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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 SPITM, QSPITM,
and MICROWIRETM 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.
Applications
Portable Data Logging
Hand-Held Measurement Devices
Medical Instruments
System Diagnostics
Solar-Powered Remote Systems
420mA-Powered Remote Systems
Receive-Signal Strength Indicators
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
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
5
10
9
8
7
6
SCLK
DOUT
DIN
CS
GND
CH1
CH0
V
DD
MAX1108
MAX1109
µ
MAX
TOP VIEW
COM
REF
INPUT
SHIFT
REGISTER
CONTROL
LOGIC
T/H
SAR
INTERNAL
OSCILLATOR
OUTPUT
SHIFT
REGISTER
V
DD
ANALOG
INPUT
MUX
INTERNAL
REFERENCE
DOUT
SCLK
DIN
CH0
COM
REF
CH1
CS
GND
CHARGE
REDISTRIBUTION
DAC
MAX1108
MAX1109
Functional Diagram
19-1399; Rev 0; 10/98
Pin Configuration
Ordering Information
PART
MAX1108
CUB
MAX1108EUB
-40°C to +85°C
0°C to +70°C
TEMP. RANGE
PIN-PACKAGE
10 µMAX
10 µMAX
MAX1109
CUB
MAX1109EUB
-40°C to +85°C
0°C to +70°C
10 µMAX
10 µMAX
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.
MAX1108/MAX1109
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.)
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.
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, 10sec) .............................+300°C
V
DD
= 2.7V to 3.6V
V
DD
= 5.5V (Note 2)
No missing codes over temperature
CONDITIONS
±0.15
±0.5
bits
8
Resolution
LSB
±0.2
INL
Relative Accuracy (Note 1)
LSB
±1
DNL
Differential Nonlinearity
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
DD
= 5.5V (Note 2)
V
DD
= 2.7V to 3.6V
LSB
±0.5
Offset Error
±0.2
±1
LSB
±1
Gain Error (Note 3)
ppm/°C
±0.8
Gain Temperature Coefficient
T
A
= T
MIN
to T
MAX
T
A
= +25°C
mV
50
V
DD
/ 2 Sampling Accuracy
dB
49
SINAD
Signal-to-Noise Plus Distortion
dB
-70
THD
Total Harmonic Distortion
(up to the 5th harmonic)
LSB
±0.5
TUE
Total Unadjusted Error
±1
LSB
±0.1
Channel-to-Channel
Offset Matching
-3dB rolloff
Unipolar input, V
COM
= 0
MHz
0.8
Full-Power Bandwidth
MHz
1.5
BW
-3dB
Small-Signal Bandwidth
0
V
REF
Input Voltage Range (Note 4)
dB
68
SFDR
Spurious-Free Dynamic Range
Bipolar input, V
COM
or V
CH1
= V
REF
/ 2,
referenced to COM or CH1
V
±V
REF
/ 2
V
CH_
pF
18
C
IN
Input Capacitance
On/off-leakage current,
V
COM
or V
CH
= 0 or V
DD
µA
±0.01
±1
Multiplexer Leakage Current
DC ACCURACY
DYNAMIC PERFORMANCE
(10kHz sine-wave input, 2.048Vp-p, 50ksps, 500kHz external clock)
ANALOG INPUTS
µA
MAX1108/MAX1109
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
_______________________________________________________________________________________
3
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.)
CONDITIONS
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
External clock, 500kHz, 10 sclks/conv
Internal clock
External clock, 2MHz
µs
20
t
CONV
Conversion Time (Note 5)
35
µs
1
t
ACQ
Track/Hold Acquisition Time
ps
<50
Aperture Jitter
ns
10
Aperture Delay
kHz
400
Internal Clock Frequency
(Note 6)
0 to 0.5mA (Note 7)
ppm/°C
±50
REF Tempco
µA
150
I
REFSC
REF Short-Circuit Current
mV
2.5
Load Regulation
kHz
50
500
V
1.968
2.048
2.128
V
REF
Output Voltage
+2.048V at REF, full scale,
500kHz external clock
µA
1
20
Input Current
V
2.7
3
5.5
V
DD
Supply Voltage
Power down, V
DD
= 2.7V to 3.6V
Full-scale input, V
DD
= 2.7V to 3.6V
0.5
2.5
I
DD
mV
±0.4
±4
PSR
Power-Supply Rejection (Note 9)
V
DD
= 2.7V to 3.6V,
C
L
= 10pF
V
DD
= 5.5V,
C
L
= 10pF
105
250
130
µF
1
Capacitive Bypass at REF
V
0.2
V
HYST
Input Hysteresis
V
0.8
V
IL
Threshold Voltage Low
µA
±1
I
IH
Input Current High
V
DD
3.6V
V
DD
> 3.6V
V
2
V
3
V
IH
