MAX6126 Maxim, MAX6126 Datasheet - Page 14

• Manufacturer Part Number: MAX6126
• Description: Ultra-High-Precision / Ultra-Low-Noise / Series Voltage Reference
• Manufacturer: Maxim

racy is needed. The MAX6126 has the same type of
Kelvin connection to cancel drops in the ground return
line. Connect the load to ground and bring a connection
from GNDS to exactly the same point.
Figure 2 shows a typical circuit providing a precision
current source. The OUTF output provides the bias cur-
rent for the bipolar transistor. OUTS and GNDS sense
the voltage across the resistor and adjust the current
sourced by OUTF accordingly. For even higher preci-
sion, use a MOSFET to eliminate base current errors.
Figure 3 shows a typical circuit providing the reference
for a high-resolution, 16-bit MAX541 D/A converter.
In a data converter application, the reference voltage of
the converter must stay within a certain limit to keep the
error in the data converter smaller than the resolution
limit through the operating temperature range. Figure 4
shows the maximum allowable reference voltage tem-
perature coefficient to keep the conversion error to less
than 1 LSB, as a function of the operating temperature
range (T
parameter. The graph assumes the reference voltage
temperature coefficient as the only parameter affecting
accuracy.
In reality, the absolute static accuracy of a data con-
verter is dependent on the combination of many para-
meters such as integral nonlinearity, differential
nonlinearity, offset error, gain error, as well as voltage
reference changes.
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
14
Temperature Range for a 1 LSB Maximum
High-Resolution DAC and Reference from
______________________________________________________________________________________
Temperature Coefficient vs. Operating
MAX
- T
Applications Information
MIN
) with the converter resolution as a
Precision Current Source
a Single Supply
Error
Figure 2. Precision Current Source
Figure 3. 14-Bit High-Resolution DAC and Positive Reference
from a Single 3V Supply
MAX6126
MAX6126
GND
GND
IN
IN
GNDS
OUTS
OUTF
GNDS
OUTS
OUTF
3V SUPPLY
REF
V
MAX541
OUT(NOMINAL)
R
DAC
GND
V
DD
I
SOURCE
OUT
/ R = I
ANALOG
OUTPUT
SOURCE