AD7960BCPZ datasheet(18/24 Pages) AD

18 / 24 page

AD7960

Data Sheet

Rev. 0 | Page 18 of 24

POWER SUPPLY

The AD7960 uses both 5 V (VDD1) and 1.8 V (VDD2) power

supplies, as well as a digital input/output interface supply (VIO).

Drive the EN3 to EN0 pins with a 1.8 V logic level. VIO and

VDD2 can be taken from the same 1.8 V source; however, it is

best practice to isolate the VIO and VDD2 pins using separate

traces as well as to decouple each pin separately.

The 5 V and 1.8 V supplies required for the AD7960 can be

generated using Analog Devices, Inc., LDOs such as the

ADP7104-5 and the ADP124-1.8. Figure 33 shows the PSRR vs.

supply frequency of the AD7960. The AD7960 core power

scales with throughput as shown in Figure 34, offering

significant power budget savings at lower speed operation.

Figure 33. PSRR vs. Supply Frequency

Power-Up

As is best practice for all ADCs, power on the core supplies

prior to applying an external reference (where applicable).

Apply the analog inputs last.

When powering up the AD7960 device, first apply 1.8 V (VDD2,

VIO) to the device, then ramp 5 V (VDD1). Set the reference

configuration pins, EN0, EN1, and EN2, to the correct values.

When an internal reference buffer is used (governed by the EN1

and EN0 values), apply the external reference of 2.048 V to the

REFIN pin or 5 V/4.096 V to the REF pin.

Figure 34. ADC Core Power Dissipation vs. Throughput, Self Clocked Mode,

CNV± in CMOS Mode, Internal Reference Buffer Disabled

100

110

100

10k

100k

FREQUENCY (Hz)

VDD2 = 1.8V

VIO = 1.8V

VDD1 = 5V

THROUGHPUT (MHz)

AD7960BCPZ bảng dữ liệu(PDF) 18 Page - Analog Devices