MS8607-02BA01 PHT Combination Sensor
DA8607-02BA01_003 www.meas-spec.com July 7th, 2015
000086072885 ECN2515 1/21
• Integrated pressure, humidity and temperature sensor
•
QFN package 5 x 3 x 1 mm3
•
Operating ra n g e: 10 to 2000 mbar, 0%RH to 100%RH,
-40 to 85 °C
•
High-resolution module: 0.016 mbar, 0.04%RH, 0.01°C
•
Supply voltage: 1.5 to 3.6 V
•
Fully factory calibrated sensor
•
I2C interface
DESCRIPTION
The MS8607 is the novel digital combination sensor of MEAS pro vidin g 3 en viron mental physica l measurement s
all-in-one: pressure, humidity and temperature (PHT). This product is optimal for applications in which key
requirements such as ultra low power consumption, high PHT accuracy and compactness are critical. High
pressure resolution combined with high PHT linearity makes the MS8607 an ideal candidate for environmental
monitoring and altimeter in smart phones and tablet PC, as well as PHT applications such as HVAC and
weather stations. This new sensor module generation is based on leading MEMS technologies and latest
benefits from Measurement Specialties proven experience and know-how in high volume manufacturing of
sensor modules, which has been widely used for over a decade.
FEATURES
FIELD OF APPL ICATION
• Smart phones and Tablet PCs
• HVAC applications
• Weather station
• Printers
• Home Appliance and humidifiers
TECHNICAL DATA
Sensor Performances (VDD = 3 V)
Characteristics Pressure [mbar] Relative Humidity [%RH] Temperature [°C]
Min Typ Max Min Typ Max Min Typ Max
Max. Operating Range 10 2000 0 100 -40 +85
Absolute Accuracy @25°C 300…1100mbar 20…80%RH @ 25°C
-2 2 -3 3 -1 1
Resolution (highest mode) 0.016 0.04 0.01
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PERFORMANCE SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Condition
Min.
Typ.
Max.
Unit
Supply voltage
VDD
-0.3
3.6
V
Storage temperature
TS
-20
85
°C
Overpressure
Pmax
6
bar
Maximum Soldering
Temperature
Tmax 40 sec max
250 °C
ESD rating
Human Body Model
-2
2
kV
Latch up
JEDEC standard No 78
-100
100
mA
ELECTRICAL CHARACTERISTICS
Parameter
General electrical characteristics
Symbol
Condition
Min.
Typ.
Max.
Unit
Operating Supply voltage
VDD
1.5
3.0
3.6
V
Operating Tem perature
T
-40
+25
+85
°C
VDD to GND Capacitor
220
470
nF
Supply current P or T
(1 Pressure or temp erature
conversion per sec.) IPT
OSR 8192
4096
2048
1024
512
256
20.09
10.05
5.02
2.51
1.26
0.63
µA
Supply current H
(1 humidity conversion per
sec.) IH
OSR 8192
4096
2048
1024
6.22
3.11
1.56
0.78
µA
Peak supply current
(during P or T conversion)
1.25 mA
Peak supply current
(during humidity conversion)
0.45 mA
Standby supply current
@ 25°C, VDD = 3V
0.03
0.24
µA
Pressure and temperature
Relative humidity
Condition
Min.
Typ.
Max.
Min.
Typ.
Max.
Unit
ADC Output Wor d
24
16
bit
ADC Conversion time(3)
OSR 8192
4096
2048
1024
512
256
16.44
8.22
4.13
2.08
1.06
0.54
17.2
8.61
4.32
2.17
1.10
0.56
13.82
6.98
3.55
1.84
-
-
15.89
8.03
4.08
2.12
-
-
ms
Heater: power dissipation
and temperature increase
over humidity sen sor
2 - 13
0.5 - 1.5 mW
°C
Low battery indicator
accuracy
±50 (Typ.) mV
(3): Maximum values must be applied to determine waiting times in I2C communication
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PERFORMANCE SPECIFICATIONS (CONTINUED)
PHT CH ARACTERIST ICS (VDD = 3.0 V, T = 25 °C UNLESS OTHERWISE NOTED)
Pressure [mbar]
Relative Humidity [%RH]
Temperature [°C]
Min.
Typ.
Max.
Min.
Typ.
Max.
Min.
Typ.
Max.
