AD9553

Rev. 0 | Page 32 of 44

REGISTER MAP

A bit that labeled “aclr” is an active high, autoclearing bit. When set to a Logic 1 state, the control logic automatically returns it to a

Logic 0 state upon completion of the indicated task.

Table 27. Register Map

Addr.

(Hex)

Register

Name

(MSB)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

(LSB)

Bit 0

Default

0x00

Serial port

control

0

LSB first

Soft reset

(aclr)

1

1

Soft reset

LSB first

0

0x18

0x04

Readback

control

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Readback

control

0x00

0x05

I/O update

Unused

Unused

Unused

Unused

Unused

Unused

Unused

I/O update

(aclr)

0x00

0x0A

PLL charge

pump and

PFD control

Charge pump current control[7:0]

(3.5 μA granularity, ~900 μA full scale)

0x80

0x0B

Enable SPI

control of

charge

pump

current

Enable SPI

control of

antiback-

lash

period

Charge pump

mode[1:0]

Disable

charge

pump

PFD

feedback

input edge

control

PFD

reference

input edge

control

Force VCO

to midpoint

frequency

0x30

0x0C

Unused

Unused

Unused

Unused

Unused

Charge pump clock div[2:0]

0x00

0x0D

Antibacklash control[1:0]

Unused

Unused

Unused

Unused

Unused

PLL lock

detector

power-

down

0x00

0x0E

VCO control

Calibrate

VCO (aclr)

Enable

ALC

ALC threshold[2:0]

Enable SPI

control of

VCO

calibration

Boost VCO

supply

Enable SPI

control of

VCO band

setting

0x70

0x0F

VCO level control[5:0]

Unused

Unused

0x80

0x10

VCO band control[6:0]

Unused

0x80

0x11

PLL and

output

frequency

control

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused

0x00

0x12

Feedback divider (N)[19:12]

0x80

0x13

Feedback divider (N)[11:4]

0x00

0x14

Feedback divider (N) [3:0]

Enable SPI

control of

feedback

divider

Enable SPI

control of

output

dividers

Unused

Reset PLL

(aclr)

0x00

0x15

0x20

0x16

0x00

0x17

Enable test

port

Test mux[1:0]

Unused

0x01

0x18

0

Unused

Unused

Unused

Unused

Unused

0x00

0x19

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused

0x20

0x1A

Input

receiver and

band gap

control

Reference

reset (aclr)

Band gap voltage adjust[4:0]

(00000 = maximum, 11111 = minimum)

Unused

Enable SPI

control of

band gap

voltage

0x00

0x1B

XTAL

control

Disable SPI

control of

XTAL tuning

capacitance

0

XTAL tuning capacitor control[5:0]

(0.25 pF per bit, inverted binary coding)

0x80

0x1C

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused

0x00

0x1D

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused

0x00

0x1E

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused

Unused