AD9515SLASHPCBZ datasheet(19/28 Pages) AD

19 / 28 page

Data Sheet

AD9515

Rev. B | Page 19 of 28

Synchronization is initiated by pulling the SYNCB pin low for a

minimum of 5 ns. The input clock does not have to be present

at the time the command is issued. The synchronization occurs

after four input clock cycles.

The synchronization applies to clock outputs:



that are not turned OFF



where the divider is not divide = 1 (divider bypassed)

An output with its divider set to divide = 1 (divider bypassed)

is always synchronized with the input clock, with a propagation

delay.

The SYNCB pin must be pulled up for normal operation. Do

not let the SYNCB pin float.

RSET RESISTOR

The internal bias currents of the AD9515 are set by the

RSET resistor. This resistor should be as close as possible to

the value given as a condition in the Specifications section

(RSET = 4.12 kΩ). This is a standard 1% resistor value and

should be readily obtainable. The bias currents set by this

resistor determine the logic levels and operating conditions of

the internal blocks of the AD9515. The performance figures

given in the Specifications section assume that this resistor

value is used for RSET.

VREF

The VREF pin provides a voltage level of ⅔ VS. This voltage is

one of the four logic levels used by the setup pins (S0 to S10).

These pins set the operation of the AD9515. The VREF pin

provides sufficient drive capability to drive as many of the setup

pins as necessary, up to all on a single part. The VREF pin

should be used for no other purpose.

SETUP CONFIGURATION

The specific operation of the AD9515 is set by the logic levels

applied to the setup pins (S10 to S0). These pins use four-state

logic. The logic levels used are VS and GND, plus ⅓ VS and

⅔ VS. The ⅓ VS level is provided by the internal self-biasing on

each of the setup pins (S10 to S0). This is the level seen by a

setup pin that is left not connected (NC). The ⅔ VS level is

provided by the VREF pin. All setup pins requiring the ⅔VS

level must be tied to the VREF pin.

SETUP PIN

S0 TO S10

60k



30k



Figure 27. Setup Pin (S0 to S10) Equivalent Circuit

The AD9515 operation is determined by the combination of

logic levels present at the setup pins. The setup configurations

for the AD9515 are shown in Table 10 to Table 15. The four

logic levels are referred to as 0, ⅓, ⅔, and 1. These numbers

represent the fraction of the VS voltage that defines the logic

levels. See the setup pin thresholds in Table 6.

The meaning of some of the setup pins depends on the logic

level set on other pins. For example, the effect of the S9/S10

pair of pins depends on the state of S8. S8 selects whether the

phase value selected by S9/S10 affects either OUT0 or OUT1. In

addition, if OUT1 is selected to have its phase controlled, the

effect further depends on the state of S0. If S = 0, the delay

block for OUT1 is bypassed, and the logic levels on S9/S10 set

the phase value of the OUT1 divider. However, if S0 ≠ 0, then

the full-scale delay for OUT1 is set by the logic level on S0, and

S9/S10 set the delay block fine delay (fraction of full scale).

Additionally, if a nonzero phase value is selected by S2/S3/S4

(for OUT0) or S5/S6/S7 (for OUT1), this phase overrides the

phase value selected by S9/S10. This allows a phase delay to be

selected on OUT0 while also selecting a time delay on OUT1.

S1 selects the logic level of each output. OUT0 is LVPECL. The

LVPECL output differential voltage (VOD) can be selected from

two levels: 400 mV or 780 mV. OUT1 can be set to either LVDS

or CMOS levels.

OUT0 can be turned off (powered down) by setting S2/S3/S4 to

0/1/0. OUT1 can be turned off by setting S5/S6/S7 to 0/1/0.

Do not set S2/S3/S4/S5/S6/S7 to 1/1/1/1/1/1.

AD9515/PCBZ 数据表(PDF) 19 Page - Analog Devices

AD9515/PCBZ 数据表(HTML) 19 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

数据表下载