DS1085

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Table 1. DEVICE COMPARISONS BY PART NUMBER

PART NUMBER

STEP SIZE (kHz)

DAC SPAN (MHz)

OFFSET SIZE (MHz)

DS1085Z-10

10

10.24

5.12

DS1085Z-25

25

25.60

6.40

DS1085Z-50

50

51.20

6.40

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 8.1kHz.

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, 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

DESCRIPTION

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).

Power Supply

4

GND

Ground

5CTRL0

A multifunction control input pin that can be programmed to function as

a mux select, output 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).

6CTRL1

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.

8SCL

Input pin for the 2-wire serial interface used to synchronize data

movement over the serial interface.