19-0247; Rev. 1; 4/97
Low-Power, 8-Channel,
Serial 10-Bit ADC
________________General Description
The MAX192 is a low-cost, 10-bit data-acquisition system
that combines an 8-channel multiplexer, high-bandwidth
track/hold, and serial interface with high conversion
speed and ultra-low power consumption. The device
operates with a single +5V supply. The analog inputs are
software configurable for single-ended and differential
(unipolar/bipolar) operation.
The 4-wire serial interface connects directly to SPI™,
QSPI™, and Microwire™ devices, without using external
logic. A serial strobe output allows direct connection to
TMS320 family digital signal processors. The MAX192
uses either the internal clock or an external serial-
interface clock to perform successive approximation A/D
conversions. The serial interface can operate beyond
4MHz when the internal clock is used. The MAX192 has
an internal 4.096V reference with a drift of ±30ppm typi-
cal. A reference-buffer amplifier simplifies gain trim and
two sub-LSBs reduce quantization errors.
The MAX192 provides a hardwired
SHDN
pin and two
software-selectable power-down modes. Accessing the
serial interface automatically powers up the device, and
the quick turn-on time allows the MAX192 to be shut
down between conversions. By powering down
between conversions, supply current can be cut to
under 10µA at reduced sampling rates.
The MAX192 is available in 20-pin DIP and SO pack-
ages, and in a shrink-small-outline package (SSOP)
that occupies 30% less area than an 8-pin DIP. The
data format provides hardware and software compati-
bility with the MAX186/MAX188. For anti-aliasing filters,
consult the data sheets for the MAX291–MAX297.
o
8-Channel Single-Ended or 4-Channel Differential
Inputs
o
Single +5V Operation
o
Low Power: 1.5mA (operating)
2µA (power-down)
o
Internal Track/Hold, 133kHz Sampling Rate
o
Internal 4.096V Reference
o
4-Wire Serial Interface is Compatible
with SPI, QSPI, Microwire, and TMS320
o
20-Pin DIP, SO, SSOP Packages
o
Pin-Compatible 12-Bit Upgrade (MAX186/MAX188)
MAX192
_______________Ordering Information
PART
MAX192ACPP
MAX192BCPP
MAX192ACWP
MAX192BCWP
MAX192ACAP
MAX192BCAP
MAX192AEPP
MAX192BEPP
MAX192AEWP
MAX192BEWP
MAX192AEAP
MAX192BEAP
MAX192AMJP
MAX192BMJP
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
PIN-PACKAGE INL (LSB)
20 Plastic DIP
20 Plastic DIP
20 Wide SO
20 Wide SO
20 SSOP
20 SSOP
20 Plastic DIP
20 Plastic DIP
20 Wide SO
20 Wide SO
20 SSOP
20 SSOP
20 CERDIP
20 CERDIP
±1/2
±1
±1/2
±1
±1/2
±1
±1/2
±1
±1/2
±1
±1/2
±1
±1/2
±1
________________________Applications
Automotive
Pen-Entry Systems
Consumer Electronics
Portable Data Logging
Robotics
Battery-Powered Instruments, Battery
Management
Medical Instruments
___________________Pin Configuration
TOP VIEW
CH0 1
CH1 2
CH2 3
CH3 4
CH4 5
CH5 6
CH6 7
20 V
DD
19 SCLK
18 CS
MAX192
17 DIN
16 SSTRB
15 DOUT
14 DGND
13 AGND
12 REFADJ
11 VREF
____________________________Features
See last page for Typical Operating Circuit.
CH7 8
AGND 9
SHDN 10
SPI and QSPI are trademarks of Motorola Corp.
Microwire is a trademark of National Semiconductor Corp.
