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-radiated
emissions from the power supply at its fundamental
frequency, as well as harmonic frequencies. The device
consists of a resistor-programmed master oscillator, fac-
tory-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 emissions. 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.
●
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
Features
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
DS1090U-1+
DS1090U-2+
DS1090U-4+
DS1090U-8+
DS1090U-16+
Typical Operating Circuit
V
IN
V
OUT
DS1090U-32+
Add “T” for Tape & Reel orders.
V
CC
DC-DC
STEP-DOWN
CONVERTER
OUT
JC0
Pin Configuration
TOP VIEW
V
CC
DS1090
JC1
R
SET
45kΩ
TO 91kΩ
GND
J0
J1
OUT 1
R
SET
2
V
CC
3
8
JC1
JC0
J1
J0
DS1090
7
6
5
GND 4
µSOP
EconOscillator is a trademark of Maxim Integrated Products, Inc.
19-7500; Rev 3; 9/16
DS1090
Low-Frequency, Spread-Spectrum EconOscillator
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.
(T
A
= -40°C to +85°C)
Supply Voltage
Recommended DC Operating Conditions
PARAMETER
Input Logic 1 (J0, J1, JC0, JC1)
Input Logic 0 (J0, J1, JC0, JC1)
SYMBOL
V
CC
V
IH
V
IL
(Note 1)
CONDITIONS
MIN
3.0
0.7 x
V
CC
-0.3
TYP
MAX
5.5
V
CC
+
0.3
+0.3 x
V
CC
UNITS
V
V
V
DC Electrical Characteristics
PARAMETER
Supply Current
High-Level Output Voltage (OUT)
Low-Level Output Voltage (OUT)
High-Level Input Current
(J0, J1, JC0, JC1)
Low-Level Input Current
(J0, J1, JC0, JC1)
Resistor Current
(V
CC
= +3.0V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted.)
SYMBOL
I
CC
V
OH
VOL
I
IH
I
IL
I
RES
CONDITIONS
C
L
= 15pF, V
CC
= 3.3V, R
SET
= 40kΩ
MIN
TYP
1.4
1.7
2.4
0.4
+1.0
-1.0
150
MAX
3
UNITS
mA
V
V
µA
µA
µA
CL = 15pF, V
CC
= 5.5V, R
SET
= 40kΩ
I
OH
= -4mA
V
CC
= min
I
OL
= 4mA
V
IH
= VCC
V
IL
= 0V
V
CC
= max
www.maximintegrated.com
Maxim Integrated
│
2
DS1090
Low-Frequency, Spread-Spectrum EconOscillator
AC Electrical Characteristics
PARAMETER
Internal Master Oscillator
Frequency
Output Frequency Tolerance
(V
CC
= +3.0V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted.)
SYMBOL
f
MOSC
∆f
OUT
V
CC
= 3.3V,
T
A
= +25°C
T
A
= +25°C, R
SET
= 60kΩ,
V
CC
= 3.0V to 3.6V (Notes 2, 3)
T
A
= +25°C, R
SET
= 60kΩ,
V
CC
= 4.5V to 5.5V (Notes 2, 3)
V
CC
= 3.3V
(Notes 2, 3, 4)
J0 = GND, J1 = GND
Peak-to-Peak Dither (3σ)
(Note 5)
t
POR
+
t
STAB
C
L
J0 = GND, J1 = V
CC
J0 = V
CC
, J1 = V
CC
(Note 6)
(Note 7)
<4MHz (Note 4)
t
R
, t
F
C
L
= 15pF
4MHz to 8MHz, T
A
= +25°C (Note 3)
45
50
20
J0 = VCC, J1 = GND
CONDITIONS
MIN
4.0
-3.0
-0.5
-1.25
-2.0
0
2
4
8
0.1
0.5
30
55
ms
pF
%
ns
%
TYP
MAX
8.0
+3.0
+0.5
%
+1.25
+2.0
%
UNITS
MHz
%
Voltage Frequency Variation
∆f
OUT
Temperature Frequency Variation
∆f
OUT
Power-Up Time
Load Capacitance
Output Duty Cycle
Output Rise/Fall Time
Note
Note
Note
Note
Note
1:
2:
3:
4:
5:
All voltages referenced to ground.
This is the change observed in output frequency due to changes in temperature or voltage.
See the
Typical Operating Characteristics
section.
Parameter is guaranteed by design and is not production tested.
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.
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