DAC0806 NSC [National Semiconductor], DAC0806 Datasheet - Page 7

• Manufacturer Part Number: DAC0806
• Description: 8-Bit D/A Converters
• Manufacturer: NSC [National Semiconductor]

Test Circuits
Application Hints
REFERENCE AMPLIFIER DRIVE AND COMPENSATION
The reference amplifier provides a voltage at pin 14 for con-
verting the reference voltage to a current and a turn-around
circuit or current mirror for feeding the ladder The reference
amplifier input currrent I
regardless of the set-up method or reference voltage polarity
Connections for a positive voltage are shown in Figure 7
The reference voltage source supplies the full current I
For bipolar reference signals as in the multiplying mode
FIGURE 6 Reference Current Slew Rate Measurement (Note 7)
FIGURE 8 Negative V
(Continued)
14
must always flow into pin 14
REF
(Note 7)
TL H 5687– 11
14
TL H 5687– 9
7
R15 can be tied to a negative voltage corresponding to the
minimum input level It is possible to eliminate R15 with only
a small sacrifice in accuracy and temperature drift
The compensation capacitor value must be increased with
increases in R14 to maintain proper phase margin for R14
values of 1 2 5 and 5 k
37 and 75 pF The capacitor may be tied to either V
ground but using V
FIGURE 9 Programmable Gain Amplifier or
Digital Attenuator Circuit (Note 7)
FIGURE 7 Positive V
EE
increases negative supply rejection
minimum capacitor values are 15
REF
(Note 7)
TL H 5687 – 10
TL H 5687 – 12
EE
or