19-1388; Rev 0; 11/98
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin µMAX
General Description
The MAX157/MAX159 low-power, 10-bit analog-to-digi-
tal converters (ADCs) are available in 8-pin µMAX and
DIP packages. Both devices operate with a single
+2.7V to +5.25V supply and feature a 7.4µs succes-
sive-approximation ADC, automatic power-down, fast
wake-up (2.5µs), an on-chip clock, and a high-speed,
3-wire serial interface.
Power consumption is only 3.2mW (V
DD
= +3.6V) at the
maximum sampling rate of 108ksps. At slower through-
put rates, the 0.2µA automatic shutdown further
reduces power consumption.
The MAX157 provides 2-channel, single-ended opera-
tion and accepts input signals from 0 to V
REF
. The
MAX159 accepts pseudo-differential inputs ranging
from 0 to V
REF
. An external clock accesses data
through the 3-wire serial interface, which is SPI™,
QSPI™, and MICROWIRE™ compatible.
Excellent dynamic performance and low power, com-
bined with ease of use and a small package size, make
these converters ideal for battery-powered and data
acquisition applications, or for other circuits with
demanding power-consumption and space require-
ments. For pin-compatible 12-bit upgrades, see the
MAX144/MAX145 data sheet.
Features
o
Single-Supply Operation (+2.7V to +5.25V)
o
Two Single-Ended Channels (MAX157)
Single Pseudo-Differential Channel (MAX159)
o
Low Power
0.9mA (at 108ksps, +3V)
100µA (at 10ksps, +3V)
10µA (at 1ksps, +3V)
<0.2µA (power-down mode)
o
Internal Track/Hold
o
108ksps Sampling Rate
o
SPI/QSPI/MICROWIRE-Compatible 3-Wire
Serial Interface
o
Space-Saving 8-Pin µMAX Package
o
Pin-Compatible 12-Bit Upgrades Available
MAX157/MAX159
Ordering Information
PART
TEMP.
RANGE
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
PIN-
PACKAGE
8 µMAX
8 µMAX
8 Plastic DIP
8 Plastic DIP
8 µMAX
8 µMAX
8 Plastic DIP
8 Plastic DIP
8 CERDIP*
8 CERDIP*
8 µMAX
8 µMAX
8 Plastic DIP
8 Plastic DIP
8 µMAX
8 µMAX
8 Plastic DIP
8 Plastic DIP
8 CERDIP*
8 CERDIP*
INL
(LSB)
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
±0.5
±1
Applications
Battery-Powered Systems
Portable Data Logging
Isolated Data Acquisition
Process-Control Monitoring
Instrumentation
Test Equipment
Medical Instruments
System Supervision
MAX157ACUA
MAX157BCUA
MAX157ACPA
MAX157BCPA
MAX157AEUA
MAX157BEUA
MAX157AEPA
MAX157BEPA
Pin Configuration
TOP VIEW
V
DD
1
CH0 (CH+)
2
CH1 (CH-)
3
8
7
SCLK
DOUT
CS/SHDN
REF
MAX157AMJA -55°C to +125°C
MAX157BMJA -55°C to +125°C
MAX159ACUA
0°C to +70°C
MAX159BCUA
0°C to +70°C
MAX159ACPA
0°C to +70°C
MAX159BCPA
0°C to +70°C
MAX159AEUA -40°C to +85°C
MAX159BEUA -40°C to +85°C
MAX159AEPA
MAX159BEPA
MAX159AMJA
MAX159BMJA
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
MAX157
MAX159
6
5
GND
4
µMAX/DIP
( ) ARE FOR MAX159 ONLY.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
*Contact
factory for availability.