Operating Range
Extended Range (4)
300
10
1200
2000
0 100 -40 85
Absolute Accuracy
@25°C
300…1100 mbar
20 …80%RH
@25°C
-2
2
-3
3
-1
1
Absolute Accuracy
300…1100mbar, -20...85°C
5…95%RH
-20...85°C
-4
4
-5
5
-2
2
Relative Accuracy
@25°C
700…1000 mbar (5)
±0.1 (6)
Resolution
RMS(7)
OSR 8192
4096
2048
1024
512
256
0.016
0.021
0.028
0.039
0.062
0.11
0.04
-
-
0.7
0.002
0.003
0.004
0.006
0.009
0.012
Maximum error with
supply voltage
(Condition)
±0.5 ±0.25 ±0.3
(VDD = 1.5 V … 3.6 V)
Long-term stability
±1 / year
±0.5 / year
±0.3 / year
Reflow soldering impact
-0.6
2
Recoverin g time after
reflow
(8)
5 days 5 days
Response Time
(Condition)
< 5ms 5 sec.
(at 63% of signal recovery,
From 33%RH to 75%RH,
At 3m/s air flow)
(4): Linear range of ADC
(5): Auto-zero at one pressure point
(6): Characteriz ed value performed on qualification devices
(7): Character ization performed sequentially (P&T conversion followed by H conversion)
(8): Recovering time at least 66% of the reflow impact
DIGITAL INPUTS (SDA, SCL)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
Serial data cloc k
SCL
400
kHz
Input high volta ge
VIH
80% VDD
100% VDD
V
Input low voltage
VIL
0% VDD
20% VDD
V
DIGITAL OUTPUTS (SDA)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
Output high voltage
VOH
Isource = 1 mA
80% VDD
100% VDD
V
Output low voltage
VOL
Isink = 1 mA
0% VDD
20% VDD
V
Load Capacitance
CLOAD
16
pF
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PERFORMANCE CHARACTERISTICS
PHT ACCURACY AND PHT ERROR VERSUS SUPPLY VOLTAGE (TYPICAL)
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FUNCTIONAL DESCRIPTION
GENERAL
The MS8607 includes two sensors with distinctive MEMS technologies to measure pressure, humidity and
temperature. The first sensor is a piezo-resistive sensor providing pressure and temperature. The second
sensor is a capacitive type humidity sensor providing relative humidity. Each sensor is interfaced to a ΔΣ ADC
integrate d circuit for the d igital convers ion. The MS8607 converts both analog out put voltages to a 24-bit d igital
value for the pressure and temperature measurements, and a 12-bit digital value for the relative humidity
measurement.
SERIAL I2C INTERFACE
The external microcontroller clocks in the data through the input SCL (Serial CLock) and SDA (Serial DAta).
Both sensors respond on the same pin SDA which is bidirectional for the I2C bus interface. Two distinct I2C
addresses are used (one for pressure and temperature, the oth er for relative humidity, see Figure 2).
Module reference
Mode
Pins used
MS860702BA01
I2C
SDA, SCL
Figure 1: Communication Protocol and pins
Sensor type
I2C address (binary value)
I2C address (hex. value)
Pressure and Temperature P&T
1110110
0x76
Relative Humidity RH
1000000
0x40
Figure 2: I2C addresses
COMMANDS FOR PRESSURE AND TEMPERATURE
For pressure and temperature sensing, five commands are possible:
1. Reset
2. Read PROM P&T (112 bit of calibration words)
3. D1 conversion
4. D2 conversion
5. Read ADC (24 bit pressure / temperature)
Each command is represented over 1 byte (8 bits) as described in Figure 3. After ADC read commands, the
device will return 24 bit result and af ter the PROM read 16 bit results. The address of the PROM is embedded
inside of the read PROM P&T command using the a2, a1 and a0 bits.
