MAX1447 Datasheet, PDF (10/24 Pages) Maxim Integrated Products – 3.5- and 4.5-Digit, Single-Chip ADCs with LED Drivers

3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
Pin Description (continued)
PIN
MAX1496
19
20
21
22
23
24
MAX1447/
MAX1498
18
20
21
22
23
24
25
25
26
26
27
27
28
28
—
6
—
7
—
19
—
29
NAME
FUNCTION
DIG3
SEGA
SEGB
SEGC
SEGD
SEGE
Digit 3 Driver
Segment A Driver
Segment B Driver
Segment C Driver
Segment D Driver
Segment E Driver
VLED ^{LED Display Segment Driver Supply. Connect to a +2.7V to +5.25V supply. Bypass with a}
0.1µF capacitor to GLED.
SEGF
SEGG
SEGDP
Segment F Driver
Segment G Driver
Segment DP Driver
AV_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.
DV_DD
DIG4
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.
Digit 4 Driver
Active-High LED Enable. The MAX1447/MAX1498 display driver turns off when the LED_EN
LED_EN is driven to logic low. The MAX1447/MAX1498 LED display driver turns on when LED_EN is
driven to logic high.
Decimal-Point Enable Input. Controls the decimal point of the LED. See the Decimal-Point
—
30
DPON Control section. Connect to DVDD (MAX1447/MAX1498) or VDD (MAX1496) to enable the
decimal point.
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.
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