AD9739BBCRL Analog Devices Inc, AD9739BBCRL Datasheet - Page 48

• Manufacturer Part Number: AD9739BBCRL
• Description: 14 Bit 2.5 GSPS DAC
• Manufacturer: Analog Devices Inc

Specifications of AD9739BBCRL

• Number Of Bits: 14
• Data Interface: Serial
• Number Of Converters: 1
• Voltage Supply Source: Analog and Digital
• Power Dissipation (max): 980mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 160-CSPBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Settling Time: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD9739
Always connect a 10 kΩ resistor from the I120 pin to ground
and use the digital controls to vary the full-scale current. The
AD9739 is not a multiplying DAC. Applying an analog signal to
I120 is not supported.
VREF (Pin C14) must be bypassed to ground with a 1 nF
capacitor. The band gap voltage is present on this pin and can
be buffered for use in external circuitry. The typical output
impedance is near 5 kΩ. An external reference can be used to
overdrive the internal reference by connecting it to the VREF
pin (Pin C14). IPTAT (Pin D14) can be used to track the
internal temperature of the chip by monitoring the output
current of this pin. The output current is approximately 10 μA
at 25°C with a slope of approximately 20 nA/°C.
ANALOG OUTPUTS
The AD9739 provides complementary current outputs, IOUTP
and IOUTN. IOUTP provides a near full-scale current output,
I
IOUTN provides the DAC dc offset. Due to the quad switch
architecture, the dc offset of the AD9739 is approximately 1/16
of the DAC full-scale current. The current output appearing at
IOUTP and IOUTN is a function of both the input code and
the I
where DAC CODE = 0 to 16,383 (decimal) and IOUTFS is
found using Equation 1.
Figure 104, Figure 105, and Figure 106 contain plots for
FSC[9:0] equal to 0.512 and 1023 to show the equivalent gain
and offset values for the midpoints and endpoints of the full-
scale gain transfer curve.
OUTFS
OUTFS
IOUTP
IOUTN
, when all bits are high (DAC CODE = 16,383), while
35
30
25
20
15
10
5
0
0
and can be expressed as
=
=
⎛
⎜
⎝
⎛
⎜
⎝
DAC
16383
200
16384
Figure 103. IFS vs. DAC Gain Code
CODE
−
16384
DAC
⎞
⎟
⎠
400
DAC GAIN CODE
×
CODE
I
OUTFS
⎞
⎟
⎠
×
600
I
OUTFS
800
1000
Rev. 0 | Page 48 of 56
(2)
(3)
The complementary current outputs can be configured for
single-ended or differential operation. IOUTP and IOUTN can
be converted into complementary single-ended voltage outputs
using load resistors.
Figure 106. Gain Curve for FSC[9:0] = 1023, DAC OFFSET = 1.932 mA
Figure 105. Gain Curve for FSC[9:0] = 512, DAC OFFSET = 1.228 mA
Figure 104. Gain Curve for FSC[9:0] = 0, DAC OFFSET = 0.257 mA
20
18
16
14
12
10
32
28
24
20
16
12
8
7
6
5
4
3
2
1
0
8
6
4
2
0
8
4
0
0
0
0
4096
4096
4096
DAC CODE
DAC CODE
DAC CODE
8192
8192
8192
12,288
12,288
12,288
16,384
16,384
16,384