The DS1090 is a low-cost, dithered oscillator intended
to be used as an external clock for switched-mode
power supplies and other low-frequency applications.
The dithering or sweeping function reduces peak-radi-
ated emissions from the power supply at its fundamen-
tal frequency, as well as harmonic frequencies. The
device consists of a resistor-programmed master oscil-
lator, factory-programmed clock prescaler, and a pin-
programmed dither circuit. These features allow the
DS1090 to be used in applications where a spread-
spectrum clock is desired to reduce radiated emis-
sions. A combination of factory-set prescalers and
external resistor allows for output frequencies ranging
from 125kHz to 8MHz. Both dither frequency and dither
percentage are set using control pins.
Features
♦
Low-Cost, Spread-Spectrum EconOscillator™
♦
Simple User Programming
♦
Output Frequency Programmable from 125kHz
to 8MHz
♦
Dither Percentage Programmable from 0% to 8%
♦
Dither Rate Programmable (f
MOSC
/ 512, 1024,
2048, or 4096 )
♦
3.0V to 5.5V Single-Supply Operation
♦
CMOS/TTL-Compatible Output
♦
Operating Temperature Range: -40°C to +85°C
DS1090
Ordering Information
PART
OUTPUT
FREQUENCY
RANGE
4MHz to 8MHz
2MHz to 4MHz
1MHz to 2MHz
500kHz to
1MHz
250kHz to
500kHz
125kHz to
250kHz
PRESCALER
1
2
4
8
16
32
PIN-
PACKAGE
8 μSOP
8 μSOP
8 μSOP
8 μSOP
8 μSOP
8 μSOP
Applications
Switched-Mode Power Supplies
Servers
Printers
Embedded Microcontrollers
Industrial Controls
Automotive Applications
DS1090U-1+
DS1090U-2+
DS1090U-4+
DS1090U-8+
DS1090U-16+
DS1090U-32+
Add “T” for Tape & Reel orders.
Typical Operating Circuit
V
IN
V
OUT
Pin Configuration
TOP VIEW
V
CC
DC-DC
STEP-DOWN
CONVERTER
OUT
JC0
OUT 1
R
SET
2
8
7
JC1
JC0
J1
J0
V
CC
DS1090
V
CC
3
6
5
GND 4
DS1090
JC1
R
SET
45kΩ
TO 91kΩ
GND
J0
J1
μSOP
EconOscillator is a trademark of Dallas Semiconductor.
______________________________________________
Maxim Integrated Products
1
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.
Low-Frequency, Spread-Spectrum
EconOscillator
DS1090
ABSOLUTE MAXIMUM RATINGS
Voltage Range on V
CC
Relative to Ground ...........-0.5V to +6.0V
Voltage Range on Input Pins
Relative to Ground.................................-0.5V to (V
CC
+ 0.5V),
not to exceed 6.0V
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature .......................................See IPC/JEDEC
J-STD-020A Specification
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
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