JAJSEG6A January 2018 – April 2020 ADC12DJ2700
PRODUCTION DATA.
The PD input pin allows the ADC12DJ2700 devices to be entirely powered down. Power-down can also be controlled by MODE (see the device configuration register). The serial data output drivers are disabled when PD is high. When the device returns to normal operation, the JESD204 link must be re-established, and the ADC pipeline and decimation filters contain meaningless information so the system must wait a sufficient time for the data to be flushed. If power-down for power savings is desired, the system must power down the supply voltages regulators for VA19, VA11, and VD11 rather than make use of the PD input or MODE settings.
CAUTION
Powering down the high-speed data outputs (DA0± ... DA7±, DB0± ... DB7±) for extended times may damage the output serializers, especially at high data rates. Powering down the serializers occurs when the PD pin is held high, the MODE register is programmed to a value other than 0x00 or 0x01, the PD_ACH or PD_BCH registers settings are programmed to 1, or when the JMODE register setting is programmed to a mode that uses less than the 16 total lanes that the device allows. For instance, JMODE 0 uses eight total lanes and therefore the four highest-indexed lanes for each JESD204B link (DA4± ... DA7±, DB4± ... DB7±) are powered down in this mode. When the PD pin is held high or the MODE register is programmed to a value other than 0x00 or 0x01, all output serializers are powered down. When the PD_ACH or PD_BCH register settings are programmed to 1, the associated ADC channel and lanes are powered down. To prevent unreliable operation, the PD pin and MODE register must only be used for brief periods of time to measure temperature diode offsets and not used for long-term power savings. Furthermore, using a JMODE that uses fewer than 16 lanes results in unreliable operation of the unused lanes. If the system never uses the unused lanes during the lifetime of the device, then the unused lanes do not cause issues and can be powered down. If the system may make use of the unused lanes at a later time, the reliable operation of the serializer outputs can be maintained by enabling JEXTRA_A and JEXTRA_B, which results in the VD11 power consumption to increase and the output serializers to toggle.