DIP/SO/SSOP
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
Low-Power, 8-Channel,
Serial 10-Bit ADC
MAX192
ABSOLUTE MAXIMUM RATINGS
V
DD
to AGND........................................................... -0.3V to +6V
AGND to DGND.................................................... -0.3V to +0.3V
CH0–CH7 to AGND, DGND ...................... -0.3V to (V
DD
+ 0.3V)
CH0–CH7 Total Input Current.......................................... ±20mA
VREF to AGND .......................................... -0.3V to (V
DD
+ 0.3V)
REFADJ to AGND...................................... -0.3V to (V
DD
+ 0.3V)
Digital Inputs to DGND.............................. -0.3V to (V
DD
+ 0.3V)
Digital Outputs to DGND ........................... -0.3V to (V
DD
+ 0.3V)
Digital Output Sink Current .................................................25mA
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 11.11mW/°C above +70°C) ......... 889mW
SO (derate 10.00mW/°C above +70°C) ...................... 800mW
SSOP (derate 8.00mW/°C above +70°C) ................... 640mW
CERDIP (derate 11.11mW/°C above +70°C) .............. 889mW
Operating Temperature Ranges
MAX192_C_P ..................................................... 0°C to +70°C
MAX192_E_P .................................................. -40°C to +85°C
MAX192_MJP ............................................... -55°C to +125°C
Storage Temperature Range ............................ -60°C to +150°C
Lead Temperature (soldering, 10sec) ............................ +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
(V
DD
= 5V ±5%, f
CLK
= 2.0MHz, external clock (50% duty cycle), 15 clocks/conversion cycle (133ksps), 4.7µF capacitor at VREF pin,
T
A
= T
MIN
to T
MAX,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
Relative Accuracy (Note 2)
Differential Nonlinearity
Offset Error
Gain Error
Gain Temperature Coefficient
Channel-to-Channel
Offset Matching
DYNAMIC SPECIFICATIONS
(10kHz sine-wave input, 4.096Vp-p, 133ksps, 2.0MHz external clock)
Signal-to-Noise + Distortion Ratio
Total Harmonic Distortion
(up to the 5th harmonic)
Spurious-Free Dynamic Range
Channel-to-Channel Crosstalk
Small-Signal Bandwidth
Full-Power Bandwidth
CONVERSION RATE
Conversion Time (Note 4)
Track/Hold Acquisition Time
Aperture Delay
Aperture Jitter
Internal Clock Frequency
t
CONV
t
AZ
10
<50
1.7
Internal clock
External clock, 2MHz, 12 clocks/conversion
5.5
6
1.5
10
µs
µs
ns
ps
MHz
SINAD
THD
SFDR
65kHz, V
IN
= 4.096Vp-p (Note 3)
-3dB rolloff
66
-70
70
-75
4.5
800
dB
dB
dB
dB
MHz
kHz
External reference, 4.096V
External reference, 4.096V
±0.8
±0.1
DNL
MAX192A
MAX192B
No missing codes over temperature
10
±1/2
±1
±1
±2
±2
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Low-Power, 8-Channel,
Serial 10-Bit ADC
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±5%, f
CLK
= 2.0MHz, external clock (50% duty cycle), 15 clocks/conversion cycle (133ksps), 4.7µF capacitor at VREF pin,
T
A
= T
MIN
to T
MAX,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
External Clock Frequency
ANALOG INPUT
Common-mode range (any input)
Single-ended range (unipolar only)
Analog Input Voltage
(Note 6)
Differential range
Multiplexer Leakage Current
Input Capacitance
VREF Output Voltage
VREF Short-Circuit Current
VREF Tempco
Load Regulation (Note 8)
Capacitive Bypass at VREF
Capacitive Bypass at REFADJ
REFADJ Adjustment Range
EXTERNAL REFERENCE AT VREF
(buffer disabled, VREF = 4.096V)
Input Voltage Range
Input Current
Input Resistance
Shutdown VREF Input Current
Buffer Disable Threshold
REFADJ
EXTERNAL REFERENCE AT REFADJ
Capacitive Bypass at VREF
Reference-Buffer Gain
REFADJ Input Current
Internal compensation mode
External compensation mode
0
4.7
1.678
±50
µF
V/V
µA
V
DD
-
50mV
12
2.5
200
20
1.5
10
V
DD
+
50mV
350
V
µA
kΩ
µA
V
0mA to 0.5mA output load
Internal compensation
External compensation
Internal compensation
External compensation
0
4.7
0.01
0.01
±1.5
±30
2.5
Unipolar
Bipolar
0
0
0
-V
REF
-2
±0.01
16
4.066
4.096
4.126
30
V
DD
V
REF
V
REF
+V
REF
2
±1
µA
pF
V
mA
ppm/°C
mV
µF
µF
%
V
SYMBOL
CONDITIONS
External compensation, 4.7µF
Internal compensation (Note 5)
Used for data transfer only
MIN
0.1
0.1
10
TYP
MAX
2.0
0.4
MHz
UNITS
MAX192
On/off leakage current; V
IN
= 0V, 5V
(Note 5)
T
A
= +25°C (Note 7)
INTERNAL REFERENCE
(reference buffer enabled)
_______________________________________________________________________________________
3
Low-Power, 8-Channel,
Serial 10-Bit ADC
MAX192
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±5%, f
CLK
= 2.0MHz, external clock (50% duty cycle), 15 clocks/conversion cycle (133ksps), 4.7µF capacitor at VREF pin,
T
A
= T
MIN
to T
MAX,
unless otherwise noted. Typical values are at T
A
= +25°C.)
