AD9779ABSVZ Analog Devices Inc, AD9779ABSVZ Datasheet - Page 39

• Manufacturer Part Number: AD9779ABSVZ
• Description: IC DAC 16BIT 1.0GSPS 100TQFP
• Manufacturer: Analog Devices Inc

Specifications of AD9779ABSVZ

• Data Interface: Serial
• Design Resources: Interfacing ADL5370 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0016) Interfacing ADL5371 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0017) Interfacing ADL5372 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0018) Interfacing ADL5373 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0019) Interfacing ADL5374 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0020) Interfacing ADL5375 to AD9779A Dual-Channel, 1 GSPS High Speed DAC (CN0021)
• Number Of Bits: 16
• Number Of Converters: 2
• Voltage Supply Source: Analog and Digital
• Power Dissipation (max): 300mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 100-TQFP Exposed Pad, 100-eTQFP, 100-HTQFP, 100-VQFP
• Resolution (bits): 16bit
• Sampling Rate: 1GSPS
• Input Channel Type: Parallel
• Digital Ic Case Style: QFP
• No. Of Pins: 100
• Operating Temperature Range: -40°C To +85°C
• Number Of Channels: 2
• Resolution: 16b
• Interface Type: Parallel
• Single Supply Voltage (typ): 3.3V
• Dual Supply Voltage (typ): Not RequiredV
• Architecture: Interpolation Filter
• Power Supply Requirement: Analog and Digital
• Output Type: Current
• Single Supply Voltage (min): 3.13V
• Single Supply Voltage (max): 3.47V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 100
• Package Type: TQFP EP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AD9779A-EBZ - BOARD EVALUATION FOR AD9779A
• Settling Time: -
• Lead Free Status / Rohs Status: Compliant

FULL-SCALE CURRENT GENERATION
INTERNAL REFERENCE
Full-scale current on the I DAC and Q DAC can be set from
8.66 mA to 31.66 mA. Initially, the 1.2 V band gap reference is
used to set up a current in an external resistor connected to I120
(Pin 75). A simplified block diagram of the reference circuitry is
shown in Figure 75. The recommended value for the external
resistor is 10 kΩ, which sets up an I
120 μA, which in turn provides a DAC output full-scale current
of 20 mA. Because the gain error is a linear function of this resistor,
a high precision resistor improves gain matching to the internal
matching specification of the devices. Internal current mirrors
provide a current-gain scaling, where I DAC or Q DAC gain is a
10-bit word in the SPI port register (Register 0x0B, Register 0x0C,
Register 0x0F, and Register 0x10). The default value for the DAC
gain registers gives an I
I
FS
=
1.2
R
V
×
⎛
⎜
⎝
27
12
+
FS
⎛
⎜
⎝
of approximately 20 mA. I
1024
6
×
DAC Gain
REFERENCE
in the resistor of
⎞
⎟
⎠
⎞
⎟
⎠
×
32
FS
is equal to
Rev. A | Page 39 of 60
0.1µF
35
30
25
20
15
10
VREF
5
0
10kΩ
I120
0
AD9776A/AD9778A/AD9779A
200
AD9776A/AD9778A/AD9779A
1.2V BAND GAP
Figure 76. I
Figure 75. Reference Circuitry
DAC GAIN CODE
400
FS
vs. DAC Gain Code
Q DAC GAIN
I DAC GAIN
CURRENT
SCALING
600
Q DAC
I DAC
800
DAC FULL-SCALE
REFERENCE
CURRENT
1000