EVALUATION KIT AVAILABLE
MAX187/MAX189
+5V, Low-Power, 12-Bit Serial ADCs
General Description
The MAX187/MAX189 serial 12-bit analog-to-digital con-
verters (ADCs) operate from a single +5V supply and
accept a 0 to 5V analog input. Both parts feature an 8.5Fs
successive-approximation ADC, a fast track/hold (1.5Fs),
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, QSPIK,
and MICROWIRE
M
.
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 PDIP and
16-pin SO packages. Power consumption is 7.5mW and
reduces to only 10FW in shutdown.
Excellent AC characteristics and very low power con-
sumption combined with ease of use and small package
size make these converters ideal for remote DSP and
sensor applications, or for circuits where power con-
sumption and space are crucial.
S
12-Bit Resolution
S
±½ LSB Integral Nonlinearity (MAX187A/MAX189A)
S
Internal Track/Hold, 75kHz Sampling Rate
S
Single +5V Operation
S
Low Power: 2µA Shutdown Current
1.5mA Operating Current
S
Internal 4.096V Buffered Reference (MAX187)
S
3-Wire Serial Interface, Compatible with SPI, QSPI,
and MICROWIRE
S
Small-Footprint 8-Pin PDIP and 16-Pin SO
Features
Applications
Portable Data Logging
Remote Digital Signal Processing
Isolated Data Acquisition
High-Accuracy Process Control
Ordering Information
appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to
www.maximintegrated.com/MAX187.related.
Functional Diagram
GND 5
A
V
= 1.638
(4.096V)
REF-
DAC
REF+
10kI
+2.5V
BANDGAP
REFERENCE
(MAX187 ONLY)
OUTPUT
SHIFT
REGISTER
6 DOUT
8 SCLK
12-BIT
SAR
REF 4
AIN 2
T/H
MAX187
MAX189
V
DD
1
COMPARATOR
BUFFER ENABLE/DISABLE
CONTROL
AND
TIMING
7 CS
3 SHDN
NOTE: PIN NUMBERS SHOWN ARE FOR 8-PIN DIPs ONLY
QSPI is a trademark of Motorola.
MICROWIRE is a registered trademark of National Semiconductor Corp.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-0196; Rev 1; 3/12
MAX187/MAX189
+5V, Low-Power, 12-Bit Serial ADCs
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)......................... ... .......20s
DOUT Current..................................................................Q20mA
Continuous Power Dissipation (T
A
= +70NC)
8-Pin PDIP (derate 9.1mW/NC above +70NC)..............727mW
16-Pin Wide SO (derate 14.5mW/NC above 70NC).....1157mW
Operating Temperature Ranges
MAX187_C_ _/MAX189_C_ _..............................0NC to +70NC
MAX187_E_ _/MAX189_E_ _...........................-40NC to +85NC
Storage Temperature Range.............................-60NC to +150NC
Lead Temperature (soldering, 10s) .................................+300NC
Soldering Temperature (reflow) .......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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%; V
GND
= 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal refer-
ence: 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)
Differential Nonlinearity
Offset Error
DNL
MAX18_B
MAX18_C
No missing codes over temperature
MAX18_A
MAX18_B/C
MAX187
Gain Error (Note 3)
Gain Temperature Coefficient
Signal-to-Noise Plus
Distortion Ratio
Total Harmonic Distortion
(Up to the 5
th
Harmonic)
Spurious-Free Dynamic Range
Small-Signal Bandwidth
Full-Power Bandwidth
CONVERSION RATE
Conversion Time
Track/Hold Acquisition Time
Throughput Rate
t
CONV
t
ACQ
External clock, 4MHz, 13 clocks
5.5
1.5
75
8.5
Fs
Fs
ksps
MAX189A
MAX189B/C
External reference, 4.096V
Q0.8
DYNAMIC SPECIFICATIONS (10kHz Sine Wave Input, 0 to 4.096V