1
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin µMAX
MAX157/MAX159
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND. .............................................................-0.3V to +6V
CH0, CH1 (CH+, CH-) 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 +6V
DOUT to GND.............................................-0.3V to (V
DD
+ 0.3V)
DOUT Sink Current ............................................................ 25mA
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 4.1mW/°C above +70°C) ......................330mW
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
Operating Temperature Ranges
MAX157/MAX159_C_A .......................................0°C to +70°C
MAX157/MAX159_E_A ....................................-40°C to +85°C
MAX157/MAX159_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
= +2.7V to +5.25V, V
REF
= 2.5V, 0.1µF capacitor at REF, f
SCLK
= 2.17MHz, 16 clocks/conversion cycle (108ksps),
CH- = GND for MAX159, 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 (Note 3)
Gain Temperature Coefficient
Channel-to-Channel Offset
Matching
Channel-to-Channel Gain
Matching
External reference, V
REF
= 2.5V
±0.8
±0.02
±0.02
RES
INL
DNL
MAX15_A
MAX15_B
No missing codes over temperature
10
±0.5
±1
±0.5
±2
±2
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
LSB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS
(f
IN
(sine wave) = 10kHz, V
IN
= 2.5Vp-p, 108ksps, external f
SCLK
= 2.17MHz, CH- = GND for MAX159)
Signal-to-Noise Ratio plus
Distortion
Total Harmonic Distortion
(including 5th-order harmonic)
Spurious-Free Dynamic Range
Channel-to-Channel Crosstalk
Small-Signal Bandwidth
Full-Power Bandwidth
SINAD
THD
SFDR
f
IN
= 65kHz, V
IN
= 2.5Vp-p (Note 4)
-3dB rolloff
66
-70
70
-75
2.25
1.0
dB
dB
dB
dB
MHz
MHz
2
_______________________________________________________________________________________
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin µMAX
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +5.25V, V
REF
= 2.5V, 0.1µF capacitor at REF, f
SCLK
= 2.17MHz, 16 clocks/conversion cycle (108ksps),
CH- = GND for MAX159, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
CONVERSION RATE
Conversion Time (Note 5)
T/H Acquisition Time
Aperture Delay
Aperture Jitter
Serial Clock Frequency
ANALOG INPUTS
Analog Input Voltage Range
(Note 6)
Multiplexer Leakage Current
Input Capacitance
EXTERNAL REFERENCE
Input Voltage Range (Note 7)
Input Current
Input Resistance
Shutdown REF Input Current
DIGITAL INPUTS (CS/SHDN, SCLK) AND DIGITAL OUTPUT (DOUT)
V
DD
≤
3.6V
Input High Voltage
V
IH
V
DD
> 3.6V
Input Low Voltage
Input Hysteresis
Input Leakage Current
Input Capacitance
Output Low Voltage
Output High Voltage
Three-State Output Leakage
Current
Three-State Output Capacitance
C
OUT
V
IL
V
HYS
I
IN
C
IN
V
OL
V
OH
V
IN
= 0 or V
DD
(Note 8)
I
SINK
= 5mA
I
SINK
= 16mA
I
SOURCE
= 0.5mA
CS/SHDN
= V
DD
CS/SHDN
= V
DD
(Note 8)
V
DD
- 0.5
±10
15
0.5
0.2
±1
15
0.4
2.0
3.0
0.8
V
REF
V
REF
= 2.5V
18
0
V
DD
+ 50mV
100
25
0.01
10
140
V
µA
kΩ
µA
C
IN
V
IN
On/off-leakage current, V
IN
= 0 to V
DD
0
±0.01
16
V
REF
±1
V
µA
µA
f
SCLK
External clock mode
Internal clock mode, for data transfer only
0.1
0
t
CONV
t
ACQ
25
<50
2.17
5
External clock, f
SCLK
= 2.17MHz, 16 clock
cycles per conversion
Internal clock
7.4
5
7
2.5
µs
ns
ps
MHz
MHz
µs
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX157/MAX159
V
V
V
µA
pF
V
V
µA
pF
_______________________________________________________________________________________
3
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin µMAX
MAX157/MAX159
