LT1124IS8#TR Linear Technology, LT1124IS8#TR Datasheet - Page 11

• Manufacturer Part Number: LT1124IS8#TR
• Description: IC OPAMP DUAL PREC HS LN 8SOIC
• Manufacturer: Linear Technology

Specifications of LT1124IS8#TR

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Slew Rate: 4.5 V/µs
• Gain Bandwidth Product: 12.5MHz
• Current - Input Bias: 8nA
• Voltage - Input Offset: 25µV
• Current - Supply: 2.3mA
• Voltage - Supply, Single/dual (±): ±4 V ~ 18 V
• Operating Temperature: -40°C ~ 85°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: -

APPLICATIONS INFORMATION
High Speed Operation
When the feedback around the op amp is resistive (R
a pole will be created with R
capacitance (R
(C
R
phase shift and even oscillation. A small capacitor (C
in parallel with R
With R
is completely removed.
Unity Gain Buffer Applications
When R
signal pulse (>1V), the output waveform will look as
shown in Figure 3.
S
IN
and R
≈ 2pF). In low closed loop gain confi gurations and with
S
F
(C
F
≤ 100Ω and the input is driven with a fast, large
–
+
R
in the kilohm range, this pole can create excess
S
S
Figure 3. Unity-Gain Buffer Applications
+ C
Figure 2. High Speed Operation
S
R
IN
F
, C
F
C
) = R
S
eliminates this problem (see Figure 2).
S
), and the amplifi er input capacitance
F
C
–
+
F,
the effect of the feedback pole
OUTPUT
F
C
, the source resistance and
C
R
IN
F
F
OUTPUT
1124/25 F02
4.5V/μs
1124/25 F03
F
F
),
)
During the fast feedthrough-like portion of the output, the
input protection diodes effectively short the output to the
input and a current, limited only by the output short circuit
protection, will be drawn by the signal generator. With
R
requirements (I
in its active mode and a smooth transition will occur.
Noise Testing
Each individual amplifi er is tested to 4.2nV/√Hz voltage
noise; i.e., for the LT1124 two tests, for the LT1125 four
tests are performed. Noise testing for competing multiple
op amps, if done at all, may be sample tested or tested
using the circuit shown in Figure 4.
e
If the LT1125 were tested this way, the noise limit would
be
screen? What if three of the four amplifi ers are at a typical
2.7nV/√Hz, and the fourth one was contaminated and has
6.9nV/√Hz noise?
RMS Sum =
This passes an 8.4nV/√Hz spec, yet one of the ampli-
fi ers is 64% over the LT1125 spec limit. Clearly, for
proper noise measurement, the op amps have to be tested
individually.
n OUT
F
√
≥500Ω, the output is capable of handling the current
4 • (4.2nV/√Hz)
Figure 4. Competing Quad Op Amp Noise Test Method
+
–
=
A
√
(e
√
nA
(2.7)
)
2
L
+ (e
≤ 20mA at 10V) and the amplifi er stays
+
–
2
B
+ (2.7)
2
nB
= 8.4nV/√Hz. But is this an effective
)
2
+ (e
2
LT1124/LT1125
+ (2.7)
–
+
nC
C
)
2
2
+ (e
+ (6.9)
nD
)
–
+
2
2
D
= 8.33nV/√Hz
1124/25 F04
11
OUT
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