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GE
Measurement & Control
Advanced Sensors
®
ChipCap 2
Application Guide
916-127 Rev. A
June 2012
ChipCap 2 Humidity and Temperature Sensor
1.
2.
Contents
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1
Preliminary Consideration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2
Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3
Heating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.4
Soldering Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.5
Storage and Handling Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.6
Reconditioning Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.7
Material Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.8
Traceability Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.9
Shipping Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Interface Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1
Digital Output (I²C Interface) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 Power Pads (5.VCORE, 6.VSS, 7.VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.2 Serial Clock & Data Pads (3. SDA, 4. SCL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.3 Alarm Pads (1. Alarm Low, 8. Alarm High) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2
Analog Output (PDM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.1 Power Pads (5.VCORE, 6.VSS, 7.VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2 PDM Output Pads (1.PDM_T, 2.PDM_H) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.3 Alarm Pads (8.Alarm_High, 1.Alarm_Low [optional]) . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.4 Serial Clock & Data Pads (3.SDA, 4.SCL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.5 Typical Circuit Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.
4.
Electrical Specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1
Absolute Maximum Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2
Electrical Specification and Recommended Operating Conditions. . . . . . . . . . . . . . . 10
3.3
Output Pad Drive Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4
ESD/Latch-Up-Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Communicating with ChipCap 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1
Power–On Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2
I2C Features and Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3
Measurement Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Application Guide
iii
Contents
ChipCap 2 Humidity and Temperature Sensor
4.3.1 Data Fetch in Update Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
4.3.2 Data Fetch in Sleep Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
5.
4.4
Status Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4.5
I2C Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4.6
Data Fetch (DF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
4.7
Measurement Request (MR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.8
Ready Pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.9
Command Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.10
Command Encodings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4.11
Command Response and Data Fetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4.12
EEPROM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Converting PDM to Analog Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
5.1
PDM (Pulse Density Modulation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
5.2
Low Pass Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
5.3
Analog Output Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
5.3.1 Polynomial Equation Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
5.3.2 Polynomial Equation Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.
7.
iv
Alarm Function (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.1
Alarm Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.2
Alarm Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.3
Alarm Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.4
Alarm Output Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.5
Alarm Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Part Number List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Application Guide
ChipCap 2 Humidity and Temperature Sensor
1.
General Information
1.1 Preliminary Consideration
To maximize the performance of ChipCap 2, it is important to plan an appropriate location of the sensor at the design
stage. Airflow and proper exposure to ambient air must be secured for ChipCap 2 to ensure expected performance.
Airflow holes must NOT be blocked. Any heat generating parts near ChipCap 2 will distort the proper measurement of
relative humidity and temperature reading, and heat generating parts should be avoided or measures should be taken to
prevent heat transfer.
1.2 Operating Conditions
Figure 1 below shows ChipCap 2‘s maximum and recommended normal operating condition. Within the normal range,
ChipCap 2 performs in a stable manner. Prolonged exposures to conditions outside normal range, especially at
humidity over 90%RH, may temporarily offset the RH signal up to ±3%RH. When it returns to the normal range, it will
gradually recover back to the calibration state.
The re-conditioning procedure in section 1.6 on page 3 will help reduce this recovery time. Long term exposure to
extreme conditions may also accelerate aging of the sensor.
Figure 1: Operating Conditions
1.3
Heating
Though within the accuracy tolerance, self-heating in the sensor IC may affect accurate measurement of temperature
and RH%. The measurement error from self heating can be reduced by keeping “Active State” to the minimum, and by
regulating the operating voltage within 3.3 ±0.5V, 5.0 ±0.5V. A sampling time of more than 200ms is recommended for
measurement.
Other heat sources such as power electronics, microcontrollers, and display near the sensor may affect the accurate
measurement. Sensor location near such heat sources should be avoided by maintaining distance or a thermal buffer. A
thin metal pattern, or even better, “milling slits” around the sensor also may help reduce the error.
Application Guide
1
ChipCap 2 Humidity and Temperature Sensor
1.4 Soldering Instruction
ChipCap 2 is designed for a mass production reflow soldering process. It is qualified for soldering profile according to
IPC/JEDEC J-STD-020D (see Figure 2 below) for Pb-free assembly in standard reflow soldering ovens or
IR/Convection reflow ovens to withstand peak temperature at 260°C and peak time up to 40 sec. For soldering in Vapor
Phase Reflow (VPR) ovens, the peak conditions are limited to TP < 240°C with tP <40sec and ramp-up/down speeds
shall be limited to 10°C/sec. For manual soldering, contact time should be limited to 5 seconds at up to 350°C.
