DS1077L
3V EconOscillator/Divider
www.maxim-ic.com
FEATURES
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Processor-controlled or stand-alone solid-
state oscillator
Frequency changes on the fly
Dual, low-jitter, synchronous fixed-
frequency outputs
2-wire serial interface
Frequency outputs 4.87kHz to 66.666MHz
±1.25% variation over temperature and
voltage
±0.5% initial tolerance
Nonvolatile frequency settings
Single 2.7V to 3.6V supply
No external components
Power-down mode
Synchronous output gating
PIN ASSIGNMENTS
OUT1
OUT0
V
CC
GND
1
2
3
4
8
7
6
5
SCL
SDA
CTRL1
CTRL0
150mil SO
118mil µSOP*
PIN DESCRIPTIONS
OUT1
OUT0
V
CC
GND
CTRL1
CTRL0
SDA
SCL
STANDARD FREQUENCY OPTION
Note: x denotes package option
DS1077Lx-40
40.000MHz to 4.87kHz
DS1077Lx-50
50.000MHz to 6.09kHz
DS1077Lx-60
60.000MHz to 7.32kHz
DS1077Lx-66
66.666MHz to 8.13kHz
Contact the factory for the availability of
additional frequencies.
- Main Oscillator Output
- Reference Output
- Power-Supply Voltage
- Ground
- Control Pin for OUT1
- Control Pin for OUT0
- 2-Wire Serial Data
Input/Output
- 2-Wire Serial Clock
ORDERING INFORMATION
Note: XXX denotes frequency option
DS1077LZ-XXX 8-pin 150mil SO
DS1077LU-XXX* 8-pin 118mil µSOP
DESCRIPTION
The DS1077L is a dual-output, programmable, fixed-frequency oscillator requiring no external
components for operation. The DS1077L can be used as a processor-controlled frequency synthesizer or
as a stand-alone oscillator. The two synchronous output operating frequencies are user-adjustable in
submultiples of the master frequency through the use of two on-chip programmable prescalers and
dividers. The specific output frequencies chosen are stored in nonvolatile (EEPROM) memory. The
DS1077L defaults to these values upon power-up.
The DS1077L features a 2-wire serial interface that allows in-circuit on-the-fly programming of the
programmable prescalers (P0 & P1) and divider (N) with the desired values being stored in nonvolatile
(EEPROM) memory. Design changes can be accommodated in-circuit, on-the-fly by simply programming
different values into the device (or reprogramming previously programmed devices). Alternatively, for
fixed-frequency applications previously programmed devices can be used and no connection to the serial
interface is required. Preprogrammed devices can be ordered in customer-requested frequencies.
The DS1077L is available in SO or µSOP packages, allowing the generation of a clock signal easily,
economically, and using minimal board area. Chip-scale packaging is also available on request.
*Future product. Contact factory for availability.
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010202
DS1077L
BLOCK DIAGRAM DS1077L
Figure 1
INTERNAL
OSCILLATOR
CTRL0
Enable
Power-Down
MUX
Select
MCLK
SEL0
EN0
PDN 0
CONTROL
LOGIC
(TABLE 1)
DIV1
0M1
P0
PRESCALER
(M DIVIDER)
0M0
1M1
OUT0
1M0
EN0
0M1
0M0
DIV1
SEL0
PDN0
PDN1
CONTROL
REGISTERS
P1
PRESCALER
(M DIVIDER)
PROGRAMMABLE
“N” DIVIDER
OUT1
2-WIRE
INTERFACE
1M1
1M0
Power-Down
Enable
PDN1
CONTROL
LOGIC
(TABLE 2)
CTRL1
SDA
SCL
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DS1077L
OVERVIEW
A block diagram of the DS1077L is shown in Figure 1. The DS1077L consists of four major components:
1) internal master oscillator, 2) prescalers, 3) programmable divider, and 4) control registers.
The internal oscillator is factory trimmed to provide a master frequency (master clk) that can be routed
directly to the outputs (OUT0 & OUT1) or through separate prescalers (P0 & P1). OUT1 can also be
routed through an additional divider (N).
The prescaler (P0) divides the master clock by 1, 2, 4, or 8 to be routed directly to the OUT0 pin.
The prescaler (P1) divides the master clock by 1, 2, 4, or 8 that can be routed to the OUT1 pin or to the
divider (N) input, which is then routed to the OUT1 pin.
The programmable divider (N) divides the prescaler output (P1) by any number selected between 2 and
1025 to provide the main output (OUT1) or it can be bypassed altogether by use of the DIV1 register bit.
The value of N is stored in the N register.
