LTC5532EDC#PBF Linear Technology, LTC5532EDC#PBF Datasheet - Page 12

• Manufacturer Part Number: LTC5532EDC#PBF
• Manufacturer: Linear Technology

Specifications of LTC5532EDC#PBF

• Pin Count: 6
• Screening Level: Industrial
• Lead Free Status / Rohs Status: Compliant

APPLICATIO S I FOR ATIO
LTC5532
Operation
The LTC5532 RF detector integrates several functions to
provide RF power detection over frequencies ranging from
300MHz to 7GHz. These functions include an internal fre-
quency compensated buffer amplifier, an RF Schottky di-
ode peak detector and a level shift amplifier to convert the
RF input signal to DC. The LTC5532 has both gain setting
and voltage offset adjustment capabilities.
Buffer Amplifier
The output buffer amplifier is capable of supplying typi-
cally 4mA into a load. The negative terminal V
out to a pin for gain selection. External resistors connected
between V
the gain of this amplifier.
The amplifier is unity gain stable; however a minimum
gain of two is recommended to improve low output
voltage accuracy. The amplifier has a bandwidth of 2MHz
with a gain of 2. For increased gain applications, the
bandwidth is reduced according to the formula:
A capacitor can be placed across the feedback resistor R
to shape the frequency response. In addition, the ampli-
fier can be used as a comparator. V
a reference voltage. When the internal detector output
12
Gain = 1 + R
Bandwidth = 4MHz/(Gain) = 4MHz • R
OUT
and V
A
/R
B
U
M
(R
A
) and V
U
M
to ground (R
M
W
ADJUSTMENT
can be connected to
RF
OFFSET
B
IN
/(R
M
A
R1
(OPT)
is brought
U
+ R
B
) will set
Demo Board Schematic
39pF
C4
B
)
1
2
3
LTC5532ES6
RF
GND
V
A
OS
IN
V
V
OUT
V
voltage (which is connected to the positive input of the
buffer amplifier) exceeds the external voltage on V
will switch high.
The V
amplifier. V
starting voltage is not to be changed. The buffer is initially
trimmed nominally to 120mV (Gain = 2x) with V
nected to ground.
The V
voltage. This function, in combination with gain adjust-
ment enables the LTC5532 output to span the input range
of a variety of analog-to-digital converters. V
change until V
V
where gain is the output buffer gain. For a buffer gain of 2x,
V
RF Detector
The internal RF Schottky diode peak detector and level
shift amplifier convert the RF input signal to a low fre-
quency signal. The detector demonstrates excellent effi-
ciency and linearity over a wide range of input power. The
Schottky diode is biased at about 55 A and drives a 25pF
internal peak detector capacitor.
CC
M
OUT
OUT
V
6
5
4
OUT
for V
will exactly track V
OS
OS
= 0.5 • V
input controls the DC input voltage to the buffer
pin is used to change the initial V
C2
100pF
C3
(OPT)
OS
OS
>120mV is:
OS
must be connected to ground if the DC
R2
10k
1%
R3
10k
1%
C1
0.1 F
OS
exceeds 120mV. The starting voltage at
V
2.7V TO 6V
V
GND
CC
OUT
• Gain
5532 DB
OS
above 120mV.
OUT
OUT
M
OS
starting
will not
, V
con-
OUT
5532f