No-Clean solder flux should be used.
Figure 2: Soldering Profile
JEDEC standard
TP ≤260°C, tP < 40sec, TL<220°C, tL<150sec.
Ramp-up/down speed < 5°C/sec.
IMPORTANT: Test or measurement right after reflow soldering may read an offset as the sensor needs time for
re-hydration. The recovery time may vary depending on reflow soldering profile and ambient storage
condition.
For most of the standard reflow soldering, the following rehydration process will bring the sensor back to less than
±1%RH of the original calibration state.
Re-hydration: 30 ±5°C, 80 ±5%RH, Duration: 60 hrs
Contact GE customer support for customized recovery measures specific to your reflow soldering process.
For Land Pattern drawing and dimensions, see Figure 4 on page 4.
2
Application Guide
ChipCap 2 Humidity and Temperature Sensor
1.5 Storage and Handling Information
ChipCap 2 contains a polymer based capacitive humidity sensor sensitive to environment, and should NOT be handled
as an ordinary electronic component.
Chemical vapors at high concentration may interface with the polymer layers, and, coupled, with long exposure time,
may cause a shift in both offset and sensitivity of the sensor.
Although the sensor endures the extreme conditions of -50°C~150°C, 0%~100%RH (non condensing), long term
exposure in such an environment may also offset the sensor reading. Hence, once the package is opened, it is
recommended to store it in a clean environment with temperature at 5°C~55°C and humidity at 10%~70%RH.
ChipCap 2 is ESD protected up to 4000V and has Latchup of ±100°C or (up to +8V / down to -4V) relative to
VSS/VSSA, and is also packed in ESD protected shipping material. Normal ESD precautions are required when
handling in the assembly process.
1.6 Reconditioning Procedure
If ChipCap 2 is exposed to extreme conditions or contaminated with chemical vapors, the following reconditioning
procedure will recover the sensor back to calibration state.
Baking:
120°C for 3 hrs and
Re-Hydration: 30±5°C at 80 ±5%RH for 60 hrs
1.7 Material Contents
ChipCap 2 consists of a sensor cell and IC (polymer /glass and silicon substrate) packaged in a surface mountable LCC
(Leadless Chip Carrier) type package. The sensor housing consists of a PPS (Poly Phenylene Sulfide) cap with epoxy
glob top on a standard FR4 substrate. Pads are made of Au plated Cu. The device is free of Pb, Cd and Hg.
A RoHS compliant / REACH report is available.
Application Guide
3
ChipCap 2 Humidity and Temperature Sensor
1.8 Traceability Information
ChipCap 2 is laser marked with product type and lot identification. Further information about an individual sensor is
electronically stored on the chip.
The first line denotes the sensor type: CC2-A for PDM output, CC2-D for I²C output.
Lot identification is printed on the second line with a 5 digit alphanumeric code.
An electronic identification code stored on the chip can be decoded and allows for tracking on a batch level through
production, calibration and testing.
Figure 3: Laser Marking
1.9 Shipping Package
ChipCap 2 is provided in tape and reel shipment packaging, sealed into antistatic ESD trays. Standard packaging sizes
are 2,500 or 500 units per reel. The drawing of the packaging tapes with sensor orientation and packing box dimensions
are shown in Figure 4 below and Figure 5 on the next page.
CC2
Land Pattern (a)
CC2
Packing Reel and Tape (b)
Figure 4: Packaging Tapes
4
Application Guide
ChipCap 2 Humidity and Temperature Sensor
1.9 Shipping Package (cont.)
Inbox: 500 ea
Dimension: 215 x 210 x 30 mm
Inbox: 2,500 each
Dimension: 360 x 355 x 50 mm
Outbox: 5,000 each (5 x Inbox 500)
Dimension: 320 x 225 x 235 mm
Outbox: 25,000 each (10 x Inbox 2500)
Dimensions: 520 x 370 x 385 mm
Figure 5: Packing (Box)
Application Guide
5
ChipCap 2 Humidity and Temperature Sensor
2.
Interface Specification
2.1 Digital Output (I ² C Interface)
Figure 6: Pin Assignments
Pin-No
2.1.1
Name
Table 1: Pin Assignments
Description
1
Alarm_Low
Low alarm output
2
Ready
Ready signal (conversion complete output)
3
SDA
I2C data
4
SCL
I2C clock
5
VCORE
Core voltage
6
VSS
Ground supply
7
VDD
Supply voltage (2.7-5.5V)
8
Alarm_High
High alarm output
Power Pads (5.VCORE, 6.VSS, 7.VDD)
ChipCap 2 is capable of operating on a wide range of power supply voltages from 2.7V to 5.5V.
