DS1085 Frequency Synthesizer Datasheet

DS1085 Datasheet, PDF, Equivalent


Part Number

DS1085

Description

EconOscillator Frequency Synthesizer

Manufacture

Maxim Integrated

Total Page 21 Pages
Datasheet
Download DS1085 Datasheet


DS1085
www.maxim-ic.com
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
ORDERING INFORMATION
DEVICE
PACKAGE
DS1085Z-10
150mil SO
DS1085Z-25
150mil SO
DS1085Z-50
150mil SO
STEP
SIZE
10kHz
25kHz
50kHz
DS1085
EconOscillator Frequency Synthesizer
PIN ASSIGNMENT
OUT1
OUT0
VCC
GND
1
2
3
4
8
7
6
5
SO (150mil)
SCL
SDA
CTRL1
CTRL0
PIN DESCRIPTION
OUT1 - Main Oscillator Output
OUT0 - Reference Oscillator Output
VCC
GND
- Power-Supply Voltage
- Ground
CTRL1 - Control Pin for OUT1
CTRL0 - Control Pin for OUT0
SDA
- 2-Wire Serial Data Input/Output
SCL - 2-Wire Serial Clock
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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DS1085
DS1085
External control inputs, CTRL1 and CTRL0, enable or disable the two oscillator outputs. Both outputs
feature a synchronous enable that ensures no output glitches when the output is enabled and a constant
time interval (for a given frequency setting) from an enable signal to the first output transition. These
inputs also can be configured to disable the master oscillator, putting the device into a low-power mode
for power-sensitive applications.
Figure 1. DS1085 BLOCK DIAGRAM
0M0 0M1
1M0 1M1
OVERVIEW
A block diagram of the DS1085 is shown in Figure 1. The DS1085 consists of five major components:
§ Master oscillator control DAC
§ Internal master oscillator (66MHz to 133MHz)
§ Prescalers (divide-by-1, 2, 4, or 8)
§ Programmable divider (divide-by-1 to 1025)
§ Control registers
The internal master oscillator provides the reference clock (MCLK), which is fed to the prescalers and
programmable dividers. The frequency of the oscillator can be user-programmed over a two-to-one range
in increments equal to the step size, by means of a 10-bit control DAC. The master oscillator range is
66MHz to 133MHz, which is larger than the range possible with the 10-bit DAC resolution and available
step sizes. Therefore, an additional register (OFFSET) is provided that can be used to select the range of
frequency over which the DAC is used (see Table 1).
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Features www.maxim-ic.com FEATURES § User-Progra mmable Frequency Synthesizer § Program mable From 8.1kHz to 133MHz § Dual Syn chronous Outputs § 8.2MHz to 133MHz Re ference Oscillator Output § 8.1kHz to 133MHz Main Oscillator Output § Three Resolution Options § 2-Wire Serial Int erface § 0.75% Absolute Accuracy § No nvolatile (NV) Frequency Settings § Si ngle 5V Supply § No External Timing Co mponents § Power-Down Mode ORDERING I NFORMATION DEVICE PACKAGE DS1085Z-10 150mil SO DS1085Z-25 150mil SO DS1 085Z-50 150mil SO STEP SIZE 10kHz 25k Hz 50kHz DS1085 EconOscillator Frequen cy Synthesizer PIN ASSIGNMENT OUT1 OU T0 VCC GND 1 2 3 4 8 7 6 5 SO (150mi l) SCL SDA CTRL1 CTRL0 PIN DESCRIPTIO N OUT1 - Main Oscillator Output OUT0 - Reference Oscillator Output VCC GND - Power-Supply Voltage - Ground CTRL1 - Control Pin for OUT1 CTRL0 - Contro l Pin for OUT0 SDA - 2-Wire Serial Da ta Input/Output SCL - 2-Wire Serial Cl ock OSCILLATOR OUTPUT RANGE 8.1kHz to 133MHz 8.1kHz to 133MHz 8.1kHz to 13.
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