clc417 National Semiconductor Corporation, clc417 Datasheet - Page 4

• Manufacturer Part Number: clc417
• Description: Dual Low-power, Programmable Gain Buffer
• Manufacturer: National Semiconductor Corporation

http://www.national.com
Description
The CLC417 is a dual current feedback buffer with the
following features:
The convenient 8-pin package and internal resistors
make common applications, like that seen on the front
page, easily feasible in a limited amount of space. The
professional video quality differential gain and phase
errors and low power capabilities of the CLC417 make
this product a good choice for video applications.
If gains other than +1, -1, or +2V/V are required, then the
CLC416 can be used. The CLC416 is a dual current
feedback amplifier with near identical performance, and
allows for external feedback and gain resistors.
Closed Loop Gain Selection
Gains of +1, +2, and -1V/V can be achieved by both of
the CLC417’s amplifiers. Implement the gain selection
by connecting the inverting (-IN) and non-inverting (+IN)
pins as described in the table below.
The gain accuracy of the CLC417 is excellent and
stable over temperature. The internal feedback and gain
setting resistors, R
R
temperature coefficient of ~ 2000ppm/°C. Although the
absolute values of R
temperature, their ratio (R
external resistor is used in series with R
over temperature will be impacted by temperature coeffi-
cient differences between internal and external resistors.
CLC417 Typical Performance Characteristics
f
and R
+1V/V
+2V/V
-1V/V
Gain
A
60
50
40
20
10
30
Gains of +1, -1, and 2 are achievable without
external resistors
Differential gain and phase errors of 0.01%
and 0.03° into a 150
Low, 3.9mA, supply current per amplifier
v
10k
PSRR and CMRR
CMRR
PSRR
g
have a process variation of ±20% and a
100k
Frequency (Hz)
input signal
input signal
f
and R
f
ground
and R
1M
+IN
Input Connections
g
f
, are diffused silicon resistors.
g
/R
10M
change with processing and
load
g
) remains constant. If an
100M
input signal
NC (open)
g
, gain accuracy
ground
CLC417 OPERATION
-IN
6
5
4
3
2
1
-50
Typical DC Errors vs. Temperature
Temperature ( C)
0
V
IO
4
(V
I
BI
Non-Inverting Unity Gain Considerations
Gains of +1V/V are obtained by removing all resistive
and capacitive connections between the inverting
pins and ground on the CLC417 amplifiers. Too much
capacitive coupling between the inverting pin and ground
may cause stability problems. Minimize this capacitive
coupling by removing the ground plane near the
input and output pins. The response labeled
Figure 1 is the result of the inverting pin left open and all
capacitive coupling removed. A flatter response can be
obtained
inverting and non-inverting pins as shown in Figure 2.
The two remaining plots in Figure 1 illustrate a 300
resistor and a short connected between pins 2 and 3 of
the CLC417.
cc
50
= ±5V, A
Figure 2: Optional Unity Gain Configuration
I
BN
Output1
Input1
SMA
SMA
Figure 1: Frequency Response vs.
1
by
v
100
= +2, R
1
0
-1
-2
-3
Unity Gain Configuration
50
inserting
R
in
L
Frequency (MHz)
R
50
= 100 ; unless specified)
R
1.0
0.8
0.6
0.4
0.2
out
0
Power Derating Curves
0
10
NOTE: The same technique can also
be applied to Channel B. Bypass
capacitors not shown.
R = 300
20
a
Open
Short
Ambient Temperature ( C)
40
250
resistor
250
60
250
-
+
+
-
80
250
100 120 140 160 180
between
100
AJP
AJE
open in
the