OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

DS1085LZ-5+W

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21
1 of 21 051606
FEATURES
§ User-Programmable Frequency Synthesizer
§ Programmable From 4.1kHz to 66MHz
§ Dual Synchronous Outputs
§ 4.13MHz to 66MHz Reference Oscillator
Output
§ 4.1kHz to 66MHz Main Oscillator Output
§ Single 3.0 to 3.6V Supply
§ Three Resolution Options
§ 2-Wire Serial Interface
§ 0.75% Absolute Accuracy
§ Nonvolatile (NV) Frequency Settings
§ No External Timing Components
§ Power-Down Mode
ORDERING INFORMATION
PIN ASSIGNMENT
SO (150mil)
PIN DESCRIPTION
OUT1 - Main Oscillator Output
OUT0 - Reference Oscillator Output
V
CC
- Power-Supply Voltage
GND - Ground
CTRL1 - Control Pin for OUT1
CTRL0 - Control Pin for OUT0
SDA - 2-Wire Serial Data Input/Output
SCL - 2-Wire Serial Clock
DEVICE PACKAGE
STEP
SIZE
OSCILLATOR
OUTPUT RANGE
DS1085LZ-5 150mil SO 5kHz 4.1kHz to 66MHz
DS1085LZ-12 150mil SO 12.5kHz 4.1kHz to 66MHz
DS1085LZ-25 150mil SO 25kHz 4.1kHz to 66MHz
DESCRIPTION
The DS1085L is a dual-output frequency synthesizer requiring no external timing components for
operation. It can be used as a standalone oscillator or as a dynamically programmed, processor-controlled
peripheral device. An internal master oscillator can be programmed from 33MHz to 66MHz with three
resolution options of 5kHz, 12.5kHz, and 25kHz. A programmable 3-bit prescaler (divide-by-1, 2, 4, or 8)
permits the generation of a reference oscillator output (OUT0) from the master, ranging from 4.13MHz to
66MHz. A second independent prescaler and a 1-to-1025 divider allow the generation of a main oscillator
output (OUT1) from 4.1kHz to 66MHz. The two outputs, although synchronous with the master, can be
independently programmed. The combination of programmable master oscillator, prescalers, and dividers
allows the generation of thousands of user-specified frequencies. All master oscillator, prescaler, and
divider settings are stored in NV (EEPROM) memory, providing a default value on power-up that allows
it to be used as a standalone oscillator. A 2-wire serial interface allows in-circuit, on-the-fly programming
of the master oscillator, prescalers (P0 and P1), and divider (N). This allows dynamic frequency
modification, if required, or, for fixed-frequency applications, the DS1085L can be used with factory- or
user-programmed values.
DS1085L
3.3V EconOscillator Frequenc
y
Synthesize
r
www.maxim-ic.com
SCL
CTRL0
SD
A
CTRL1
OUT1
OUT0
V
CC
GND
8
7
6
5
1
2
3
4
EconOscillator is a trademark of Dallas Semiconductor.
DS1085L
2 of 21
External control inputs, CTRL1 and CTRL0, enable or disable the two oscillator outputs. Both outputs
feature a synchronous enable that ensures no output glitches when the output is enabled and a constant
time interval (for a given frequency setting) from an enable signal to the first output transition. These
inputs can also be configured to disable the master oscillator, putting the device into a low-power mode
for power-sensitive applications.
Figure 1. DS1085L BLOCK DIAGRAM
OVERVIEW
A block diagram of the DS1085L is shown in Figure 1. The DS1085L consists of five major components:
§ Internal master oscillator (33MHz to 66MHz)
§ Master oscillator control DAC
§ Prescalers (divide-by-1, 2, 4, or 8)
§ Programmable divider (divide-by-1 to 1025)
§ Control registers
The internal master oscillator provides the reference clock (MCLK), which is fed to the prescalers and
programmable dividers. The frequency of the oscillator can be user-programmed over a two-to-one range
in increments equal to the step size, by means of a 10-bit control DAC. The master oscillator range is
33MHz to 66MHz, which is larger than the range possible with the 10-bit DAC resolution and available
step sizes. Therefore, an additional register (OFFSET) is provided that can be used to select the range of
frequency over which the DAC is used (see Table 1).
0M0 0M1
1M0
1M1
DS1085L
3 of 21
Table 1. DEVICE COMPARISONS BY PART NUMBER
PART NUMBER STEP SIZE (kHz) DAC SPAN (MHz) OFFSET SIZE (MHz)
DS1085LZ-5 5 5.12 2.56
DS1085LZ-12 12.5 12.80 3.20
DS1085LZ-25 25 25.60 3.20
For further description of use of the OFFSET register see the REGISTER FUNCTIONS section.
The master clock can be routed directly to the outputs (OUT0 and OUT1) or through separate prescalers
(P0 and P1). In the case of OUT1, an additional programmable divider (N) can be used to generate
frequencies down to 4.1kHz.
The prescaler (P0) divides MCLK by 1, 2, 4, or 8 before routing MCLK to the reference output (OUT0)
pin.
The prescaler (P1) divides MCLK by 1, 2, 4, or 8 before routing MCLK to the programmable divider (N),
and ultimately to the main output (OUT1) pin.
The programmable divider (N) divides the prescaler output (P1) by any number selected between two and
1025 (10 bits) 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 DIV register.
The control registers are user-programmable through a 2-wire serial interface to determine operating
frequency (values of DAC, OFFSET, P0, P1, and N) and modes of operation. Once programmed, the
register settings are nonvolatile and only need reprogramming if it is desired to reconfigure the device.
PIN DESCRIPTIONS
PIN NAME FUNCTION
1 OUT1
This main oscillator output frequency is determined by the control
register settings for the oscillator (DAC and OFFSET), prescaler P1
(mode bits 1M0 and 1M1), and divider N (DIV).
2 OUT0
The reference output is taken from the output of the reference select mux.
Its frequency is determined by the control register settings for prescaler
P0 (mode bits 0M0 and 0M1) (see Table 2).
3 Vcc Power Supply
4 GND Ground
5 CTRL0
A multifunction control input pin that can be programmed to function as
a mux select, ouput enable, and/or a power-down. Its function is
determined by the user-programmable control register values of EN0,
SEL0, and PDN0 (see Table 2).
6 CTRL1
A multifunction control input pin that can be programmed to function as
an output enable and/or a power-down. Its function is determined by the
user-programmable control register value of PDN1 (see Table 3).
7 SDA I/O pin for the 2-wire serial interface used for data transfer.
8 SCL
Input pin for the 2-wire serial interface used to synchronize data
movement over the serial interface.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21

DS1085LZ-5+W

Mfr. #:
Buy DS1085LZ-5+W
Manufacturer:
Maxim Integrated
Description:
Programmable Oscillators 3.3V EconOscillator f Synthesize
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet