LMH6654MA National Semiconductor, LMH6654MA Datasheet - Page 14

• Manufacturer Part Number: LMH6654MA
• Description: IC, OP-AMP, 260MHZ, 200V/µs, SOIC-8
• Manufacturer: National Semiconductor

Specifications of LMH6654MA

• Op Amp Type: Voltage Feedback
• No. Of Amplifiers: 1
• Bandwidth: 260MHz
• Slew Rate: 200V/µs
• Supply Voltage Range: ± 2.5V To ± 6V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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COMPONENTS SELECTION AND FEEDBACK RESISTOR
It is important in high-speed applications to keep all compo-
nent leads short since wires are inductive at high frequency.
For discrete components, choose carbon composition axially
leaded resistors and micro type capacitors. Surface mount
components are preferred over discrete components for min-
imum inductive effect. Never use wire wound type resistors in
high frequency applications.
Large values of feedback resistors can couple with parasitic
capacitance and cause undesired effects such as ringing or
oscillation in high-speed amplifiers. Keep resistors as low as
possible consistent with output loading consideration. For a
gain of 2 and higher, 402Ω feedback resistor used for the typ-
ical performance plots gives optimal performance. For unity
gain follower, a 25Ω feedback resistor is recommended rather
than a direct short. This effectively reduces the Q of what
FIGURE 3. Non-Inverting Amplifier Configuration
14
would otherwise be a parasitic inductance (the feedback wire)
into the parasitic capacitance at the inverting input.
BIAS CURRENT CANCELLATION
In order to cancel the bias current errors of the non-inverting
configuration, the parallel combination of the gain setting R
and feedback R
resistance R
straint with the non-inverting gain equation, allows both R
R
For inverting configuration, bias current cancellation is ac-
complished by placing a resistor R
equal in value to the resistance seen by the inverting input
(R
minimized through the use of a shunt capacitor.
g
f
//(R
to be determined explicitly from the following equations:
g
+R
s
). The additional noise contribution of R
seq
R
f
as defined in Figure 3. Combining this con-
f
resistors should equal the equivalent source
= A
V
R
seq
20016542
and R
g
b
= R
on the non-inverting input
f
/(A
V
−1)
b
can be
f
and
g