Datasheet
MAX1447/MAX1496/MAX1498
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
10 ______________________________________________________________________________________
Detailed Description
The MAX1447/MAX1496/MAX1498 low-power, highly
integrated ADCs with LED drivers convert a ±2V differ-
ential input voltage (one count is equal to 100µV for the
MAX1447/MAX1498 and 1mV for the MAX1496) with a
sigma-delta ADC and output the result to an LED. An
additional ±200mV input range (one count is equal to
10µV for the MAX1447/MAX1498 and 100µV for the
MAX1496) is available to measure small signals with
increased resolution.
The devices operate from a single 2.7V to 5.25V power
supply and offer 3.5-digit (MAX1496) or 4.5-digit
(MAX1447/MAX1498) conversion results. An internal
2.048V reference, internal charge pump, and a high-accu-
racy on-chip oscillator eliminate external components.
The devices also feature on-chip buffers for the differen-
tial input signal and external-reference inputs, allowing
direct interface with high-impedance signal sources. In
addition, they use continuous internal offset-calibration
and offer >100dB of 50Hz and 60Hz line-noise rejec-
tion. Other features include data hold and peak detec-
tion and overrange/underrange detection.
Analog Input Protection
Internal protection diodes limit the analog input range
from VNEG to (AV
DD
+ 0.3V) for the MAX1447/
MAX1498, and from VNEG to (V
DD
+ 0.3V) for the
MAX1496. If the analog input exceeds this range, limit
the input current to 10mA.
Internal Analog Input/Reference Buffers
The MAX1447/MAX1496/MAX1498 analog input/refer-
ence buffers allow the use of high-impedance signal
sources. The input buffers’ common-mode input range
allows the analog inputs and the reference to range from
-2.2V to +2.2V.
Pin Description (continued)
PIN
MAX1496
MAX1447/
MAX1498
NAME
FUNCTION
19 18 DIG3 Digit 3 Driver
20 20
SEGA
Segment A Driver
21 21
SEGB
Segment B Driver
22 22
SEGC
Segment C Driver
23 23
SEGD
Segment D Driver
24 24
SEGE
Segment E Driver
25 25 VLED
LED Display Segment Driver Supply. Connect to a +2.7V to +5.25V supply. Bypass with a
0.1µF capacitor to GLED.
26 26
SEGF
Segment F Driver
27 27
SEGG
Segment G Driver
28 28
SEGDP
Segment DP Driver
—6AV
DD
Analog Positive Supply Voltage. Connect AV
DD
to a +2.7V to +5.25V power supply. Bypass
AV
DD
to GND with a 0.1µF capacitor.
—7
DV
DD
Digital Positive Supply Voltage. Connect DV
DD
to a +2.7V to +5.25V power supply. Bypass
DV
DD
to GND with a 0.1µF capacitor.
—19DIG4 Digit 4 Driver
—29
LED_EN
Active-High LED Enable. The MAX1447/MAX1498 display driver turns off when the LED_EN
is driven to logic low. The MAX1447/MAX1498 LED display driver turns on when LED_EN is
driven to logic high.
—30
DPON
Decimal-Point Enable Input. Controls the decimal point of the LED. See the Decimal-Point
Control section. Connect to DV
DD
(MAX1447/MAX1498) or V
DD
(MAX1496) to enable the
decimal point.