temperature ............ –40°C to +85°C
Storage Temperature Range................. –65°C to +125°C
Maximum Junction Temperature........................... 150°C
+
+
IN
CAP
CAP
–
–
IN
GND
V
CC
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
= 43°C/W
θ
JA
EXPOSED PAD (PIN 9) SHOULD BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
8-Lead (3mm × 3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
LT5538IDD#PBF
LT5538IDD#TRPBF
LCVG
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 ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2)
SYMBOL
RF Input
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Frequency Range
DC Common Mode Voltage
Input Resistance
40 to 3800
MHz
V
V
CC
–0.5
394
Ω
f
= 40 MHZ
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–75 to 10
76
dBm
dB
1dB Linearity Error (Note 3)
(Note 5)
19.9
mV/dB
dBm
dBm
Logarithmic Intercept
Sensitivity
–87.5
–72
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
IN
P
IN
P
IN
= –50dBm; –40°C < T < 85°C
0.1/0.6
–0.1/0.6
–0.2/0.6
dB
dB
dB
A
A
= –30dBm; –40°C < T < 85°C
= –10dBm; –40°C < T < 85°C
A
5538f
2
LT5538
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
–62
–61
MAX
UNITS
dBc
2nd Order Harmonic Distortion
3rd Order Harmonic Distortion
Pin = –10dBm; At RF Input
Pin = –10dBm; At RF Input
dBc
f
= 450 MHz
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–75 to 10
75
dBm
dB
1 dB Linearity Error (Note 3)
(Note 5)
19.6
mV/dB
dBm
dBm
Logarithmic Intercept
Sensitivity
–87.3
–71.5
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
IN
P
IN
P
IN
= –50dBm; –40°C < T < 85°C
0.1/0.6
0.1/0.5
–0.1/0.5
dB
dB
dB
A
A
= –30dBm; –40°C < T < 85°C
= –10dBm; –40°C < T < 85°C
A
2nd Order Harmonic Distortion
3rd Order Harmonic Distortion
Pin = –10dBm; At RF Input
Pin = –10dBm; At RF Input
–43
–44
dBc
dBc
f
= 880 MHz
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–75 to 10
75
dBm
dB
1 dB Linearity Error (Note 3)
(Note 5)
19.0
mV/dB
dBm
dBm
Logarithmic Intercept
Sensitivity
–88.8
–71.5
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
IN
P
IN
P
IN
= –50dBm; –40°C < T < 85°C
0.1/0.7
0.1/0.4
0.1/0.4
dB
dB
dB
A
A
= –30dBm; –40°C < T < 85°C
= –10dBm; –40°C < T < 85°C
A
2nd Order Harmonic Distortion
3rd Order Harmonic Distortion
Pin = –10dBm; At RF Input
Pin = –10dBm; At RF Input
–37
–40
dBc
dBc
f
= 2140 MHz
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–72 to 10
70
dBm
dB
1 dB Linearity Error (Note 3)
(Note 5)
17.7
mV/dB
dBm
dBm
Logarithmic Intercept
Sensitivity
–89.0
–69.0
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
IN
P
IN
P
IN
= –50dBm; –40°C < T < 85°C
0.3/0.4
0.4/0.1
0.7/0.5
dB
dB
dB
A
A
= –30dBm; –40°C < T < 85°C
= –10dBm; –40°C < T < 85°C
A
f
= 2700 MHz
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–72 to 10
65
dBm
dB
1 dB Linearity Error (Note 3)
(Note 5)
17.6
mV/dB
dBm
Logarithmic Intercept
–87.5
5538f
3
LT5538
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Sensitivity
–69.5
dBm
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
IN
P
IN
P
IN
= –50dBm; –40°C < T < 85°C
0.3/0.3
0.7/–0.3
1.1/–0.9
dB
dB
dB
A
A
= –30dBm; –40°C < T < 85°C
= –10dBm; –40°C < T < 85°C
A
f
= 3600 MHz
RF
RF Input Power Range
Linear Dynamic Range
Output Slope
–65 to 10
57
dBm
dB
1 dB Linearity Error (Note 3)
(Note 5)
18
mV/dB
dBm
dBm
Logarithmic Intercept
Sensitivity
–81.4
–63
Output Variation vs Temperature
Normalized to Output at 25°C
●
●
●
P
P
P
= –45dBm; –40°C < T < 85°C
0.6/–0.3
0.9/–0.6
1.4/–1.2
dB
dB
dB
IN
IN
IN
A
A
= –25dBm; –40°C < T < 85°C
= –5dBm; –40°C < T < 85°C
A
Output Interface
Output DC Voltage
Output Impedance
Source Current
Sink Current
No RF Signal Present
0.350
150
10
V
Ω
mA
μA
ns
200
100
180
Rise Time
0.5V to 1.6V, 10% to 90%, f = 880 MHz
RF
Fall Time
1.6V to 0.5V, 10% to 90%, f = 880 MHz
ns
RF
Power Up/Down
●
●
ENBL = High (On)
ENBL = Low (Off)
ENBL Input Current
Turn ON time
1
3
V
V
0.3
VENBL = 5V
205
300
1
μA
ns
μs
Turn OFF Time
Power Supply
Supply Voltage
Supply Current
Shutdown Current
5.25
36
V
mA
μA
29
1
ENBL = Low
100
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.