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +5.25V, V
REF
= 2.5V, 0.1µF capacitor at REF, f
SCLK
= 2.17MHz, 16 clocks/conversion cycle (108ksps),
CH- = GND for MAX159, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
POWER REQUIREMENTS
Positive Supply Voltage
Positive Supply Current
Positive Supply Current
Power-Supply Rejection
(Note 9)
V
DD
I
DD
I
DD
PSR
Operating mode
Shutdown,
CS/SHDN
= GND
V
DD
= 2.7V to 5.25V, full-scale input
+2.7
0.9
0.2
±0.15
+5.25
2.0
5
V
mA
µA
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS (Figure 7)
(V
DD
= +2.7V to +5.25V, V
REF
= 2.5V, 0.1µF capacitor at REF, f
SCLK
= 2.17MHz, 16 clocks/conversion cycle (108ksps),
CH- = GND for MAX159, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Wake-Up Time
CS/SHDN
Fall to Output Enable
CS/SHDN
Rise to Output
Disable
SCLK Fall to Output Data Valid
SCLK Clock Frequency
SYMBOL
t
WAKE
t
DV
t
TR
t
DO
f
SCLK
C
L
= 100pF (Figure 1)
C
L
= 100pF (Figure 1)
C
L
= 100pF
External clock
Internal clock, SCLK for data transfer only
External clock
SCLK Pulse Width High
t
CH
Internal clock, SCLK for data transfer only
(Note 8)
External clock
SCLK Pulse Width Low
SCLK to
CS/SHDN
Setup
CS/SHDN
Pulse Width
t
CL
t
SCLKS
t
CS
Internal clock, SCLK for data transfer only
(Note 8)
20
0.1
0
215
50
215
50
60
60
ns
ns
ns
ns
CONDITIONS
MIN
2.5
120
120
120
2.17
5
TYP
MAX
UNITS
µs
ns
ns
ns
MHz
Note 1:
Tested at V
DD
= +2.7V.
Note 2:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after full-scale range has been
calibrated.
Note 3:
Offset nulled.
Note 4:
The on channel is grounded; the sine wave is applied to off channel (MAX157 only).
Note 5:
Conversion time is defined as the number of clock cycles times the clock period; clock has 50% duty cycle.
Note 6:
The common-mode range for the analog inputs is from GND to V
DD
(MAX159 only).
Note 7:
ADC performance is limited by the converter’s noise floor, typically 300µVp-p.
Note 8:
Guaranteed by design. Not subject to production testing.
Note 9:
Measured as V
FS
(2.7V) - V
FS
(5.25V).
4
_______________________________________________________________________________________
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin µMAX
Typical Operating Characteristics
(V
DD
= +3.0V, V
REF
= 2.5V, 0.1µF capacitor at REF, f
SCLK
= 2.17MHz, 16 clocks/conversion cycle (108ksps); CH- = GND for
MAX159; T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX157/159 toc01
MAX157/MAX159
SUPPLY CURRENT
vs. TEMPERATURE
MAX157/159 toc02
SUPPLY CURRENT
vs. SAMPLING RATE
V
REF
= V
DD
CODE = 1010101000
C
L
= 50pF
MAX157/159 toc03
1500
V
REF
= V
DD
R
L
=
∞
C
L
= 50pF
CODE = 1010101000
1500
V
REF
= V
DD
R
L
=
∞
C
L
= 50pF
CODE = 1010101000
10,000
1300
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
1100
SUPPLY CURRENT (µA)
1250
1000
100
1000
900
10
750
700
1
500
2.5
3.0
3.5
4.0
V
DD
(V)
4.5
5.0
5.5
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
500
0.1
0.1
1
10
100
1k
10k
100k
SAMPLING RATE (sps)
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
V
REF
= V
DD
SHUTDOWN CURRENT (nA)
800
MAX157/159 toc04
SHUTDOWN CURRENT
vs. TEMPERATURE
V
REF
= V
DD
SHUTDOWN CURRENT (nA)
800
MAX157/159 toc05
1000
1000
600
600
400
400
200
200
0
2.5
3.0
3.5
4.0
V
DD
(V)
4.5
5.0
5.5
0
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
OFFSET ERROR vs. SUPPLY VOLTAGE
MAX157/159 toc06
OFFSET ERROR vs. TEMPERATURE
MAX157/159 toc07
0.20
0.20
OFFSET ERROR (LSB)
OFFSET ERROR (LSB)
0.15
0.15
0.10
0.10
0.05
0.05
0
2.5
3.0
3.5
4.0
V
DD
(V)
4.5
5.0
5.5
0
-60 -35
-10
15
40
65
90
115 140
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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