AD7541 Intersil Corporation, AD7541 Datasheet - Page 7

• Manufacturer Part Number: AD7541
• Description: 12-Bit/ Multiplying D/A Converter
• Manufacturer: Intersil Corporation

Test Circuits
Dynamic Performance
The dynamic performance of the DAC, also depends on the
output amplifier selection. For low speed or static applica-
tions, AC specifications of the amplifier are not very critical.
For
openloop gain and gain/phase-margin specifications of the
amplifier should be selected for the desired performance.
The output impedance of the AD7541 looking into I
varies between 10k
(R
Similarly the output capacitance varies between the
minimum and the maximum values depending on the input
+15V
FEED-BACK
FIGURE 7. OUTPUT CAPACITANCE TEST CIRCUIT
high-speed
BIT 1 (MSB)
BIT 12 (LSB)
in parallel with the ladder resistance).
(Continued)
applications
NC
4
5
17
17
AD7541
+5V
FIGURE 10. GENERAL DAC CIRCUIT WITH COMPENSATION CAPACITOR, C
0V
3
(R
+15V
16
DIGITAL INPUT
FEEDBACK
18
1
2
BIT 12 (LSB)
FIGURE 9. OUTPUT CURRENT SETTLING TIME TEST CIRCUIT
BIT 1 (MSB)
slew-rate,
SCOPE
+10V
BIT 2
NC
BIT 12 (LSB)
BIT 1 (MSB)
V
alone) and 5k
1K
REF
V
REF
settling-time,
+10V
100mV
1MHz
4
5
15
17
4
5
15
AD7541
17
OUT1
AD7541
AD7541
3
P-P
3
GND
+15V
10-15
16
GND
+15V
16
18
1
2
1
2
EXTRAPOLATE
code. These variations necessitate the use of compensation
capacitors, when high speed amplifiers are used.
A capacitor in parallel with the feedback resistor (as shown
in Figure 10) provides the necessary phase compensation to
critically damp the output.
A small capacitor connected to the compensation pin of the
amplifier may be required for unstable situations causing
oscillations. Careful PC board layout, minimizing parasitic
capacitances, is also vital.
I
V
OUT2
R
I
I
REF
OUT1
OUT2
+100mV
FEEDBACK
= 20V
FIGURE 8. FEEDTHROUGH ERROR TEST CIRCUIT
P-P
100
C
10kHz SINE WAVE
BIT 1 (MSB)
BIT 12 (LSB)
C
3t: 5% SETTLING
9t: 0.01% SETTLING
-
+
A
OSCILLOSCOPE
4
5
15
17
AD7541
V
3
OUT
GND
+15V
16
C
18
1
2
I
I
OUT1
OUT2
3
2
HA2600
6
V
OUT