SYMBOL
–– –— –
— — —
EXTERNAL REFERENCE AT CS , SH
DIGITAL INPUTS (DIN, SCLK,REFADJDN )
DIN,SCLK,
CS
Input High Voltage
DIN,SCLK,
CS
Input Low Voltage
DIN, SCLK,
CS
Input Hysteresis
DIN, SCLK,
CS
Input Leakage
DIN, SCLK,
CS
Input Capacitance
SHDN
Input High Voltage
SHDN
Input Low Voltage
SHDN
Input Current, High
SHDN
Input Current, Low
SHDN
Input Mid Voltage
SHDN
Voltage, Floating
SHDN
Max Allowed Leakage,
Mid Input
DIGITAL OUTPUTS (DOUT, SSTRB)
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Leakage Capacitance
POWER REQUIREMENTS
Positive Supply Voltage
Positive Supply Current
Positive Supply Rejection
(Note 9)
V
DD
Operating mode
I
DD
Fast power-down
Full power-down
PSR
V
DD
= 5V ±5%; external reference, 4.096V;
full-scale input
5 ±5%
1.5
30
2
±0.06
2.5
70
10
±0.5
V
mA
µA
mV
V
OL
V
OH
I
L
C
OUT
I
SINK
= 5mA
I
SINK
= 16mA
I
SOURCE
= 1mA
CS
= 5V
CS
= 5V (Note 5)
4
±10
15
0.3
0.4
V
V
µA
pF
V
INH
V
INL
V
HYST
I
IN
C
IN
V
INH
V
INL
I
INH
I
INL
V
IM
V
FLT
SHDN
= open
SHDN
= open
-100
SHDN
= V
DD
SHDN
= 0V
-4.0
1.5
2.75
100
V
DD
- 1.5
V
IN
= 0V or V
DD
(Note 5)
V
DD
- 0.5
0.5
4.0
0.15
±1
15
PARAMETER
CONDITIONS
MIN
2.4
0.8
TYP
MAX
UNITS
V
V
V
µA
pF
V
V
µA
µA
V
V
nA
Note 1:
Tested at V
DD
= 5.0V; single-ended, unipolar.
Note 2:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after the full-scale range has
been calibrated.
Note 3:
Grounded on-channel; sine wave applied to all off channels.
Note 4:
Conversion time defined as the number of clock cycles times the clock period; clock has 50% duty cycle.
Note 5:
Guaranteed by design. Not subject to production testing.
Note 6:
The common-mode range for the analog inputs is from AGND to V
DD
.
Note 7:
Sample tested to 0.1% AQL.
Note 8:
External load should not change during conversion for specified accuracy.
Note 9:
Measured at V
SUPPLY
+ 5% and V
SUPPLY
- 5% only.
4
_______________________________________________________________________________________
Low-Power, 8-Channel,
Serial 10-Bit ADC
TIMING CHARACTERISTICS
(V
DD
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
Acquisition Time
DIN to SCLK Setup
DIN to SCLK Hold
SCLK Fall to Output Data Valid
CS
Fall to Output Enable
CS
Rise to Output Disable
CS
to SCLK Rise Setup
CS
to SCLK Rise Hold
SCLK Pulse Width High
SCLK Pulse Width Low
SCLK Fall to SSTRB
CS
Fall to SSTRB Output Enable
(Note 5)
CS
Rise to SSTRB Output
Disable (Note 5)
SSTRB Rise to SCLK Rise
(Note 5)
SYMBOL
t
AZ
t
DS
t
DH
t
DO
t
DV
t
TR
t
CSS
t
CSH
t
CH
t
CL
t
SSTRB
t
SDV
t
STR
t
SCK
C
LOAD
= 100pF
External clock mode only, C
LOAD
= 100pF
External clock mode only, C
LOAD
= 100pF
Internal clock mode only
0
C
LOAD
= 100pF
C
LOAD
= 100pF
C
LOAD
= 100pF
100
0
200
200
200
200
200
20
CONDITIONS
MIN
1.5
100
0
150
100
100
TYP
MAX
UNITS
µs
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
MAX192
Note 5:
Guaranteed by design. Not subject to production testing.
__________________________________________Typical Operating Characteristics
POWER-SUPPLY REJECTION
vs. TEMPERATURE
0.30
0.25
0.20
PSR (LSBs)
0.15
0.10
0.05
0
-0.05
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
VREFADJ (V)
V
DD
= +5V ±5%
2.456
OFFSET MATCHING (LSBs)
INTERNAL REFERENCE VOLTAGE
vs. TEMPERATURE
CHANNEL-TO-CHANNEL OFFSET MATCHING
vs. TEMPERATURE
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0
-60 -40 -20
2.455
2.454
2.453
2.452
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
_______________________________________________________________________________________
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