DA6501.001
27 October 2008
MAS6501
This is preliminary information on a new
product under development. Micro Analog
Systems Oy reserves the right to make any
changes without notice.
16-Bit Analog-to-Digital Converter
•
Standby Current Consumption
0.1 µA
•
Low Supply Current
•
Low Power Consumption
•
Resolution 16 Bits
•
Ratiometric
∆Σ
ADC
•
ENOB 14 Bits
•
Serial Data Output (I
2
C bus)
DESCRIPTION
The MAS6501 is a 16 bit Analog-to-Digital
Converter (ADC), which employs a delta-sigma (∆Σ)
conversion technique. With the linear input signal
range of 282 mV
PP
its resolution is 14 bits.
The MAS6501 is designed especially to
meet the requirement for low power consumption,
thus making it an ideal choice for battery powered
systems. The MAS6501 is equipped with a standby
function, i.e. the ADC is in power down between
each conversion. By utilizing this and overall low
power consumption, current consumption values of
1.6 µA (one pressure conversion in a second with
full 14-bit accuracy) or less can be achieved.
The MAS6501 has an on-chip second order
decimator filter to process the output of the second
order
∆Σ
-modulator. The ADC also has two
selectable conversion ranges with two optional
offset levels.
2
A bi-directional 2-wire I C bus is used for
configuring
conversion
parameters,
starting
conversion and reading out the A/D conversion
result.
MAS6501 has one input channel suitable for
piezo resistive pressure sensor. In addition to
pressure measurement configuration the device can
be configured to temperature measurement.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
Low Standby Current Consumption 0.1 µA Typ
Low Supply Current: 0.2 µA..1.6 µA
Supply Voltage: 2.0 V…3.6 V
Ratiometric
∆Σ
Conversion
Two Input Signal Ranges (VDD=2.35V):
325 mV
PP
, 98 mV
PP
Two Optional Offsets (VDD=2.35V):
123 mV, 33 mV
Over Sampling Ratio: 512, 256, 128, 64
Conversion Times 32.2 ms…2.5 ms
In Fast Mode: Over Sampling Ratio 64,
Conversion Time 2.5 ms, Resolution 10 Bits
Good Noise Performance due to
∆Σ
Architecture
2
2-Wire I C Interface
APPLICATIONS
•
•
•
•
•
Battery Powered Systems
Low Frequency Measurement Applications
Pressure and Temperature Measurement
Current/Power Consumption Critical Systems
Industrial and Process Control Applications in
Noisy Environments
I
2
C is a registered trademark of Philips Inc.
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DA6501.001
27 October 2008
BLOCK DIAGRAM
VDD
PI
NI
COMMON
S&H
ADC
DIG
FIL
DIG
INT
EOC
SDA
SCL
XCLR
GND
MCLK
Figure 1.
MAS6501 block diagram
ABSOLUTE MAXIMUM RATINGS
All Voltages with Respect to Ground
Parameter
Supply Voltage
Voltage Range for All Pins
Latchup Current Limit
Symbol
V
CC
Conditions
During conversion
No conversion
For all pins,
test according to
Micro Analog Systems
specification ESQ0141.
See note below.
Min
- 0.3
- 0.3
- 0.3
- 100
Max
3.8
6.0
V
IN
+ 0.3
+ 100
Unit
V
V
mA
I
LUT
Junction Temperature
Storage Temperature
T
Jmax
T
S
- 55
+ 175
+125
°
C
°
C
Note:
Stresses beyond the values listed may cause a permanent damage to the device. The device may not
operate under these conditions, but it will not be destroyed.
Note:
This is a CMOS device and therefore it should be handled carefully to avoid any damage by static voltages
(ESD).
Note:
In latchup testing the supply voltages are connected normally to the tested device. Then pulsed test current is fed
to each input separately and device current consumption is observed. If the device current consumption increases
suddenly due to test current pulses and the abnormally high current consumption continues after test current pulses are
cut off then the device has gone to latch up. Current pulse is turned on for 10 ms and off for 20 ms.
RECOMMENDED OPERATION CONDITIONS
Parameter
Supply Voltage
Operating Temperature
Symbol
V
CC
T
A
Conditions
Min
2.0
-20
Typ
2.35
+25
Max
3.6
+60
Unit
V
°
C
The device performance may deteriorate in the long run if the Recommended Operation Conditions limits are continuously exceeded.
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DA6501.001
27 October 2008
ELECTRICAL CHARACTERISTICS
T
A
= -20
o
C to +60
o
C, Typ T
A
= 25
o
C, VDD = 2.35 V, R
sensor
= 4.5kΩ unless otherwise noted
Parameter
Average ADC Current
during Conversion Time
(see Conversion Time at
bottom)
Average ADC Current in
Pressure and Temperature
Measurement during
Conversion Period
(no sensor current
included)
Symbol
I
CONV
Conditions
Max value at VDD = 3.6 V
Min
Typ
30
Max
50
Unit
µA
I
ADC
Average Supply Current in
Pressure Measurement
during Conversion Period
(including sensor bridge
current)
I
SAVG_P
Average Supply Current in
Temperature Measurement
(including sensor bridge
current)
I
SAVG_T
Peak Supply Current
During Pressure
Measurement
Peak Supply Current
During Temperature
Measurement
Standby Current
Conversion Time
I
SC
I
SC
I
SS
t
CONV
1 conversion/s (conversion
period 1 s), XENMCLKDIV=1,
R
sensor
= 4.5 kΩ,
Max value at VDD = 3.6 V
OSR=512
OSR=256
OSR=128
OSR=64
1 conversion/s (conversion
period 1 s), XENMCLKDIV=1,
R
sensor
= 4.5 kΩ,
Max value at VDD = 3.6 V
OSR=512
OSR=256
OSR=128
OSR=64
1 conversion/s (conversion
period 1 s), XENMCLKDIV=1,
R
sensor
= 4.5 kΩ,
Max value at VDD = 3.6 V
OSR=512
OSR=256
OSR=128
OSR=64
VDD = 2.35 V, R
sensor
= 4.5 kΩ
VDD = 2.35 V, R
sensor
= 4.5 kΩ
VDD = 2.35 V
MCLK = 32768 Hz,
XENMCLKDIV=1
OSR=512
OSR=256
OSR=128
OSR=64
0.5
0.25
0.13
0.07
0.9
0.5
0.3
0.2
µA
1.6
0.8
0.5
0.3
2.5
1.3
0.7
0.4
µA
0.9
0.5
0.3
0.2
0.52
1.5
0.8
0.4
0.3
µA
mA
0.19
mA
0.1
0.5
µA
16.1
8.3
4.4
2.5
ms
Note:
XENMCLKDIV refer to the I
2
C serial interface control bits, see table 1 on page 5.
