19-3166; Rev 0; 1/04
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
General Description
The MAX1447/MAX1496/MAX1498 low-power, 3.5- and
4.5-digit, analog-to-digital converters (ADCs) with inte-
grated light-emitting diode (LED) drivers operate from a
single 2.7V to 5.25V power supply. They include an
internal reference, a high-accuracy on-chip oscillator,
and a multiplexed LED display driver. An internal charge
pump generates the negative supply needed to power
the integrated input buffers for single-supply operation.
The ADC is configurable for either a ±2V or ±200mV
input range and it outputs its conversion results to an
LED. The MAX1496 is a 3.5-digit (±1999 count) device
and the MAX1447/MAX1498 are 4.5-digit (±19,999
count) devices.
The MAX1447/MAX1496/MAX1498 do not require exter-
nal precision integrating capacitors, autozero capaci-
tors, crystal oscillators, charge pumps, or other circuitry
required with dual-slope ADCs (commonly used in
panel meter circuits).
These devices also feature on-chip buffers for the dif-
ferential signal and reference input, allowing direct
interface with high-impedance signal sources. In addi-
tion, they use continuous internal offset-calibration and
offer >100dB rejection of 50Hz and 60Hz line noise.
Other features include data hold and peak detection
and overrange/underrange detection. The MAX1447
features on-demand enhanced offset calibration for
improved offset performance.
The MAX1447/MAX1498 are available in a 32-pin, 7mm
✕
7mm TQFP package and the MAX1496 is available in
28-pin SSOP and 28-pin PDIP packages. All devices in
this family operate over the -40°C to +85°C extended
temperature range.
Features
♦
High Resolution
MAX1447/MAX1498: 4.5 Digits (±19,999 Count)
MAX1496: 3.5 Digits (±1999 Count)
♦
Sigma-Delta ADC Architecture
No Integrating Capacitors Required
No Autozeroing Capacitors Required
>100dB of Simultaneous 50Hz and 60Hz
Rejection
♦
Selectable Input Range of ±200mV or ±2V
♦
Selectable Voltage Reference: Internal 2.048V or
External
♦
Internal High-Accuracy Oscillator Needs No
External Components
♦
Automatic Offset Calibration
♦
On-Demand Enhanced Offset Calibration
(MAX1447)
♦
Operate from a Single 2.7V to 5.25V Supply
♦
Low Power (Exclude LED-Driver Current)
Maximum 744µA Operating Current (MAX1496)
Maximum 960µA Operating Current
(MAX1447/MAX1498)
Maximum 325µA Shutdown Current
♦
Multiplexed Common-Cathode LED Drivers
Resistor-Programmable Segment Current
♦
Small 32-Pin, 7mm x 7mm TQFP Package (4.5
Digits), 28-Pin SSOP Package (3.5 Digits)
♦
Also Available in a PDIP Package (3.5 Digits)
MAX1447/MAX1496/MAX1498
Applications
Digital Panel Meters
Hand-Held Meters
Digital Voltmeters
Digital Multimeters
Pin Configurations appear at end of data sheet.
PART
MAX1447ECJ
MAX1496EAI*
MAX1496EPI
MAX1498ECJ
Ordering Information
TEMP RANGE
PIN-
RESOLUTION
PACKAGE
(DIGITS)
4.5
3.5
3.5
4.5
-40°C to +85°C 32 TQFP
-40°C to +85°C 28 SSOP
-40°C to +85°C 28 PDIP
-40°C to +85°C 32 TQFP
*Future
product—contact factory for availability.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
MAX1447/MAX1496/MAX1498
ABSOLUTE MAXIMUM RATINGS
AV
DD
to GND (MAX1447/MAX1498) ........................-0.3V to +6V
DV
DD
to GND (MAX1447/MAX1498)........................-0.3V to +6V
AIN+, AIN- to GND
(MAX1447/MAX1498) ......................VNEG to (AV
DD
to +0.3V)
REF+, REF- to GND
(MAX1447/MAX1498) ..................... VNEG to (AV
DD
to +0.3V)
INTREF, RANGE, DPSET1, DPSET2, HOLD, PEAK,
DPON to GND (MAX1447/MAX1498) ..-0.3V to (DV
DD
+ 0.3V)
VNEG to GND (MAX1447/MAX1498).......-2.6V to (AV
DD
+ 0.3V)
LED_EN to GND (MAX1447/MAX1498) ...-0.3V to (DV
DD
+ 0.3V)
ISET to GND (MAX1447/MAX1498) .........-0.3V to (AV