The recommended supply voltage is either 3.3 ±0.5V or 5.0 ±0.5V. The power supply should be connected to VDD
(power supply pad 7). VDD and VSS (Ground pad 6) should be decoupled with a 220nF capacitor.
IMPORTANT: Vcore must not be connected to VDD, and it must always be connected to an external 100nF capacitor to
ground. (see Figure 7, “Typical Application Circuit (I2C),” on page 7).
6
Application Guide
ChipCap 2 Humidity and Temperature Sensor
2.1.2
Serial Clock & Data Pads (3. SDA, 4. SCL)
The sensor’s data is transferred in and out through the SDA pad, while the communication between ChipCap 2 and the
microcontroller (MCU) is synchronized through the SCL pad.
ChipCap 2 has an internal temperature compensated oscillator that provides time base for all operation, and uses an
I ² C -compatible communication protocol with support for 100 KHz to 400 KHz bit rates.
External pull-up resistors are required to pull the drive signal high; they can be included in the I/O circuits of
microcontroller.
Further information about timing and communication between the sensor and microcontroller is explained in Section 4,
“Communicating with ChipCap 2” on page 13.
2.1.3
Alarm Pads (1. Alarm Low, 8. Alarm High)
The alarm output can be used to monitor whether the sensor reading has exceeded or fallen below pre-programmed
values. The alarm can be used to drive an open-drain load connected to VDD, or it can function as a full push-pull
driver. If a high voltage application is required, external devices can be controlled with the Alarm pins, as demonstrated
in Figure 21 on page 30
The two alarm outputs can be used simultaneously, and these alarms can be used in combination with the I2C. Further
information about alarm control is explained in Section 6.
•
VDD and Ground is decoupled by a 220nF capacitor.
•
Vcore (Not Used) and Ground is decoupled by 100nF capacitor.
•
Pull-up resistors should be included between ChipCap 2 and MCU.
VDD
VDD
SCL
uC
(master)
SDA
GND
VDD
READY
ALARM_HIGH
ALARM_LOW
CC2 D
(slave)
2.2k:< RPU < 10k:
2.7V < VDD < 5.5V
Figure 7: Typical Application Circuit (I2C)
Application Guide
7
ChipCap 2 Humidity and Temperature Sensor
2.2 Analog Output (PDM)
Figure 8: Pin Assignments
Table 2: Pin Assignments for Analog Output
Pin-No
2.2.1
Name
Description
1
PDM_T
Temperature PDM
2
PDM_H
Humidity PDM
3
SDA
I2C data (Not Used)
4
SCL
5
VCORE
I2C clock (Not Used)
Core voltage
6
VSS
Ground supply
7
VDD
Supply voltage (2.7-5.5V)
8
Alarm_High
High Alarm output
Power Pads (5.VCORE, 6.VSS, 7.VDD)
ChipCap 2 is capable of operating on a wide range of power supply voltages from 2.7V to 5.5V. The recommended
supply voltage is either 3.3 ±0.5V or 5.0 ±0.5V.
The power supply should be connected to VDD (power supply pad 7). VDD and VSS (Ground pad 6) should be
decoupled with a 220 nF capacitor.
IMPORTANT: Vcore must not be connected to VDD, and it must always be connected to an external 100 nF capacitor to
ground (see Figure 9 on page 9).
8
Application Guide
ChipCap 2 Humidity and Temperature Sensor
2.2.2
PDM Output Pads (1.PDM_T, 2.PDM_H)
Temperature PDM (Pulse Density Modulation) appears on the PDM_T/Alarm_Low pad (1) and corrected Humidity
PDM appears on the PDM_H pad (2).
When pad (1) is selected for Temperature PDM, the Alarm_Low function is disabled and only one Alarm function
(Alarm_High: pad 8) is usable.
Note: The ChipCap 2 PDM output is pre-programmed in the factory for Humidity and Temperature output mode.
2.2.3
Alarm Pads (8.Alarm_High, 1.Alarm_Low [optional])
As ChipCap 2 PDM is factory set for Humidity and Temperature output mode, only the High Alarm output can be used
in combination with ChipCap 2 PDM.
If both high and low alarm functions are required, pads 1 and 8 will be programmed at factory to use as Alarm_Low
and Alarm_High respectively with required high and low humidity values. In such a case, ChipCap 2 will output the
corrected humidity PDM only, See Section 6 for the alarm function.
