AD9524SLASHPCBZ datasheet(26/56 Pages) AD

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AD9524

Data Sheet

Rev. E | Page 26 of 56

RESET MODES

The AD9524 has a power-on reset (POR) and several other ways to

apply a reset condition to the chip.

Power-On Reset

During chip power-up, a power-on reset pulse is issued when

3.3 V supply reaches ~2.6 V (<2.8 V) and restores the chip

either to the setting stored in EEPROM (EEPROM pin = 1) or

to the on-chip setting (EEPROM pin = 0). At power-on, the

AD9524 executes a SYNC operation, which brings the outputs

into phase alignment according to the default settings. The

output drivers are held in sync for the duration of the internally

generated power-up sync timer (~70 ms). The outputs begin to

toggle after this period.

Reset via the RESET Pin

RESET, a reset (an asynchronous hard reset is executed by briefly

pulling RESET low), restores the chip either to the setting stored in

EEPROM (EEPROM pin = 1) or to the on-chip setting (EEPROM

pin = 0). A reset also executes a sync operation, which brings the

outputs into phase alignment according to the default settings.

When EEPROM is inactive (EEPROM pin = 0), it takes ~2 µs for

the outputs to begin toggling after RESET is issued. When

EEPROM is active (EEPROM pin = 1), it takes ~40 ms for the

outputs to toggle after RESET is brought high.

Reset via the Serial Port

The serial port control register allows for a reset by setting Bit 2

and Bit 5 in Register 0x000. When Bit 5 and Bit 2 are set, the

chip enters a reset mode and restores the chip either to the setting

stored in EEPROM (EEPROM pin = 1) or to the on-chip -setting

(EEPROM pin = 0), except for Register 0x000. Except for the self-

clearing bits, Bit 2 and Bit 5, Register 0x000 retains its previous value

prior to reset. During the internal reset, the outputs

hold static. Bit 2

and Bit 5

are self-clearing. However, the self-clearing operation does

not complete until an additional serial port SCLK cycle completes,

and the AD9524 is held in reset until Bit 2 and Bit 5 self clear.

Reset to Settings in EEPROM when EEPROM Pin = 0 via the

Serial Port

The serial port control register allows the chip to be reset to settings

in EEPROM when the EEPROM pin = 1 via Register 0xB02, Bit 1.

This bit is self-clearing. This bit does not have any effect when the

EEPROM pin = 0. It takes ~40 ms for the outputs to begin toggling

after the Soft_EEPROM register is cleared.

POWER-DOWN MODE

Chip Power-Down via PD

Place the AD9524 into a power-down mode by pulling the PD pin

low. Power-down turns off most of the functions and currents

inside the AD9524. The chip remains in this power-down state

until PD is returned to a logic high state. When taken out of power-

down mode, the AD9524 returns to the settings programmed into

its registers prior to the power-down, unless the registers are

changed by new programming while the PD pin is held low.

AD9524/PCBZ 数据表(PDF) 26 Page - Analog Devices

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