XRD64L44 Datasheet, PDF (1/15 Pages) Exar Corporation – Dual 10-Bit 50MSPS CMOS ADC

Preliminary
FEATURES
• 10-Bit Resolution
• Two Monolithic Complete 10-Bit ADCs
• 50 MSPS Conversion Rate
• On-Chip Track-and-Hold
• On-Chip Voltage Reference
• Low 5 pF Input Capacitance
• TTL/CMOS Outputs
• Tri-State Output Buffers
• Single +3V or +5V Power Supply Operation
• Low Power Dissipation: 250mW-typ @ 3.0V
• -40°C to +85°C Operation Temperature Range
XRD64L44
Dual 10-Bit 50MSPS CMOS ADC
APPLICATIONS
• Medical Ultrasound Imaging
• I & Q Modems
March 2000-1
BENEFITS
• Reduction of Components
• Reduction of System Cost
• High Performance @ Low Power Dissipation
• Long Term Time and Temperature Stability
GENERAL DESCRIPTION
The XRD64L44 is two 10-bit, monolithic, 50 MSPS
ADCs. Manufactured using a standard CMOS pro-
cess, the XRD64L44 offers low power, low cost and
excellent performance. The on-chip track-and-hold
amplifier(T/H) and voltage reference (VREF) eliminate
the need for external active components, requiring only
an external ADC conversion clock for the application.
The XRD64L44 analog input can be driven with ease
due to the high input impedance of RIN = 25KOhms
and CIN = 5pF.
The design architecture uses 17 time- interleaved 10-
bit SAR ADCs in each converter to achieve high
conversion rate of 50 MSPS minimum. In order to
insure and maintain accurate 10-bit operation with
respect to time and temperature, XRD64L44 incorpo-
rates an auto-calibration circuit which continuously
adjusts and matches the offset and linearity of each
ADC. This auto-calibration circuit is transparent to the
user after the initial 3.4ms calibration (168,000 initial
clock cycles).
The power dissipation is only 250mW at 50 MSPS and
225mW at 40 MSPS with +3.0V power supply.
The digital output data is straight binary format, and
the tri-state disable function is provided for common
bus interface.
The XRD64L44 internal reference provides cost sav-
ings and simplifies the design/development. The out-
put voltage of the internal reference is set by two
external resistors. The internal reference can be dis-
abled if an external reference is used for a power
savings of 50mW.
ORDERING INFORMATION
Part Number
XRD64L44AIV
Package Type
64-Lead TQFP
Temperature Range
-40°C to +85°C
Rev. P1.00
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 • [phone] • FAX [phone]