Datasheet

Data Sheet AD9552
Rev. E | Page 27 of 32
Address Bit Bit Name Description
0x18 [7:3] P
1
divider Bits[4:0] of the 6-bit P
1
divider for OUT1 (1 ≤ P
1
≤ 63). Do not set these bits to 000000. Default is
P
1
= 10 0000 (32). The P
1
bits are ineffective unless Register 0x19[7] = 1.
[2:0] P
0
divider The 3-bit P
0
divider for OUT1. The P
0
divide value is as follows:
000 = 4 (default).
001 = 5.
010 = 6.
011 = 7.
100 = 8.
101 = 9.
110 = 10.
111 = 11.
The P
0
bits are ineffective unless Register 0x19[7] = 1.
0x19 7 Enable SPI control of
OUT1 dividers
Controls functionality of OUT1 dividers.
0 = OUT1 dividers defined by the Y[5:0] pins (default).
1 = contents of Register 0x17 and Register 0x18 define OUT1 dividers (P
0
and P
1
).
[6:0] Unused Unused.
Input Receiver and Band Gap Control (Register 0x1A)
Table 22.
Address Bit Bit Name Description
0x1A
7
Receiver reset
Input receiver reset control. This is an autoclearing bit.
0 = normal operation (default).
1 = reset input receiver logic.
[6:2] Band gap voltage adjust
Controls the band gap voltage setting from minimum (0 0000) to maximum (1 1111).
Default is 0 0000.
1
Unused
Unused.
0 Enable SPI control of band gap
voltage
Enables functionality of Bits[6:2].
0 = the device automatically selects receiver band gap voltage (default).
1 = Bits[6:2] define the receiver band gap voltage.
XTAL Control (Register 0x1B to Register 0x1D)
Table 23.
Address Bit Bit Name Description
0x1B 7 Disable SPI control of XTAL
tuning capacitance
Disables functionality of Bits[5:0].
0 = tuning capacitance defined by Bits[5:0].
1 = the device automatically selects XTAL tuning capacitance (default).
6 Unused Unused.
[5:0] XTAL tuning capacitor control Capacitance value coded as inverted binary (0.25 pF per bit); that is, 111111 is 0 pF,
111110 is 0.25 pF, and so on. The default value, 000000, is 15.75 pF.
0x1C [7:0] Unused Unused.
0x1D [7:3] Unused Unused.
2 Select 2× frequency multiplier Select/bypass the 2× frequency multiplier.
0 = bypassed (default).
1 = selected.
1 Unused Unused.
0 Use crystal resonator Automatic external reference select override.
0 = the device automatically selects the external reference path if an external
reference signal is present (default).
1 = the device uses the crystal resonator input whether or not an external reference
signal is present.