19-1399; Rev 1; 6/03
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
General Description
The MAX1108/MAX1109 low-power, 8-bit, dual-channel,
analog-to-digital converters (ADCs) feature an internal
track/hold (T/H) voltage reference, clock, and serial inter-
face. The MAX1108 is specified from +2.7V to +3.6V and
consumes only 105µA. The MAX1109 is specified from
+4.5V to +5.5V and consumes only 130µA. The analog
inputs are software configurable, allowing unipolar/bipolar
and single-ended/differential operation; battery monitor-
ing capability is also included.
The full-scale analog input range is determined by the
internal reference of +2.048V (MAX1108) or +4.096V
(MAX1109), or by an externally applied reference rang-
ing from 1V to V
DD
. The MAX1108/MAX1109 also feature
a software power-down mode that reduces power con-
sumption to 0.5µA when the device is not in use. The
4-wire serial interface directly connects to SPI™, QSPI™,
and MICROWIRE™ devices without external logic.
Conversions up to 50ksps are performed using either the
internal clock or an external serial-interface clock.
The MAX1108 and MAX1109 are available in a 10-pin
µMAX package with a footprint that is just 20% of an
8-pin plastic DIP.
Features
o
Single Supply: +2.7V to +3.6V (MAX1108)
+4.5V to +5.5V (MAX1109)
o
Low Power: 105µA at +3V and 50ksps
0.5µA in Power-Down Mode
o
Software-Configurable Unipolar or Bipolar Inputs
o
Input Voltage Range: 0 to V
DD
o
Internal Track/Hold
o
Internal Reference: +2.048V (MAX1108)
+4.096V (MAX1109)
o
Reference Input Range: 1V to V
DD
o
SPI/QSPI/MICROWIRE-Compatible Serial Interface
o
V
DD
Monitoring Mode
o
Small 10-Pin µMAX Package
MAX1108/MAX1109
Ordering Information
PART
MAX1108CUB
MAX1108EUB
MAX1109CUB
MAX1109EUB
TEMP RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
10 µMAX
10 µMAX
10 µMAX
Applications
Portable Data Logging
Hand-Held Measurement Devices
Medical Instruments
System Diagnostics
Solar-Powered Remote Systems
4–20mA-Powered Remote Systems
Receive-Signal Strength Indicators
Functional Diagram
V
DD
CS
SCLK
INPUT
SHIFT
REGISTER
OUTPUT
SHIFT
REGISTER
Pin Configuration
DIN
DOUT
TOP VIEW
V
DD
1
CH0
CH1
GND
REF
2
3
4
5
10
SCLK
9
DOUT
DIN
CS
COM
REF
MAX1108
MAX1109
CONTROL
LOGIC
CH0
CH1
COM
ANALOG
INPUT
MUX
INTERNAL
REFERENCE
T/H
INTERNAL
OSCILLATOR
SAR
MAX1108
MAX1109
8
7
6
CHARGE
REDISTRIBUTION
DAC
µMAX
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.
GND
________________________________________________________________
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.
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
MAX1108/MAX1109
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ..............................................................-0.3V to +6V
CH0, CH1, COM, REF, DOUT to GND .......-0.3V to (V
DD
+ 0.3V)
DIN, SCLK,
CS
to GND ............................................-0.3V to +6V
Continuous Power Dissipation (T
A
= +70°C)
10-pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
Operating Temperature Ranges
MAX110_CUB ......................................................0°C to +70°C
MAX110_EUB ...................................................-40°C to +85°C
Storage Temperature Range .............................-65°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—MAX1108
(V
DD
= +2.7V to +3.6V; unipolar input mode; COM = GND, f
SCLK
= 500kHz, external clock mode (50% duty cycle); 10 clocks/conver-
sion cycle (50ksps); 1µF capacitor at REF, external +2.048V reference at REF; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical
values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Relative Accuracy (Note 1)
Differential Nonlinearity
Offset Error
Gain Error (Note 3)
Gain Temperature Coefficient
Total Unadjusted Error
Channel-to-Channel
Offset Matching
V
DD
/ 2 Sampling Accuracy
DYNAMIC PERFORMANCE
(10kHz sine-wave input, 2.048Vp-p, 50ksps, 500kHz external clock)
Signal-to-Noise Plus Distortion
Total Harmonic Distortion
(up to the 5th harmonic)
Spurious-Free Dynamic Range
Small-Signal Bandwidth
Full-Power Bandwidth
ANALOG INPUTS
Unipolar input, V
COM
= 0
Input Voltage Range (Note 4)
V
CH_
Bipolar input, V
COM
or V
CH1
= V
REF
/ 2,
referenced to COM or CH1
On/off-leakage current,
V
COM
or V
CH
= 0 or V
DD
C
IN
±0.01
18
0
V
REF
±V
REF
/ 2
±1
V
SINAD
THD
SFDR
BW
-3dB
-3dB rolloff
49
-70
68
1.5
0.8
dB
dB
dB
MHz
MHz
TUE
T
A
= +25°C
T
A
= T
MIN
to T
MAX
±0.5
±0.1
50
±0.8
±1
INL
DNL
V
DD
= 2.7V to 3.6V
V
DD
= 5.5V (Note 2)
No missing codes over temperature
V
DD
= 2.7V to 3.6V
V
DD
= 5.5V (Note 2)
±0.2
±0.5
±1
8
±0.15
±0.2
±1
±1
±0.5
bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
LSB
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Multiplexer Leakage Current
Input Capacitance
µA
pF
2
_______________________________________________________________________________________
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
ELECTRICAL CHARACTERISTICS—MAX1108 (continued)
(V
DD
= +2.7V to +3.6V; unipolar input mode; COM = GND, f
SCLK
= 500kHz, external clock mode (50% duty cycle); 10 clocks/conver-
sion cycle (50ksps); 1µF capacitor at REF, external +2.048V reference at REF; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical
values are at T
A
= +25°C.)
PARAMETER
TRACK/HOLD
Conversion Time (Note 5)
Track/Hold Acquisition Time
Aperture Delay
Aperture Jitter
Internal Clock Frequency
External Clock Frequency Range
INTERNAL REFERENCE
Output Voltage
REF Short-Circuit Current
REF Tempco
Load Regulation
Capacitive Bypass at REF
EXTERNAL REFERENCE
Input Voltage Range
Input Current
POWER REQUIREMENTS
Supply Voltage
V
DD
V
DD
= 2.7V to 3.6V,
C
L
= 10pF
Supply Current (Notes 2, 8)
I
DD
V
DD
= 5.5V,
C
L
= 10pF
Internal reference
External reference
Internal reference
External reference
2.7
3
105
70
130
95
0.5
±0.4
2.5
±4
2
3
0.8
0.2
±1
±1
15
mV
V
V
V
V
µA
µA
pF
5.5
250
µA
µA
V
+2.048V at REF, full scale,
500kHz external clock
1.0
1
V
DD
+ 0.05
20
V
µA
0 to 0.5mA (Note 7)
1
V
REF
I
REFSC
(Note 6)
1.968
2.048
150
±50
2.5
2.128
V
µA
ppm/°C
mV
µF
50
For data transfer only
t
CONV
t
ACQ
Internal clock
External clock, 500kHz, 10 sclks/conv
External clock, 2MHz
20
1
10
<50
400
500
2
35
µs
µs
ns
ps
kHz
kHz
MHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1108/MAX1109
Power down, V
DD
= 2.7V to 3.6V (Note 9)
Power-Supply Rejection (Note 10)
PSR
Full-scale input, V
DD
= 2.7V to 3.6V
V
DD
≤
3.6V
V
DD
> 3.6V
DIGITAL INPUTS
(DIN,
SCLK,
and
CS)
Threshold Voltage High
Threshold Voltage Low
Input Hysteresis
Input Current High
Input Current Low
Input Capacitance
V
IH
V
IL
V
HYST
I
IH
I
IL
C
IN
_______________________________________________________________________________________
3
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
MAX1108/MAX1109
ELECTRICAL CHARACTERISTICS—MAX1108 (continued)
(V
DD
= +2.7V to +3.6V; unipolar input mode; COM = GND, f
SCLK
= 500kHz, external clock mode (50% duty cycle); 10 clocks/conver-
sion cycle (50ksps); 1µF capacitor at REF, external +2.048V reference at REF; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical
values are at T
A
= +25°C.)