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Command by te
hex value
Bit number
7
6
5
4
3
2
1
0
Bit name
PROM
CONV
-
Typ
Ad2/
Os2
Ad1/
Os1
Ad0/
Os0
Stop
Command
Reset
0
0
0
1
1
1
1
0
0x1E
Convert D1 (OSR=256)
0
1
0
0
0
0
0
0
0x40
Convert D1 (OSR=512)
0
1
0
0
0
0
1
0
0x42
Convert D1 (OSR=1024)
0
1
0
0
0
1
0
0
0x44
Convert D1 (OSR=2048)
0
1
0
0
0
1
1
0
0x46
Convert D1 (OSR=4096)
0
1
0
0
1
0
0
0
0x48
Convert D1 (OSR=8192)
0
1
0
0
1
0
1
0
0x4A
Convert D2 (OSR=256)
0
1
0
1
0
0
0
0
0x50
Convert D2 (OSR=512)
0
1
0
1
0
0
1
0
0x52
Convert D2 (OSR=1024)
0
1
0
1
0
1
0
0
0x54
Convert D2 (OSR=2048)
0
1
0
1
0
1
1
0
0x56
Convert D2 (OSR=4096)
0
1
0
1
1
0
0
0
0x58
Convert D2 (OSR=8192)
0
1
0
1
1
0
1
0
0x5A
ADC Read
0
0
0
0
0
0
0
0
0x00
PROM Read P&T
1
0
1
0
Ad2
Ad1
Ad0
0
0xA0 to 0xAE
Figure 3: Command structure for pressure and temperature sensing
COMMANDS FOR RELA TIVE HUMIDITY
For relative humidity sensing, six commands are possible:
1. Reset
2. Write user register
3. Read user register
4. Measure RH (Hold master)
5. Measure RH (No Hold master)
6. PROM read RH
Each I2C c omm unicat ion m essage st arts with the sta rt condit ion an d it is en ded with t he stop c ondit ion. T he I 2C
address for humidity sensing is 1000000. The address of the PROM is embedded inside of the PROM read
comm and using the a2, a1 and a0 bits. Figure 4 shows the commands with their respective code:
8 bits Command
hex value
Bit number
7
6
5
4
3
2
1
0
Command :
1. Reset
1
1
1
1
1
1
1
0
0xFE
2. Write user register
1
1
1
0
0
1
1
0
0xE6
3. Read user regist er
1
1
1
0
0
1
1
1
0xE7
4. Measure RH (Hold master)
1
1
1
0
0
1
0
1
0xE5
5. Measure RH (No Hold master)
1
1
1
1
0
1
0
1
0xF5
6. PROM read RH
1
0
1
0
adr2
adr1
adr0
0
0xA0 to 0xAE
Figure 4: command structure for relative humidity sensing
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USER REGISTER
The user register is used to configure several operating modes of the humidity sensor (resolution
measurements, heater) and monitor the battery state. The possible configurations of the user register are
described in the tab le below.
User register Bit
Bit Configuration/Coding
Default value
bit 7, bit 0
Measurement resolution
Bit 7
Bit 0
OSR
Resolution
0
0
4096
Highest
0
1
2048
1
0
1024
1
1
256
Lowest
‘00’
bit 6
Battery state:
‘0’ VDD>2.25V
‘1’ VDD<2.25V
‘0’
bit 3,4,5
Reserved
‘000’
bit 2
on-chip heater:
‘0’ heater disabled
‘1’ heater enabled
‘0’
bit 1
Reserved
‘0’
Figure 5: description of the user register
• Bit 7 and bit 0 configure the measurement resolution (highest resolution OSR 4096, lowest OSR 256).
• Bit 6 refers to the “Battery state”, which can be monitored.
• Bits 1,3,4,5 ar e res erved bi ts, which m us t not be changed an d defaul t values of respec tive res erved bi ts
may change over time without prior notice. Therefore, for any writing to user register, default values of
reserved bits must be read first.
• Bit 2 conf igures th e heater. It can be used f or f unctionali ty dia gnosis : relati ve hu m idity drops upon r ising
temperature. The heater consumes about 5.5mW and provides a temperature increase of
approximatively 0.5-1.5°C over the humidity sensor.
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PRESSURE AND TEMPERATURE CALCULATION
Figure 6: Flow chart for pressure and temperature reading and software compensation.
