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General Description

The DS1087L is a clock generator that produces a

spread-spectrum (dithered) square-wave output of fre-

quencies from 130kHz to 66.6MHz. The DS1087L is

shipped from the factory programmed at a specific fre-

quency and spread-spectrum percentage. The user still

has access to an internal frequency divider, selectable

2% or 4% dithered output, and programmable output

power-down/disable mode through a 2-wire program-

ming interface. All the device settings are stored in non-

volatile (NV) EEPROM allowing it to operate in

stand-alone applications. The DS1087L has power-

down and output-enable control pins for power-sensi-

tive applications.

Applications

Printers

Copiers

PCs

Computer Peripherals

Cell Phones

Cable Modems

Features

♦ Factory Programmed Square-Wave Generator

from 130kHz to 66.6MHz

♦ No External Timing Components Required

♦ EMI Reduction

♦ 2.7V to 3.6V Supply

♦ User Programmable Down to 130kHz with Divider

(Dependent on Master Oscillator Frequency)

♦ 2% or 4% Selectable Dithered Output

♦ Glitchless Output-Enable Control

♦ 2-Wire Serial Interface

♦ Nonvolatile Settings

♦ Power-Down Mode

♦ Programmable Output Power-Down/Disable Mode

DS1087L

3.3V Spread-Spectrum EconOscillator

______________________________________________ Maxim Integrated Products 1

PDN

OEGND

SCL

SDASPRD

OUT

µSOP (118 mils)

TOP VIEW

DS1087L

Pin Configuration

Ordering Information

Rev 0; 7/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

DS1087LU-yxx -40°C to +85°C

8 µSOP (118 mils)

EconOscillator is a trademark of Dallas Semiconductor.

Typical Operating Circuits appear at end of data sheet.

Standard Frequency Options

PART

FREQUENCY (MHz)

SPREAD (%)

DS1087LU-202

2.0480 2

DS1087LU-402

2.0480 4

DS1087LU-210

10.0 2

DS1087LU-216

16.6 2

DS1087LU-266

66.6 2

DS1087LU-466

66.6 4

DS1087LU-yxx

Fixed up to 66.6 2 or 4

Custom frequencies and over 20 standard frequencies avail-

able, contact factory.

Summary of content (12 pages)

