LT1677C View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LT1677C' PDF : 16 Pages View PDF
LT1677
TYPICAL APPLICATIO
This 2-wire remote Geophone preamp operates on a
current-loop principle and so has good noise immunity.
Quiescent current is ≈10mA for a VOUT of 2.5V. Excitation
will cause AC currents about this point of ~±4mA for a
VOUT of ~±1V max. The op amp is configured for a voltage
gain of ~107. Components R5 and Q1 convert the voltage
into a current for transmission back to R10, which con-
verts it into a voltage again. The LM334 and 2N3904 are
not temperature compensated so the DC output contains
temperature information.
2-Wire Remote Geophone Preamp
LINEAR V +
TECHNOLOGY
R
LM334Z
6mA
V–
R8
11Ω
3V
C
LT1431CZ
R
A
R6
4.99k +
R7
24.9k
C3
220µF
GEOSOURCE –
MD-105
RL = 847Ω
GEOPHONE
+
R4
14k
R1
150Ω 2 –
7
R3
16.2k
LT1677
3+
4
AV
=
R2 +
R1
R3||R4
+ RL
≅
107
R2
100k
C2
0.1µF
6
R9
20Ω
Q1
2N3904
R5
243Ω
C4
1000pF
1677 TA03
12V
VOUT
2.5V ±1V
R10
250Ω
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C-Load is a trademark of Linear Technology Corporation.
COMMENTS
Lowest Noise 0.85nV/√Hz
0.002% THD, Max Noise 1.2nV/√Hz
Similar to LT1007
Similar to LT1037
Precision C-LoadTM Stable
4.2nV/√Hz, 10fA/√Hz
6nV/√Hz, 1fA/√Hz
2.2MHz Bandwidth, 1.2V/µs SR
16 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900q FAX:(408)434-0507 q www.linear-tech.com
1677i LT/TP 0200 4K • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2000
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