14-Bit, 80 MSPS, 3 V A/D Converter
AD9245
FUNCTIONAL BLOCK DIAGRAM
FEATURES
AVDD
DRVDD
Single 3 V supply operation (2.7 V to 3.6 V)
SNR = 72.7 dBc to Nyquist
AD9245
SFDR = 87.6 dBc to Nyquist
Low power: 366 mW
VIN+
VIN–
8-STAGE
MDAC1
A/D
3
SHA
1 1/2-BIT PIPELINE
Differential input with 500 MHz bandwidth
On-chip reference and sample-and-hold
DNL = 0.5 LSB
Flexible analog input: 1 V p-p to 2 V p-p range
Offset binary or twos complement data format
Clock duty cycle stabilizer
4
16
A/D
REFT
REFB
CORRECTION LOGIC
OTR
14
OUTPUT BUFFERS
D13 (MSB)
D0 (LSB)
VREF
APPLICATIONS
SENSE
CLOCK
0.5V
MODE
SELECT
DUTY CYCLE
STABILIZER
High end medical imaging equipment
IF sampling in communications receivers:
WCDMA, CDMA-One, CDMA-2000, TDS-CDMA
Battery-powered instruments
REF
SELECT
AGND
CLK
PDWN MODE DGND
03583-B-001
Hand-held scopemeters
Low cost digital oscilloscopes
Figure 1. Functional Block Diagram
Power sensitive military applications
excellent overall ADC performance. The digital output data is
presented in straight binary or twos complement formats. An
out-of-range (OTR) signal indicates an overflow condition that
can be used with the most significant bit to determine low or
high overflow. Fabricated on an advanced CMOS process, the
AD9245 is available in a 32-lead LFCSP and is specified over
the industrial temperature range (–40°C to +85°C).
GENERAL DESCRIPTION
The AD9245 is a monolithic, single 3 V supply, 14-bit, 80 MSPS
analog-to-digital converter featuring a high performance
sample-and-hold amplifier (SHA) and voltage reference. The
AD9245 uses a multistage differential pipelined architecture
with output error correction logic to provide 14-bit accuracy at
80 MSPS and guarantee no missing codes over the full operat-
ing temperature range.
PRODUCT HIGHLIGHTS
1. The AD9245 operates from a single 3 V power supply and
features a separate digital output driver supply to accommo-
date 2.5 V and 3.3 V logic families.
The wide bandwidth, truly differential SHA allows a variety of
user-selectable input ranges and common modes, including
single-ended applications. It is suitable for multiplexed systems
that switch full-scale voltage levels in successive channels, and
for sampling single-channel inputs at frequencies well beyond
the Nyquist rate. Combined with power and cost savings over
previously available analog-to-digital converters, the AD9245 is
suitable for applications in communications, imaging, and
medical ultrasound.
2. Operating at 80 MSPS, the AD9245 consumes a low 366 mW.
3. The patented SHA input maintains excellent performance for
input frequencies up to 100 MHz, and can be configured for
single-ended or differential operation.
4. The AD9245 is pin compatible with the AD9215, AD9235,
and AD9236. This allows a simplified migration from 10 bits
to 14 bits and 20 MSPS to 80 MSPS.
5. The clock DCS maintains overall ADC performance over a
wide range of clock pulsewidths.
A single-ended clock input is used to control all internal con-
version cycles. A duty cycle stabilizer (DCS) compensates for
wide variations in the clock duty cycle while maintaining
6. The OTR output bit indicates when the signal is beyond the
selected input range.
Rev. B
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