DS1094LU-42M+ Maxim Integrated Products, DS1094LU-42M+ Datasheet - Page 7

• Manufacturer Part Number: DS1094LU-42M+
• Description: IC ECONOSCILLATOR SS 8-USOP
• Manufacturer: Maxim Integrated Products
• Series: EconOscillator™r
• Type: Clock Generatorr

Specifications of DS1094LU-42M+

• Pll: No
• Input: Clock
• Output: Clock
• Number Of Circuits: 1
• Ratio - Input:output: 2:4
• Differential - Input:output: No/No
• Frequency - Max: 2MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Frequency-max: 2MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 3. Phase Generator Settings
Table 4. Dither Amount Settings
*The frequency is dithered down from the programmed value
of f
Table 5. Dither Frequency Settings
The prescaler divides the master oscillator frequency,
f
calculated using the following formula:
where PRESCALER can be 0 to 3. The prescaler is con-
figured using bits P1 and P0 in the PRESCALER regis-
ter. Valid settings are shown in Table 2. The location of
bits P1 and P0 in the PRESCALER register is shown in
the Control Registers section.
Note that the PRESCALER register also contains bits
controlling other features of the device (dither amount,
dither rate, and phase).
The four oscillator outputs (OUT1 to OUT4) can be con-
figured in either two-phase, three-phase, or four-phase
mode. The output waveforms of each mode are illus-
trated in Figure 1. Likewise, the figure also shows a
comparison of f
phase shifts between the three modes. Bits Ph1 and
Ph0 in the PRESCALER register are used to select the
desired mode (see Table 3). The location of bits Ph1
MOSC
MOSC
, by 1, 2, 4, or 8. The resultant frequency, f
BITS Ph1, Ph0
.
Multiphase Spread-Spectrum EconOscillator
BITS D1, D0
BITS J1, J0
00
01
10
11
00
01
10
11
00
01
10
11
f
OSC
OUT
= f
, the duty cycle, and the output
MOSC
/ 2
PRESCALER
DITHER FREQUENCY
DITHER AMOUNT*
Phase Generator
Three-Phase
Four-Phase
f
Two-Phase
f
f
f
MOSC
_____________________________________________________________________
Reserved
MOSC
MOSC
MOSC
MODE
0%
2%
4%
8%
/1024
/128
/256
/512
Prescaler
OSC
, is
and Ph0 in the PRESCALER register is shown in the
Control Registers section.
The triangle wave generator is used to dither the mas-
ter oscillator frequency, adding spread-spectrum func-
tionality to the DS1094L by injecting an offset element
into the master oscillator. Both the dither amount (%)
and dither frequency are programmable. The dither
amount is controlled by bits J1 and J0 in the
PRESCALER register. The dither frequency is con-
trolled by bits D1 and D0, also in the PRESCALER reg-
ister. The bit settings are shown in Table 4 and 5. The
location of bits J1, J0, D1, and D0 in the PRESCALER
register is shown in the Control Registers section.
When dither is enabled (by selecting a percentage
other than 0%), the master oscillator frequency, f
is dithered between the programmed f
selected percentage down from the programmed
f
grammed to 2MHz (DAC register = 0Ah) and the dither
amount is programmed to 2%, the frequency of f
Figure 1. DS1094L Output Waveforms
Figure 2. DS1094L Dither Waveform
MOSC
PROGRAMMED f
(2, 4, OR 8% OF f
PROGRAMMED f
THREE-PHASE
FOUR-PHASE
(see Figure 2). For example, if f
TWO-PHASE
MOSC
MOSC
MOSC
-
)
OUT1
OUT2
OUT3
OUT4
OUT1
OUT2
OUT3
OUT4
OUT1
OUT2
OUT3
OUT4
f
OSC
DITHER FREQ.
Triangle Wave Generator
1
TIME
IF DITHER AMOUNT = 0%
f
50% DUTY CYCLE
180 DEGREES
OUT OF PHASE
f
33% DUTY CYCLE
120 DEGREES
OUT OF PHASE
f
50% DUTY CYCLE
90 DEGREES OUT
OF PHASE
OUT
OUT
OUT
= f
= f
= f
MOSC
OSC
MOSC
OSC
OSC
/ 3
/ 4
DITHER
AMOUNT
(2, 4, OR 8%)
and the
is pro-
MOSC
MOSC
7
,