Size
[1]
[bit]
min
C1
Pressure sensitivity | SENS
T1
unsigned int 16
16
0
65535
46372
C2
Pressure offset | OFF
T1
unsigned int 16
16
0
65535
43981
C3
Temperature coefficient of pressure sensitivity | TCS
unsigned int 16
16
0
65535
29059
C4
Temperature coefficient of pressure offset | TCO
unsigned int 16
16
0
65535
27842
C5
Reference temperature | T
REF
unsigned int 16
16
0
65535
31553
C6
Temperature coefficient of the temperature | TEMPSENS
unsigned int 16
16
0
65535
28165
D1
Digital pressure value
unsigned int 32
24
0
16777215
6465444
D2
Digital temperature value
unsigned int 32
24
0
16777215
8077636
dT
Difference between actual and reference temperature
[2]
dT
= D2 - T
REF
=
D2
-
C5 * 2
8
signed int 32
25
-16776960
16777215
68
2000
= 20.00 °C
OFF
Offset at actual temperature
[3]
OFF
=
OFF
T1
+
TCO
*
dT =
C2
*
2
17
+
(C4
*
dT
)
/
2
6
signed int 64
41
-17179344900
25769410560
5764707214
SENS
Sensitivity at actual temperature
[4]
SENS
=
SENS
T1
+
TCS
*
dT
=
C1 * 2
16
+
(
C3
*
dT
)
/
2
7
signed int 64
41
-8589672450
12884705280
3039050829
110002
= 1100.02 mbar
Notes
[1]
[2]
[3]
[4]
min and max have to be defined
min and max have to be defined
Maximal size of intermediate result during evaluation of variable
120000
1000
58
P
Recommended
variable type
Description | Equation
signed int 32
Actual temperature (-40…85°C with 0.01°C resolution)
TEMP
=
20°C
+
dT
*
TEMPSENS
=
2000
+
dT
*
C6
/
2
23
Read digital pressure and temperature data
signed int 32
Temperature compensated pressure (10…1200mbar with
0.01mbar resolution)
P
= D1 * SENS - OFF =
(D1 * SENS / 2
21
- OFF) / 2
15
min and max have to be defined
Convert calibration data into coefficients (see bit pattern of W1 to W4)
Variable
Example /
Typical
Value
Calculate temperature compensated pr essure
8500
-4000
TEMP
41
Start
Maximum values for calculation results:
P
MIN
= 10mbar P
MAX
= 2000mbar
T
MIN
= -40°C T
MAX
= 85°C T
REF
= 20°C
Read calibration data (factory calibrated) from PROM
Read digital pressure and temperature data
Calculate temperature
Calculate temperature compensated pressure
Pressure and temperature value first order
max
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PRESSURE COMPENSATION (SECOND ORDER OVER TEMPERATURE)
In order to optimize the accurac y over tem peratur e range at low tem peratur e, it is rec omm ended to com pensate
the pressure non-linear it y over the t emper ature. This can be achieved b y correcting the c alculated t em perature,
offset and sensitivity by a second-order correction factor. The second-order factors are calculated as follows:
Figure 7: Flow chart for pressure and temperature to the optimum accuracy.
Yes
No
SENS2 = 29 ⋅ (TEMP – 2000)2/ 24
SENS2 = 0
SENS = SENS - SENS2
TEMP<20°C
Low temperature
T2 = 3 ⋅ dT
2
/ 2
33
OFF2 = 0
T2 = T2 = 5
⋅ dT
2
/ 2
38
OFF2 = 61 ⋅ (TEMP – 2000)2 / 24
OFF = OFF - OFF2
TEMP = TEMP - T2
Low temperature
High temperature
Calculate pressure and temperature
TEMP<-15°C
No
Yes
SENS2 = SENS2 + 9 ⋅ (TEMP + 1500)2
Low temperature
OFF2 = OFF2 + 17 ⋅ (TEMP + 1500)2
Very low temperature
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RELATIVE HUMIDITY CALCULATION
Figure 8: Flow chart for humidity reading.
To accommodate any proces s variation (nominal capac itance value of the hu midity sensor), tolerances of the sensor
above 100%RH and below 0%RH must be considered. As a consequence:
118%RH corresponds to 0xFF which is the maximum RH digital output that can be sent out from the ASIC.
RH output can reach 118%RH and above this value, there will have a clamp of the RH output to this value.
-6%RH corresponds to 0x00 whic h is the minimum RH digital output that can be sent out from the ASIC. RH
output can reach -6%RH and below this value, there will have a clamp of the RH output to this value.
The relative humidity is obtained by the following formula (result in %RH):
⋅+−=
16
23
125
6D
RH
As example, the transferred 16-bit relative humidity data 0x7C80: 31872 corresponds to a relative humidity of
54.8%RH.
Finally, 1st order temperature compensation is computed for optimal accuracy over [0…+85°C] temperature
range. The final compensated relative humidity value RHcompensated is calculated as:
()
coeffdcompensate
TTEMPRHRH ⋅−+
=20
TEMP Temperature calculated on p.9 unit [°C]
Tcoeff Temperature correction coefficient unit [%RH / °C]
Optimal relative humidity accuracy over [0…+85°C] temperature range is obtained with Tcoeff = -0.18
D3
Digital relative humidity value
unsigned int 16
16
0
65535
31872
RH
Actual relative humidity (-6 %RH…118%RH
RH
= - 600 + 12500 * D3 / 2
signed int 16
31
- 600
11900
= 54.8 %RH
Notes
[1]
Maximal size of intermediate result during evaluation of variable
Read digital pressure and temperature data
Start
Maximum values for calculation results:
RH
MIN
= -6 %RH RH
MAX
= 118 %RH
Read digital relative humidity data
Calculate relative humidity
Display relative h umidi t y valu e
Description | Equation
Recommended
variable type
Size[1]
Value
min
max
[bit]
Variable
Example /
Typical
16
5480
with 0.01 %RH resolution)
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APPLICATION CIRCUIT
The MS8607 is a circuit that can be used in conjunction with a microcontroller by I2C protocol interface. It is
designed f or lo w-voltag e system s with a supp l y vo ltage of 3 V and ca n be us e d i n i ndus tria l pres s ure / hum idity /
temperature applications.
