LMH6628MA National Semiconductor, LMH6628MA Datasheet - Page 10

• Manufacturer Part Number: LMH6628MA
• Description: IC, OP-AMP, 300MHZ, 550V/µs, SOIC-8
• Manufacturer: National Semiconductor

Specifications of LMH6628MA

• Op Amp Type: Voltage Feedback
• No. Of Amplifiers: 2
• Bandwidth: 300MHz
• Slew Rate: 550V/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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Application Section
A current source, built around Q1, provides the necessary
bias current for the second amplifier and prevents saturation
when power is applied. The resistor, R, closes the loop while
diode D2 prevents negative saturation when V
V
capacitor’s voltage.
The maximum speed of detection is limited by the delay of
the op amps and the diodes. The use of Schottky diodes will
provide faster response.
ADJUSTABLE OR BANDPASS EQUALIZER
A "boost" equalizer can be made with the LMH6628 by
summing a bandpass response with the input signal, as
shown in Figure 7.
The overall transfer function is shown in Eq. 5.
C
. A MOS-type switch (not shown) can be used to reset the
FIGURE 6.
FIGURE 7.
(Continued)
20038537
IN
is less than
20038506
10
To build a boost circuit, use the design equations Eq. 6 and
Eq. 7.
Select R
frequency circuits - R
10pF and 2000pF. Use Eq. 7 to determine the parallel com-
bination of R
5kΩ criteria or by other requirements based on the imped-
ance V
ing the value of K from Eq. 8.
Figure 8 shows an example of the response of the circuit of
Figure 9, where f
follows: R
= 50Ω, C = 120pF.
in
2
is capable of driving. Finish the design by determin-
a
and C using Eq. 6. Use reasonable values for high
=2.1kΩ, R
a
and R
o
is 2.3MHz. The component values are as
b
b
. Select R
2
= 68.5Ω, R
between 10Ω and 5kΩ, C between
FIGURE 8.
a
and R
2
= 4.22kΩ, R = 500Ω, KR
b
by either the 10Ω to
20038543
(4)
(5)
(6)
(7)