2.2.4
Serial Clock & Data Pads (3.SDA, 4.SCL)
For ChipCap 2 PDM output, both SDA and SCL pads are not used and must be connected to VDD.
2.2.5
Typical Circuit Connection
VDD and Ground are decoupled by a 220nF capacitor. Vcore (Not Used) and Ground are also decoupled by a 100nF
capacitor. SCL and SDL (not used) are connected to VDD.
Between ChipCap 2 and MCU (μC), Low Pass Filtering (see Section 5.2 on page 26 for more information) with 10 kΩ
resistors and 6,400 nF capacitors is added to create an analog signal.
VDD
VCORE
2.7V < VDD < 5.5 V
100nF
SCL
SDA
GND
VDD
220nF
PDM_H
R
PDM_T
ALARM_HIGH
6400nF
CC2 A
uC
(master)
R
6400nF
Figure 9: Typical Application Circuit (PDM)
Application Guide
9
ChipCap 2 Humidity and Temperature Sensor
3.
Electrical Specification
3.1 Absolute Maximum Rating
Table 3 below shows the Absolute Maximum Ratings for ChipCap 2. Exposure to these extreme condition for extended
period may deteriorate the sensor performance and accelerate aging. Functional operation is not implied at these
conditions.
Table 3: Absolute Maximum Rating
Parameter
Symbol
Min
Max
Unit
Supply Voltage (VDD)
VDD
-0.3
6.0
V
Supply Voltage at I/O pads
VIO
-0.3
VDD+0.3
V
Storage Temperature Range
TSTOR
-55
150
°C
Tj
-55
150
°C
Junction Temperature
3.2 Electrical Specification and Recommended Operating Conditions
The operating conditions recommended for ChipCap 2 are given in Table 4 and the electrical specification is shown in
Table 5 on the next page.
Table 4: Recommended Operating Conditions
Parameter
Supply Voltage to Gnd
Ambient Temperature Range
External Capacitance between VDD pin and Gnd
External Capacitance between Vcore and Gnd
Pull-up on SDA and SCL
10
Symbol
Min
VSUPPLY
Max
Unit
2.7
5.5
V
TAMB
-40
125
C
CVSUPPLY
100
470
nF
CVCORE
RPU
Typ
220
100
1
2.2
nF
10
k
Application Guide
ChipCap 2 Humidity and Temperature Sensor
Parameter
Table 5: Electrical Characteristics Specifications
Symbol
Conditions
Min Typ Max
Units
Supply
Supply Current (varies with update
rate and output mode)
IDD
At maximum update rate
750 1100
μA
Extra Current with PDM enabled
IPDM
At maximum update rate
150
μA
Sleep Mode Current
Isleep
-40 to 85°C
0.6
1
μA
-40 to 125°C
1
3
μA
90
%VSUPPLY
PDM Output
Voltage Range
VPDM_Ra 3V±10%, 3.3V±10%, 5V±10%
10
nge
PDM Frequency
fPDM
fSYS/
8
KHz
Filter Settling Time1
tSETT
0% to 90% LPFilter 10kW/400nF
9.2
ms
Ripple1
VRIPP
0% to 90% LPFilter 10kW/400nF
1.0
mV/V
PDM Additional Error
EPDM
-40 to 125°C
0.1
0.5
%
0
0.2
VSUPPLY
(Including Ratiometricity Error)
Digital I/O
Voltage Output Level Low
VOL
Voltage Output Level High
VOH
Voltage Input Level Low
VIL
Voltage Input Level High
VIH
0.8
1
0
0.8
VSUPPLY
0.2
1
VSUPPLY
VSUPPLY
Total System
,
Start-Up-Time
Power-on (POR) to data ready
tSTA
At nominal frequency; fastest and 4.25
slowest settings
55
ms
Update Rate (Update Mode)
tRESP_UP Fastest and slowest settings
0.70
165
ms
Response Time (Sleep Mode)
tRESP_SL Fastest and slowest settings
1.25
45
ms
1. Please refer to section 5.2 on page 26.
Application Guide
11
ChipCap 2 Humidity and Temperature Sensor
3.3 Output Pad Drive Strength
The output pad drive strength at different supply voltages and operating temperatures is shown in Table 6 and Table 7
below.
