Datasheet

LTC6431-15
10
643115f
operaTion
The LTC6431-15 is a highly linear, fixed-gain amplifier that
is configured to operate single ended. Its core signal path
consists of a single amplifier stage minimizing stability is-
sues. The input is a Darlington pair for high input impedance
and high current gain. Additional circuit enhancements
increase the output impedance and minimize the effects
of internal Miller capacitance.
The LTC6431-15 starts with a classic RF gain-block topol-
ogy but adds additional enhancements to achieve dramati-
cally improved linearity. Shunt and series feedback are
added to lower the input/output impedance and match them
simultaneously to the 50Ω source and load. Meanwhile,
an internal bias controller optimizes the internal operating
point for peak linearity over environmental changes. This
circuit architecture provides low noise, excellent RF power
handling capability and wide bandwidth—characteristics
that are desirable for IF signal chain applications.
Figure 1. Application, Test Circuit A
TesT circuiT a
PORT
INPUT
PORT
OUTPUT
643115 F01
C7
1000pF
L1
560nH
DNC
DNC
DNC
DNC
DNC
DNC
OUT
GND
T_DIODE
DNC
DNC
DNC
IN
GND
V
CC
DNC DNC DNC
DNC GND V
CC
DNC DNC DNC
C6
0.1µF
C3
1000pF
V
CC
= 5V
C1
60pF
OPTIONAL
STABILITY
NETWORK
R1
350Ω
C5
1nF
LTC6431-15