LT1800CS5 查看數據表（PDF） - Linear Technology
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LT1800CS5 Datasheet PDF : 18 Pages
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LT1800
TYPICAL APPLICATION
Low Power High Voltage Amplifier
Certain materials used in optical applications have charac-
teristics that change due to the presence and strength of a
DC electric field. The voltage applied across these materials
should be precisely controlled to maintain desired proper-
ties, sometimes as high as 100’s of volts. The materials
are not conductive and represent a capacitive load.
The circuit of Figure 6 shows the LT1800 used in an ampli-
fier capable of a 250V output swing and providing precise
130V
0.1MF
5V
10k
4.99k 1k
Q5
Q6
5V
Q1
Q2 5V
DC output voltage. When no signal is present, the op
amp output sits at about mid-supply. Transistors Q1 and
Q3 create bias voltages for Q2 and Q4, which are forced
into a low quiescent current by degeneration resistors
R4 and R5. When a transient signal arrives at VIN, the op
amp output moves and causes the current in Q2 or Q4
to change depending on the signal polarity. The current,
limited by the clipping of the LT1800 output and the 3kΩ
of total emitter degeneration, is mirrored to the output
devices to drive the capacitive load. The LT1800 output
then returns to near mid-supply, providing the precise DC
output voltage to the load. The attention to limit the current
of the output devices minimizes power dissipation thus
allowing for dense layout, and inherits better reliability.
Figure 7 shows the time domain response of the amplifier
providing a 200V output swing into a 100pF load.
+
R2
2k
LT1800
–
VIN
R1
2k
C2
8pF
150V
C1
39pF
R3
200k
R4
R6
2k
2k
R5
R7
2k
2k
Q3
Q4
VOUT
MATERIAL UNDER
ELECTRIC FIELD
100pF
10k
Q7
AV = VOUT/VIN = –100
Q8
±130V SUPPLY IQ = 130MA
OUTPUT SWING = ±128.8V
OUTPUT OFFSET 20mV
4.99k
1k OUTPUT SHORT-CIRCUIT CURRENT 3mA
10% TO 90% RISE TIME 8Ms, 200V OUTPUT STEP
SMALL-SIGNAL BANDWIDTH 150kHz
–130V
Q1, Q2, Q7, Q8: ON SEMI MPSA42
Q3, Q4, Q5, Q6: ON SEMI MPSA92
1800 F06
VIN
2V/DIV
VOUT
50V/DIV
10μs/DIV
1800 F07
Figure 6. Low Power, High Voltage Amplifier
Figure 7. Large-Signal Time Domain
Response of the Amplifier
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
LT1399
Triple 300MHz Current Feedback Amplifier
0.1dB Gain Flatness to 150MHz, Shutdown
LT1498/LT1499 Dual/Quad 10MHz, 6Vμs Rail-to-Rail Input and Output C-Load™ Op Amps High DC Accuracy, 475μV VOS(MAX), 4mV/°C Max Drift,
Max Supply Current 2.2mA per Amp
LT1630/LT1631 Dual/Quad 30MHz, 10V/μs Rail-to-Rail Input and Output Op Amps
High DC Accuracy, 525μV VOS(MAX), 70mA Output Current,
Max Supply Current 4.4mA per Amplifier
LT1801/LT1802 80MHz, 25V/μs Low Power Rail-to-Rail Input/Output Precision Op Amps
LT1806/LT1807 Single/Dual 325MHz, 140V/μs Rail-to-Rail Input and Output Op Amps
Dual/Quad Version of the LT1800
High DC Accuracy, 550μV VOS(MAX), Low Noise 3.5nV/√Hz,
Low Distortion –80dB at 5MHz, Power-Down (LT1806)
LT1809/LT1810 Single/Dual 180MHz Rail-to-Rail Input/Output Op Amps
350V/μs Slew Rate, Low Distortion –t at 5MHz,
Power-Down (LT1809)
C-Load is a trademark of Linear Technology Corporation.
18 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
1800fa
LT 0709 REV A • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2009
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