to –20dBm. The dynamic range is defined as the range over which the
linearity error is within 1dB.
Note 4: Sensitivity is defined as the minimum input power required for the
linearity error within 3dB of the ideal log-linear transfer curve.
Note 2: Specifications over the –40°C to 85°C temperature range are
assured by design, characterization and correlation with statistical process
control.
Note 5: Logarithmic Intercept is an extrapolated input power level from the
best-fitted log-linear straight line, where the output voltage is 0V.
Note 3: The linearity error is calculated by the difference between the
incremental slope of the output and the average slope from –50dBm
5538f
4
LT5538
TYPICAL PERFORMANCE CHARACTERISTICS (Test Circuit shown in Figure 5)
Output Voltage, Linearity Error vs
Input Power at 40MHz
VOUT Variation vs Input Power at
40MHz
Supply Current vs Supply Voltage
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
3
2
40
35
30
25
20
15
10
V
CC
= 5V
V
CC
= 5V
NORMALIZED AT 25°C
2
1
1
0
0
–1
–2
–3
–1
–2
–3
T
T
T
= –40°C
= 25°C
= 85°C
T
T
T
= –40°C
= 25°C
= 85°C
A
A
A
A
A
A
T
T
= –40°C
= 85°C
A
A
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
2.5
3.5
4
4.5
5
5.5
3
SUPPLY VOLTAGE V (V)
CC
5538 G02
5538 G03
5538 G01
VOUT Variation vs Input Power at
450MHz
Output Voltage, Linearity Error vs
Input Power at 880MHz
Output Voltage, Linearity Error vs
Input Power at 450MHz
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
2
1
0
3
2
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
NORMALIZED AT 25°C
2
1
1
0
0
–1
–1
–2
–3
–1
–2
–3
T
T
T
= –40°C
= 25°C
= 85°C
T
T
T
= –40°C
= 25°C
= 85°C
–2
–3
A
A
A
A
A
A
T
T
= –40°C
= 85°C
A
A
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
–65
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
5538 G04
5538 G05
5538 G06
VOUT Variation vs Input Power at
2.14GHz
Output Voltage, Linearity Error vs
Input Power at 2.14GHz
VOUT Variation vs Input Power at
880MHz
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
3
2
3
2
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
NORMALIZED AT 25°C
NORMALIZED AT 25°C
2
1
1
1
0
0
0
–1
–2
–3
–1
–2
–3
–1
–2
–3
T
T
T
= –40°C
= 25°C
= 85°C
A
A
A
T
T
= –40°C
= 85°C
T
T
= –40°C
= 85°C
A
A
A
A
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
–75 –65
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–75 –65
5538 G08
5538 G09
5538 G07
5538f
5
LT5538
TYPICAL PERFORMANCE CHARACTERISTICS (Test Circuit shown in Figure 5)
Output Voltage, Linearity Error vs
Input Power at 2.7GHz
VOUT Variation vs Input Power at
2.7GHz
Output Voltage, Linearity Error vs
Input Power at 3.6GHz
1.8
1.5
1.2
0.9
0.6
0.3
0
3
3
2
1.8
1.5
1.2
0.9
0.6
0.3
0
3
V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
NORMALIZED AT 25°C
2
2
1
1
1
0
0
0
–1
–2
–3
–1
–2
–3
–1
–2
–3
T
T
T
= –40°C
= 25°C
= 85°C
T
T
T
= –40°C
= 25°C
= 85°C
A
A
A
A
