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19-0196; Rev 0; 10/93
ANUAL
N KIT M
LUATIO ATA SHEET
EVA
WS D
FOLLO
+5V, Low-Power, 12-Bit Serial ADCs
________________________________Features
o
o
o
o
o
12-Bit Resolution
±
1
⁄
2
LSB Integral Nonlinearity (MAX187A/MAX189A)
Internal Track/Hold, 75kHz Sampling Rate
Single +5V Operation
Low Power: 2µA Shutdown Current
1.5mA Operating Current
o
Internal 4.096V Buffered Reference (MAX187)
o
3-Wire Serial Interface, Compatible with SPI,
QSPI, and Microwire
o
Small-Footprint 8-Pin DIP and 16-Pin SO
__________________General Description
The MAX187/MAX189 serial 12-bit analog-to-digital
converters (ADCs) operate from a single +5V supply
and accept a 0V to 5V analog input. Both parts feature
an 8.5µs successive-approximation ADC, a fast
track/hold (1.5µs), an on-chip clock, and a high-speed
3-wire serial interface.
The MAX187/MAX189 digitize signals at a 75ksps
throughput rate. An external clock accesses data from
the interface, which communicates without external
hardware to most digital signal processors and micro-
controllers. The interface is compatible with SPI™,
QSPI™, and Microwire™.
The MAX187 has an on-chip buffered reference, and
the MAX189 requires an external reference. Both the
MAX187 and MAX189 save space with 8-pin DIP and
16-pin SO packages. Power consumption is 7.5mW
and reduces to only 10µW in shutdown.
Excellent AC characteristics and very low power con-
sumption combined with ease of use and small pack-
age size make these converters ideal for remote DSP
and sensor applications, or for circuits where power
consumption and space are crucial.
MAX187/MAX189
_________________Ordering Information
PART
MAX187ACPA
MAX187BCPA
MAX187CCPA
MAX187ACWE
MAX187BCWE
MAX187CCWE
MAX187BC/D
TEMP. RANGE PIN-PACKAGE ERROR
(LSB)
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
0°C to +70°C
8 Plastic DIP
8 Plastic DIP
8 Plastic DIP
16 Wide SO
16 Wide SO
16 Wide SO
Dice*
±
1
⁄
2
±1
±2
±
1
⁄
2
±1
±2
±1
___________________________Applications
Portable Data Logging
Remote Digital Signal Processing
Isolated Data Acquisition
High-Accuracy Process Control
Ordering Information continued on last page.
* Dice are specified at T
A
= +25°C, DC parameters only.
** Contact factory for availability and processing to MIL-STD-883.
________________Functional Diagram
OUTPUT
SHIFT
REGISTER
6
DOUT
8
SCLK
_________________Pin Configurations
TOP VIEW
GND
5
AV = 1.638
+2.5V
BANDGAP
REFERENCE
(MAX187 ONLY)
10k
(4.096V)
REF-
DAC
REF+
V
DD
AIN
12-BIT
SAR
1
2
8
7
SCLK
CS
DOUT
GND
REF
AIN
4
2
SHDN
3
REF
4
MAX187
MAX189
6
5
T/H
COMPARATOR
MAX187
MAX189
VDD
1
7
BUFFER ENABLE/DISABLE CONTROL
AND
TIMING
3
DIP
CS
SHDN
NOTE: PIN NUMBERS SHOWN ARE FOR 8-PIN DIPs ONLY.
Pin Configurations continued on last page.
™ SPI and QSPI are trademarks of Motorola. Microwire is a trademark of National Semiconductor.
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
+5V, Low-Power, 12-Bit Serial ADCs
MAX187/MAX189
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND .............................................................-0.3V to +6V
AIN to GND................................................-0.3V to (V
DD
+ 0.3V)
REF to GND ...............................................-0.3V to (V
DD
+ 0.3V)
Digital Inputs to GND.................................-0.3V to (V
DD
+ 0.3V)
Digital Outputs to GND..............................-0.3V to (V
DD
+ 0.3V)
SHDN
to GND.............................................-0.3V to (V
DD
+ 0.3V)
REF Load Current (MAX187) .........................4.0mA Continuous
REF Short-Circuit Duration (MAX187)................................20sec
DOUT Current ..................................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ..500mW
16-Pin Wide SO (derate 8.70mW/°C above +70°C) ...478mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C) ......440mW
Operating Temperature Ranges:
MAX187_C_ _/MAX189_C_ _.............................0°C to +70°C
MAX187_E_ _/MAX189_E_ _ ..........................-40°C to +85°C
MAX187_MJA/MAX189_MJA .......................-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%; GND = 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal
reference: V
REF
= 4.096V, 4.7µF capacitor at REF pin, or MAX189—external reference: V
REF
= 4.096V applied to REF pin, 4.7µF
capacitor at REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
MAX18_A
Relative Accuracy (Note 2)
MAX18_B
MAX18_C
Differential Nonlinearity
Offset Error
DNL
No missing codes over temperature
MAX18_A
MAX18_B/C
MAX187
Gain Error (Note 3)
MAX189A
MAX189B/C
Gain Temperature Coefficient
External reference, 4.096V
±0.8
