DC747A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747
LOG-LINEAR RF/IF DETECTOR
LT5537
DESCRIPTION
Demonstration circuit 747 is a log-linear RF/IF detector
featuring the LT®5537.
The LT5537 is a wide dynamic range RF/IF log detector, operational from below 10MHz to 1000MHz. The
lower limit of the operating frequency range can be
extended to near DC by the use of an external capacitor. The input dynamic range at 200MHz with ±3dB
nonlinearity is 90dB (from –76dBm to 14dBm, single-
ended 50Ω input). The detector output voltage slope
is normally 20mV/dB, and the typical temperature
coefficient is 0.01dB/°C at 200MHz.
Design files for this circuit board are available. Call
the LTC factory.
LTC is a trademark of Linear Technology Corporation
Table 1. Typical Performance Summary (VCC = 3V, ENBL = 3V, TA = 25°C, unless otherwise noted. Test circuit shown in Figure 1.)
PARAMETER
CONDITION
VALUE
Supply Voltage
2.7V to 5.25V
Supply Current
13.5mA
Shutdown Current
ENBL Voltage
ENBL Input Current
ENBL = Low
500µA
Low, Chip Disabled
0.3V max
High, Chip Enabled
1.0V min
VENBL = 0V
0µA
VENBL = 3V
100µA
RF/IF Input DC Common Mode Voltage
(VCC – 0.4) V
Small-Signal Impedance
Measured at 200MHz
1.73kΩ // 1.45pF
Output Start Voltage
No Input Signal Present
0.4V
Response Time
Input from –30dBm to 0dBm, CLOAD = 2.5pF
110ns
Baseband Modulation Bandwidth
Output Load Capacitance = 2.5pF
6MHz
Input Frequency Range
Operation at lower frequency is possible. See LT5537 datasheet.
10MHz to 1GHz
50Ω Termination
Maximum Input Power for
Monotonic Output
200MHz
14.0dBm
600MHz
11.6dBm
1GHz
9.4dBm
f = 10MHz
Linear Dynamic Range
±3dB Error
88.8dB
±1dB Error
72.5dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
19.6mV/dB
Intercept
VOUT = 0V, extrapolated
-97dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-76.7dBm
Temperature Coefficient
PIN = -20dBm
-0.007dB/°C
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747
LOG-LINEAR RF/IF DETECTOR
f = 100MHz
Linear Dynamic Range
±3dB Error
90.5dB
±1dB Error
82.8dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
20.3mV/dB
Intercept
VOUT = 0V, extrapolated
-95dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-77dBm
Temperature Coefficient
PIN = -20dBm
-0.004dB/°C
±3dB Error
90.3dB
±1dB Error
83.5dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
21.2mV/dB
Intercept
VOUT = 0V, extrapolated
-94dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-76.4dBm
Temperature Coefficient
PIN = -20dBm
0.010dB/°C
±3dB Error
88.2dB
f = 200MHz
Linear Dynamic Range
f = 400MHz
Linear Dynamic Range
±1dB Error
70.8dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
23.1mV/dB
Intercept
VOUT = 0V, extrapolated
-91dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-75.3dBm
Temperature Coefficient
PIN = -20dBm
0.019dB/°C
±3dB Error
85.8dB
±1dB Error
72.5dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
25.2mV/dB
Intercept
VOUT = 0V, extrapolated
-89dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-74.1dBm
Temperature Coefficient
PIN = -20dBm
0.026dB/°C
±3dB Error
63.5dB
f = 600MHz
Linear Dynamic Range
f = 1GHz
Linear Dynamic Range
±1dB Error
51.7dB
Slope
R1 = 33k (The output slope is adjustable using R1.)
31.4mV/dB
Intercept
VOUT = 0V, extrapolated
-80dBm
Sensitivity
Sensitivity can be improved by as much as 10dB by using a narrowband input matching network. See LT5537 datasheet.
-69.2dBm
Temperature Coefficient
PIN = -20dBm
0.031dB/°C
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747
LOG-LINEAR RF/IF DETECTOR
QUICK START PROCEDURE
Demonstration circuit 747 is easy to set up to evaluate the performance of the LT5537. Refer to Figure 1
for proper measurement equipment setup and follow
the procedure below:
5.
Connect signal generator’s output to demo board
INPUT port (SMA connector J1) via coaxial cable.
A 3dB attenuator may be inserted to improve input
match.
1.
Connect voltmeter’s negative (-) lead to demo
board GND test point (E4 or E5).
6.
2.
Connect voltmeter’s positive (+) lead to the demo
board OUTPUT test point (E2).
Using a jumper cable, connect demo board VCC test
point (E3) to ENBL test point (E1). Now the detector is enabled (on) and is ready for measurement.
3.
Connect DC power supply’s negative (-) output to
demo board GND test point (E4 or E5).
4.
Connect DC power supply’s positive (+) output
(2.7V to 5.25V) to demo board VCC test point (E3).
NOTE: Do
not exceed 5.5V, the absolute maximum
supply voltage.
NOTE: Make
sure that the power is not applied to
ENBL before it is applied to VCC. The voltages on
the ENBL test point must never exceed VCC + 0.2V.
7.
Apply RF input signal and measure OUTPUT DC
voltages.
NOTE: Do not exceed +22dBm, the absolute maximum RF input power.
Figure 1. Proper Measurement Equipment Setup
3
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747
LOG-LINEAR RF/IF DETECTOR
4
Similar pages