Figure 9: Typical application circuit
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I2C INTERFACE: PRESSURE AND TEMPERATURE
COMMANDS
Each I2C com municatio n mess age starts with the start conditio n and it is end ed with the s top cond ition. The I2C
address for pressure and temperature sensing is 1110110. The description of the commands related to pressure
and temperature sensing is detailed on p. 5.
RESET SEQUENCE
The Res et s e que nce s ha ll be s en t o nc e af ter po wer -on to make s ur e tha t th e c a libr atio n PRO M ge ts lo ade d into
the internal register. It can be also used to reset the device PROM from an unknown condition.
The res et c an be s e nt at any t im e. In th e e ve nt t hat th e r e is n ot a suc c es sf ul po we r on r eset this ma y be caused
by the SDA b eing block ed by the m odule in the ack nowledge state. T he only way to get t he ASIC to function is
to send several SCLs followed by a reset sequence or to repeat power on reset.
1 1 1 0 1100 0 000111 1 00
S W A A P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read
N = Not Acknowledge
cmd byte
Device Address
Device Address
command
Figure 10: I2C Reset Command
PROM READ P&T SEQUENCE
The read command for PROM shall be executed once after reset by the user to read the content of the
calibratio n PROM and to c alculate the calibration coefficients. T here are in tot al 7 address es resulting in a total
memory of 112 bit. The addresses contain factory data and the setup, calibration coefficients, the serial code
and CRC (see details on p. 15, Figure 22). The command sequence is 8 bits long with a 16 bit result which is
clock ed with t he MSB f irs t. T he PR OM Read command cons is ts of two par ts. F irs t c om mand sets up the system
into PROM read mode (Figure 11). The second part gets the data from the system (Figure 12).
111011000101001100
S W A A P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read
N = Not Acknowledge
Device Address
Device Address
cmd byte
command
Figure 11: I2C Command to read P&T memory PROM address 0xA6
1 1 1 0 1 1 0 1 0 X X X X X X X X 0 X X X X X X X X 0
S R A A N P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read N = Not Acknowledage
Memory bi t 7 - 0
Device Address
Device Address
Memory bi t 15 - 8
data
data
Figure 12: I2C answer from ASIC (Pressure and temperature)
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CONVERSION SEQUENC E
The conver sion com m and is used to init iate uncom pens ated press ure (D1) or uncom pens ated tem perature ( D2)
conversion. After the conversion, using ADC read command the result is clocked out with the MSB first. If the
conversi on is not ex ecute d bef ore the AD C read com mand, or the A DC read c om m and is repeated, it wil l give 0
as the outp ut resu lt. If the ADC read com mand is sent duri ng con version the r esult w ill be 0, the convers ion will
not stop and the final result will be wrong. Conversion sequence sent during the already started conversion
process will yield incorrect result as well. A conversion can be started by sending the command to the ASIC.
When the command is sent to the system it stays busy until conversion is done. W hen conversion is finished,
the data can be accessed by sending a Read command. When the Acknowledge bit is sent from the ASIC, 24
SCL cycles may be sent to receive all result bits. Every 8 bits the system waits for the Ack nowledg e bit.
1110 1 1 0 0 0 0 1 0 0 100 0 0
SW A A P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read
N = Not Acknowledge
cmd byte
Device Address
Device Address
command
Figure 13: I2C command to initiate a pressure conversion (OSR=4096, typ=D1)
1 1 1 0 1 1 0 0 000000000 0
S W A A P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read
N = Not Acknowledge
Device Address
Device Address
cmd byte
command
Figure 14: I2C ADC read sequence
111011010XXXXXXXX0XXXXXXXX0XXXXXXXX0
S R A A A N P
From M aster S = Start Condi t i on W = Write A = Ack nowl edge
From S l ave P = Stop Condi ti on R = Re ad N = Not A ck nowledge
Dat a 23 - 16
Dat a 7 - 0
Dat a 15 - 8
Devi c e Address
Devi c e Address
Figure 15: I2C answer from the ASI C
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I2C INTERFACE: RELATIVE HUMIDITY
COMMANDS
Each I2C c om munication m ess age s tar ts w ith t he st art c ondit io n an d i t is end ed with th e s top c o nd ition. The I2C
address for humidity sensing is 1000000. The description of the commands related to humidity sensing is
detailed on p. 6.