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DA6501.001
27 October 2008
ELECTRICAL CHARACTERISTICS
T
A
= -20
o
C to +60
o
C, Typ T
A
= 25
o
C, VDD = 2.35 V, R
sensor
= 4.5kΩ unless otherwise noted
Parameter
Resolution
Symbol
Conditions
ISR = 325 mV
ISR = 98 mV
ISRLIN = 282 mV, OSR = 512
ISRLIN = 85 mV, OSR = 512
Min
Typ
16
4.9
1.5
17
5.1
4
3
14
13
12
10
32768
Max
Unit
Bit
µV
µV
LSB
LSB
Bit
Accuracy
Integral Nonlinearity
Differential Nonlinearity
ENOB
(Effective Number of Bits)
INL
DNL
ISRLIN = 282 mV
OSR=512
OSR=256
OSR=128
OSR=64
MCLK
t
DEL
DUTYC
SCL
ISR
ISRLIN
MCLK = 32768 Hz
30000
0.1
External Clock Signal
Delay Between End of
Conversion and ADC
Result Read-Out
Duty Cycle of MCLK
Serial Data Clock
Input Signal Conversion
Range
Linear Input Signal
Conversion Range
Output Code Values
Temperature Measurement
Resistors
35000
Hz
ms
Master Clock Division Enabled
XENMCLKDIV=0
ISCR = 1
ISCR = 0
ISCR = 1
ISCR = 0
60/40
50/50
40/60
400
%
kHz
mV
mV
325
98
282
85
0
-15%
7710
17000
3073
17000
-280
65152
+15%
Temperature Measurement
Resistors Temp Coefficient
R
1
R
2
R
3
R
4
TC
R
Ω
TBD
TBD
ppm /
°
C
Note:
ISCR refer to the I
2
C serial interface control bits, see table 1 on page 5.
TBD = To Be Defined
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DA6501.001
27 October 2008
MAS6501 CONTROL REGISTER
Table 1.
MAS6501 control register bit description
Bit Name
Description
Bit Number
7-6
OSRS(1:0)
Over Sampling Ratio
(OSR) selection
Value
11
01
10
00
0
1
1
0
1
0
0
1
0
1
1
0
Function
OSR = 512
OSR = 256
OSR = 128
OSR = 64
No Conversion
Start Conversion
Pressure configuration
Temperature configuration
325 mV (282 mV linear range)
98 mV (85 mV linear range)
MCLK division enabled
MCLK division disabled
Offset enabled
Offset disabled
+123 mV
+33 mV
5
4
3
2
1
0
SCO
PTS
ISCR
XENMCLKDIV
XOSENABLE
OSSELECT
Start Conversion
Pressure/Temperature
Selection
Input Signal
Conversion Range
Enable Master Clock
Division
Enable offset
Offset value selection
MAS6501 has one control register for configuring
the measurement setup. See table 1 for control
register bit definitions. Control register values are
set via I2C bus.
First two OSRS bits of the control register define
four selectable over sampling ratios. The higher
OSR the better ADC accuracy but the longer
conversion time.
The SCO bit controls the A/D conversion. When
SCO = 0, no A/D conversion takes place. When
SCO = 1, the A/D converter turns on and the analog
data is being converted. Then MCLK must be
clocked at least until EOC pin goes high indicating
that conversion has been accomplished.
PTS bit selects between pressure and temperature
measurement. In temperature measurement the
sensor is connected in bridge configuration together
with four integrated resistors (see figure 3 on page 8
and resistors R1, R2, R3 and R4).
ISCR selects between two A/D conversion ranges.
The XENMCLKDIV bit controls the internal clock
frequency of MAS6501, fCLK(INT). When the bit is
low, the MCLK division is enabled and the internal
clock frequency fCLK(INT) = fMCLK/2, where
fMCLK is the master clock frequency. When the
XENMCLKDIV bit is high, the MCLK division is
disabled and fCLK(INT) = fMCLK.
In the XENMCLKDIV = 1 mode the duty cycle
should be as close to 50 % as possible. In this
mode, the conversion time is made half (see page 3
conversion time values with XENMCLKDIV = 1)
compared to clock speed division mode
XENMCLKDIV = 0 whereas the resolution remains
unchanged. In XENMCLKDIV = 0 mode the
conversion time and also current consumption are
doubled but then the external master clock signal
MCLK does not need to have close to 50% duty
cycle.
XOSENABLE can be used to enable input signal
range offset option. At 1 value no offset is applied
but at 0 value an offset value which is determined
with OSSELECT bit is used.
OSSELECT selects between two offset values. No
offset
is
applied
if
offset
is
disabled
(XOSENABLE=1).
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stm32/stm8
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