DD
+ 0.3V)
V
DD
to GND (MAX1496) ...........................................-0.3V to +6V
AIN+, AIN- to GND (MAX1496)..............VNEG to (V
DD
to +0.3V)
REF+, REF- to GND (MAX1496) ........... VNEG to (V
DD
to +0.3V)
INTREF, RANGE, DPSET1, DPSET2, HOLD, PEAK,
DPON to GND (MAX1496) .....................-0.3V to (V
DD
+ 0.3V)
VNEG to GND (MAX1496)..........................-2.6V to (V
DD
+ 0.3V)
ISET to GND (MAX1496) ............................-0.3V to (V
DD
+ 0.3V)
VLED to GLED ..........................................................-0.3V to +6V
GLED to GND ........................................................-0.3V to +0.3V
SEG_ to GLED..........................................-0.3V to (VLED + 0.3V)
DIG_ to GLED ..........................................-0.3V to (VLED + 0.3V)
DIG_ Sink Current .............................................................300mA
DIG_ Source Current...........................................................50mA
SEG_ Sink Current ..............................................................50mA
SEG_ Source Current..........................................................50mA
Maximum Current Input into Any Other Pin ........................50mA
Continuous Power Dissipation (T
A
= +70°C)
32-Pin TQFP (derate 20.7mW/°C above +70°C).....1652.9mW
28-Pin SSOP (derate 9.5mW/°C above +70°C) ...........762mW
28-Pin PDIP (derate 14.3mW/°C above +70°C)......1142.9mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, V
LED
= +2.7V to +5.25V, GLED = 0, V
REF+
- V
REF-
= 2.048V (external reference),
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
DC ACCURACY
Noise-Free Resolution
Integral Nonlinearity (Note 1)
Range Change Ratio
Rollover Error
Output Noise
Offset Error (Zero Input Reading)
Gain Error
Offset Drift (Zero Reading Drift)
Gain Drift
INPUT CONVERSION RATE
Conversion Rate
5
Hz
Offset
V
IN
= 0 (Note 2)
(Note 3)
V
IN
= 0 (Note 4)
-0
-0.5
0.1
±1
INL
MAX1447/MAX1498
MAX1496
2.000V range
200mV range
(V
AIN+
- V
AIN-
= 0.100V) on 200mV range
(V
AIN+
- V
AIN-
= 0.100V) on 2.0V range
V
AIN+
- V
AIN-
= full scale
V
AIN-
- V
AIN+
= full scale
-19,999
-1999
±1
±1
10:1
±1
10
0
+0.5
+19,999
+1999
Counts
Counts
Ratio
Counts
µV
P-P
Readings
% FSR
µV/°C
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, V
LED
= +2.7V to +5.25V, GLED = 0, V
REF+
- V
REF-
= 2.048V (external reference),
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
RANGE = GND
AIN Input Voltage Range (Note 5)
AIN Absolute Input Voltage
Range to GND
Normal-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode Rejection
Input Leakage Current
Input Capacitance
Average Dynamic Input Current
(Note 6)
-20
CMR
CMR
50Hz and 60Hz ±2%
For 50Hz and 60Hz ±2%, R
SOURCE
< 10kΩ
At DC
RANGE = DV
DD
(MAX1447/MAX1498) or
V
DD
(MAX1496)
CONDITIONS
MIN
-2.0
-0.2
-2.2
100
150
100
10
10
+20
TYP
MAX
+2.0
+0.2
+2.2
V
UNITS
MAX1447/MAX1496/MAX1498
ANALOG INPUTS (AIN+, AIN-) (bypass to GND with 0.1µF or greater capacitors)
V
dB
dB
dB
nA
pF
nA
INTERNAL REFERENCE (REF- = GND, INTREF = DV
DD
(MAX1447/MAX1498) or V
DD
(MAX1496) (bypass REF+ to GND with a
4.7µF capacitor)
REF Output Voltage
REF Output Short-Circuit Current
REF Output Temperature
Coefficient
Load Regulation
Line Regulation
Noise Voltage
0.1Hz to 10Hz
10Hz to 10kHz
Differential, V
REF+
- V
REF-
-2.2
50Hz and 60Hz ±2%
CMR
CMR
For 50Hz and 60Hz ±2%, R
SOURCE
< 10kΩ
At DC
100
150
100
10
10
(Note 6)
-20
+20
TC
VREF
I
SOURCE
= 0 to 300µA, I
SINK
= 0 to 30µA
V
REF
2.007
2.048
1
40
6
50
25
400
2.048
+2.2
2.089
V
mA
ppm/°C
mV/µA
µV/V
µV
P-P
EXTERNAL REFERENCE (INTREF = GND) (bypass REF+ and REF- to GND with 0.1µF or greater capacitors)
REF Input Voltage
Absolute REF+, REF- Input
Voltage to GND
Normal-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode Rejection
Input Leakage Current
Input Capacitance
Average Dynamic Input Current
V
V
dB
dB
dB
nA
pF
nA
_______________________________________________________________________________________
3
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
MAX1447/MAX1496/MAX1498
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, V
LED
= +2.7V to +5.25V, GLED = 0, V
REF+
- V
REF-
= 2.048V (external reference),
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
CHARGE PUMP
Output Voltage
Input Current
VNEG
I
IN
C
VNEG
= 0.1µF to GND
V
IN
= 0 or DV
DD
= V
DD
MAX1447/MAX1498
Input Low Voltage
V
INL
MAX1496
MAX1447/MAX1498
Input High Voltage
V
INH
MAX1496
Input Hysteresis
POWER SUPPLY
(Note 7)
V
DD
Voltage
AV
DD
Voltage
DV
DD
Voltage
Power-Supply Rejection V
DD
Power-Supply Rejection AV
DD
Power-Supply Rejection DV
DD
MAX1496 V
DD
Current (Note 9)
V
DD
AV
DD
DV
DD
PSRR
PSRR
A
PSRR
D
I
VDD
MAX1496
MAX1447/MAX1498
MAX1447/MAX1498
(Note 8)
(Note 8)
(Note 8)
V
DD
= 5.25V
V
DD
= 3.3V
Standby mode
MAX1447/MAX1498 AV
DD
Current (Note 9)
AV
DD
= 5.25V
I
AVDD
AV
DD
= 3.3V
Standby mode
MAX1447/MAX1498 DV
DD
Current (Note 9)
LED Drivers Bias Current
DV
DD
= 5.25V
I
DVDD
DV
DD
= 3.3V
Standby mode
From AV
DD
or V
DD
120
2.70
2.70
2.70
80
80
100
664
618
268
744
663
325
640
600
305
320
180
20
µA
µA
µA
µA
5.25
5.25
5.25
V
V
V
dB
dB
dB
V
HYS
0.7 x
DV
DD
0.7 x
V
DD
200
mV
-2.60
-10
-2.42
-2.30
+10
0.3 x
DV
DD
0.3 x
V
DD
V
µA
DIGITAL INPUTS (INTREF, RANGE, PEAK, HOLD, DPSET1, DPSET2, DPON)
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
V
4
_______________________________________________________________________________________
3.5- and 4.5-Digit, Single-Chip ADCs
with LED Drivers
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, V
LED
= +2.7V to +5.25V, GLED = 0, V
REF+
- V
REF-
= 2.048V (external reference),
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
LED DRIVERS
(Table 5)
LED Supply Voltage
LED Shutdown Supply Current
LED Supply Current
Display Scan Rate
Segment Current Slew Rate
DIG_ Voltage Low
Segment Drive Source Current
Matching
Segment Drive Source Current
Interdigit Blanking Time
V
LED
I
SHDN
I
LED
f
OSC
∆I
SEG
/∆t
V
DIG
∆I
SEG
I
SEG
V
LED
- V
SEG
= 0.6V, R
ISET
= 25kΩ
16.0
I
DIG_
= 176mA
LED driver shutdown mode
Seven segments and decimal point on,
R
ISET
= 25kΩ
MAX1447/MAX1498
MAX1496
176
512
640
25
0.178
3
21.5
4
0.300
±10
25.5
2.70
5.25
10
180
V
µA
mA
Hz
mA/µs
V
%
mA
µs
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1447/MAX1496/MAX1498
Note 1:
Integral nonlinearity is the deviation of the analog value at any code from its theoretical value after nulling the gain error and
offset error.
Note 2:
Offset calibrated.
Note 3:
Offset nulled.
Note 4:
Drift error is eliminated by recalibration at the new temperature.
Note 5:
The input voltage range for the analog inputs is given with respect to the voltage on the negative input of the differential pair.
Note 6:
V
AIN
+ or V
AIN
- = -2.2V to +2.2V. V
REF
+ or V
REF
- = -2.2V to +2.2V. All input structures are identical. Production tested on
AIN+ and REF+ only.
Note 7:
Power-supply currents are measured with all digital inputs at either GND or DV
DD
.
Note 8:
Measured at DC by changing the power-supply voltage from 2.7V to 5.25V and measuring the effect on the conversion
error with external reference. PSRR at 50Hz and 60Hz exceeds 120dB with filter notches at 50Hz and 60Hz (Figure 2).
Note 9:
LED drivers are disabled.
_______________________________________________________________________________________
5
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