RESET SEQUENCE
This command is used for rebooting the humidity sensor by switching the power off and on again. Upon
reception of this c omm and, the humidity sensor s ystem r einitiali zes and starts oper ation acc ording to th e def ault
settings with the exception of the heater bit in the user register. The reset takes less than 15ms.
100000000111111100
S W A A P
From M ast er S = S t art Condi t i on W = Write A = Ack nowl edge
From S l ave P = Stop Condit i on R = Re ad N = Not A ck nowl edge
Device A ddres s
c m d byt e
command
Device A ddres s
Figure 16: I2C Reset Command
READ AND WRITE USER REG ISTER SEQUENCE
The f ollowing sequence illustrates ho w to read and wr ite the user register. F irst, it reads the content of the user
register. Then it writes the user register for configuring the humidity sensor to 8 bits measurement resolution
from the default configuration.
100000000111001110
S W A A
1 0 0 0 0 0 0 1 0 X X X X X X X X 0
S R A N
1000000001110011000000000 1 0
S W A A A P
From M ast er S = S t art Condi t i on W = Write A = Ack nowl edge
From S l ave P = Stop Condit i on R = Re ad N = Not A ck nowl edge
command
Device A ddres s
Device A ddres s
Us er Regist er Dat a 7 - 0
Device A ddres s
command
Device A ddres s
c m d byt e
Us er Regist er Dat a 7 - 0
Device A ddres s
c m d byt e
Device A ddres s
Figure 17: I2C read and write user register commands
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MEASURE RH HOLD/NO HOLD SEQUENCE
MS8607 has t wo different operation modes to measure relative humidity (RH): Hold Master m ode and No Hold
Master mode.
No Hold Master mode allows for processing other I²C comm unication tasks on a bus while the humidit y sensor
is m eas uring. Fi gure 18 and 19 illustrat e t he c om munication s equ ence of both modes. I n th e H o ld Mas ter mode,
the humidit y sensor pulls down the SCK lin e while measuring to for ce the master into a wait s tate. By releasing
the SCK line, the humidity sens or indicates t hat internal processing is com pleted and that tr ansm ission may be
continued.
In the No Hold Master mode, the MCU has to poll for the termination of the internal processing of the humidity
sensor. This is done by sending a start condition followed by the I²C header (0x81) as shown below. If the
internal pr ocessing is f inished, the humidity sensor ack nowledges the pol l of the MCU and d ata can be read by
the MCU. If the meas urement pr ocessing is no t finished, t he humidit y sensor answers the Not Acknowledge bit
and start condition must be issued once more.
For both modes, the measurement is stored into 14 bits. The two remaining least significant bits (LSBs) are
used for transmitting status information. Bit1 of the two LSBs must be set to ‘1’. Bit0 is currently not assigned.
100000000111001010
S W A A
100000010 XXXXXXXX0XXXXXX100
Hold during measurement
S R A A A
100101110 From M aster S = St art Condi t i on W = Write A = Ack nowl edge
From S l ave P = St op Conditi on R = Read N = Not A ck nowl edge
Chec ksum N P On hol d
Device A ddres s
command
Device A ddres s
c m d byt e
Device A ddres s
Dat a 15 - 8
Dat a 7 - 2
Status
Device A ddres s
Hold during measurement
Figure 18: I2C M easur e RH Hold Master communication sequence
100000000111101010
S W A A
100000010XXXXXXXX0XXXXXX100100101110
S R A A A Checks um N P
From M aster S = Start Condi t i on W = Write A = Ack nowl edge
From S l ave P = Stop Condit i on R = Re ad N = Not Ack nowledge
Dat a 7 - 2
Status
Devi c e Address
c m d byt e
Devi c e Address
Devi c e Address
command
Devi c e Address
Dat a 15 - 8
Figure 19: I2C Measure RH No Hold Master communication sequence
For Hold Mas ter seq uenc e , t he Acknowledge bit that follo ws the Sta tus bi t may be chang ed t o Not Ac k nowledge
bit followed by a stop condition to omit checksum transmission.
For No Hold Master sequence, if measurement is not completed upon “read” command, sensor does not
provide ACK on bit 27 (more of these iterations are possible). If bit 45 is changed to NACK followed by stop
condition, checksum transmission is omitted.