A
A
T
T
= –40°C
= 85°C
A
A
–70
–50 –40 –30 –20 –10
INPUT POWER (dBm)
0
10
–60
–50 –40 –30 –20 –10
INPUT POWER (dBm)
0
10
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–70 –60
–65
5538 G10
5538 G11
5538 G12
VOUT Variation vs Input Power at
3.6GHz
Slope Distribution vs
Logarithmic Intercept Distribution
vs Temperature at 2.14GHz
Temperature at 2.14GHz
3
2
16
14
12
10
8
40
35
30
25
20
15
10
5
T
T
T
= –40°C
= 25°C
= 85°C
T
T
T
= –40°C
= 25°C
= 85°C
V
= 5V
A
A
A
A
A
A
CC
NORMALIZED AT 25°C
1
0
6
–1
–2
–3
4
2
T
T
= –40°C
= 85°C
A
A
0
0
–98 –96 –94 –92 –90 –88 –86 –84 –82 –80 –78
LOGARITHMIC INTERCEPT (dBm)
–50 –40 –30 –20 –10
INPUT POWER (dBm)
0
10
16 16.8 17.6 18.4 19.2 20 20.8
SLOPE (mV/dB)
–70 –60
5538 G15
5538 G13
5538 G14
Output Voltage, Linearity Error vs
VCC @40MHz
Output Voltage, Linearity Error vs
VCC @2140MHz
Output Voltage, Linearity Error vs
VCC @3600MHz
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
1.8
1.5
1.2
0.9
0.6
0.3
0
3
2.0
1.7
1.4
1.1
0.8
0.5
0.2
3
NORMALIZED AT 5V
V
CC
= 5V
NORMALIZED AT 5V
2
2
2
1
1
1
0
0
0
–1
–2
–3
–1
–2
–3
–1
–2
–3
V
CC
V
CC
= 5V
= 3V
V
CC
= 5V
= 3V
V
CC
V
CC
= 5V
= 3V
CC
V
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
–75
–55 –45 –35 –25 –15 –5
INPUT POWER (dBm)
5
–65
5538 G16
5538 G18
5538 G17
5538f
6
LT5538
PIN FUNCTIONS
ENBL (Pin 1): Enable Pin. An applied voltage above 1V will
activate the bias for the IC. For an applied voltage below
0.3V, the circuits will be shut down (disabled) with a cor-
respondingreductioninpowersupplycurrent.Iftheenable
function is not required, then this pin can be connected
This pin should be connected to ground with an external
ac-decoupling capacitor for low frequency operation.
GND (Pin 4, Exposed Pad Pin 9): Circuit Ground Return
for the entire IC. This pin must be soldered to the printed
circuit board ground plane.
to V . Typical enable pin input currents are 100ꢀA for
CC
V
(Pin 5): Power Supply Pin. This pin should be de-
EN = 3V and 200ꢀA for EN = 5V, respectively. Note that at
CC
coupled using 100pF and 0.1μF capacitors.
no time should the ENBL pin voltage be allowed to exceed
–
+
V
CC
by more than 0.3V.
CAP , CAP (Pins 6, 7): Optional Filter Capacitor Pins.
Thesepinsareinternallyconnectedtothedetectoroutputs
infrontoftheoutputbufferamplifier. Anexternallow-pass
filtering can be formed by connecting a capacitor to Vcc
from each pin for filtering a low frequency modulation sig-
nal. See the Applications Information section for detail.
+
IN (Pin 2): RF Input Pin. The pin is internally biased to
V
–0.5V and should be DC blocked externally. The input
CC
–
isconnectedviainternal394ΩresistortotheIN pinwhich
should be connected to ground with an ac-decoupling
capacitor.
–
OUT (Pin 8): Detector DC Output Pin.
IN (Pin 3): AC Ground Pin. The pin is internally biased to
V –0.5Vandcoupledtogroundviainternal20pFcapacitor.
