LMH6704MA/NOPB National Semiconductor, LMH6704MA/NOPB Datasheet - Page 9

• Manufacturer Part Number: LMH6704MA/NOPB
• Description: IC BUFFER PROG GAIN 650MHZ 8SOIC
• Manufacturer: National Semiconductor
• Series: LMH®r

Specifications of LMH6704MA/NOPB

• Amplifier Type: Buffer
• Number Of Circuits: 1
• Slew Rate: 3000 V/µs
• -3db Bandwidth: 650MHz
• Current - Input Bias: 5µA
• Voltage - Input Offset: 2000µV
• Current - Supply: 11.5mA
• Current - Output / Channel: 90mA
• Voltage - Supply, Single/dual (±): 8 V ~ 12 V, ±4 V ~ 6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• For Use With: LMH730227 - BOARD EVALUATION FOR SOIC PKGLMH730165 - BOARD EVALUATIONLMH730216 - BOARD EVAL HS MONO AMP SOT23
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Gain Bandwidth Product: -
• Other names: *LMH6704MA; *LMH6704MA/NOPB; LMH6704MA

Application Information
approximately 250 µA. Because of the pull up resistor on the
disable circuit, the I
tive supply currents respectively) are not balanced in the
disabled state. The positive supply current (I
mately 350 µA while the negative supply current (I
250 µA. The remaining I
the disable pin.
The disable function can be used to create analog switches
or multiplexers. Implement a single analog switch with one
LMH6704 positioned between an input and output. Create
an analog multiplexer with several LMH6704’s. Use the cir-
cuit shown in for multiplexer applications because there is no
RG to shunt signals to ground.
EVALUATION BOARDS
National Semiconductor provides the following evaluation
boards as a guide for high frequency layout and as an aid in
device testing and characterization. Many of the datasheet
plots were measured with these boards.
An evaluation board is shipped upon request when a sample
order is placed with National Semiconductor.
DRIVING CAPACITIVE LOADS
Capacitive output loading applications will benefit from the
use of a series output resistor R
of a series output resistor, R
output under capacitive loading. Capacitive loads of 5 to 120
pF are the most critical, causing ringing, frequency response
peaking and possible oscillation. The chart “Suggested R
vs. Cap Load” gives a recommended value for selecting a
series output resistor for mitigating capacitive loads. The
values suggested in the charts are selected for .5 dB or less
of peaking in the frequency response. This gives a good
compromise between settling time and bandwidth. For appli-
cations where maximum frequency response is needed and
some peaking is tolerable, the value of R
slightly from the recommended values.
LAYOUT CONSIDERATIONS
Whenever questions about layout arise, use the evaluation
board as a guide. The CLC730216 is the evaluation board
supplied with samples of the LMH6704. To reduce parasitic
capacitances ground and power planes should be removed
near the input and output pins. For long signal paths con-
trolled impedance lines should be used, along with imped-
Device
LMH6704MA
LMH6704MF
FIGURE 7. Decoupling Capacitive Loads
Package
SOIC-8
SOT23-6
CC
and I
EE
current of 100 µA flows through
EE
ISO
currents (positive and nega-
ISO
, to stabilize the amplifier
. Figure 7 shows the use
Evaluation Board
Part Number
CLC730227
CLC730216
ISO
(Continued)
can be reduced
CC
) is approxi-
EE
20103606
) is only
ISO
9
ance matching elements at both ends. Bypass capacitors
should be placed as close to the device as possible. Bypass
capacitors from each rail to ground are applied in pairs. The
larger electrolytic bypass capacitors can be located farther
from the device, the smaller ceramic capacitors should be
placed as close to the device as possible. In Figure 1, Figure
2, and Figure 3 C
second order harmonic distortion. Another option to using
C
for each supply bypass.
VIDEO PERFORMANCE
The LMH6704 has been designed to provide excellent per-
formance with production quality video signals in a wide
variety of formats such as HDTV and High Resolution VGA.
NTSC and PAL performance is nearly flawless with DG of
0.02% and DP of 0.02˚. Best performance will be obtained
with back terminated loads. The back termination reduces
reflections from the transmission line and effectively masks
transmission line and other parasitic capacitances from the
amplifier output stage. Figure 8 shows a typical configuration
for driving a 75Ω Cable. The amplifier is configured for a gain
of two to make up for the 6 dB of loss in R
POWER DISSIPATION
Follow these steps to determine the Maximum power dissi-
pation for the LMH6704:
1. Calculate the quiescent (no-load) power:
2. Calculate the RMS power dissipated in the output stage:
3. Calculate the total RMS power: P
The maximum power that the LMH6704, package can dissi-
pate at a given temperature can be derived with the following
equation:
SS
P
P
are the voltage and current across the external load and
V
is to use pairs of 0.01 µF and 0.1 µF ceramic capacitors
AMP
D
S
(rms) = rms ((V
is the total supply current
FIGURE 8. Typical Video Application
= I
CC*
(V
SS
S
is optional, but is recommended for best
), where V
S
- V
OUT
S
)*I
= V
OUT
+
), where V
T
- V
= P
−
OUT
AMP
OUT
.
+P
www.national.com
D
and I
20103608
OUT