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Regarding the calculation of the relative humidit y value, the Status bits m ust be set to ‘0’. Refer to “Conver sion
of signal out puts” section p. 10. T he maximum durat ion for measur ement depends on the type of m easurement
and resolution chosen. Maximum values shall be chosen for the communication planning of the MCU.
I²C communication allows for repeated start conditions without closing prior sequence with stop condition.
PROM READ RH SEQUENCE
The RH PROM memory contains 7 addresses resulting in a total memory of 112 bit. The addresses contain
factory defined data and CRC (see deta ils on p. 17, Figure 23). T he com m and sequence is 8 b its long with a 16
bit result which is clocked with the MSB first. The RH PROM Read command consists of two parts. First
command sets up the system into PROM read mode (Figure 20). The second part gets the data from the system
(Figure 21).
111011000101001100
S W A A P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read
N = Not Acknowledge
Device Address
Device Address
cmd byte
command
Figure 20: I2C Command to read memory address 0xA6
111011010XXXXXXXX0XXXXXXXX0
S R A A N P
From Master
S = Start Condition
W = Write A = Acknowledge
From Slave P = Stop Condition R = Read N = Not Acknow ledage
Memory bi t 7 - 0
Device Address
Device Address
Memory bi t 15 - 8
data
data
Figure 21: I2C answer from ASIC (Pressure and temperature)
CYCLIC REDUNDANCY CHECK (CRC)
MS8607 cont ains two sepa rate PROM memories with identica l size (112-Bit): one f or pressure and tem perature
P&T (F igure 22), the other f or r elative h umidity RH (Fig ure 23). Eac h PROM memor y can be acc es sed using the
I2C commands PROM Read P&T and PROM Read RH (p. 6).
Address
(Hex.)
Bit
15 Bit
14
Bit
13
Bit
12
Bit
11
Bit
10
Bit
9
Bit
8
Bit
7
Bit
6
Bit
5
Bit
4
Bit
3
Bit
2
Bit
1
Bit
0
0xA0
CRC
Factory defined
0xA2
C1
0xA4
C2
0xA6
C3
0xA8
C4
0xAA
C5
0xAC
C6
Figure 22: P&T Memory PROM mapping for pressure and temperature
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Address
(Hex.)
Bit
15 Bit
14 Bit
13 Bit
12 Bit
11 Bit
10 Bit
9 Bit
8 Bit
7 Bit
6 Bit
5 Bit
4 Bit
3 Bit
2 Bit
1 Bit
0
0xA0
Factory defined
0xA2
Factory defined
0xA4
Factory defined
0xA6
Factory defined
0xA8
Factory defined
0xAA
Factory defined
0xAC
Factory defined
CRC
Figure 23: RH Memory PROM mapping for relative humidity
A 4-bit CRC has been implemented to check the data integrity in both PROM memories. The C code below
describes the CRC calculation for P&T Memory PROM and for RH Memory PROM.
C CODE EXAMPLE FOR CRC-4 CALCULATION (P&T MEMOR Y P ROM)
unsigned char crc4_PT(unsigned int n_prom[]) // n_prom defined as 8x unsigned int (n_prom[8])
{
int cnt; // simple counter
unsigned int n_rem=0; // crc remainder
unsigned char n_bit;
n_prom[0]=((n_prom[0]) & 0x0FFF); // CRC byte is replaced by 0
n_prom[7]=0; // Subsidiary value, set to 0
for (cnt = 0; cnt < 16; cnt++) // operation is perform ed on bytes
{ // choose LSB or MSB
if (cnt%2==1) n_rem ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF);
else n_rem ^= (unsigned short) (n_prom[cnt>>1]>>8);
for (n_bit = 8; n_bit > 0; n_bit--)
{
if (n_rem & (0x8000)) n_rem = (n_rem << 1) ^ 0x3000;
else n_rem = (n_rem << 1);
}
}
n_rem= ((n_rem >> 12) & 0x000F); // fin a l 4-bit remainder is CRC code
return (n_rem ^ 0x00);
}
C CODE EXAMPLE FOR CRC-4 CALCULATION (RH MEMORY PROM)
unsigned char crc4_RH(unsigned int n_prom[]) // n_prom defined as 8x unsigned int (n_prom[8])
{
int cnt; // simple counter
unsigned int n_rem=0; // crc remainder
unsigned char n_bit;
n_prom[6]=((n_prom[6]) & 0xFFF0); // CRC byte is replaced by 0
n_prom[7]=0; // Subsidiary value, set to 0
for (cnt = 0; cnt < 16; cnt++) // operation is performed on bytes
{ // choose LSB or MSB
if (cnt%2==1) n_rem ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF);
else n_rem ^= (unsigned short) (n_prom[cnt>>1]>>8);
for (n_bit = 8; n_bit > 0; n_bit--)
{
if (n_rem & (0x8000)) n_rem = (n_rem << 1) ^ 0x3000;
else n_rem = (n_rem << 1);
}
}
n_rem= ((n_rem >> 12) & 0x000F); // fin a l 4-bit remainder is CRC code
return (n_rem ^ 0x00);
}
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PIN CONFIGURATIO N
Pin
Nam
Type
Function
1 VDD P Positive supply voltage
3 GND G Ground
7 SDA IO I2C data IO
8
SCL
I
Serial data cloc k
2,4,5,6
NC
DEVICE PACK AGE OUTLINE
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RECOMMENDED PAD LAYOUT
Pad layout for bottom side of the MS8607-02BA01 soldered onto printed circuit b oar d.
