AD9776A Analog Devices, AD9776A Datasheet - Page 31

• Manufacturer Part Number: AD9776A
• Description: Dual 12-Bit, 1 GSPS, Digital-to-Analog Converter
• Manufacturer: Analog Devices

Specifications of AD9776A

• Resolution (bits): 12bit
• Dac Update Rate: 1GSPS
• Dac Settling Time: n/a
• Max Pos Supply (v): +3.47V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: Par

Register Name
PLL Control
Misc. Control
I DAC Control
Aux DAC1 Control
Q DAC Control
Register
Address
0x08
0x08
0x09
0x09
0x09
0x09
0x0A
0x0A
0x0C
0x0B
0x0C
0x0C
0x0E
0x0D
0x0E
0x0E
0x0E
0x10
0x0F
0x10
0x10
Bits
7:2
1:0
7
6:5
4:3
2:0
7:5
4:0
1:0
7:0
7
6
1:0
7:0
7
6
5
1:0
7:0
7
6
Parameter
PLL Band Select[5:0]
PLL VCO Drive[1:0]
PLL enable
PLL VCO Divide Ratio[1:0]
PLL Loop Divide Ratio[1:0]
PLL Bias[2:0]
VCO Control Voltage[2:0]
(read only)
PLL Loop Bandwidth[4:0]
I DAC Gain Adjustment[9:8]
I DAC Gain Adjustment[7:0]
I DAC sleep
I DAC power-down
Auxiliary DAC1 Data[9:8]
Auxiliary DAC1 Data[7:0]
Auxiliary DAC1 sign
Auxiliary DAC1 current
direction
Auxiliary DAC1 power-down
Q DAC Gain Adjustment[9:8]
Q DAC Gain Adjustment[7:0]
Q DAC sleep
Q DAC power-down
Rev. B | Page 31 of 56
Function
This sets the operating frequency range of the
VCO. For details (see Table 23).
Controls the signal strength of the VCO output. Set
to 11 for optimal performance.
0: PLL off, DAC sample clock is sourced directly by
the REFCLK input.
1: PLL on, DAC clock synthesized internally from
REFCLK input via PLL clock multiplier.
Sets the value of the VCO output divider, which
determines the ratio of the VCO output frequency
to the DAC sample clock frequency, f
00: f
01: f
10: f
11: f
Sets the value of the DACCLK divider, which
determines the ratio of the DAC sample clock
frequency to the REFCLK frequency, f
00: f
01: f
10: f
11: f
Controls VCO bias current. Set to 011 for optimal
performance.
000 to 111, proportional to voltage at VCO control
voltage input, readback only. A value of 011
indicates the VCO centered in its frequency range.
Controls the bandwidth of the PLL filter. Increasing
the value lowers the loop bandwidth. Set to 01111
for optimal performance.
The I DAC Gain Adjustment[9:0] value is the I DAC
10-bit gain setting word. Bit 9 is the MSB and Bit 0
is the LSB.
0: I DAC on.
1: I DAC off, but reference remains powered.
0: I DAC on.
1: I DAC off.
The auxiliary DAC 1 Data [9:0] value is the Aux DAC1
10-bit output current control word. Magnitude of
the auxiliary DAC current increases with increasing
value. Bit 9 is the MSB and Bit 0 is the LSB.
0: AUX1_P active.
1: AUX1_N active.
0: source.
1: sink.
0: auxiliary DAC1 on.
1: auxiliary DAC1 off.
The Q DAC Gain Adjustment[9:0] value is the Q DAC
10-bit gain setting word. Bit 9 is the MSB and Bit 0
is the LSB.
0: Q DAC on.
1: Q DAC off.
0: Q DAC on.
1: Q DAC off.
VCO
VCO
VCO
VCO
DACCLK
DACCLK
DACCLK
DACCLK
/f
/f
/f
/f
DACCLK
DACCLK
DACCLK
DACCLK
/f
/f
/f
/f
REFCLK
REFCLK
REFCLK
REFCLK
= 1.
= 2.
= 4.
= 8.
= 2.
= 4.
= 8.
= 16.
AD9776A/AD9778A/AD9779A
VCO
DACCLK
/f
DACCLK
/f
REFCLK
.
.
Default
111001
11
0
10
10
010
000
11111
01
11111001
0
0
00
00000000
0
0
0
01
11111001
0
0