a
FEATURES
Phase and Frequency Detection
ECL/TTL/CMOS Compatible
Linear Transfer Function
No “Dead Zone”
MIL-STD-883 Compliant Versions Available
APPLICATIONS
Low Phase Noise Reference Loops
Fast-Tuning “Agile” IF Loops
Secure “Hopping” Communications
Coherent Radar Transmitter/Receiver Chains
Ultrahigh Speed
Phase/Frequency Discriminator
AD9901
PHASE-LOCKED LOOP
REFERENCE
INPUT
LOW-
PASS
FILTER
VCO
OSCILLATOR
OUTPUT
AD9901
1/N
OPTIONAL 1/N PRESCALER
TYPICAL OF DIGITAL PLLs
GENERAL DESCRIPTION
The AD9901 is a digital phase/frequency discriminator capable
of directly comparing phase/frequency inputs up to 200 MHz.
Processing in a high speed trench-oxide isolated process, com-
bined with an innovative design, gives the AD9901 a linear
detection range, free of indeterminate phase detection zones
common to other digital designs.
With a single +5 V supply, the AD9901 can be configured to
operate with TTL or CMOS logic levels; it can also operate
with ECL inputs when operated with a –5.2 V supply. The
open-collector outputs allow the output swing to be matched to
post-filtering input requirements. A simple current setting resis-
tor controls the output stage current range, permitting a reduc-
tion in power when operated at lower frequencies.
A major feature of the AD9901 is its ability to compare
phase/frequency inputs at standard IF frequencies without
prescalers. Excessive phase uncertainty which is common with
standard PLL configurations is also eliminated. The AD9901
provides the locking speed of traditional phase/frequency dis-
criminators, with the phase stability of analog mixers.
The AD9901 is available as a commercial temperature range
device, 0°C to +70°C, and as a military temperature device,
–55°C to +125°C. The commercial versions are packaged in a
14-lead ceramic DIP and a 20-lead PLCC.
The AD9901 Phase/Frequency Discriminator is available in
versions compliant with MIL-STD-883. Refer to the Analog
Devices
Military Products Databook
or current AD9901/883B
data sheet for specifications.
FUNCTIONAL BLOCK DIAGRAM
D
REFERENCE
INPUT
FLIP-FLOP
REFERENCE
INPUT
Q
D
Q
Q
REFERENCE
FREQUENCY
DISCRIMINATOR
FLIP-FLOP
Q
R
OUTPUT
OUTPUT
D
Q
XOR
S
OSCILLATOR
INPUT
FLIP-FLOP
OSCILLATOR
INPUT
Q
D
Q
OSCILLATOR
FREQUENCY
DISCRIMINATOR
FLIP-FLOP
Q
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1999
AD [ ANALOG DEVICES ]
