AD7482 Datasheet, PDF (1/16 Pages) Analog Devices – 3MSPS, 12-Bit SAR ADC

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3 MSPS, 12-Bit SAR ADC
AD7482
FEATURES
Fast Throughput Rate: 3 MSPS
Wide Input Bandwidth: 40 MHz
No Pipeline Delays with SAR ADC
Excellent DC Accuracy Performance
Two Parallel Interface Modes
Low Power:
90 mW (Full Power) and 2.5 mW (NAP Mode)
Standby Mode: 2 ␮A Max
Single 5 V Supply Operation
Internal 2.5 V Reference
Full-Scale Overrange Mode (using 13th Bit)
System Offset Removal via User Access Offset Register
Nominal 0 V to 2.5 V Input with Shifted Range
Capability
14-Bit Pin Compatible Upgrade AD7484 Available
GENERAL DESCRIPTION
The AD7482 is a 12-bit, high speed, low power, successive-
approximation ADC. The part features a parallel interface with
throughput rates up to 3 MSPS. The part contains a low noise,
wide bandwidth track-and-hold that can handle input fre-
quencies in excess of 40 MHz.
The conversion process is a proprietary algorithmic successive-
approximation technique that results in no pipeline delays. The
input signal is sampled, and a conversion is initiated on the
falling edge of the CONVST signal. The conversion process is
controlled via an internally trimmed oscillator. Interfacing is via
standard parallel signal lines, making the part directly compat-
ible with microcontrollers and DSPs.
The AD7482 provides excellent ac and dc performance specifi-
cations. Factory trimming ensures high dc accuracy resulting in
very low INL, offset, and gain errors.
The part uses advanced design techniques to achieve very low
power dissipation at high throughput rates. Power consumption
in the normal mode of operation is 90 mW. There are two power-
saving modes: a NAP Mode that keeps the reference circuitry alive
for a quick power-up while consuming 2.5 mW, and a STANDBY
Mode that reduces power consumption to a mere 10 µW.
FUNCTIONAL BLOCK DIAGRAM
AV_DD AGND C_BIAS DV_DD V_DRIVE DGND
REFSEL
2.5 V
REFERENCE
BUF
REFOUT
REFIN
VIN
T/H
12-BIT
ALGORITHMIC SAR
AD7482
D12
MODE1
MODE2
CLIP
NAP
STBY
RESET
CONVST
CONTROL
LOGIC AND I/O
REGISTERS
D11
D10
D9
D8
D7
D6
D5
The AD7482 features an on-board 2.5 V reference but can also
accommodate an externally provided 2.5 V reference source. The
nominal analog input range is 0 V to 2.5 V, but an offset shift
capability allows this nominal range to be offset by ± 200 mV.
This allows the user considerable flexibility in setting the bottom
end reference point of the signal range, a useful feature when
using single-supply op amps.
The AD7482 also provides the user with an 8% overrange
capability via a 13th bit. Thus, if the analog input range strays
outside the nominal by up to 8%, the user can still accurately
resolve the signal by using the 13th bit.
The AD7482 is powered by a 4.75 V to 5.25 V supply. The part
also provides a V_DRIVE Pin that allows the user to set the voltage
levels for the digital interface lines. The range for this V_DRIVE Pin
is 2.7 V to 5.25 V. The part is housed in a 48-lead LQFP package
and is specified over a –40°C to +85°C temperature range.
REV. 0
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© Analog Devices, Inc., 2002