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DS1090U-32+T

P1-P3P4-P6P7-P8
General Description
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.
Applications
Switched-Mode Power Supplies
Servers
Printers
Embedded Microcontrollers
Industrial Controls
Automotive Applications
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
Low-Frequency, Spread-Spectrum
EconOscillator
______________________________________________
Maxim Integrated Products
1
J1
J0GND
1
2
8
7
JC1
JC0R
SET
V
CC
OUT
μSOP
TOP VIEW
3
4
6
5
DS1090
Pin Configuration
Ordering Information
DS1090
V
OUT
V
IN
DC-DC
STEP-DOWN
CONVERTER
OUT
GND
V
CC
V
CC
R
SET
JC0
JC1
J0
J1
45kΩ
TO 91kΩ
Typical Operating Circuit
Rev 1; 2/07
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.
Add “T” for Tape & Reel orders.
PART
OUTPUT
FREQUENCY
RANGE
PRESCALER
PIN-
PACKAGE
DS1090U-1+ 4MHz to 8MHz 1 8 μSOP
DS1090U-2+ 2MHz to 4MHz 2 8 μSOP
DS1090U-4+ 1MHz to 2MHz 4 8 μSOP
DS1090U-8+
500kHz to
1MHz
8 8 μSOP
DS1090U-16+
250kHz to
500kHz
16 8 μSOP
DS1090U-32+
125kHz to
250kHz
32 8 μSOP
EconOscillator is a trademark of Dallas Semiconductor.
DS1090
Low-Frequency, Spread-Spectrum
EconOscillator
2 _____________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED DC OPERATING CONDITIONS
(T
A
= -40°C to +85°C)
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted.)
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.
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage V
CC
(Note 1) 3.0 5.5 V
Input Logic 1 (J0, J1, JC0, JC1) V
IH
0.7 x
V
CC
V
CC
+
0.3
V
Input Logic 0 (J0, J1, JC0, JC1) V
IL
-0.3
+0.3 x
V
CC
V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
C
L
= 15pF, V
CC
= 3.3V, R
SET
= 40kΩ 1.4
Supply Current I
CC
C
L
= 15pF, V
CC
= 5.5V, R
SET
= 40kΩ 1.7 3
mA
I
OH
= -4mA
High-Level Output Voltage (OUT) V
OH
V
CC
= min
2.4 V
Low-Level Output Voltage (OUT) V
OL
I
OL
= 4mA 0.4 V
High-Level Input Current
(J0, J1, JC0, JC1)
I
IH
V
IH
= V
CC
+1.0 µA
Low-Level Input Current
(J0, J1, JC0, JC1)
I
IL
V
IL
= 0V -1.0 µA
Resistor Current I
RES
V
CC
= max 150 µA
DS1090
Low-Frequency, Spread-Spectrum
EconOscillator
_____________________________________________________________________ 3
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Internal Master Oscillator
Frequency
f
MOSC
4.0 8.0 MHz
Output Frequency Tolerance f
OUT
V
CC
= 3.3V,
T
A
= +25°C
-3.0 +3.0 %
T
A
= +25°C, R
SET
= 60k,
V
CC
= 3.0V to 3.6V (Notes 2, 3)
-0.5 +0.5
Voltage Frequency Variation f
OUT
T
A
= +25°C, R
SET
= 60k,
V
CC
= 4.5V to 5.5V (Notes 2, 3)
-1.25 +1.25
%
Temperature Frequency Variation f
OUT
V
CC
= 3.3V
(Notes 2, 3, 4)
-2.0 +2.0 %
J0 = GND, J1 = GND 0
J0 = V
CC
, J1 = GND 2
J0 = GND, J1 = V
CC
4
Peak-to-Peak Dither (3)
(Note 5)
J0 = V
CC
, J1 = V
CC
8
%
Power-Up Time
t
POR
+
t
STAB
(Note 6) 0.1 0.5 ms
Load Capacitance C
L
(Note 7) 30 pF
4MHz to 8MHz, T
A
= +25°C (Note 3) 45 55
Output Duty Cycle
<4MHz (Note 4) 50
%
Output Rise/Fall Time t
R
, t
F
C
L
= 15pF 20 ns
AC ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted.)
Note 1: All voltages referenced to ground.
Note 2: This is the change observed in output frequency due to changes in temperature or voltage.
Note 3: See the Typical Operating Characteristics section.
Note 4: Parameter is guaranteed by design and is not production tested.
Note 5: This is a percentage of the output period. Parameter is characterized but not production tested. This can be varied from
0% to 8%.
Note 6: This indicates the time between power-up and the outputs becoming active. An on-chip delay is intentionally introduced to
allow the oscillator to stabilize. t
STAB
is equivalent to ~500 clock cycles and is dependent upon the programmed
output frequency.
Note 7: Output voltage swings can be impaired at high frequencies combined with high output loading.
P1-P3P4-P6P7-P8

DS1090U-32+T

Mfr. #:
Buy DS1090U-32+T
Manufacturer:
Maxim Integrated
Description:
Programmable Oscillators Low-Frequency Spread Spctrm EconOscillat
Lifecycle:
New from this manufacturer.
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