DS1085
EconOscillator Frequency Synthesizer
www.maxim-ic.com
FEATURES
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User-Programmable Frequency Synthesizer
Programmable From 8.1kHz to 133MHz
Dual Synchronous Outputs
8.2MHz to 133MHz Reference Oscillator
Output
8.1kHz to 133MHz Main Oscillator Output
Three Resolution Options
2-Wire Serial Interface
0.75% Absolute Accuracy
Nonvolatile (NV) Frequency Settings
Single 5V Supply
No External Timing Components
Power-Down Mode
PIN ASSIGNMENT
OUT1
OUT0
V
CC
GND
1
2
3
4
8
7
6
5
SCL
SDA
CTRL1
CTRL0
SO (150mil)
PIN DESCRIPTION
OUT1
OUT0
V
CC
GND
CTRL1
CTRL0
SDA
SCL
- Main Oscillator Output
- Reference Oscillator Output
- Power-Supply Voltage
- Ground
- Control Pin for OUT1
- Control Pin for OUT0
- 2-Wire Serial Data Input/Output
- 2-Wire Serial Clock
ORDERING INFORMATION
DEVICE
DS1085Z-10
DS1085Z-25
DS1085Z-50
PACKAGE
150mil SO
150mil SO
150mil SO
STEP
SIZE
10kHz
25kHz
50kHz
OSCILLATOR
OUTPUT RANGE
8.1kHz to 133MHz
8.1kHz to 133MHz
8.1kHz to 133MHz
DESCRIPTION
The DS1085 is a dual-output frequency synthesizer requiring no external timing components for
operation. It can be used as a standalone oscillator or as a dynamically programmed, processor-controlled
peripheral device. An internal master oscillator can be programmed from 66MHz to 133MHz with three
resolution options of 10kHz, 25kHz, and 50kHz. A programmable, 3-bit prescaler (divide-by-1, 2, 4, or 8)
permits the generation of a reference oscillator output (OUT0) from the master, ranging from 8.2MHz to
133MHz. A second independent prescaler and a 1-to-1025 divider allows the generation of a main
oscillator output (OUT1) from 8.1kHz to 133MHz. The two outputs, although synchronous with the
master, can be independently programmed. The combination of programmable master oscillator,
prescalers, and dividers allows the generation of thousands of user-specified frequencies. All master
oscillator, prescaler, and divider settings are stored in NV (EEPROM) memory, providing a default value
on power-up that allows it to be used as a standalone oscillator. A 2-wire serial interface allows in-circuit,
on-the-fly programming of the master oscillator, prescalers (P0 and P1), and divider (N). This allows
dynamic frequency modification, if required, or, for fixed-frequency applications, the DS1085 can be
used with factory- or user-programmed values.
EconOscillator is a trademark of Dallas Semiconductor.
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DALLAS [ DALLAS SEMICONDUCTOR ]