Table 6: Output High Drive Strength
Output High Drive Strength (mA)
-40°C
25°C
125°C
VSUPPLY (V)
Min
Typ
Min
Typ
Min
Typ
2.7
7.2
10.5
5.9
8.4
4.7
6.6
3.3
12.1
16.6
9.6
12.9
7.4
10.0
5.5
20.0
20.0
20.0
20.0
20.0
20.0
Table 7: Output Low Drive Strength
Output Low Drive Strength (mA)
-40°C
25°C
125°C
VSUPPLY (V)
Min
Typ
Min
Typ
Min
Typ
2.7
20.0
20.0
16.0
20.0
11.7
14.9
3.3
20.0
20.0
20.0
20.0
18.2
20.0
5.5
20.0
20.0
20.0
20.0
20.0
20.0
3.4 ESD/Latch-Up-Protection
All external module pins have ESD protection of up to 4000V and latch-up protection of ±100 mA or (up to +8V/down
to -4V) relative to VSS/VSSA. The internal module pin VCORE has ESD protection of up to 2000V. The ESD test
follows the Human Body Model with 1.5kOhm/100 pF based on MIL 883, Method 3015.7.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
4.
Communicating with ChipCap 2
4.1 Power–On Sequence
On system power-on reset (POR), the ChipCap 2 wakes as an I²C device regardless of the output protocol programmed
in EEPROM. After power-on reset, it enters the command window. It then waits for a Start_CM command for 10 ms if
Fast Startup bit is not set in EEPROM (Factory Setting) or for 3 ms if fast startup bit is set in EEPROM (see Figure 10).
If the ChipCap 2 receives the Start_CM command during the command window, it enters and remains in Command
Mode.
The Command Mode is primarily used for initializing ChipCap 2.
If during the power-on sequence, the command window expires without receiving a Start_CM or if the part receives a
Start_NOM command in Command Mode, the device will immediately assume its programmed output mode and will
perform one complete measurement cycle.
4.2 I2C Features and Timing
The ChipCap 2 uses I2C-compatible communication protocol with support for 100kHz and 400kHz bit rates. The I2C
slave address (0x00 to 0x7F) is selected by the Device_ID bits in the Cust_Config EEPROM word (see Table 16 on
page 32 for bit assignments).
See Figure 11 for I²C Timing Diagram and Table 8 on page 14 for definitions of the parameters shown in the diagram.
Note: A Detailed Timing Chart and Reference Programming Code are available upon request.
Measurement Cycle
Command
Window
Power applied to device.
Command window starts after
a short power-on-reset window.
Temperature
Conversion
Humidity
Conversion
When the Fast Startup bit is not set in
EEPROM, the command window is
10ms.
DSP
Calculations
1st corrected signal measurement
written to output register (I2C,
PDMs, Alarms)
Figure 10: Power On Sequence with Fast Start-up Bit Set in EERPROM
SDA
tSUDAT
tLOW
tBUS
tHDSTA
SCL
tHDSTA
tHDDAT
tHIGH
tSUSTA
tSUSTO
Figure 11: I2C Timing Diagram
Application Guide
13
ChipCap 2 Humidity and Temperature Sensor
4.2 I2C Features and Timing (cont.)
Table 8: I2C Parameters
Parameter
Symbol
Min
fSCL
20
tHDSTA
0.1
s
Minimum SCL clock low width 1
tLOW
0.6
s
Minimum SCL clock high width 1
tHIGH
0.6
s
Start condition setup time relative to SCL edge
tSUSTA
0.1
s
Data hold time on SDA relative to SCL edge
tHDDAT
0
Data setup time on SDA relative to SCL edge
tSUDAT
0.1
s
Stop condition setup time on SCL
tSUSTO
0.1
s
tBUS
1
s
SCL clock frequency
Start condition hold time relative to SCL edge
Bus free time between stop condition and start condition
Typ
Max
Units
400
kHz
0.5
s
1. Combined low and high widths must equal or exceed minimum SCL period.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
4.3 Measurement Modes
The ChipCap 2 can be programmed to operate in either Sleep Mode or Update Mode. The measurement mode is
selected with the Measurement_Mode bit in the ChipCap 2 Config Register word. In Sleep Mode, the part waits for
commands from the master before taking measurements (see section 4.3.2 on page 15).
4.3.1
Data Fetch in Update Mode
In Update Mode, I2C is used to fetch data from the digital output register using a Data Fetch (DF) command.
Detecting when data is ready to be fetched can be handled either by polling or by monitoring the Ready pin (see section
4.8 on page 20 for details on the Ready pin). The status bits of a DF tell whether or not the data is valid or stale (see
Table 9 on page 17 regarding the status bits). As shown in Figure 12 below, after a measurement cycle is complete,
valid data can be fetched. If the next data fetch is performed too early, the data will be the same as the previous fetch
with stale status bits. As shown in Figure 12 below, a rise on the Ready pin can also be used to tell when valid data is
ready to be fetched.