P-P
, 75ksps)
SINAD
THD
SFDR
Rolloff -3dB
80
4.5
0.8
70
-80
dB
dB
dB
MHz
MHz
12
Q½
Q1
Q2
Q1
Q1½
Q3
Q3
Q1
Q3
ppm/NC
LSB
LSB
LSB
LSB
Bits
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Maxim Integrated
2
MAX187/MAX189
+5V, Low-Power, 12-Bit Serial ADCs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V ±5%; V
GND
= 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal refer-
ence: 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
Aperture Delay
Aperture Jitter
ANALOG INPUT
Input Voltage Range
Input Capacitance (Note 4)
INTERNAL REFERENCE (MAX187 Only, Reference Buffer Enabled)
TA = +25NC
REF Output Voltage
REF Short-Circuit Current
MAX187AC/BC
REF Tempco
Load Regulation (Note 5)
Input Voltage Range
Input Current
Input Resistance
Shutdown REF Input Current
DIGITAL INPUTS (SCLK,
CS, SHDN)
SCLK,
CS
Input High Voltage
SCKL,
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
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
V
SHDN
= V
DD
or 0V
1.5
2.75
100
V
IN
= 0V or V
DD
(Note 4)
V
DD
- 50mV
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
12
MAX187AE/BE
MAX187C
0 to 6mA output load
2.50
EXTERNAL REFERENCE AT REF (Buffer Disabled, V
REF
= 4.096V)
V
DD
+ 50mV
200
20
1.5
10
350
V
µA
kI
µA
Q30
Q30
Q30
1
mV
V
REF
TA = TMIN to
TMAX
MAX187_C
MAX187_E
4.076
4.060
4.050
4.096
4.116
4.132
4.140
Q30
Q50
Q60
ppm/NC
mA
V
16
0 to V
REF
V
pF
SYMBOL
t
APR
CONDITIONS
MIN
TYP
10
< 50
MAX
UNITS
ns
ps
Maxim Integrated
3
MAX187/MAX189
+5V, Low-Power, 12-Bit Serial ADCs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V ±5%; V
GND
= 0V; unipolar input mode; 75ksps, f
CLK
= 4.0MHz, external clock (50% duty cycle); MAX187—internal refer-
ence: 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
DIGITAL OUTPUT (DOUT)
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Output Capacitance
POWER REQUIREMENTS
Supply Voltage
Supply Current
V
DD
I
DD
Operating mode
Power-down mode
Power-Supply Rejection
PSR
V
DD
= +5V
Q5%;
external reference,
4.096V; full-scale input (Note 6)
MAX187
MAX189
4.75
1.5
1.0
2
Q0.06
5.25
2.5
2.0
10
Q0.5
V
mA
FA
mV
V
OL
V
OH
I
L
C
OUT
I
SINK
= 5mA
I
SINK
= 16mA
I
SOURCE
= 1mA
V
CS
= 5V
V
CS
= 5V (Note 4)
4
Q10
15
0.3
0.4
V
V
FA
pF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS
(V
DD
= +5V ±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
DQ
t
DV
t
TR
t
SCLK
t
CH
t
CL
t
CSO
t
CS
100
100
50
500
CONDITIONS
CS
= high (Note7)
C
LOAD
= 100pF
C
LOAD
= 100pF
C
LOAD
= 100pF
MAX18_ _C/E
MAX18_ _M
MIN
1.5
20
20
150
200
100
100
5
TYP
MAX
UNITS
µs
ns
ns
ns
MHz
ns
ns
ns
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.
Maxim Integrated
4
MAX187/MAX189
+5V, Low-Power, 12-Bit Serial ADCs
Typical Operating Characteristics
POWER-SUPPLY REJECTION
vs. TEMPERATURE
MAX187 toc01
V
REF
vs. TEMPERATURE
INTERNAL REFERENCE VOLTAGE (V)
4.089
4.088
4.087
4.086
4.085
4.084
4.083
4.082
4.081
4.080
MAX187 toc02
0.16
POWER-SUPPLY REJECTION (mV)
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0
-60
-20
20
60
100
4.090
140
-60
-20
20
60
100
140
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY vs. TEMPERATURE
2.2
SUPPLY CURRENT (mA)
1.8
MAX187
1.4
1.0
0.6
0.2
0
-60
-20
20
60
100
140
-60
MAX189
MAX187 toc03
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
SHUTDOWN SUPPLY CURRENT (µA)
6
5
4
3
2
1
MAX187 toc04
7
-20
20
60
100
140
TEMPERATURE (°C)
TEMPERATURE (°C)
Maxim Integrated
5
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