PARAMETER
DIGITAL OUTPUT
(DOUT)
Output High Voltage
Output Low Voltage
Three-State Leakage Current
Three-State Output Capacitance
Acquisition Time
DIN to SCLK Setup Time
DIN to SCLK Hold Time
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
Wake-Up Time
Wake-Up Time
V
OH
V
OL
I
L
C
OUT
t
ACQ
t
DS
t
DH
t
DO
t
DV
t
TR
t
CSS
t
CSH
t
CH
t
CL
t
WAKE
External reference
Internal reference (Note 11)
Figure 1, C
LOAD
= 100pF
Figure 1, C
LOAD
= 100pF
Figure 2, C
LOAD
= 100pF
100
0
200
200
20
12
I
SOURCE
= 0.5mA
I
SINK
= 5mA
I
SINK
= 16mA
CS
= V
DD
CS
= V
DD
1.0
100
0
20
200
240
240
0.8
±0.01
15
±10
V
DD
- 0.5
0.4
V
V
V
µA
pF
µs
ns
ns
ns
ns
ns
ns
ns
ns
ns
µs
ms
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS
(Figures 8, 9, and 10)
ELECTRICAL CHARACTERISTICS—MAX1109
(V
DD
= +4.5V to +5.5V; unipolar input mode; COM = GND, f
SCLK
= 500kHz, external clock (50% duty cycle); 10 clocks/conversion
cycle (50ksps); 1µF capacitor at REF, external +4.096V reference at REF; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical values
are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Relative Accuracy (Note 1)
Differential Nonlinearity
Offset Error
Gain Error (Note 3)
Gain Temperature Coefficient
Total Unadjusted Error
Channel-to-Channel
Offset Matching
V
DD
/ 2 Sampling Accuracy
TUE
T
A
= +25°C
T
A
= T
MIN
to T
MAX
±0.5
±0.1
50
±0.8
±1
INL
DNL
V
DD
= 4.5V to 5.5V
No missing codes over temperature
V
DD
= 4.5V to 5.5V
±0.2
8
±0.15
±0.5
±1
±1
±1
bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
LSB
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
4
_______________________________________________________________________________________
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
ELECTRICAL CHARACTERISTICS—MAX1109 (continued)
(V
DD
= +4.5V to +5.5V; unipolar input mode; COM = GND, f
SCLK
= 500kHz, external clock (50% duty cycle); 10 clocks/conversion
cycle (50ksps); 1µF capacitor at REF, external +4.096V reference at REF; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical values
are at T
A
= +25°C.)
PARAMETER
Signal-to-Noise Plus Distortion
Total Harmonic Distortion
(up to the 5th harmonic)
Spurious Free Dynamic Range
Small-Signal Bandwidth
Full-Power Bandwidth
ANALOG INPUTS
Unipolar input, V
COM
= 0
Input Voltage Range (Note 4)
V
CH_
Bipolar input, V
COM
or V
CH1
= V
REF
/ 2,
referenced to COM or CH1
On/off-leakage current,
V
CH
= 0 or V
DD
C
IN
Internal clock
External clock, 500kHz, 10 sclks/conv
External clock, 2MHz
20
1
10
<50
400
50
For data transfer only
V
REF
I
REFSC
0 to 0.5mA (Note 7)
1
1.0
+4.096V at REF, full scale,
500kHz external clock
1
V
DD
+ 0.05
20
3.936
4.096
5
±50
2.5
500
2
4.256
±0.01
18
35
0
V
REF
±V
REF
/ 2
±1
V
SYMBOL
SINAD
THD
SFDR
BW
-3dB
-3dB rolloff
CONDITIONS
MIN
TYP
49
-70
68
1.5
0.8
MAX
UNITS
dB
dB
dB
MHz
MHz
DYNAMIC PERFORMANCE
(10kHz sine-wave input, 4.096Vp-p, 50ksps, 500kHz external clock)
MAX1108/MAX1109
Multiplexer Leakage Current
Input Capacitance
TRACK/HOLD
Conversion Time (Note 5)
Track/Hold Acquisition Time
Aperture Delay
Aperture Jitter
Internal Clock Frequency
External Clock Frequency Range
INTERNAL REFERENCE
Output Voltage
REF Short-Circuit Current
REF Tempco
Load Regulation
Capacitive Bypass at REF
EXTERNAL REFERENCE
Input Voltage Range
Input Current
t
CONV
t
ACQ
µA
pF
µs
µs
ns
ps
kHz
kHz
MHz
V
mA
ppm/°C
mV
µF
V
µA
_______________________________________________________________________________________
5
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