Figure 12: I2C Data Fetching in Update Mode
4.3.2
Data Fetch in Sleep Mode
In Sleep Mode, the ChipCap 2 core will only perform conversions when ChipCap 2 receives a Measurement Request
command (MR); otherwise, the ChipCap 2 is always powered down. Measurement Request commands can only be
sent using I2C, so Sleep Mode is not available for PDM. The Alarms can be used in Sleep Mode but only in
combination with I2C.
Note: Sleep Mode power consumption is significantly lower than Update Mode power consumption (see Table 5 on
page 11 for exact values).
Application Guide
15
ChipCap 2 Humidity and Temperature Sensor
4.3.2
Data Fetch in Sleep Mode (cont.)
Figure 13 below shows the measurement and communication sequence for Sleep Mode. The master sends an MR
command to wake the ChipCap 2 from power down. After ChipCap 2 wakes up, a measurement cycle is performed
consisting of both a temperature and a capacitance conversion followed by the ChipCap 2 Core correction calculations.
At the end of a measurement cycle, the digital output register and alarms will be updated before powering down. An
I2C data fetch (DF) is performed during the power-down period to fetch the data from the output register. In I2C the
user can send another MR to start a new measurement cycle without fetching the previous data. After the data has been
fetched, the ChipCap 2 remains powered down until the master sends an MR command.
ChipCap 2
Activity
Power
Down
Temp
Cap
Conv & Calc Conv & Calc
Write new corrected
signal measurement to
output register (I2C)
Command wakes
ChipCap 2
I2C
Activity
Power
Down
Valid read
occurs
Figure 13: Measurement Sequence in Sleep Mode
ChipCap 2
Activity
Power
Down
I2C
Activity
Temp
Cap
Conv & Calc Conv & Calc
Command wakes
ChipCap 2
Stale values
Power
Down
Write new corrected
signal measurement to
output register (I2C)
Valid read
occurs
Figure 14: I2C Data Fetching in Sleep Mode
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
4.3.2
Data Fetch in Sleep Mode (cont.)
In Sleep Mode, I2C are used to request a measurement with a MR command and to fetch data from the digital output
register using a Data Fetch (DF) command (see section 4.7 on page 20 for details on the MR command).
Detecting when data is ready to be fetched can be handled either by polling or by monitoring the Ready pin (see section
4.8 on page 20 for details on the Ready pin). The status bits of a DF tell whether the data is valid or stale (see section
4.4 regarding the status bits). As shown in Figure 14 on the previous page, after a measurement cycle is complete, valid
data can be fetched. If the next data fetch is performed too early, the data will be the same as the previous fetch with
stale status bits. A rise on the Ready pin (Figure 14) can also be used to tell when valid data is ready to be fetched.
4.4 Status Bits
Status bits (the two MSBs of the fetched high data byte, see Table 9 below) are provided in I2C but not in PDM. The
status bits are used to indicate the current state of the fetched data.
Table 9: Status Bits
2C)
PDM Output
Definition
00B
Clipped normal
output
Valid data: Data that has not been fetched since the last
measurement cycle.
01B
Not applicable
Stale data: Data that has already been fetched since the
last measurement cycle.
10B
Not applicable
Command Mode: The ChipCap 2 is in Command Mode.
11B
Not used
Status Bits (I
Not used
4.5 I2C Commands
As detailed in Table 10 below, there are two types of commands which allow the user to interface with the ChipCap 2
in the I2C.
Table 10: I2C Command Bits
Type
Description
Communication
Supported
Reference
Sections
Data Fetch (DF)
Used to fetch data in any digital mode
I2C
Section 4.6
Measurement Request (MR)
Used to start measurements in Sleep Mode
I2C
Section 4.7
Application Guide
17
ChipCap 2 Humidity and Temperature Sensor
4.6 Data Fetch (DF)
The Data Fetch (DF) command is used to fetch data in any digital output mode.
An I2C Data Fetch command starts with the 7-bit slave address and the 8th bit = 1 (READ).
The ChipCap 2 as the slave sends an acknowledgement (ACK) indicating success.
The number of data bytes returned by the ChipCap 2 is determined by when the master sends the NACK and stop
condition. Figure 15 on page 19 shows examples of fetching two, three and four bytes respectively.
