DC1077A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A
MEAN-SQUARED RF/IF DETECTOR
LT5570
DESCRIPTION
Demonstration circuit 1077A is a Mean-Squared RF/IF
detector featuring the LT®5570 IC.
The LT5570 is a wide dynamic range Mean Squared
RF Power detector, operational from 40MHz to
2700MHz. The input dynamic range at 880MHz, with
±1dB nonlinearity, is 61dB (from –48dBm to +13dBm,
single-ended 50Ω input). The detector output voltage
slope is normally 37mV/dB, and the typical output
variation over temperature is ±0.4dB at 880MHz.
The 1077A Demo Board is optimized for wide frequency range of 40MHz to 880MHz.
Design files for this demo board are available. Call
the LTC factory.
LTC is a trademark of Linear Technology Corporation
Table 1. Typical Performance Summary (VCC = 5V, ENBL = 5V, TA = 25°C, unless otherwise noted. Test circuit shown in Figure 2.)
PARAMETER
CONDITION
VALUE
Supply Voltage
4.75V to 5.25V
Supply Current
26.5mA
Shutdown Current
ENBL = Low
0.1µA
Low, Chip Disabled
1V max
HIGH, Chip Enabled
2V min
VENBL = 0V
0µA
VENBL = 5V
68µA
Output Start Voltage
No Input Signal Present
0.1V
Rise Time
0.2V to 1.6V, 10% to 90%, C1 = 22nF, FRF = 2140 MHz
1µs
Fall Time
1.6V to 0.2V, 90% to 10%, C1 = 22nF, FRF = 2140 MHz
8µs
Input Frequency Range
Optimized for DC1077A demo board
40MHz to 880MHz
±1 dB linearity error
62 dB
ENBL Voltage
ENBL Input Current
f = 500MHz
Linear Dynamic Range
Slope
36.9mV/dB
Logarithmic Intercept
-54.8dBm
Output Variation vs Temperature
PIN = -50 to +13dBm
±0.5 dB
Deviation from CW Response
12 dB peak-to-average ratio (4 carrier WCDMA)
0.3 dB
±1 dB linearity error
62 dB
f = 880MHz
Linear Dynamic Range
Slope
36.9mV/dB
Logarithmic Intercept
-54.8dBm
Output Variation vs Temperature
PIN = -50 to +13dBm
±0.5 dB
Deviation from CW Response
12 dB peak-to-average ratio (4 carrier WCDMA)
0.2 dB
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A
MEAN-SQUARED RF/IF DETECTOR
QUICK START PROCEDURE
Demonstration circuit 1077A is easy to set up to
evaluate the performance of the LT5570. Refer to
Figure 1 for proper measurement equipment setup
and follow the procedure below:
1.
Connect voltmeter’s negative (-) lead to demo
board GND test point (TP2).
2.
Connect voltmeter’s positive (+) lead to the demo
board OUTPUT test point (TP4).
3.
Connect DC power supply’s negative (-) output to
demo board GND test point (TP2).
4.
6.
Connect signal generator’s output to demo board
INPUT port (SMA connector J1) via coaxial cable.
Using a jumper cable, connect demo board VCC test
point (E3) to ENBL test point (TP3). Now the detector is enabled (on) and is ready for measurement.
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.
NOTE: Make sure that the power is not applied to
Enable (EN) test point before it is applied to VCC.
The voltage on the EN test point must never exceed VCC + 0.2V.
Connect DC power supply’s positive (+) output
(4.75V to 5.25V) to demo board VCC test point
(TP1).
Do not exceed 5.5V, the absolute maximum supply
voltage.
5.
A 3dB attenuator may be inserted to improve input
match.
7.
Apply RF input signal and measure OUTPUT DC
voltages.
Do not exceed +15dBm, the absolute maximum RF
input power.
Figure 1. Proper Measurement Equipment Setup
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A
MEAN-SQUARED RF/IF DETECTOR
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A
MEAN-SQUARED RF/IF DETECTOR
DEMO BOARD MODIFICATIONS:
Modifications for Single-Ended RF Input configuration without RF Input Transformer:
Part
Value
T2
C8
3.3pF
Manufacturer Part Number
Notes
MA-COM, MABAES0061
Remove T2 transformer
AVX, 0402YA330KAT
Remove capacitor C8
Place 150 ohm resistor (0402 body size) instead
C10
1nF
0805 size capacitor from any supplier
Place 1nF capacitor between pins 5 & 1 of T2 transformer (refer to tr-r pin-out on schematic)
R2
0-ohm
0-ohm resistor (or copper jumper)
Place 0-ohm resistor between pins 2 & 3 of T2 transformer (refer to tr-r pin-out on schematic)
NOTE: Refer to the demo board schematic below
DC1077A Demo Board Schematic with modifications for Single-Ended RF Input without RF Input Transformer
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