CC
BLOCK DIAGRAM
5
1
V
CC
DC OFFSET CANCELLATION
ENBL
+
–
IN
2
3
RF LIMITER
RF LIMITER
RF LIMITER
RF LIMITER
RF LIMITER
IN
8
RF DETECTOR CELLS
OUT
4
9
6
7
5538 BD01
–
+
GND
CAP CAP
5538f
7
LT5538
APPLICATIONS INFORMATION
The LT5538 is a 40MHz to 3.8 GHz logarithmic RF power
detector. It consists of cascaded limiting amplifiers and
RF detectors. The output currents from every RF detector
are combined and low-pass filtered before applied to the
output buffer amplifier. As a result, the final DC output
voltageapproximatesthelogarithmoftheamplitudeofthe
input signal. The LT5538 is able to accurately measure an
RF signal over a 70dB dynamic range (–68dBm to 2dBm
at 2.1GHz) with 50Ω single-ended input impedance. The
slope of linear to log transfer function is about 17.7mV/dB
at 2.1GHz. Within the linear dynamic range, very stable
output is achieved over the full temperature range from
–40°C to 85°C and over the full operating frequency
range from 40MHz to 3.8GHz. The absolute variation over
temperature is typically within 1dB over 65dB dynamic
range at 2.1GHz.
matching elements are needed for a proper impedance
matching to a 50Ω source as shown in Figure 2. Refer to
Figure 6 for the circuit schematic of the input matching
network.TheinputimpedancevsfrequencyoftheRFinput
+
port IN is detailed in Table 1.
Table 1. RF Input Impedance
FREQUENCY
(MHz)
RF INPUT
IMPEDANCE (Ω)
S11
MAG
0.800
0.790
0.785
0.772
0.756
0.737
0.720
0.707
0.697
0.687
0.678
0.669
0.659
0.649
0.638
0.627
0.615
0.602
0.589
0.574
0.560
ANGLE(°)
38.5
40
47.3 + j129.7
246.6 + j210.7
408.7 – j37.8
192.9 – j190.9
105.6 – j158.4
69.3 – j127.4
51.8 – j106.2
41.5 – j90.9
34.2 – j78.7
29.2 – j60.0
25.4 – j60.7
22.6 – j53.8
20.5 – j47.7
18.9 – j42.4
17.9 – j37.6
17.1 – j33.4
16.4 – j29.5
16.1 – j26.0
15.9 – j22.8
15.9 – j20.0
15.9 – j17.5
100
11.5
200
–1.5
400
–14.9
–25.3
–34.4
–42.7
–50.6
–58.2
–65.6
–73.1
–80.4
–87.7
–94.6
–101.5
–108.2
–114.7
–121.0
–127.0
–132.8
–137.9
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
3800
RF INPUT
The simplified schematic of the input circuit is shown in
+
–
–
Figure 1. The IN and IN pins are internally biased to
CC
V
–0.5V. The IN pin is internally coupled to ground via
20pF capacitor. An external capacitor of 1nF is needed to
connect this pin to ground for low frequency operation.
+
–
The impedance between IN and IN is about 394Ω. The
+
RF input pin IN should be DC blocked when connected
to ground or other matching components. A 56Ω resistor
(R1) connected to ground will provide better than 10dB
input return loss over the operating frequency range up
to 1.5GHz. At higher operating frequency, additional LC
0
V
CC
–5
5.3k
394
5.3k
–10
–15
–20
–25
–30
+
–
IN
IN
W/O L1 AND C8
20p
+
–
L1 = 1.5nH, C8 = 1pF
C4, C11 = 12pF, C8 = 0.7pF
0
0.8 1.2 1.6
2
2.4 2.8 3.2 3.6 4.0
0.4
5538 F01
FREQUENCY (GHz)
5538 F02
Figure 1. Simplified Schematic of the Input Circuit
Figure 2. Input Return Loss with Additional LC Matching Network
5538f
8
LT5538
APPLICATIONS INFORMATION
OUTPUT INTERFACE
When the part is enabled, the output impedance is about
150Ω. When it is disabled, the output impedance is about
29.5kΩ referenced to ground.
The output interface of the LT5538 is shown in Figure 3.
This output buffer circuit can source 10mA current to the
load and sink 200 μA current from the load. The small-
signal output bandwidth is approximately 4MHz when the
output is resistively terminated or open. The full-scaled
10% to 90% rise and fall times are 100nS and 180nS,
respectively. The output transient responses at varied
input power levels are shown in Figure 4.
