DAC8812 Datasheet, PDF (12/18 Pages) Texas Instruments – Dual, Serial Input 16-Bit Multiplying Digital-to-Analog Converter

DAC8812
SBAS349A – AUGUST 2005 – REVISED DECEMBER 2005
www.ti.com
Figure 15 shows the gain vs frequency performance at various attenuation settings using a 3 pF external
feedback capacitor connected across the I_OUTX and R_FBX terminals. In order to maintain good analog
performance, power-supply bypassing of 0.01 µF, in parallel with 1 µF, is recommended. Under these conditions,
clean power supply with low ripple voltage capability should be used. Switching power supplies is usually not
suitable for this application due to the higher ripple voltage and P_SS frequency-dependent characteristics. It is
best to derive the DAC8812 5-V supply from the system analog supply voltages (do not use the digital 5-V
supply); see Figure 31.
15 V
Analog
2R
Power
+
5V
Supply
R
V_DD
V_REFX
2R
R
2R
R
2R
R
R
5 kW
R_FBX
S2
S1
I_OUTX
A_GNDX
15 V
V_CC
A1
+
V_EE
DGND
DGND
Digital interface connections omitted for clarity.
Switches S1 and S2 are closed, V_DD must be powered.
Figure 31. Recommended Kelvin-Sensed Hookup
V_OUT
Load
CS
CLK
SDI
EN
D0
16
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
A0
DAC _A
B
A1 Decode
Power-
on
Reset
V_REF A B
Input
Register R
DAC A
Register R
DAC A
Input
Register R
DAC B
Register R
DAC B
Set
MSB
Set
MSB
V_DD
R_FBB
I_OUTA
A_GNDA
R_FBB
I_OUTB
A_GNDB
DGND
MSB
LDAC
RS
Figure 32. System Level Digital Interfacing
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