SHIPPING PAC KA GE
Reserved area:
Please do not route
tracks between pads
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MOUNTING AND ASSEMBLY CONSIDERATIONS
SOLDERING
Please refer to the application note AN808 available on our website for all soldering issues.
MOUNTING
The MS8607 can be placed with automatic Pick & Place equipment using vacuum nozzles. It will not be
damaged by the vac uum. Due to th e l o w stres s ass em bly the sensor does not s h o w press ur e h ysteresis eff ec ts .
It is important to solder all contact pads.
CONNECTION TO PCB
The package outline of the module allows the use of a flexible PCB for interconnection. This can be important
for applications in watches and other special devices.
CLEANING
The MS8607 has be en manufactur ed und er c le anr oo m conditions. It is t her ef ore r ec om mended to as s emble the
sensor under class 10’000 or better conditions. Should this not be possible, it is recommended to protect the
sensor ope ning dur ing as sem bl y from enter ing partic les and dus t. To av oid clea ning of the PCB , sol der pas te of
type “no-clean” shall be used. Cleaning might damage the sensor!
ESD PRECAUTIONS
The electrical contact pads are protected against ESD up to 2 kV HBM (human body model). It is therefore
essentia l to gro und m ac hines and per son nel pro perl y during as sem bly and handl ing of the d evice. T he MS 8607
is shipped in antistatic transport boxes. Any test adapters or production transport boxes used during the
assembly of the sensor shall be of an equivalent antistatic material.
DECOUPLING CAPACITOR
Particular care must be taken when connecting the device to the power supply. A minimum 220nF ceramic
capacitor must be placed as close as possible to the MS8607 VDD pin. This capacitor will stabilize the power
supply during data conversion and thus, provide the highest possible accuracy.
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ORDERING INFORMATION
Part Numbe r / Art. Number
Product
Delivery Form
MS860702BA01-50 PHT Combination Sensor Module 5x3mm
Tape & Reel
FACTORY CONTACTS
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Tel: +41 32 847 9550
Fax: + 41 32 847 9569
e-mail: sales.ch@meas-spec.com
Website: www.meas-spec.com
Measurement Specialties (China), Ltd.
No. 26 Langshan Road
Shenzhen High-Tech Park (North)
Nanshan District, Shenzhen, 518057
China
Tel: +86 755 3330 5088
Fax: +86 755 3330 5099
e-mail: pfg.cs.asia@meas-spec.com
Website: www.meas-spec.com
Measurement Specialties
45738 Northport Loop West
Fremont, CA 94538
Tel: +1 800 767 1888
Fax: +1 510 498 1578
e-mail: pfg.cs.amer@meas-spec.com
Website: www.meas-spec.com
The information in this sheet has been carefully reviewed and is believed to be accurate; however, no responsibility is assumed for
inaccuracies. Furthermore, this information does not convey to the purchaser of such devices any license under the patent rights to the
manufacturer. Measurem ent Specialt ies, I nc. reserves the right to make c hanges without further not ic e to any product herein. Measurement
Specialti es, Inc. makes no warranty, repres entation or guarantee regarding the suitability of its product for any particular purpose, nor does
Measurement Specialties, Inc. assume any liability arising out of the application or use of any product or circuit and specifically disclaims
any and all liability, including without limitation consequential or incidental damages. Typical parameters can and do vary in different
applications. All operating parameters must be validated for each customer application by customer’s technical experts. Measurement
Specialti es, Inc. does not convey any license under its patent rights nor the rights of others.
