FEATURES
Superb Clamping Characteristics
3 mV Clamp Error
1.5 ns Overdrive Recovery
Minimized Nonlinear Clamping Region
240 MHz Clamp Input Bandwidth
؎3.9 V Clamp Input Range
Wide Bandwidth
AD8036
AD8037
Small Signal
240 MHz 270 MHz
Large Signal (4 V p-p) 195 MHz 190 MHz
Good DC Characteristics
2 mV Offset
10 V/؇C Drift
Ultralow Distortion, Low Noise
–72 dBc typ @ 20 MHz
4.5 nV/√Hz Input Voltage Noise
High Speed
Slew Rate 1500 V/s
Settling 10 ns to 0.1%, 16 ns to 0.01%
؎3 V to ؎5 V Supply Operation
APPLICATIONS
ADC Buffer
IF/RF Signal Processing
High Quality Imaging
Broadcast Video Systems
Video Amplifier
Full Wave Rectifier
PRODUCT DESCRIPTION
The AD8036 and AD8037 are wide bandwidth, low distortion
clamping amplifiers. The AD8036 is unity gain stable. The
AD8037 is stable at a gain of two or greater. These devices
allow the designer to specify a high (VCH) and low (VCL) output
clamp voltage. The output signal will clamp at these specified
levels. Utilizing a unique patent pending CLAMPIN™ input
clamp architecture, the AD8036 and AD8037 offer a 10×
improvement in clamp performance compared to traditional
output clamping devices. In particular, clamp error is typically
3 mV or less and distortion in the clamp region is minimized.
This product can be used as a classical op amp or a clamp
amplifier where a high and low output voltage are specified.
The AD8036 and AD8037, which utilize a voltage feedback
architecture, meet the requirements of many applications which
previously depended on current feedback amplifiers. The AD8036
and AD8037 exhibit an exceptionally fast and accurate pulse
response (16 ns to 0.01%), extremely wide small-signal and
FUNCTIONAL BLOCK DIAGRAM
8-Lead Plastic DIP (N), Cerdip (Q),
and SO Packages
NC
1
–INPUT
AD8036/
AD8037
8
VH
2
7
+VS
+INPUT
3
6
OUTPUT
–VS
4
5
VL
(Top View)
NC = NO CONNECT
large-signal bandwidths and ultralow distortion. The AD8036
achieves –66 dBc at 20 MHz, and 240 MHz small-signal and
195 MHz large-signal bandwidths. The AD8036 and AD8037’s
recover from 2× clamp overdrive within 1.5 ns. These characteristics position the AD8036/AD8037 ideally for driving as well as
buffering flash and high resolution ADCs.
In addition to traditional output clamp amplifier applications,
the input clamp architecture supports the clamp levels as additional inputs to the amplifier. As such, in addition to static dc
clamp levels, signals with speeds up to 240 MHz can be applied
to the clamp pins. The clamp values can also be set to any value
within the output voltage range provided that VH is greater that
VL. Due to these clamp characteristics, the AD8036 and AD8037
can be used in nontraditional applications such as a full-wave
rectifier, a pulse generator, or an amplitude modulator. These
novel applications are only examples of some of the diverse
applications which can be designed with input clamps.
The AD8036 is offered in chips, industrial (–40°C to +85°C)
and military (–55°C to +125°C) package temperature ranges
and the AD8037 in industrial. Industrial versions are available
in plastic DIP and SOIC; MIL versions are packaged in cerdip.
4
AD8036
VH = 3V
3
OUTPUT VOLTAGE – Volts
a
Low Distortion, Wide Bandwidth
Voltage Feedback Clamp Amps
AD8036/AD8037
VH = 2V
2
VH = 1V
1
0
VL = –1V
–1
–2
VL = –2V
VL = –3V
–3
CLAMPIN is a trademark of Analog Devices, Inc.
–4
–4
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
–3
–2
–1
0
1
INPUT VOLTAGE – Volts
2
3
4
Figure 1. Clamp DC Accuracy vs. Input Voltage
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2000
