MAX547BEQH+D Maxim Integrated Products, MAX547BEQH+D Datasheet - Page 11

• Manufacturer Part Number: MAX547BEQH+D
• Description: IC DAC 13BIT OCTAL PAR 44-PLCC
• Manufacturer: Maxim Integrated Products

Specifications of MAX547BEQH+D

• Settling Time: 5µs
• Number Of Bits: 13
• Data Interface: Parallel
• Number Of Converters: 8
• Voltage Supply Source: Dual ±
• Power Dissipation (max): 1.07W
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-LCC, 44-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

load regulation is specified to 20ppm/mA max over
temperature, resulting in a maximum error of 36ppm
(90µV). This corresponds to a maximum error caused
by reference load regulation of only 0.147LSB
[0.147LSB = 90µV/(5V/8192)LSB] over temperature.
If you want a ±4.096V full-scale output swing (1LSB =
1mV), you can use the calibrated, low-drift, low-dropout
MAX676. Operating from a 5V supply, it is fully speci-
fied to drive two REF_ inputs with less than 60.4µV error
(0.0604LSB) over temperature, caused by the maxi-
mum load step.
Another way to obtain high accuracy is to buffer a refer-
ence with an op amp. When driving all reference inputs
simultaneously, keep the closed-loop output imped-
ance of the op amp below 0.03Ω to ensure an error of
less than 0.1LSB. The op amp must also drive the
capacitive load (typically 500pF to 1200pF).
Each reference input can also be buffered separately
by using the circuit in Figure 6. A reference load step
caused by a digital transition only affects the DAC pair
where the code transition occurs. It also allows the use
of references with little drive capability. Keep the
closed-loop output impedance of each op amp below
0.12Ω, to ensure an error of less than 0.1LSB. Figure 6
shows the op amp’s inverting input directly connected
to the MAX547’s reference terminal. This eliminates the
Table 5. Reference, AGND – and Output Relationships
Bipolar Zero Level, or
Unipolar Mid-scale,
(Code = 1000000000000)
Differential Reference Voltage
(V
Negative Full-scale Output
(Code = All 0s)
Positive Full-Scale Output
(Code = All 1s)
LSB Weight
VOUT
Digital Code (D, 0 to 8191)
DR
)
–
as a Function of
PARAMETER
______________________________________________________________________________________
Reference Buffering
BIPOLAR OPERATION
(
——— - 1
(
4096
(AGND_ = 0V)
———
AGND_ (=0V)
4095
4096
D
-REF –
———
REF –
REF _
4096
) (
) (
REF_
REF_
Octal, 13-Bit Voltage-Output
DAC with Parallel Interface
)
)
influence of board lead resistance by sensing the volt-
age with a low-current path sense line directly at the
reference input.
Adding feedback resistors to individual reference
buffer amplifiers enables different reference voltages to
be generated from a single reference.
Figure 5. Optional Schottky Diode between V
POSITIVE UNIPOLAR
(AGND_ = REF_/2)
SYSTEM GND
AGND –
(
(
———
———
OPERATION
8191
8192
8192
(
D
REF – /2
———
V
REF _
8192
SS
0V
(
) (
) (
= ———
1N5817
REF_
REF_
REF _
)
2
)
)
)
V
SS
AGND _ +
AGND _ +
CUSTOM OPERATION
MAX547
GND
REF – - AGND –
AGND – - V
AGND –
(
———
V
4096
—--—- - 1
(
4096
SS
DR
———
D
4095
4096
and GND
DR
) (
) (
V
DR
V
DR
)
11
)