+
–
EXTERNAL FILTERING AT CAP , CAP
+
–
TheCAP andCAP PinsareinternallybiasedatV –0.36V
CC
via a 200Ω resistor from voltage supply V as shown in
CC
Figure 3. These two pins are connected to the differential
outputs of the internal RF detector cells. In combination
with the 20pF in parallel, a low-pass filter is formed with
–3dB corner frequency of 20MHz. The high frequency
rectified signals (particularly second-order harmonic of
the RF signal) from the detector cells are filtered and then
the DC output is amplified by the output buffer amplifier. In
some applications, the LT5538 may be used to measure a
modulatedRFsignalwithlowfrequencyAMcontent(lower
than 20MHz), a large modulation signal may be present
at these two pins due to insufficient low-pass filtering,
resulting in output voltage fluctuation at the LT5538’s
output. Its DC content may also vary depending upon the
modulation frequency. To assure stable DC output of the
LT5538, external capacitors C6 and C9 can be connected
V
CC
+
–
200
20p
200
100μA
C6
C9
OUT
+
–
CAP
CAP
150
+
–
+
–
OUTPUT CURRENTS
FROM RF DETECTORS
200μA
LT5538
5538 F03
+
–
from CAP and CAP to V to filter out this low frequency
CC
Figure 3. Simplified Schematic of the Output Interface
AM modulation signal. Assume the modulation frequency
of the RF signal is f
, the capacitor value in Farads of
MOD
C6 and C9 can be chosen by the following formula:
3.0
2.5
2.0
1.5
1.0
0.5
0
6
AT 880MHZ
RF PULSE ON
2
C6 (or C9) ≥ 10/(2π • 200 • f
)
MOD
RF PULSE OFF
RF PULSE OFF
–2
–6
–10
–14
–18
PIN = 0dBm
PIN = 10dBm
PIN = 20dBm
PIN = 30dBm
PIN = 40dBm
PIN = 50dBm
Do not connect these two filtering capacitors to ground
or any other low voltage reference at any time to avoid an
abnormal start-up condition.
0
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
TIME (μs)
0.2
5538 F04
Figure 4. Simplified Circuit Schematic of the Output Interface
5538f
9
LT5538
APPLICATIONS INFORMATION
ENBL (ENABLE) PIN OPERATION
μA. To disable or turn off the chip, this voltage should be
below 0.3V. It is important that the voltage applied to the
A simplified circuit schematic of the ENBL Pin is shown
in Figure 5. The enable voltage necessary to turn on the
LT5538 is 1V. The current drawn by the ENBL pin varies
with the voltage applied at the pin. When the ENBL volt-
age is 3V, the ENBL current is typically 100 μA. When the
ENBL voltage is 5V, the ENBL current is increased to 200
ENBL pin should never exceed V by more than 0.3V.
CC
Otherwise,thesupplycurrentmaybesourcedthroughthe
upper ESD protection diode connected at the ENBL pin.
Under no circumstances should voltage be applied to the
ENBL Pin before the supply voltage is applied to the V
pin. If this occurs, damage to the IC may result.
CC
V
CC
ENBL
42k
42k
5538 F05
Figure 5. Simplified Schematic of the Enable Circuit
TEST CIRCUIT
R4
ENABLE
LT5538
R5
O
4.99k
1
2
3
4
8
7
6
5
C4
V
OUT
ENBL
OUT
L1
C7
OPT
RF
INPUT
+
+
IN
CAP
1.5nH
C6
OPT
–
–
1nF
IN
CAP
R1
56Ω
C8
1pF
C5
1nF
C9
OPT
GND
V
CC
5V
5538 TC01
9
C10
100pF
C1
0.1μF
C2
100pF
Figure 6. Evaluation Board Circuit Schematic
3.6GHz to 3.8GHz
40MHz to 2.7GHz
REF DES
C1
VALUE
SIZE
PART NUMBER
REF DES
C4, C11
C8
VALUE
12pF
SIZE
PART NUMBER
0.1μF
100pF
1nF
0603
0402
0603
0402
0402
0402
0402
AVX 0603ZC104KAT
0402
0402
MURATA, GRM155C1H120JZ01B
MURATA, GJR155C1HR70BB01
C2, C10
C4, C5
C8
AVX 0402YC101KAT
0.7pF
OPEN
AVX 0402ZC102K
C5
1pF
AVX 0402YA1ROCAT
VISHAY, CRCW040256ROFKED
VISHAY, CRCW04024K99FKED
TOKO, LL1005-FH2IN5S
NOTE: Replace L with C
1
11.
