LTC6412
800MHz, 31dB Range
Analog-Controlled VGA
FEATURES DESCRIPTION
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800MHz 3dB Small-Signal Bandwidth
The LTC 6412 is a fully differential variable gain ampli er
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Continuously-Adjustable Gain Control
with linear-in-dB analog gain control. It is designed for
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14dB to +17dB Linear-in-dB Gain Range
AC-coupled operation in IF receiver chains from 1MHz
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35dBm OIP3 at 240MHz Across All Gain Settings
to 500MHz. The part has a constant OIP3 across a wide
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10dB Noise Figure at Maximum Gain
output amplitude range and across the 31dB gain control
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(IIP3 NF) = +8dBm at 240MHz Across All Gains
range. The output noise (NF + Gain) is also at versus gain
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2.7nV/Hz Input Referred Noise
to provide a uniform spurious-free dynamic range (SFDR)
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Differential Inputs and Outputs
>120dB over the full gain control range at 240MHz.
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50 Input Impedance Across all Gains
The LTC6412 is ideal for interfacing with the LT 5527 and
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Single Supply Operation from 3V to 3.6V
LT5557 downconverting mixers, LTC6410-6 IF ampli er
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110mA Supply Current
and the LTC6400/LTC6401/LTC6416 ADC drivers for use
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4mm 4mm 0.75mm 24-Pin QFN Package
in 12-, 14-, and 16-bit ADC applications.
APPLICATIONS
The LTC6412 recovers quickly from an overdrive condition,
and the EN pin allows for a fast output signal disable to
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IF Signal Chain Automatic Gain Control (AGC)
protect sensitive downstream components. Asserting the
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2.5G and 3G Cellular Basestation Transceivers
SHDN pin reduces the current consumption below 1mA
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WiMAX, WiBro, WLAN Receivers
for power-down or sleep modes.
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Satellite and GPS Receiver IF
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
3.3V Fully Differential 240MHz IF Receiver Chain with 31dB Gain Control
VGA Gain vs Frequency
Over Gain Control Range
3.3V
20
3.3V
G
MAX
0.1F
1nF
10
3.3V
3.3V
180nH 180nH
10nF
BPF
V
DD
+OUT
+IN
0
+ +OUT
+IN +
V
A
IN
LTC6400-8
LTC6412 0.1F LTC2208
IF INPUT
V
CM
A 10
IN IN
V
OUT
IN
OUT
V
GND
CM
0.1F
G
MIN
10nF
GAIN CONTROL
20
6412 TA01
(+ SLOPE MODE)
2.2F
30
0.1F
10nF 0.1F 0.1F
1 10 100 1000 10000
FREQUENCY (MHz)
6412 G01
6412fa
1
GND
V
CC
V
CM
DECL1
SHDN
DECL2
V
G
EN
V
REF
+V
G
GAIN (dB)LTC6412
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
Total Supply Voltage (V to GND) ...........................3.8V TOP VIEW
CC
Ampli er Input Current (+IN, IN) ........................20mA
Ampli er Output Current (+OUT, OUT) ...............70mA
24 23 22 21 20 19
Input Current (+V , V , V , EN, SHDN ) .........10mA
G G REF
GND 1 18 GND
Input Current (V , DECL1, DECL2) ....................10mA
+IN 2 17 +OUT
CM
IN OUT
RF Input Power, Continuous, 50 ......................+15dBm 3 16
25
V 4 15 GND
CM
RF Input Power, 100s pulse, 50 ....................+20dBm
V 5 14 DECL2
CM
Operating Temperature Range (Note 2).... 40C to 85C
V 6 13 V
CC CC
Speci ed Temperature Range (Note 3) .... 40C to 85C
7 8 9 10 11 12
Storage Temperature Range ................... 65C to 150C
Junction Temperature ........................................... 150C
UF PACKAGE
24-LEAD (4mm 4mm) PLASTIC QFNs
T = 150C, = 37C/W
JMAX JA
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE
LTC6412CUF#PBF LTC6412CUF#TRPBF 6412 0C to 70C
24-Lead (4mm 4mm) Plastic QFN
LTC6412IUF#PBF LTC6412IUF#TRPBF 6412 24-Lead (4mm 4mm) Plastic QFN 40C to 85C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based nish parts.
For more information on lead free part marking, go to: