19-3977; Rev 0; 1/06
Microcontroller-Interface,
4.5-/3.5-Digit Panel Meters with 4–20mA Output
General Description
The MAX1366/MAX1368 low-power, 4.5- and 3.5-digit,
panel meters feature an integrated sigma-delta analog-
to-digital converter (ADC), LED display drivers, voltage
digital-to-analog converter (DAC), and a 4–20mA (or 0
to 16mA) current driver.
The MAX1366/MAX1368’s analog input voltage range is
programmable to either ±2V or ±200mV. The MAX1368
drives a 3.5-digit (±1999 count) display and the
MAX1366 drives a 4.5-digit (±19,999 count) display.
The ADC output directly drives the LED display as well
as the voltage DAC, which, in turn, drives the 4–20mA
(or 0 to 16mA) current-loop output.
In normal operation, the 0 to 16mA/4–20mA current-
loop output follows the ±2V or ±200mV analog input to
drive remote panel-meter displays, data loggers, and
other industrial controllers. For added flexibility, the
MAX1366/MAX1368 allow direct access to the ADC
result, DAC output, and the V/I converter input.
The sigma-delta ADC does not require external preci-
sion integrating capacitors, autozero capacitors, crystal
oscillators, charge pumps, or other circuitry commonly
required in dual-slope ADC panel-meter circuits. On-
chip analog input and reference buffers allow direct
interface with high-impedance signal sources. Excellent
common-mode rejection and digital filtering provides
greater than 100dB rejection of simultaneous 50Hz and
60Hz line noise. Other features include data hold and
peak detection and overrange/underrange detection.
The MAX1366/MAX1368 require a 2.7V to 5.25V supply,
a 4.75V to 5.25V V/I supply, and a 7V to 30V loop sup-
ply. They are available in a space-saving (7mm x
7mm), 48-pin TQFP package and operate over the
extended (-40°C to +85°C) temperature range.
KIT
ATION
EVALU
BLE
AVAILA
Features
♦
Microcontroller (µC)-Interface, Digital Panel Meter
20-Bit Sigma-Delta ADC
4.5-Digit Resolution (±19,999 Count, MAX1366)
3.5-Digit Resolution (±1999 Count, MAX1368)
No Integrating/Autozeroing Capacitors
100MΩ Input Impedance
±200mV or ±2.000V Input Range
♦
LED Display
Common-Cathode 7-Segment LED Driver
Programmable LED Current (0 to 20mA)
2.5Hz Update Rate
♦
Output DAC and Current Driver
±15-Bit DAC with 14-Bit Linear V/I Converter
Selectable 0 to 16mA or 4–20mA Current Output
Unipolar/Bipolar Modes
±50µA Zero Scale, ±40ppmFS/°C (typ)
±0.5% Gain Error, ±25ppmFS/°C (typ)
Separate 7V to 30V Supply for Current-Loop
Output
♦
2.7V to 5.25V ADC/DAC Supply
♦
4.75V to 5.25V V/I Converter Supply
♦
Internal 2.048V Reference or External Reference
♦
SPI™-/QSPI™-/MICROWIRE™-Compatible Serial
Interface
♦
48-Pin, 7mm x 7mm TQFP Package
MAX1366/MAX1368
Applications
Industrial Process Control
Automated Test Equipment
Data-Acquisition Systems
Digital Panel Meters
Digital Voltmeters
Digital Multimeters
PART
PART
MAX1366ECM
MAX1368ECM
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
48 TQFP
48 TQFP
Selector Guide
PACKAGE CODE
C48-6
C48-6
RESOLUTION
(DIGITS)
4.5
3.5
Pin Configuration appears at end of data sheet.
Typical Operating Circuits appear at end of data sheet.
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
MAX1366ECM
MAX1368ECM
________________________________________________________________
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.
Microcontroller-Interface, 4.5-/3.5-Digit Panel
Meters with 4–20mA Output
MAX1366/MAX1368
ABSOLUTE MAXIMUM RATINGS
(With reference to GND, unless otherwise specified.)
AV
DD
, DV
DD ....................................................................
-0.3V to +6.0V
AIN+, AIN-, REF+, REF-.........................V
NEGV
to (AV
DD
+ 0.3V)
REG_FORCE, CMP, DAC_VDD, DACVOUT,
CONV_IN, 4-20OUT .............................-0.3V to (AV
DD
+ 0.3V)
EN_BPM, EN_I, REFSELE, DACDATA_SEL,
CLK,
EOC, CS_DAC,
SCLK, DIN
DOUT .....................................................-0.3V to (DV
DD
+ 0.3V)
NEGV .......................................................-2.6V to (AV
DD
+ 0.3V)
LED_EN....................................................-0.3V to (DV
DD
+ 0.3V)
SET...........................................................-0.3V to (AV
DD
+ 0.3V)
REG_AMP, REG_VDD ...........................................-0.3V to +6.0V
LEDG .....................................................................-0.3V to +0.3V
GND_DAC .............................................................-0.3V to +0.3V
GND_V/I.................................................................-0.3V to +0.3V
SEG_ to LEDG.........................................-0.3V to (V
LEDV
+ 0.3V)
DIG_ to LEDG..........................................-0.3V to (V
LEDV
+ 0.3V)
LOWBATT ................................................-0.3V to (AV
DD
+ 0.3V)
REF_DAC .................................................-0.3V to (AV
DD
+ 0.3V)
DACVOUT ................................................-0.3V to (AV
DD
+ 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)
48-Pin TQFP (derate 22.7mW/°C above +70°C).....1818.2mW
Operating Temperature Range ...........................-40°C to +85°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
= DAC_VDD = +2.7V to +5.25V, GND = 0, LEDG = 0, V
LEDV
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external
reference), V
EXT
= 7V, V
REG_AMP
= +5.0V, C
REF+
= 0.1µF, REF- = GND, C
NEGV
= 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
ADC 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
External Clock Frequency
External Clock Duty Cycle
Update Rate
Internal clock
External clock, f
CLK
= 4.9152MHz
RANGE bit = 0
RANGE bit = 1
-2.0
-0.2
40
5
5
+2.0
+0.2
4.9152
60
MHz
%
Hz
V
AIN+
- V
AIN-
= 0 (Note 2)
(Note 3)
V
AIN+
- V
AIN-
= 0 (Note 4)
-0
-0.5
0.1
±1
INL
MAX1366
MAX1368
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
-19,999
-1999
±1
±1
10:1
±1
10
+0
+0.5
+19,999
+1999
Counts
Counts
Ratio
Counts
µV
P-P
Counts
%FSR
µV/°C
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ANALOG INPUTS (AIN+, AIN-) (bypass to GND with 0.1µF or greater capacitors)
AIN Input Voltage Range (Note 5)
V
2
_______________________________________________________________________________________
Microcontroller-Interface, 4.5-/3.5-Digit Panel
Meters with 4–20mA Output
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= DAC_VDD = +2.7V to +5.25V, GND = 0, LEDG = 0, V
LEDV
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external
reference), V
EXT
= 7V, V
REG_AMP
= +5.0V, C
REF+
= 0.1µF, REF- = GND, C
NEGV
= 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
AIN Absolute Input Voltage
Range to GND
Internal clock mode,
50Hz and 60Hz ±2%
External clock mode,
50Hz and 60Hz ±2%, f
CLK
= 4.9152MHz
CMR
CMR
For 50Hz and 60Hz ±2%, R
SOURCE
<
10kΩ
At DC
SYMBOL
CONDITIONS
MIN
-2.2
100
dB
100
150
100
10
10
(Note 6)
-20
2.048
10
20
V
REF
AV
DD
= 5V
2.007
2.048
1
TC
VREF
I
SOURCE
= 0 to 300µA, I
SINK
= 0 to 30µA
0.1Hz to 10Hz
10Hz to 10kHz
Differential, (V
REF+
- V
REF-
)
-2.2
Internal clock mode,
50Hz and 60Hz ±2%
External clock mode,
50Hz and 60Hz ±2%, f
CLK
= 4.9152MHz
CMR
CMR
For 50Hz and 60Hz ±2%, R
SOURCE
<
10kΩ
At DC
40
6
50
25
400
2.048
+2.2
2.089
+20
dB
dB
nA
pF
nA
V
pA
mV
V
mA
ppm/°C
µV/µA
µV/V
µV
P-P
TYP
MAX
+2.2
UNITS
V
MAX1366/MAX1368
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
LOWBATT Trip Threshold
LOWBATT Leakage Current
Hysteresis
LOW-BATTERY VOLTAGE MONITOR (LOWBATT)
INTERNAL REFERENCE (REF- = GND, INTREF = DV
DD
)
REF Input Voltage
REF Output Short-Circuit Current
REF Output Temperature
Coefficient
Load Regulation
Line Regulation
Noise Voltage
EXTERNAL REFERENCE (INTREF BIT = 0)
REF Input Voltage
Absolute REF+, REF- Input
Voltage to GND (V
REF+
must be
greater than V
REF-
)
V
V
100
dB
120
150
100
10
dB
dB
nA
Normal-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode Rejection
Input Leakage Current
_______________________________________________________________________________________
3
Microcontroller-Interface, 4.5-/3.5-Digit Panel
Meters with 4–20mA Output
MAX1366/MAX1368
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= DAC_VDD = +2.7V to +5.25V, GND = 0, LEDG = 0, V
LEDV
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external
reference), V
EXT
= 7V, V
REG_AMP
= +5.0V, C
REF+
= 0.1µF, REF- = GND, C
NEGV
= 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
Input Capacitance
Average Dynamic Input Current
CHARGE PUMP
Output Voltage
Input Current
Input Low Voltage
Input High Voltage
Input Hysteresis
DIGITAL OUTPUTS (DOUT,
EOC)
Output Low Voltage
Output High Voltage
Tri-State Leakage Current
Tri-State Output Capacitance
ADC POWER SUPPLY (Note 10)
AV
DD
Voltage
DV
DD
Voltage
Power-Supply Rejection AV
DD
Power-Supply Rejection DV
DD
AV
DD
Current (Notes 8, 9)
AV
DD
DV
DD
PSR
A
PSR
D
I
AVDD
(Note 7)
(Note 7)
Standby mode
DV
DD
= +5.25V
DV
DD
Current (Notes 8, 9)
DAC POWER SUPPLY
DAC Supply Voltage
DAC Supply Current
LINEAR REGULATOR AND V/I CONVERTER POWER REQUIREMENTS
REG_AMP Supply Voltage
REG_AMP Supply Current
REG_VDD Voltage
V
REG_VDD
V
REG_AMP
4.75
0.19
5.20
5.25
0.30
V
mA
V
V
DAC_VDD
2.70
0.10
5.25
0.21
V
mA
I
DVDD
DV
DD
= +3.3V
Standby mode
2.70
2.70
80
100
640
305
320
180
20
µA
5.25
5.25
V
V
dB
dB
µA
V
OL
V
OH
I
L
C
OUT
I
SINK
= 1mA
I
SOURCE
= 200µA
0.8 x
D
VDD
-10
15
+10
0.4
V
V
µA
pF
NEGV
I
IN
V
INL
V
INH
V
HYS
DV
DD
= 3V
0.7 x
DV
DD
200
C
NEGV
= 0.1µF to GND
V
IN
= 0 or DV
DD
-2.60
-10
-2.42
-2.30
+10
0.3 x
DV
DD
V
µA
V
V
mV
DIGITAL INPUTS (SCLK, DIN,
CS,
CLK)
(Note 6)
-20
SYMBOL
CONDITIONS
MIN
TYP
10
+20
MAX
UNITS
pF
nA
4
_______________________________________________________________________________________
Microcontroller-Interface, 4.5-/3.5-Digit Panel
Meters with 4–20mA Output
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= DAC_VDD = +2.7V to +5.25V, GND = 0, LEDG = 0, V
LEDV
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external
reference), V
EXT
= 7V, V
REG_AMP
= +5.0V, C
REF+
= 0.1µF, REF- = GND, C
NEGV
= 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
REG_VDD Supply Current
LED DRIVERS (Table 7)
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
LED Drivers Bias Current
Interdigit Blanking Time
4-20OUT OUTPUT ACCURACY
Zero-Scale Error
Zero-Scale Error Tempco
Gain Error
Gain-Error Tempco
Span Linearity
Power-Supply Rejection
Signal Path Noise
4–20mA Current Limit
SCLK Operating Frequency
SCLK Pulse-Width High
SCLK Pulse-Width Low
DIN-to-SCLK Setup
DIN-to-SCLK Hold
CS
Fall to SCLK Rise Setup
SCLK Rise to
CS
Rise Hold
SCLK Fall to DOUT Valid
f
SCLK
t
CH
t
CL
t
DS
t
DH
t
CSS
t
CSH
t
DO
C
LOAD
= 50pF, Figures 11, 12
PSR
V
EXT
= 7V to 36V
10pF to AGND on 4-20OUT
Limited to 12.5 x V
REF
/ 1.28kΩ
DV
DD
= 2.7V
0
100
100
50
0
50
0
120
4mA or 0mA, at +25°C
4mA or 0mA, at +25°C
±10
±40
±0.2
±25
±2
4
2.0
20
4.2
±4
±0.5
±50
µA
ppmFS/°C
%FS
ppmFS/°C
µA
µA/V
µA
RMS
mA
MHz
ns
ns
ns
ns
ns
ns
ns
V
LEDV
I
SHDN
I
LEDV
f
OSC
I
SEG
/∆t
V
DIG
∆I
SEG
I
SEG
V
LEDV
- V
SEG
= 0.6V, R
SET
= 25kΩ
From AV
DD
15.0
I
DIG_
= 176mA
Seven segments and decimal point on,
R
SET
= 25kΩ
MAX1366
MAX1368
176
512
640
25
0.178
3
21.5
120
4
0.300
±10
25.5
2.70
5.25
10
180
V
µA
mA
Hz
mA/µs
V
%
mA
µA
µs
SYMBOL
CONDITIONS
Includes 20mA programmed current
MIN
TYP
25.2
MAX
27.4
UNITS
mA
MAX1366/MAX1368
TIMING CHARACTERISTICS (Notes 11, 12, Figure 8)
_______________________________________________________________________________________
5
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