R1
56
R4
4.99k
1.5nH
L1
5538f
10
LT5538
TEST CIRCUIT
5538 TC02
Figure 7. Component Side of Evalution Board
PACKAGE DESCRIPTION
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
R = 0.115
0.38 ± 0.10
TYP
5
8
0.675 ±0.05
3.5 ±0.05
2.15 ±0.05 (2 SIDES)
1.65 ±0.05
3.00 ±0.10
(4 SIDES)
1.65 ± 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
PACKAGE
OUTLINE
(DD8) DFN 1203
4
1
0.25 ± 0.05
0.75 ±0.05
0.200 REF
0.25 ± 0.05
0.50 BSC
0.50
BSC
2.38 ±0.05
(2 SIDES)
2.38 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
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 TOP AND BOTTOM OF PACKAGE
5538f
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.
11
LT5538
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
Infrastructure
LT5514
Ultralow Distortion, IF Amplifier/ADC Driver with Digitally 850MHz Bandwidth, 47 dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control
Controlled Gain Range
LT5515
LT5516
LT5517
LT5518
1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator 20dBm IIP3, Integrated LO Quadrature Generator
0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator 21.5dBm IIP3, Integrated LO Quadrature Generator
40MHz to 900MHz Quadrature Demodulator
21dBm IIP3, Integrated LO Quadrature Generator
1.5GHz to 2.4GHz High Linearity Direct Quadrature
Modulator
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
LT5524
0.7GHz to 1.4GHz High Linearity Upconverting Mixer
1.3GHz to 2.3GHz High Linearity Upconverting Mixer
10MHz to 3700MHz High Linearity Upconverting Mixer
17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω
Matching, Single-Ended LO and RF Ports Operation
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
600 MHz 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
Low Power, Low Distortion ADC Driver with Digitally
Programmable Gain
450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control
LT5525
LT5526
High Linearity, Low Power Downconverting Mixer
High Linearity, Low Power Downconverting Mixer
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
CC
= 28mA, –65dBm LO-RF Leakage
LT5527
LT5528
LT5557
400MHz to 3.7GHz High Signal Level Downconverting
Mixer
IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply,
= 78mA, Conversion Gain = 2dB
I
CC
1.5GHz to 2.4GHz High Linearity Direct Quadrature
Modulator
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
Ultra-Low Power Active Mixer
10mA Supply Current, 10dBm IIP3, 10dB NF, Usable as Up- or Down-Converter.
700MHz to 1050MHz High Linearity Direct Quadrature
Modulator
22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5V
DC
Baseband Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz
LT5572
LT5575
1.5GHz to 2.5GHz High Linearity Direct Quadrature
Modulator
21.6dBm OIP3 at 2GHz, –158.6dBm/Hz Noise Floor, High-Ohmic 0.5V
Baseband Interface, 4-Ch W-CDMA ACPR = –67.7dBc at 2.14GHz
DC
800MHz to 2.7GHz High Linearity Direct Conversion I/Q
Demodulator
50Ω, 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
RF Power Detectors
LTC®5505
LTC5507
LTC5508
LTC5509
LTC5530
LTC5531
LTC5532
LT5534
RF Power Detectors with >40dB Dynamic Range
300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply
100kHz to 1GHz, Temperature Compensated, 2.7 to 6V Supply
44dB Dynamic Range, Temperature Compensated, SC70 Package
36dB Dynamic Range, Low Power Consumption, SC70 Package
100kHz to 1000MHz RF Power Detector
300MHz to 7GHz RF Power Detector
300MHz to 3GHz RF Power Detector
300MHz to 7GHz Precision RF Power Detector
300MHz to 7GHz Precision RF Power Detector
300MHz to 7GHz Precision RF Power Detector
Precision V
Precision V
Precision V
Offset Control, Shutdown, Adjustable Gain
Offset Control, Shutdown, Adjustable Offset
Offset Control, Adjustable Gain and Offset
OUT
OUT
OUT
50MHz to 3GHz Log RF Power Detector with 60dB
Dynamic Range
1dB Output Variation over Temperature, 38ns Response Time, Log Linear
Response
LTC5536
Precision 600Mhz to 7GHz RF Power Detector with Fast
Comparator Output
25ns Response Time, Comparator Reference Input, Latch Enable Input,
–26dBm to +12dBm Input Range
LT5537
LT5570
Wide Dynamic Range Log RF/IF Detector
2.7GHz RMS Power Detector
Low Frequency to 1GHz, 83dB Log Linear Dynamic Range
Fast Responding, up to 60dB Dynamic Range, 0.3dB Accuracy Over
Temperature and Dynamic Range
5538f
LT 0408 • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
12
●
●
© LINEAR TECHNOLOGY CORPORATION 2008
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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