Datasheet

AD9648
Rev. 0 | Page 37 of 44
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
Bit 0
(LSB)
Default
Value
(Hex)
Comments
0x0B Clock
divide
(global)
Open Open Open Open Open Clock divide ratio
000 = divide by 1
001 = divide by 2
010 = divide by 3
011 = divide by 4
100 = divide by 5
101 = divide by 6
110 = divide by 7
111 = divide by 8
0x00 The divide
ratio is
value plus 1
0x0C Enhance-
ment
control
(global)
Open Open Open Open Open Chop
0 =
disabled
1 =
enabled
Open Open 0x00 Chop mode
enabled if
Bit 2 is
enabled
0x0D Test mode
(local)
User test mode control
00 = single pattern mode
01 = alternate
continuous/repeat
pattern mode
10 = single once pattern
mode
11 = alternate once
pattern mode
Reset PN
long gen
Reset PN
short gen
Output test mode
0000 = off (default)
0001 = midscale short
0010 = positive FS
0011 = negative FS
0100 = alternating checkerboard
0101 = PN long sequence
0110 = PN short sequence
0111 = one/zero word toggle
1000 = user test mode
1111 = ramp output
0x00 When this
register is
set, the test
data is
placed on
the output
pins in
place of
normal data
0x0E BIST
enable
(global)
Open Open Open Open Open Initialize
BIST
sequence
Open BIST enable 0x00
0x10 Customer
offset
adjust
(local)
Offset adjust in LSBs from +127 to −128
(twos complement format)
0x00
0x14 Output
mode
Output port logic type
(global)
00 = CMOS, 1.8 V
10 = LVDS, ANSI
11 = LVDS, reduced
range
Output
Interleave
enable
(global)
Output port
disable (local)
Open
(global)
Output
invert
(local)
Output format
00 = offset binary
01 = twos complement
10 = Gray code
0x00 Configures
the
outputs
and the
format of
the data
0x15 Output
adjust
Open Open CMOS 1.8 V DCO drive
strength
00 = 1×
01 = 2×
10 = 3×
11 = 4×
Open Open CMOS 1.8 V data
drive strength
00 = 1×
01 = 2×
10 = 3×
11 = 4×
0x00 Determines
CMOS
output
drive
strength
properties
0x16 Clock
phase
control
(global)
Invert
DCO
clock
0 = not
inverted
1 =
inverted
Open Open Open Open Input clock divider phase adjust
relative to the encode clock
000 = no delay
001 = one input clock cycle
010 = two input clock cycles
011 = three input clock cycles
100 = four input clock cycles
101 = five input clock cycles
110 = six input clock cycles
111 = seven input clock cycles
0x00 Allows
selection of
clock
delays into
the input
clock
divider
0x17 Output
delay
(global)
DCO
clock
delay
0 =
disabled
1 =
enabled
Open Data delay
0 =
disabled
1 =
enabled
Open Open Delay selection
000 = 0.56 ns
001 = 1.12 ns
010 = 1.68 ns
011 = 2.24 ns
100 = 2.80 ns
101 = 3.36 ns
110 = 3.92 ns
111 = 4.48 ns
0x00 This sets
the fine
output
delay of
the output
clock but
does not
change
internal
timing