ADA4855-3 Analog Devices, ADA4855-3 Datasheet - Page 14

• Manufacturer Part Number: ADA4855-3
• Description: Single Supply, High Speed, Rail-to-Rail Output, Triple Op Amp
• Manufacturer: Analog Devices

Specifications of ADA4855-3

• Vcc-vee: 3V to 5.5V
• Packages: CSP
• -3db Bandwidth: 400MHz
• Slew Rate: 800V/µs
• Vos: 1mV
• Ib: 4.5µA
• # Opamps Per Pkg: 3
• Input Noise (nv/rthz): 6.5nV/rtHz

ADA4855-3
THEORY OF OPERATION
The ADA4855 is a voltage feedback op amp that employs a new
input stage that achieves a high slew rate while maintaining a
wide common-mode input range. The input common-mode
range of the ADA4855 extends from 200 mV below the negative
rail to 1 V below the positive rail. This feature makes the ADA4855
ideal for single-supply applications. In addition, this new input
stage does not sacrifice noise performance for slew rate. At
6.8 nV/√Hz, the ADA4855 is one of the lowest noise rail-to-
rail output video amplifiers in the market.
Besides a novel input stage, the ADA4855 employs the Analog
Devices, Inc., patented rail-to-rail output stage. This output
stage makes efficient use of the power supplies, allowing the op
amp to drive up to three video loads to within 350 mV of the
positive power rail. In addition, this output stage provides the
amplifier with very fast overdrive characteristics, which is an
important property in video applications.
Rev. 0 | Page 14 of 20
The ADA4855 comes in a 16-lead LFCSP that has an exposed
thermal pad for lower operating temperature. This pad is internally
connected to the negative rail. To avoid printed circuit board (PCB)
layout problems, the ADA4855 features a new pinout flow that
is optimized for video applications. As shown in Figure 4, the
noninverting input and output pins of each amplifier are
adjacent to each other for ease of layout.
The ADA4855 is fabricated in Analog Devices dielectrically
isolated eXtra Fast Complementary Bipolar 3 (XFCB3) process,
which results in the outstanding speed and dynamic range
displayed by the amplifier.
+IN
–IN
G
m1
Figure 46. High Level Design Schematic
–V
+V
S
S
R
C
G
C
m2
1
OUT