250 MHz, General Purpose
Voltage Feedback Op Amps
AD8047/AD8048
FEATURES
Wide Bandwidth
AD8047, G = +1
Small Signal
250 MHz
Large Signal (2 V p-p) 130 MHz
AD8048, G = +2
260 MHz
160 MHz
5.8 mA Typical Supply Current
Low Distortion, (SFDR) Low Noise
–66 dBc Typ @ 5 MHz
–54 dBc Typ @ 20 MHz
5.2 nV/√Hz (AD8047), 3.8 nV/√Hz (AD8048) Noise
Drives 50 pF Capacitive Load
High Speed
Slew Rate 750 V/s (AD8047), 1000 V/s (AD8048)
Settling 30 ns to 0.01%, 2 V Step
؎3 V to ؎6 V Supply Operation
APPLICATIONS
Low Power ADC Input Driver
Differential Amplifiers
IF/RF Amplifiers
Pulse Amplifiers
Professional Video
DAC Current to Voltage Conversion
Baseband and Video Communications
Pin Diode Receivers
Active Filters/Integrators
FUNCTIONAL BLOCK DIAGRAM
8-Pin Plastic PDIP (N)
and SOIC (R) Packages
AD8047/
AD8048
8
NC
2
7
+VS
+INPUT
3
6
OUTPUT
–V S
4
5
NC
NC
1
–INPUT
(TOP VIEW)
NC = NO CONNECT
The AD8047 and AD8048’s low distortion and cap load drive
make the AD8047/AD8048 ideal for buffering high speed ADCs.
They are suitable for 12-bit/10 MSPS or 8-bit/60 MSPS ADCs.
Additionally, the balanced high impedance inputs of the voltage
feedback architecture allow maximum flexibility when designing
active filters.
The AD8047 and AD8048 are offered in industrial (–40°C to
+85°C) temperature ranges and are available in 8-lead PDIP
and SOIC packages.
PRODUCT DESCRIPTION
The AD8047 and AD8048 are very high speed and wide bandwidth amplifiers. The AD8047 is unity gain stable. The AD8048 is
stable at gains of two or greater. The AD8047 and AD8048,
which utilize a voltage feedback architecture, meet the requirements of many applications that previously depended on current
feedback amplifiers.
A proprietary circuit has produced an amplifier that combines
many of the best characteristics of both current feedback and
voltage feedback amplifiers. For the power (6.6 mA max), the
AD8047 and AD8048 exhibit fast and accurate pulse response
(30 ns to 0.01%) as well as extremely wide small signal and large
signal bandwidth and low distortion. The AD8047 achieves
–54 dBc distortion at 20 MHz, 250 MHz small signal, and
130 MHz large signal bandwidths.
1V
5ns
Figure 1. AD8047 Large Signal Transient Response,
VO = 4 V p-p, G = +1
REV. A
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