The full 14 bits of humidity data are fetched in the first two bytes. The MSBs of the first byte are the status bits.
If temperature data is needed, additional temperature bytes can be fetched. In Figure 15 on page 19, the three-byte data
fetch returns 1 byte of temperature data (8-bit accuracy) after the humidity data. A fourth byte can be fetched where the
six MSBs of the fetched byte are the six LSBs of a 14-bit temperature measurement. The last two bits of the fourth byte
are undetermined and should be masked off in the application.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
2
I C DF – 2 Bytes: Slave returns only humidity (RH) data to the master in 2 bytes.
S 6 5 4 3 2 1 0 R A 15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 N S
Device Slave Address [6:0]
RH Data [13:8]
Wait for
Slave ACK
RH Data [7:0]
Master ACK
Master ACK
Master NACK
S 6 5 4 3 2 1 0 R A 15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 A 7 6 5 4 3 2 1 0 N S
Device Slave Address [6:0]
RH Data [13:8]
RH Data [7:0]
Temp. Data [13:6]
I C DF – 3 Bytes: Slave returns 2 humidity (RH) data and temperature high byte (T[13:6]) to master
2
S Start Condition S Stop Condition
2 Slave Address Bit (Example: Bit 2)
A Acknowledge (ACK) N Not Acknowledge
(NACK)
2
Command or Data Bit (Example: Bit 2)
Read/Write
(Read = 1)
R
Status Bit
G
I2C DF - 4 Bytes: Slave returns 2 RH data and 2 Temperature data to the master.
Wait for
Slave ACK
Device Slave Address [6:0]
Start Condition
Master ACK
RH Data [13:8]
Stop Condition
Slave Address Bit (Example: Bit 2)
Master ACK
RH Data [7:0]
Acknowledge (ACK)
Master ACK
Temp. Data [13:6]
Not Acknowledge
(NACK)
Command or Data Bit (Example: Bit 2)
Status Bits
Master NACK
Temp. Data [5:0]
Read/Write
(Read:1)
Bits should be masked off
and ignored
Figure 15: I²C Measurement Packet Reads
Application Guide
19
ChipCap 2 Humidity and Temperature Sensor
4.6 Data Fetch (DF) (cont.)
Humidity & Temperature Conversion Formula
4.7
Humidity Output (%RH)
(RH_High [5:0] x 256 + RH_Low [7:0])/ 214 x 100
Temperature Output (°C)
(Temp_High [7:0] x 64 + Temp_Low [7:2]/ 4)/ 214 x 165 - 40
Measurement Request (MR)
A measurement request (MR) is a Sleep-Mode-only command sent by the master to wake up the ChipCap 2 and start a
new measurement cycle in I2C.
The I2C MR is used to wake up the device in Sleep Mode and start a complete measurement cycle starting with a
temperature measurement, followed by a humidity measurement, and then the results can be fetched by master with
I2C.
As shown in Figure 16 below, the communication contains only the slave address and the WRITE bit (0) sent by the
master.
After the ChipCap 2 responds with the slave ACK, the master creates a stop condition.
Note: The I2C MR function can also be accomplished by sending “don't care” data after the address instead of
immediately sending a stop bit.
I2C MR - Measurement Request: Slave starts a measurement cycle.
Device Slave Address [6:0]
Start Condition
Stop Condition
Wait for
Slave ACK
Acknowledge (ACK)
Slave Address Bit
(Example: Bit 2)
Read/Write Bit
(Example: Read = 1)
Figure 16: I²C Measurement Request
4.8 Ready Pin
A rise on the Ready pin indicates that new data is ready to be fetched from the I2C interface. The Ready pin stays high
until a Data Fetch (DF) command is sent; it stays high even if additional measurements are performed before the DF.
The Ready pin's output driver type is selectable as either full push-pull or open drain using the Ready_Open_Drain bit
in EEPROM word Cust_Config (see Table 16 on page 32 for bit assignments and settings). Point-to-point
communication most likely uses the full push-pull driver. If an application requires interfacing to multiple parts, then
the open drain option can allow for just one wire and one pull-up resistor to connect all the parts in a bus format.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
4.9 Command Mode
Command Mode commands are only supported for the I2C protocol. As shown in Figure 17 below, commands are
4-byte packets with the first byte being a 7-bit slave address followed by 0 for write. The second byte is the command
byte and the last two bytes form a 16-bit data field.