Threshold Voltage High
MHz
2
External Clock Frequency Range
V
1.0
V
DD
+ 0.05
Input Voltage Range
µA
±1
I
IL
Input Current Low
pF
15
C
IN
Input Capacitance
For data transfer only
Internal reference
External reference
70
Internal reference
External reference
95
µA
Supply Current (Notes 2, 8)
TRACK/HOLD
INTERNAL REFERENCE
EXTERNAL REFERENCE
POWER REQUIREMENTS
DIGITAL INPUTS
(DIN, SCLK, and CS)
Wake-Up Time
MAX1108/MAX1109
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
4
_______________________________________________________________________________________
CS = V
DD
CS = V
DD
pF
15
C
OUT
Three-State Output Capacitance
µA
±0.01
±10
I
L
Three-State Leakage Current
Figure 1, C
LOAD
= 100pF
Figure 1, C
LOAD
= 100pF
Figure 2, C
LOAD
= 100pF
ns
240
t
DV
CS Fall to Output Enable
ns
CONDITIONS
20
200
t
DO
SCLK Fall to Output Data Valid
ns
240
t
TR
CS Rise to Output Disable
ns
100
t
DS
DIN to SCLK Setup Time
µs
1.0
t
ACQ
Acquisition Time
ns
0
t
DH
DIN to SCLK Hold Time
External reference
Internal reference (Note 10)
µs
20
ns
200
t
CL
SCLK Pulse Width Low
ms
12
t
WAKE
Wake-Up Time
ns
0
t
CSH
CS to SCLK Rise Hold
ns
100
t
CSS
CS to SCLK Rise Setup
ns
200
t
CH
SCLK Pulse Width High
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
I
SINK
= 5mA
I
SOURCE
= 0.5mA
I
SINK
= 16mA
V
0.4
V
V
DD
- 0.5
V
OH
Output High Voltage
V
0.8
V
OL
Output Low Voltage
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.)
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.)
V
DD
= 4.5V to 5.5V
LSB
Offset Error
±0.2
±1
LSB
±1
V
DD
= 4.5V to 5.5V
No missing codes over temperature
Gain Error (Note 3)
ppm/°C
±0.8
CONDITIONS
Gain Temperature Coefficient
T
A
= T
MIN
to T
MAX
T
A
= +25°C
mV
50
V
DD
/ 2 Sampling Accuracy
LSB
±0.5
TUE
Total Unadjusted Error
±1
LSB
±0.1
Channel-to-Channel
Offset Matching
±0.15
±0.5
bits
8
Resolution
LSB
INL
Relative Accuracy (Note 1)
LSB
±1
DNL
Differential Nonlinearity
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
DIGITAL OUTPUT
(DOUT)
TIMING CHARACTERISTICS
(Figures 8, 9, and 10)
DC ACCURACY
MAX1108/MAX1109
Single-Supply, Low-Power,
2-Channel, Serial 8-Bit ADCs
_______________________________________________________________________________________
5
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.)
ps
<50
Aperture Jitter
ns
10
Aperture Delay
kHz
400
Internal Clock Frequency
0 to 0.5mA (Note 7)
ppm/°C
±50
REF Tempco
mA
CONDITIONS
5
I
REFSC
REF Short-Circuit Current
mV
2.5
Load Regulation
kHz
50
500
V
V
3.936
4.096
4.256
V
REF
Output Voltage
+4.096V at REF, full scale,
500kHz external clock
µA
1
20
Input Current
1.0
V
DD
+ 0.05
Input Voltage Range
µF
1
Capacitive Bypass at REF
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
External clock, 2MHz
dB
SINAD
Signal-to-Noise Plus Distortion
49
µs
1
t
ACQ
Track/Hold Acquisition Time
External clock, 500kHz, 10 sclks/conv
Internal clock
µs
20
t
CONV
Conversion Time (Note 5)
35
SFDR
Spurious Free Dynamic Range
dB
dB
68
THD
Total Harmonic Distortion
(up to the 5th harmonic)
-70
Full-Power Bandwidth
MHz
Unipolar input, V
COM
= 0
0
V
REF
-3dB rolloff
MHz
0.8
BW
-3dB
Small-Signal Bandwidth
1.5
V
CH_
Input Voltage Range (Note 4)
V
Multiplexer Leakage Current
µA
On/off-leakage current,
V
CH
= 0 or V
DD
±0.01
±1
pF
C
IN
Input Capacitance
18
Bipolar input, V
COM
or V
CH1
= V
REF
/ 2,
referenced to COM or CH1
±V
REF
/ 2
MHz
2
External Clock Frequency Range
DYNAMIC PERFORMANCE
(10kHz sine-wave input, 4.096Vp-p, 50ksps, 500kHz external clock)
ANALOG INPUTS
TRACK/HOLD
EXTERNAL REFERENCE
INTERNAL REFERENCE
For data transfer only
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