PAGE 1
Rev 0; 7/03 3.3V Spread-Spectrum EconOscillator The DS1087L is a clock generator that produces a spread-spectrum (dithered) square-wave output of frequencies from 130kHz to 66.6MHz. The DS1087L is shipped from the factory programmed at a specific frequency and spread-spectrum percentage. The user still has access to an internal frequency divider, selectable 2% or 4% dithered output, and programmable output power-down/disable mode through a 2-wire programming interface.
PAGE 2
DS1087L 3.3V Spread-Spectrum EconOscillator ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC Relative to Ground ..........-0.5V to +6.0V Voltage Range on SPRD, PDN, OE, SDA, SCL Relative to Ground* ................................-0.5V to (VCC + 0.5V) Operating Temperature Range ...........................-40°C to +85°C *This voltage must not exceed 6.0V. Programming Temperature Range .........................0°C to +70°C Storage Temperature Range .............................
PAGE 3
.3V Spread-Spectrum EconOscillator (VCC = 2.7V to 3.6V, TA = -40°C to +85°C.) PARAMETER Master Oscillator Range Available SYMBOL CONDITION f0 MIN TYP MAX UNITS 33.3 66.6 MHz Master Oscillator Frequency Tolerance ∆f0 f0 VCC = 3.3V, TA = +25°C (Note 2) -0.5 +0.5 % Voltage Frequency Variation ∆fV f0 Over voltage range, TA = +25°C (Note 3) -0.75 +0.75 % Temperature Frequency Variation ∆fT f0 0°C to +70°C, VCC = 3.3V (Note 4) -0.5 +0.
PAGE 4
DS1087L 3.3V Spread-Spectrum EconOscillator AC ELECTRICAL CHARACTERISTICS—2-WIRE INTERFACE (VCC = 2.7V to 3.6V, TA = 0°C to +70°C.
PAGE 5
3.3V Spread-Spectrum EconOscillator Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: Note 10: Note 11: Note 12: All voltages are referenced to ground. This is the absolute accuracy of the master oscillator frequency at the default settings. This is the change that is observed in master oscillator frequency with changes in voltage from nominal voltage at TA = +25°C. This is the percentage frequency change from the +25°C frequency due to temperature at VCC = 3.3V.
PAGE 6
Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. TEMPERATURE WITH OE = 0 3.5 2.0 DS1087L toc05 VCC = 3.3V OUPUT UNLOADED VCC = 2.7V OUTPUT UNLOADED 1.6 3 -40°C, +25°C, +85°C 1.4 CURRENT (µA) CURRENT (mA) 2.5 FREQUENCY = 66.6MHz 2.0 1.5 2 FREQUENCY = 206.4kHz 10 100 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 PRESCALER (DECIMAL) TEMPERATURE (°C) TEMPERATURE (°C) FREQUENCY % CHANGE vs. SUPPLY VOLTAGE FREQUENCY % CHANGE vs.
PAGE 7
3.3V Spread-Spectrum EconOscillator PIN NAME FUNCTION 1 OUT Oscillator Output 2 SPRD Dither Enable. When the pin is high, the dither is enabled. When the pin is low, the dither is disabled. 3 VCC 4 GND Power Supply Ground 5 OE Output Enable. When the pin is high, the output buffer is enabled. When the pin is low, the output is disabled but the internal master oscillator is still on. 6 PDN Power-Down. When the pin is high, the master oscillator is enabled.
PAGE 8
DS1087L 3.3V Spread-Spectrum EconOscillator Table 1. Register Summary REGISTER ADDR BINARY PRESCALER 02h X1 X1 LO/ HIZ ADDR 0Dh X1 X1 X1 WRITE EE 3Fh J0 P3 P2 P1 X1 WC A2 A1 FACTORY DEFAULT ACCESS P0 110- - - - - b R/W A0 11110000b R/W — — No Data X1 = Don’t care; read as one. Detailed Description A block diagram of the DS1087L is shown in Figure 1. Output Frequency The internal master oscillator can generate a square wave with a frequency range of 33.3MHz to 66.6MHz.
PAGE 9
3.3V Spread-Spectrum EconOscillator _______2-Wire Serial Port Operation Prescaler Divider. The prescaler bits (bits P3 to P0) divide the master oscillator frequency by 2x where x can be from 0 to 8. Any prescaler bit value entered that is greater than 8 decodes as 8. 2-Wire Serial Data Bus The DS1087L communicates through a 2-wire serial interface. A device that sends data onto the bus is defined as a transmitter, and a device receiving data as a receiver.
PAGE 10
MSB A2 A1 DEVICE ADDRESS A0 R/W IT 1 D/W DEVICE IDENTIFIER 1 EB 0 RIT 1 LSB RE A DS1087L 3.3V Spread-Spectrum EconOscillator Figure 4. Slave Address Data valid: The state of the data line represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed during the LOW period of the clock signal. There is one clock pulse per bit of data.
PAGE 11
3.3V Spread-Spectrum EconOscillator DS1087L SDA tBUF tSP tHD:STA tLOW tR tF SCL tHD:STA STOP tSU:STA tHIGH tSU:DAT START REPEATED START tSU:STO tHD:DAT Figure 5.
PAGE 12
DS1087L 3.3V Spread-Spectrum EconOscillator Typical Operating Circuits Stand-Alone Mode Processor-Controlled Mode VCC MICROPROCESSOR 4.7kΩ DITHERED 130kHz TO 66.6MHz OUTPUT VCC 4.7kΩ XTL1/OSC1 XTL2/OSC2 SCL OUT SPRD SDA DS1087L VCC PDN GND OE VCC 2-WIRE INTERFACE VCC DITHERED 130kHz TO 66.6MHz OUTPUT VCC N.C. SCL* OUT SPRD DS1087L SDA* VCC PDN GND OE DECOUPLING CAPACITORS (0.1µF and 0.