DS1091LUA-040+ Maxim Integrated Products, DS1091LUA-040+ Datasheet - Page 6

• Manufacturer Part Number: DS1091LUA-040+
• Description: Timers & Support Products Automotive Temperatu re Range Spread-Spec
• Manufacturer: Maxim Integrated Products

Specifications of DS1091LUA-040+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The DS1091L clock generator is capable of output fre-
quencies from 130kHz to 66.6MHz over the full automo-
tive temperature range (-40°C to +125°C). The device
can also produce a spread-spectrum (dithered) square-
wave output using four pin-selectable dither percent-
ages. Both center (DS1091LUA) and down (DS1091LUB)
dithering options are available. The device also features
two selectable dither rates.
The DS1091L is shipped from the factory programmed to
a customer-specified frequency.
The DS1091L can reduce radiated emission peaks. The
dither percentage is controlled by the state of the SEL0
and SEL1 pins. The output frequency can be dithered
at 0%, ±1%, ±2%, and ±4%, centered around the pro-
grammed frequency (for the DS1091LUB this can be
down dithered by 0%, -2%, -4%, and -8%).
The two select pins SEL0 and SEL1 provide a means of
selecting the dither magnitudes as follows:
A triangle-wave generator injects a control signal into the
master oscillator to dither its output. The dither rate is a
function of the output frequency, f
ting of the DR pin (see the equation below).
Figure 1B
where n is defined in
frequency. For example, for an output frequency of
27.0MHz, the dither rate would be 13.2kHz for DR = 1
and 6.6kHz for DR = 0.
Figure 1A. Center Dithered
(1%, 2%, OR 4% OF f
(1%, 2%, OR 4% OF f
PROGRAMMED f
PROGRAMMED f
PROGRAMMED f
show a plot of the output frequency vs. time.
OUT
OUT
OUT
OUT
OUT
+
-
)
)
DITHER RATE
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DITHER FREQ
Table 2
Detailed Description
1
TIME
=
as a function of output
IF DITHER AMOUNT = 0%
OUT
f
Spread Spectrum
OUT
2
n
DS1091L Frequency Spreading Profile as a Function of Dither %
, as well as the set-
Spread-Spectrum EconOscillator™
Figure 1A
Automotive Temperature Range
DITHER
AMOUNT
(±1%, ±2%,
OR ±4%)
and
Upon the application of power, the DS1091L output is
held in the low state until t
any possibility of erroneous output transitions during ini-
tial power-up.
Table 1. Dither Magnitude
Table 2. Value of n w.r.t. Output Frequency
Figure 1B. Down Dithered
OUTPUT FREQUENCY f
(2%, 4%, OR 8% OF f
f
OUT
PROGRAMMED f
LEVEL
LOGIC
16.668
33.334
PROGRAMMED f
0.130
0.261
0.522
1.043
2.084
4.168
8.334
SEL1
0
0
1
1
(min)
(MHz)
OUT
OUT
OUT
-
)
f
OUT
LOGIC
LEVEL
16.667
33.333
66.667
SEL0
0.260
0.521
1.042
2.083
4.167
8.333
0
1
0
1
(max)
DITHER FREQ
OUT
PU
1
has elapsed. This removes
DR = LOGIC
DS1091LUA
TIME
DITHER MAGNITUDE (%)
No dither
LEVEL 1
Q1
Q2
Q4
10
11
12
IF DITHER AMOUNT = 0%
4
5
6
7
8
9
DS1091L
n
DR = LOGIC
DS1091LUB
Power-Up
No dither
LEVEL 0
10
11
12
13
-2
-4
-8
5
6
7
8
9
DITHER
AMOUNT
(-2%, -4%,
OR -8%)