12
±
1
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Bits
⁄
2
LSB
±1
±2
±1
±1
1
LSB
LSB
⁄
2
±3
±3
±1
±3
ppm/°C
LSB
DYNAMIC SPECIFICATIONS
(10kHz sine wave input, 0V to 4.096V
p-p
, 75ksps)
Signal-to-Noise plus
Distortion Ratio
Total Harmonic Distortion
(up to the 5th harmonic)
Spurious-Free Dynamic Range
Small-Signal Bandwidth
Full-Power Bandwidth
SINAD
THD
SFDR
Rolloff -3dB
80
4.5
0.8
70
-80
dB
dB
dB
MHz
MHz
2
_______________________________________________________________________________________
+5V, Low-Power, 12-Bit Serial ADCs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V ±5%; GND = 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal
reference: V
REF
= 4.096V, 4.7µF capacitor at REF pin, or MAX189—external reference: V
REF
= 4.096V applied to REF pin, 4.7µF
capacitor at REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETER
CONVERSION RATE
Conversion Time
Track/Hold Acquisition Time
Throughput Rate
Aperture Delay
Aperture Jitter
ANALOG INPUT
Input Voltage Range
Input Capacitance (Note 4)
INTERNAL REFERENCE
(MAX187 only, reference buffer enabled)
T
A
= +25°C
REF Output Voltage
V
REF
T
A
= T
MIN
to T
MAX
REF Short-Circuit Current
MAX187AC/BC
REF Tempco
MAX187AE/BE
MAX187AM/BM
MAX187C
Load Regulation (Note 5)
0mA to 0.6mA output load
±30
±30
±30
±30
1
mV
MAX187_C
MAX187_E
MAX187_M
4.076
4.060
4.050
4.040
4.096
4.116
4.132
4.140
4.150
30
±50
±60
±80
ppm/°C
mA
V
16
0 to V
REF
V
pF
t
APR
t
CONV
t
ACQ
External clock, 4MHz, 13 clocks
10
<50
5.5
1.5
75
8.5
µs
µs
ksps
ns
ps
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX187/MAX189
EXTERNAL REFERENCE AT REF
(Buffer disabled, V
REF
= 4.096V)
Input Voltage Range
Input Current
Input Resistance
Shutdown REF Input Current
12
2.50
200
20
1.5
10
V
DD
+ 50mV
350
V
µA
kΩ
µA
_______________________________________________________________________________________
3
+5V, Low-Power, 12-Bit Serial ADCs
MAX187/MAX189
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V ±5%; GND = 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal
reference: V
REF
= 4.096V, 4.7µF capacitor at REF pin, or MAX189—external reference: V
REF
= 4.096V applied to REF pin, 4.7µF
capacitor at REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL INPUTS (SCLK,
CS
,
SHDN
)
SCLK,
CS
Input High Voltage
SCLK,
CS
Input Low Voltage
SCLK,
CS
Input Hysteresis
SCLK,
CS
Input Leakage
SCLK,
CS
Input Capacitance
SHDN
Input High Voltage
SHDN
Input Low Voltage
SHDN
Input Current
SHDN
Input Mid Voltage
SHDN
Voltage, Floating
SHDN
Maximum Allowed
Leakage, Mid Input
DIGITAL OUTPUT (DOUT)
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Output
Capacitance
POWER REQUIREMENTS
Supply Voltage
V
DD
Operating mode
Supply Current
I
DD
Power-down mode
Power-Supply Rejection
PSR
V
DD
= +5V, ±5%; external reference, 4.096V;
full-scale input (Note 6)
MAX187
MAX189
4.75
1.5
1.0
2
±0.06
5.25
2.5
2.0
10
±0.5
µA
mV
V
mA
V
OL
V
OH
I
L
C
OUT
I
SINK
= 5mA
I
SINK
= 16mA
I
SOURCE
= 1mA
CS
= 5V
CS
= 5V (Note 4)
4
±10
15
0.3
V
µA
pF
0.4
V
V
INH
V
INL
V
HYST
I
IN
C
IN
V
INSH
V
INSL
I
INS
V
IM
V
FLT
SHDN
= open
SHDN
= open
-100
SHDN
= V
DD
or 0V
1.5
2.75
100
V
IN
= 0V or V
DD
(Note 4)
V
DD
- 0.5
0.5
±4.0
V
DD
-1.5
0.15
±1
15
2.4
0.8
V
V
V
µA
pF
V
V
µA
V
V
nA
4
_______________________________________________________________________________________
+5V, Low-Power, 12-Bit Serial ADCs
MAX187/MAX189
TIMING CHARACTERISTICS
(V
DD
= +5.0V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
Track/Hold Acquisition Time
SCLK Fall to Output Data Valid
CS
Fall to Output Enable
CS
Rise to Output Disable
SCLK Clock Frequency
SCLK Pulse Width High
SCLK Pulse Width Low
SCLK Low to
CS
Fall
Setup Time
CS
Pulse Width
SYMBOL
t
ACQ
t
DO
t
DV
t
TR
f
SCLK
t
CH
t
CL
t
CSO
t
CS
100
100
50
500
CONDITIONS
CS
= high (Note 7)
C
LOAD
= 100pF
C
LOAD
= 100pF
C
LOAD
= 100pF
MAX18_ _C/E
MAX18_ _M
MIN
1.5
20
20
150
200
100
100
5
ns
ns
MHz
ns
ns
ns
ns
TYP
MAX
UNITS
µs
ns
Note 1:
Tested at V
DD
= +5V.
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:
MAX187—internal reference, offset nulled; MAX189–external +4.096V reference, offset nulled. Excludes reference errors.
Note 4:
Guaranteed by design. Not subject to production testing.
Note 5:
External load should not change during conversion for specified ADC accuracy.
Note 6:
DC test, measured at 4.75V and 5.25V only.
Note 7:
To guarantee acquisition time, t
ACQ
is the maximum time the device takes to acquire the signal, and is also the minimum
time needed for the signal to be acquired.
_______________________________________________________________________________________
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