DS1085
EconOscillator Frequency Synthesizer
www.maxim-ic.com
FEATURES
PIN ASSIGNMENT
CꢀUser-Programmable Frequency Synthesizer
CꢀProgrammable From 8.1kHz to 133MHz
CꢀDual Synchronous Outputs
Cꢀ8.2MHz to 133MHz Reference Oscillator
Output
1
8
OUT1
OUT0
SCL
2
7
3
4
6
5
CTRL1
CTRL0
GND
Cꢀ8.1kHz to 133MHz Main Oscillator Output
CꢀThree Resolution Options
Cꢀ2-Wire Serial Interface
SO (150mil)
Cꢀ0.75% Absolute Accuracy
CꢀNonvolatile (NV) Frequency Settings
CꢀSingle 5V Supply
PIN DESCRIPTION
CꢀNo External Timing Components
CꢀPower-Down Mode
OUT1
OUT0
VCC
- Main Oscillator Output
- Reference Oscillator Output
- Power-Supply Voltage
- Ground
GND
CTRL1 - Control Pin for OUT1
CTRL0 - Control Pin for OUT0
SDA
- 2-Wire Serial Data Input/Output
SCL - 2-Wire Serial Clock
ORDERING INFORMATION
STEP
OSCILLATOR
OUTPUT RANGE
8.1kHz to 133MHz
8.1kHz to 133MHz
8.1kHz to 133MHz
DEVICE
DS1085Z-10
DS1085Z-25
DS1085Z-50
PACKAGE
150mil SO
150mil SO
150mil SO
SIZE
10kHz
25kHz
50kHz
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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