Datasheet
MAX1447/MAX1496/MAX1498
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
14 ______________________________________________________________________________________
Decimal-Point Control
The MAX1447/MAX1496/MAX1498 allow for full deci-
mal-point control and feature leading-zero suppression.
Use the DPON, DPSET1, and DPSET2 bits in the con-
trol register to set the value of the decimal point (Tables
2 and 3). The MAX1447/MAX1496/MAX1498 overrange
and underrange display is shown in Table 4.
Leading-Zero Suppression
The MAX1447/MAX1496/MAX1498 include a leading-
zero suppression circuitry to turn off unnecessary zeros.
For example, when DPSET1 and DPSET2 = [0,0], 0.0 is
displayed instead of 000.0. This feature saves a substan-
tial amount of power from being wasted.
Interdigit Blanking
The MAX1447/MAX1496/MAX1498 also include an
interdigit blanking circuitry. Without this feature, it is
possible to see a faint digit next to a digit that is com-
pletely on. The interdigit blanking circuitry prevents
bleeding over into the next digit for a short period of
time. The typical interdigit blanking time is 4µs.
Reference
The MAX1447/MAX1496/MAX1498 reference sets the
full-scale range of the ADC transfer function. With a
nominal 2.048V reference, the ADC full-scale range is
±2V with RANGE = GND. With RANGE = DV
DD
(MAX1447/MAX1498) or V
DD
(MAX1496), the full-scale
range is ±200mV. A decreased reference voltage
decreases full-scale range (see the Transfer Functions
section).
The MAX1447/MAX1496/MAX1498 accept either an
external reference or an internal reference (INTREF).
The INTREF logic selects the reference mode.
For internal-reference operation, set INTREF to DV
DD
(MAX1447/MAX1498) or V
DD
(MAX1496), connect REF-
to GND, and bypass REF+ to GND with a 4.7µF capaci-
tor. The internal reference provides a nominal 2.048V
source between REF+ and GND. The internal-reference
temperature coefficient is typically 40ppm/°C.
Table 2. Decimal-Point Control Table—MAX1447/MAX1498
DPON DPSET1 DPSET2 DISPLAY OUTPUT ZERO INPUT READING
00 0 18888 0
00 1 18888 0
01 0 18888 0
01 1 18888 0
10 0 1888.8 0.0
10 1 188.88 0.00
11 0 18.888 0.000
11 1 1.8888 0.0000
Table 3. Decimal-Point Control Table—MAX1496
DPSET1 DPSET2 DISPLAY OUTPUT ZERO INPUT READING
00 188.8 0.0
01 18.88 0.00
10 1888 0
11 1.888 0.000
X = Don’t care.
Table 4. LED During Overrange and
Underrange Conditions
CONDITION MAX1496
MAX1447/MAX1498
Overrange 1--- 1----
Underrange -1--- -1----