AD8036-EB Analog Devices Inc, AD8036-EB Datasheet - Page 17

• Manufacturer Part Number: AD8036-EB
• Description: BOARD EVAL FOR AD8036
• Manufacturer: Analog Devices Inc
• Series: CLAMPIN™r

Specifications of AD8036-EB

• Rohs Status: RoHS non-compliant
• Channels Per Ic: 1 - Single
• Amplifier Type: Voltage Feedback
• Output Type: Single-Ended
• Slew Rate: 1200 V/µs
• -3db Bandwidth: 240MHz
• Current - Output / Channel: 70mA
• Operating Temperature: -40°C ~ 85°C
• Current - Supply (main Ic): 20.5mA
• Voltage - Supply, Single/dual (±): ±3 V ~ 6 V
• Board Type: Fully Populated
• Utilized Ic / Part: AD8036

closed-loop gain at the output. For instance, to set an output
limit of ± 1 V for an AD8037 operating at a gain of 3.0, V
V
The only restriction on using the AD8036’s and AD8037’s
+V
ence between +V
all three voltages be within the supply voltage range. For example,
if V
AD8036/AD8037 APPLICATIONS
The AD8036 and AD8037 use a unique input clamping circuit
to perform the clamping function. As a result, they provide the
clamping function better than traditional output clamping
devices and provide additional flexibility to perform other
unique applications.
There are, however, some restrictions on circuit configurations;
and some calculations need to be performed in order to figure
the clamping level, as a result of clamping being performed at
the input stage.
The major restriction on the clamping feature of the AD8036/
AD8037 is that clamping occurs only when using the amplifiers
in the noninverting mode. To clamp in an inverting circuit, an
additional inverting gain stage is required. Another restriction is
that V
voltage range of the amplifier (± 3.9 V). V
and V
Unity Gain Clamping
The simplest circuit for calculating the clamp levels is a unity
gain follower as shown in Figure 8. In this case, the AD8036
should be used since it is compensated for noninverting unity gain.
This circuit will clamp at an upper voltage set by V
applied to Pin 8) and a lower voltage set by V
applied to Pin 5).
L
IN
would need to be set to +0.333 V and –0.333 V, respectively.
L
, V
is set at –3 V, then V
L
H
1.2
can go above ground as long as V
1.6
1.4
1.0
0.8
0.6
L
be greater than V
, V
0.6
CLAMP ERROR – 25mV
AD8036
H
pins as inputs is that the maximum voltage differ-
0.8
AD8036
IN
and V
1.0
OUTPUT CLAMP AMP
INPUT VOLTAGE – +V
L
H
IN
, and that each be within the output
or V
should not exceed +3.3 V.
1.2
L
should not exceed 6.3 V, and
1.4
CLAMP ERROR – >200mV
OUTPUT CLAMP
H
IN
H
is kept higher than V
1.6
can go below ground
L
1.8
(the voltage
H
(the voltage
2.0
H
and
L
.
Clamping with Gain
Figure 9 shows an AD8037 configured for a noninverting gain
of two. The AD8037 is used in this circuit since it is compen-
sated for gains of two or greater and provides greater bandwidth.
In this case, the high clamping level at the output will occur at
2 × V
The equations governing the output clamp levels in circuits con-
figured for noninverting gain are:
where:
Amplifier offset is assumed to be zero.
H
V
IN
and the low clamping level at the output will be 2 × V
V
49.9
IN
V
V
G is the gain of the amplifier configuration
V
V
274
R
CH
CL
H
L
130
G
is the low input clamping level (Pin 5)
is the high input clamping level (Pin 8)
is the low output clamping level
is the high output clamping level
100
0.1 F
0.1 F
AD8036
0.1 F
0.1 F
V
V
AD8037
V
V
H
H
L
L
V
V
CH
V
V
V
CL
V
+5V
H
H
L
–5V
L
= G × V
= G × V
+5V
–5V
0.1 F
0.1 F
AD8036/AD8037
140
R
F
0.1 F
0.1 F
274
H
L
R
F
10 F
10 F
10 F
10 F
V
OUT
V
OUT
L
.