AD5445 Analog Devices, AD5445 Datasheet - Page 22

• Manufacturer Part Number: AD5445
• Description: High Bandwidth CMOS 12-Bit Parallel Interface Multiplying D/A Converter
• Manufacturer: Analog Devices

Specifications of AD5445

• Resolution (bits): 12bit
• Dac Update Rate: 20.4MSPS
• Dac Settling Time: 80ns
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Current Out
• Dac Input Format: Par

AD5424/AD5433/AD5445
Table 9. Suitable ADI Precision References
Part No.
ADR01
ADR01
ADR02
ADR02
ADR03
ADR03
ADR06
ADR06
ADR431
ADR435
ADR391
ADR395
Table 10. Suitable ADI Precision Op Amps
Part No.
OP97
OP1177
AD8551
AD8603
AD8628
Table 11. Suitable ADI High Speed Op Amps
Part No.
AD8065
AD8021
AD8038
AD9631
REFERENCE SELECTION
When selecting a reference for use with the AD5424/AD5433/
AD5445
reference’s output voltage temperature coefficient specification.
This parameter not only affects the full-scale error, but can also
affect the linearity (INL and DNL) performance. The reference
temperature coefficient should be consistent with the system
accuracy specifications. For example, an 8-bit system required
to hold its overall specification to within 1 LSB over the
temperature range 0°C to 50°C dictates that the maximum
system drift with temperature should be less than 78 ppm/°C.
A 12-bit system with the same temperature range to overall
specification within 2 LSBs requires a maximum drift of
10 ppm/°C. By choosing a precision reference with low output
temperature coefficient this error source can be minimized.
Table 9 suggests some references available from Analog Devices
that are suitable for use with this range of current output DACs.
family of current output DACs, pay attention to the
Output Voltage (V)
10
10
5
5
2.5
2.5
3
3
2.5
5
2.5
5
Supply Voltage (V)
±2 to ±20
±2.5 to ±15
2.7 to 5
1.8 to 6
2.7 to 6
Supply Voltage (V)
5 to 24
±2.5 to ±12
3 to 12
±3 to ±6
Initial Tolerance (%)
0.05
0.05
0.06
0.06
0.10
0.10
0.10
0.10
0.04
0.04
0.16
0.10
V
25
60
5
50
5
BW at ACL (MHz)
145
490
350
320
OS
(Max) (μV)
I
0.1
2
0.05
0.001
0.1
B
(Max) (nA)
Slew Rate (V/μs)
180
120
425
1300
Temp Drift (ppm/°C)
3
9
3
9
3
9
3
9
3
3
9
9
Rev. C | Page 22 of 28
0.1 Hz to 10 Hz
Noise (μV p-p)
0.5
0.4
1
2.3
0.5
AMPLIFIER SELECTION
The primary requirement for the current-steering mode is an
amplifier with low input bias currents and low input offset
voltage. The input offset voltage of an op amp is multiplied by
the variable gain (due to the code dependent output resistance
of the DAC) of the circuit. A change in the noise gain between
two adjacent digital fractions produces a step change in the output
voltage due to the amplifier’s input offset voltage. This output
voltage change is superimposed on the desired change in output
between the two codes and gives rise to a differential linearity
error, which, if large enough, could cause the DAC to be non-
monotonic. In general, the input offset voltage should be <1/4
LSB to ensure monotonic behavior when stepping through codes.
The input bias current of an op amp also generates an offset at
the voltage output as a result of the bias current flowing into the
feedback resistor, R
low enough to prevent significant errors in 12-bit applications.
Common-mode rejection of the op amp is important in voltage-
switching circuits, since it produces a code dependent error at
the voltage output of the circuit. Most op amps have adequate
common mode rejection for use at 8-, 10-, and 12-bit resolution.
V
1500
1000
3000
10000
OS
(Max) (μV)
I
1
1
1
1
1
1
1
1
0.8
0.8
0.12
0.12
SS
(mA)
FB
. Most op amps have input bias currents
Supply Current (μA)
600
500
975
50
850
Output Noise (μV p-p)
20
20
10
10
6
6
10
10
3.5
8
5
8
I
6000
10500
750
7000
B
(Max) (nA)
Package
SOIC-8, SOT-23, MSOP
SOIC-8, MSOP
SOIC-8, SC70-5
SOIC-8
Data Sheet
Package
SOIC-8
MSOP, SOIC-8
MSOP, SOIC-8
TSOT
TSOT, SOIC-8
Package
SOIC-8
TSOT-23, SC70
SOIC-8
TSOT-23, SC70
SOIC-8
TSOT-23, SC70
SOIC-8
TSOT-23, SC70
SOIC-8
SOIC-8
TSOT-23
TSOT-23