LT1226 Linear Technology, LT1226 Datasheet - Page 7

• Manufacturer Part Number: LT1226
• Description: Low Noise Very High Speed Operational Amplifier
• Manufacturer: Linear Technology

A
frequency domain and in the transient response. The
photo of the small signal response with 1000pF load
shows 55% peaking. The large signal response with a
10,000pF load shows the output slew rate being limited by
the short circuit current.
The LT1226 can drive coaxial cable directly, but for best
pulse fidelity the cable should be doubly terminated with
a resistor in series with the output.
Compensation
The LT1226 has a typical gain bandwidth product of 1GHz
which allows it to have wide bandwidth in high gain
TYPICAL
PPLICATI
A
V
= –25, C
V
IN
Compensation for Lower Closed-Loop Gains
V
IN
R
IN
L
A
= 1000pF
O
PPLICATI
200
1k
330pF
A
R
V
C
U
Lag Compensation
= –
S
R
R
IN
F
A
V
; R
I FOR ATIO
= +6, f < 2MHz
F
U
R
–
+
F
+
–
LT1226
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
24 (R
LT1226
O
5k
A
V
IN
U
= +25, C
|| R
W
S
C
)
L
LT1226 TA05
LT1226 TA03
= 10,000pF
V
V
OUT
OUT
U
LT1226 AI04
configurations (i.e., in a gain of 1000 it will have a
bandwidth of about 1MHz). The amplifier is stable in a
noise gain of 25 so the ratio of the output signal to the
inverting input must be 1/25 or less. Straightforward gain
configurations of +25 or –24 are stable, but there are a few
configurations that allow the amplifier to be stable for
lower signal gains (the noise gain, however, remains 25 or
more). One example is the inverting amplifier shown in the
typical applications sections below. The input signal has a
gain of –R
configuration is equivalent to a gain of –24 as far as the
amplifier is concerned. Lag compensation can also be
used to give a low frequency gain less than 25 with a high
frequency gain of 25 or greater. The example below has a
DC gain of 6, but an AC gain of +31. The break frequency
of the RC combination across the amplifier inputs should
be at least a factor of 10 less than the gain bandwidth of the
amplifier divided by the high frequency gain (in this case
1/10 of 1GHz/31 or 3MHz).
V
V
IN
IN
R2
50
100pF
F
/R
+
–
IN
LT1226
to the output, but it is easily seen that this
10k
1.2k
R1
10k
Cable Driving
V
OS
+
–
–
+
LT1226
LT1097
Null Loop
1
300k
75
100pF
R3
8
A
300k
V
= 1001
75 CABLE
25k
25
R4
75
LT1226 TA06
LT1226
LT1226 TA04
V
V
OUT
OUT
7