The control registers are user-programmable through a 2-wire serial interface to determine operating
frequency (values of P0, P1, and N) and modes of operation. The register values are stored in EEPROM
and, therefore, only need to be programmed to alter frequencies and operating modes.
PIN DESCRIPTIONS
OUTPUT 1 (OUT1)
– This pin is the main oscillator output; its frequency is determined by the control
register settings for the prescaler P1 (mode bits 1M1 and 1M0) and divider N (DIV WORD).
OUTPUT 0 (OUT0)
– A reference output, OUT0, is taken from the output of the reference-select MUX.
Its frequency is determined by the control register settings for CTRL0 and values of prescaler P0 (mode
bits 0M1 and 0M0). (See Table 1.)
CONTROL PIN 0 (CTRL0)
– A multifunctional input pin that can be selected as a MUX select, output
enable, and/or a power-down. The user-programmable control register values EN0, SEL0, and PDN0
determine its function. (See Table 1.)
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DS1077L
TABLE 1
EN0
(BIT)
0
0
SEL0
(BIT)
0
1
PDN0
(BIT)
0
0
CTRL0
(PIN)
1
0
1
0
1
0
1
0
OUT0
CTRL0
(PIN)
FUNCTION
Hi-Z
(OUT1 and OUT2) Power-Down*
Hi-Z
DEVICE
MODE
Power-Down
Active
Master Clk/M
MUX Select
Active
Master Clk
Hi-Z
1
0
0
Output Enable
Active
Master Clk
Hi-Z
1
1
0
Output Enable
Active**
Master Clk/M
Hi-Z
1
Power-Down
(OUT1 and OUT2) Power-Down
X
0
1
0
Master Clk
Active
1
Hi-Z
Power-Down
X
1
1
Power-Down
0
Master Clk/M
Active
*This mode is for applications where OUT0 is not used, but CTRL0 is used as a device shutdown.
**Default Condition
CONTROL PIN 1 (CTRL1)
– A multifunctional input pin that can be selected as an output enable
and/or a power-down. Its function is determined by the user-programmable control register value of
PDN1. (See Table 2.)
TABLE 2
PDN1
(BIT)
0
0
1
1
CTRL1
(PIN)
0
1
0
1
CTRL1
FUNCTION
Output Enable
Output Enable
Power-Down
Power-Down
OUT 1
Out Clk
Hi-Z
Out Clk
Hi-Z
(OUT1 and OUT2)
DEVICE MODE
Active*
Active*
Active
Power-Down
*Default Condition
NOTE:
Both CTRL0 and CTRL1 can be configured as power-downs, they are internally “OR” connected so that
either of the control pins may be used to provide a power-down function for the whole device, subject to
appropriate settings of the PDN0 and PDN1 register bits. (See Table 3.)
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DS1077L
TABLE 3
PDN0
PDN1
SHUTDOWN CONTROL
(BIT)
(BIT)
0
0
None*
0
1
CTRL1
1
0
CTRL0
1
1
CTRL0 or CTRL1
*CTRL0 performs a power-down if SEL0 and EN0 are both 0. (See Table 1.)
Serial Data Input/Output (SDA)
– Input/output pin for the 2-wire serial interface used for data transfer.
Serial Clock Input (SCL)
– Input pin for the 2-wire serial interface used to synchronize data movement
on the serial interface.
REGISTER FUNCTIONS
The user-programmable registers can be programmed by the user to determine the mode of operation
(MUX), operating frequency (DIV) and bus settings (BUS). Details of how these registers are
programmed can be found in a later section; in this section the functions of the registers are described.
The register setting are nonvolatile, the values are stored automatically or as required in EEPROM when
the registers are programmed via the SDA and SCL pins.
MUX WORD
MSB
Name
Default setting
*
0
PDN1
0
PDN0
0
SEL0
1
EN0
1
0M1
0
0M0
0
LSB
1M1
0
MSB
1M0
0
DIV1
0
-
x
-
x
-
x
-
x
LSB
-
x
-
x
first data byte
*This bit must be set to zero.
second data byte
DIV1 (bit)
This bit allows the output of the prescaler P1 to be routed directly to the OUT1 pin (DIV1 = 1). The N
divider is bypassed so the programmed value of N is ignored. If DIV1 = 0 (default) the N divider
functions normally.
0M1, 0M0, 1M1, 1M0 (bits)
These bits set the prescalers P0 and P1, to divide by 1, 2, 4, or 8. (See Table 4.)
TABLE 4
0M1
0
0
1
1
0M0
0
1
0
1
PRESCALER
P0 DIVISOR
“M”
1*
2
4
8
1M1
0
0
1
1
1M0
0
1
0
1
PRESCALER
P1 DIVISOR
“M”
1*
2
4
8
*Default Condition
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