MAX4186 Maxim, MAX4186 Datasheet - Page 17

• Manufacturer Part Number: MAX4186
• Description: The MAX4180 family of current-feedback amplifiers combines high-speed performance, low distortion,and excellent video specifications with ultra-low-power operation in miniature packages
• Manufacturer: Maxim

The optimum value of the external-feedback (R
gain-setting (R
MAX4187 depends on the closed-loop gain and the
application circuit’s load. Table 1 lists the optimum
resistor values for some specific gain configurations.
One-percent resistor values are preferred to maintain
consistency over a wide range of production lots.
Figures 4a and 4b show the standard inverting and
noninverting configurations. Note: The noninverting cir-
cuit gain (Figure 4) is 1 plus the magnitude of the
inverting closed-loop gain. Otherwise, the two circuits
are identical.
Several major error sources must be considered in any
op amp. These apply equally to the MAX4180–
MAX4187. Offset-error terms are given by the equation
below. Voltage and current-noise errors are root-square
summed and are therefore computed separately. In
Figure 5, the total output offset voltage is determined by
the following factors:
COMPONENT/
Table 1. Recommended Component Values
COMPONENT/BW
-3dB BW
-3dB BW (MHz)
R
R
(MHz)
BW
G
Choosing Feedback and Gain Resistors
F
(Ω)
(Ω)
R
R
G
F
Current-Feedback Amplifiers with Shutdown
(Ω)
(Ω)
R
G
1kΩ
245
1k
1k
L
MAX4182/MAX4183
) resistors used with the MAX4180–
______________________________________________________________________________________
Single/Dual/Quad, 270MHz, 1mA, SOT23,
=
A
R
V
L
1.2k
1.2k
245
= +2V/V
150Ω
R
= 1kΩ
680
680
190
L
=
DC and Noise Errors
A
R
V
100Ω
R
620
620
160
L
= +2V/V
L
= 150Ω
820
820
190
=
R
1kΩ
1.5k
270
—
L
MAX4184/MAX4185
=
100Ω
R
680
680
190
L
MAX4180
A
=
V
F
= +1V/V
150Ω
) and
R
750
205
—
L
=
A
1kΩ/150Ω
V
= +5V/V
R
520
130
120
100Ω
R
L
620
180
—
L
=
• The input offset voltage (V
• The positive input bias current (I
The equation for the total DC error at the output is:
The total output-referred noise voltage is:
=
e
gain (1 = R
resistor (R
input bias current (I
of R
input bias currents at the IN+ and IN- terminals do
not track each other and may have opposite polarity,
so there is no benefit to matching the resistance at
both inputs.
n OUT
(
V
OUT
R
1kΩ
1.1k
1.1k
245
G
L
A
)
1kΩ/150Ω
=
=
V
and R
=
= +10V/V




R
A
1
560
[
MAX4186
56
76
S
+
L
( )
V
I
F
B
) (usually 50Ω or 75Ω), plus the negative
R
R
=
150Ω
= +2V/V
R
+
/ R
750
750
190
G
F
F
L
R
. In current-feedback amplifiers, the




=
G
S
).
+

 
( )
i
( )
B-
n
I
R
B
100Ω
+
R
680
680
175
) times the parallel combination
−
L
2.4k
L
R
270
= 1kΩ
—
(
=
R
S
F

 
2
||
OS
+
R

 
) times the closed-loop
R
1kΩ
1.6k
G
( )
270
A
i
—
n
L
MAX4181
)
V
−
B+
=
+
150Ω
= +1V/V
R
R
205
1k
—
) times the source
L
A
F
V
MAX4187
||
=
V
OS
R
= +1V/V
150Ω
R
910
205
]
G
—
L




 
=
1
2
+
+
( )
R
R
100Ω
e
R
560
200
G
F
n
—
L
100Ω
R



680
200
2
=
—
L
=
17