LT1008S8 Linear Technology, LT1008S8 Datasheet - Page 9

• Manufacturer Part Number: LT1008S8
• Description: IC PREC OPAMP UNIVRSL SNGL 8SOIC
• Manufacturer: Linear Technology

Specifications of LT1008S8

• Amplifier Type: General Purpose
• Number Of Circuits: 1
• Slew Rate: 0.2 V/µs
• Current - Input Bias: 100pA
• Voltage - Input Offset: 30µV
• Current - Supply: 380µA
• Voltage - Supply, Single/dual (±): ±2 V ~ 18 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Output Type: -
• Current - Output / Channel: -
• -3db Bandwidth: -
• Gain Bandwidth Product: -

APPLICATIO S I FOR ATIO
Frequency Compensation
The LT1008 is externally frequency compensated with a
single capacitor. The two standard compensation circuits
shown earlier are identical to the LM108A/LM308A fre-
quency compensation schemes. Therefore, the LT1008
operational amplifiers can be inserted directly into
LM108A/LM308A sockets, with similar AC and upgraded
DC performance.
External frequency compensation provides the user with
additional flexibility in shaping the frequency response of
the amplifier. For example, for a voltage gain of ten and
C
of 1.2V/μs can be realized. For closed-loop gains in excess
of 200, no external compensation is necessary, and slew
rate increases to 4V/μs. The LT1008 can also be overcom-
pensated (i.e., C
tive load handling capability or to narrow noise bandwidth.
In many applications, the feedback loop around the ampli-
fier has gain (e.g., logarithmic amplifiers); overcompen-
sation can stabilize these circuits with a single capacitor.
The availability of the compensation terminals permits the
use of feedforward frequency compensation to enhance
slew rate in low closed-loop gain configurations. The
inverter slew rate is increased to 1.4V/μs. The voltage
follower feedforward scheme bypasses the amplifier’s
gain stages and slews at nearly 10V/μs.
The inputs of the LT1008 are protected with back-to-back
diodes. Current limiting resistors are not used, because the
leakage of these resistors would prevent the realization of
picoampere level bias currents at elevated temperatures.
F
= 3pF, a gain bandwidth product of 5MHz and slew rate
F
> 30pF or C
U
*DEVICE UNDER TEST
NOTE: ALL CAPACITOR VALUES ARE FOR
NONPOLARIZED CAPACITORS ONLY
U
10Ω
S
> 100pF) to improve capaci-
–
+
W
0.1μF
LT1008*
VOLTAGE
GAIN: 50,000
100k
0.1Hz to 10Hz Noise Test Circuit
U
4.7μF
2k
24.3k
+
–
LT1001
In the voltage follower configuration, when the input is
driven by a fast, large-signal pulse (>1V), the input protec-
tion diodes effectively short the output to the input during
slewing, and a current, limited only by the output short-
circuit protection, will flow through the diodes.
The use of a feedback resistor, as shown in the voltage
follower feedforward diagram, is recommended because
this resistor keeps the current below the short-circuit
limit, resulting in faster recovery and settling of the output.
0.1μF
100k
2.2μF
4.3k
INPUT
Inverter Feedforward Compensation
22μF
10k
R1
110k
500pF
2
3
SCOPE
×1
R
5μs/DIV
C1
IN
1008 AI03
–
+
5pF
C2
= 1M
LT1008
1
10k
R2
8
R3
3k
1008 AI05
C3
10pF
6
1008 AI07
V
OUT
LT1008
1008fb
9