LTC2170IUKG-12#TRPBF Linear Technology, LTC2170IUKG-12#TRPBF Datasheet - Page 20
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LTC2170IUKG-12#TRPBF
Manufacturer Part Number
LTC2170IUKG-12#TRPBF
Description
IC ADC 12BIT SER/PAR 25M 52-QFN
Manufacturer
Linear Technology
Datasheet
1.LTC2170CUKG-12PBF.pdf
(32 pages)
Specifications of LTC2170IUKG-12#TRPBF
Number Of Bits
12
Sampling Rate (per Second)
25M
Data Interface
Serial, Parallel
Number Of Converters
4
Power Dissipation (max)
238mW
Voltage Supply Source
Analog and Digital
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
52-WFQFN Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LTC2170IUKG-12#TRPBFLTC2170IUKG-12#PBF
Manufacturer:
Linear Technology
Quantity:
135
LTC2172-12/
LTC2171-12/LTC2170-12
APPLICATIONS INFORMATION
Transformer Coupled Circuits
Figure 3 shows the analog input being driven by an RF
transformer with a center-tapped secondary. The center
tap is biased with V
mal DC level. At higher input frequencies a transmission
line balun transformer (Figures 4 to 6) has better balance,
resulting in lower A/D distortion.
ANALOG
20
INPUT
ANALOG
INPUT
Figure 4. Recommended Front-End Circuit for Input
Frequencies from 70MHz to 170MHz
T1: MA/COM MABA-007159-000000
T2: MA/COM MABAES0060
RESISTORS, CAPACITORS ARE 0402 PACKAGE SIZE
0.1μF
0.1μF
T1: MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
Figure 6. Recommended Front-End Circuit for Input
Frequencies Above 300MHz
0.1μF
0.1μF
T1
T1
CM
, setting the A/D input at its opti-
T2
25Ω
25Ω
25Ω
25Ω
50Ω
2.7nH
2.7nH
0.1μF
0.1μF
50Ω
0.1μF
V
A
A
CM
IN
IN
0.1μF
4.7pF
+
–
V
A
A
CM
IN
IN
+
–
LTC2172-12
LTC2172-12
217212 F06
217212 F04
ANALOG
Amplifi er Circuits
Figure 7 shows the analog input being driven by a high
speed differential amplifi er. The output of the amplifi er is
AC-coupled to the A/D so the amplifi er’s output common
mode voltage can be optimally set to minimize distor-
tion.
At very high frequencies an RF gain block will often have
lower distortion than a differential amplifi er. If the gain
block is single-ended, then a transformer circuit (Figures
4 to 6) should convert the signal to differential before
driving the A/D.
INPUT
ANALOG
INPUT
T1: MA/COM MABA-007159-000000
T2: COILCRAFT WBC1-1LB
RESISTORS, CAPACITORS ARE 0402 PACKAGE SIZE
Figure 5. Recommended Front-End Circuit for Input
Frequencies from 170MHz to 300MHz
0.1μF
0.1μF
DIFFERENTIAL
HIGH SPEED
+
–
AMPLIFIER
Figure 7. Front-End Circuit Using a High Speed
Differential Amplifi er
T1
+
–
0.1μF
0.1μF
T2
200Ω
25Ω
25Ω
200Ω
25Ω
25Ω
0.1μF
50Ω
12pF
0.1μF
A
A
V
CM
IN
IN
+
–
0.1μF
1.8pF
V
A
A
CM
IN
IN
LTC2172-12
+
–
LTC2172-12
217212 F07
21721012f
217212 F05