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FEATURES

§ 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

PIN DESCRIPTION

OUT1

- Main Oscillator Output

OUT0

- Reference Oscillator Output

- Power-Supply Voltage

GND

- Ground

CTRL1

- Control Pin for OUT1

CTRL0

- Control Pin for OUT0

SDA

- 2-Wire Serial Data Input/Output

SCL

- 2-Wire Serial Clock

ORDERING INFORMATION

DEVICE

PACKAGE

STEP

SIZE

OSCILLATOR

OUTPUT RANGE

DS1085Z-10

150mil SO

10kHz

8.1kHz to 133MHz

DS1085Z-25

150mil SO

25kHz

8.1kHz to 133MHz

DS1085Z-50

150mil SO

50kHz

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.

DS1085

EconOscillator Frequency Synthesizer

www.maxim-ic.com

SO (150mil)

SCL

CTRL0

CTRL1

OUT1

OUT0

GND

8

7

6

5

1

2

3

4

SDA

EconOscillator is a trademark of Dallas Semiconductor.