AD9148BBCZ datasheet(71/73 Pages) AD

71 / 73 page

Preliminary Technical Data

AD9148

Rev. PrA | Page 71 of 73

EXAMPLE START-UP ROUTINE

To ensure reliable start-up of the AD9148, certain sequences

should be followed. An example start-up routine using the

following device configuration is used for this example:

•

fDATA = 122.88 MSPS

•

Interpolation = 4×, using HB1 = ’00’ and HB2 = ’000’

•

Input data = baseband data

•

Dual port mode with 1 DCI

•

fOUT = 140 MHz

•

fREFCLK = 122.88 MHz

•

PLL = enabled

•

Fine NCO = enabled

•

Inverse SINC Filter = disabled

•

Synchronization = enabled

DERIVED PLL SETTINGS

The following PLL settings can be derived from the device

configuration:

•

fDACCLK = fDATA × Interpolation = 491.52 MHz

•

fVCO = 4 × fDACCLK = 1966.08 MHz (1 GHz < fVCO < 2 GHz)

•

N1 = fDACCLK/fREFCLK = 4

•

N0 = fVCO/fDACCLK = 4

DERIVED NCO SETTINGS

The following NCO settings can be derived from the device

configuration:

•

fOUT = 140 MHz

•

fDACCLK = fDATA × Interpolation = 491.52 MHz

•

FTW = 140/(491.52) × 232 = 0x48, EAAAAA

START-UP SEQUENCE

The power clock and register write sequencing for reliable

device start-up follows:

•

Power up the device (no specific power supply sequence is

required)

•

Apply stable REFCLK input signal.

•

Apply stable DCI input signal.

•

Issue hardware reset (optional)

•

Configure device registers with the following write

sequence:

0x0C → 0xC9

0x0D → 0xD9

0x0A → 0xC0

0x0A → 0x80

0x10 → 0x48

0x14 → 0x40

0x17 → 0x80

0x17 → 0x00

0x19 → 0x80

0x19 → 0x00

0x1C → 0x40

0x1D → 0x00

0x1E → 0x01

0x54 → 0xAA

0x55 → 0xAA

0x56 → 0xEA

0x57 → 0x48

0x5A → 0x01

0x5A → 0x00

DEVICE VERIFICATION SEQUENCE

The following device polling can be conducted to verify the

device is working properly:

•

Read 0x06, Expect Bit 7 = 0, Bit 6 = 1, Bit 5 = 0, Bit 4 = 1,

Bit 2 = 1

•

Read 0x12, Expect Bit 6 = 1

•

Read 0x18, Expect 0x0F (0x07 is also normal)

•

Read 0x1A, Expect 0x0F (0x07 is also normal)

AD9148BBCZ Datasheet(PDF) 71 Page - Analog Devices

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