I2C WRITE, Command Byte, and 2 Command Data Bytes
Device Slave Address
Command Byte
Wait for
Slave ACK
Start Condition
Command Data [15:8]
Wait for
Slave ACK
Stop Condition
Slave Address Bit (Example: Bit 2)
Acknowledge (ACK)
Command Data [7:0]
Wait for
Slave ACK
Wait for
Slave ACK
Read/Write Bit (Example: Write = 0)
Command or Data Bit (Example: Bit 2)
Figure 17: I2C Command Format
Application Guide
21
ChipCap 2 Humidity and Temperature Sensor
4.10 Command Encodings
Table 11 describes all the commands that are offered in Command Mode.
Note: Only the commands listed in Table 11 are valid. Other encodings might cause unpredictable results. If data is
not needed for the command, zeros must be supplied as data to complete the 4-byte packet.
Table 11: Command List and Encodings
Third and
Fourth Bytes
Command Byte
8 Command Bits (Hex)
16 Data Bits
(Hex)
0x16 to 0x1F
0x0000
Description
EEPROM Read of addresses 0x16 to 0x1F
Response Time
100s
After this command has been sent and
executed, a data fetch must be performed.
0x56 0x5F
0xYYYY
(Y = data)
Write to EEPROM addresses 0x16 to 0x1F
12ms
The 2 bytes of data sent will be written to the
address specified in the 6 LSBs of the
command byte
0x80
0x0000
Start_NOM
Ends Command Mode and transitions to
Normal Operation Mode.
0xA0
0x0000
Start_CM
Start Command Mode: used to enter the
command interpreting mode. Start_CM is
only valid during the power-on command
window.
100s
4.11 Command Response and Data Fetch
After a command has been sent and the execution time defined in Table 11 has expired, an I2C Data Fetch (DF) can be
performed to fetch the response. As shown in Figure 18 on page 24, after the slave address has been sent, the first byte
fetched is the response byte.
The upper two status bits will always be 10 to represent Command Mode. The lower two bits are the response bits.
Table 12 on page 23 describes the different responses that can be fetched. To determine if a command has finished
executing, poll the part until a Busy response is no longer received. The middle four bits of the response byte are
command diagnostic bits where each bit represents a different diagnostic (see Table 13 on page 23).
Note: Regardless of what the response bits are, one or more of the diagnostic bits may be set indicating an error
occurred during the execution of the command.
Note: Only one command can be executed at a time. After a command is sent another command must not be sent until
the execution time of the first command defined in Table 11 above has expired.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
4.11 Command Response and Data Fetch (cont.)
For all commands except EEPROM Read and Get Revision, the data fetch should be terminated after the response byte
is read. If the command was a Get Revision, then the user will fetch a one byte Revision as shown in Figure 18 on
page 24, example 2.
The revision is coded with the upper nibble being the letter corresponding to a full layer change and the lower nibble
being the metal change number, for example A0. If the command was an EEPROM Read, then the user will fetch two
more bytes as shown in Figure 18 on page 24, example 3.
If a Corrected EEPROM Error diagnostic was flagged after an EEPROM read, the user has the option to write this data
back to attempt to fix the error. Instead of polling to determine if a command has finished executing, the user can use
the Ready pin. In this case, wait for the Ready pin to rise, which indicates that the command has executed. Then a data
fetch can be performed to get the response and data (see Figure 18 on page 24).
Encoding
Description
00
Busy
01
Positive Acknowledge
The command executed successfully.
10
Negative Acknowledge
The command was not recognized or an
EEPROM write was attempted while the
EEPROM was locked.
Bit Position
2
3
Application Guide
Table 12: Response Bits
Name
The command is busy executing.
Table 13: Command Diagnostic Bits
Name
Description
Corrected EEPROM Error A corrected EEPROM error occurred in
execution of the last command.
Uncorrectable EEPROM An uncorrectable EEPROM error occurred in
Error
execution of the last command.
4
RAM Parity Error
A RAM parity error occurred during a
microcontroller instruction in the execution of
the last command.
5
Configuration Error
An EEPROM or RAM parity error occurred in
the initial loading of the configuration
registers.
23
ChipCap 2 Humidity and Temperature Sensor
4.11 Command Response and Data Fetch (cont.)
(1) I2C DF - Command Status Response - 1 Byte
Device Slave Address [6:0]
Status Diagnostics Response
[7:6]
[5:2]
[1:0]
Wait for
Slave ACK
Device Slave Address [6:0]
Master ACK
Status Diagnostics Response
[7:6]
[5:2]
[1:0]
Master NACK
ChipCap 2 Revision
Data Byte [7:0]
(2) I2C Get Revision DF - Command Status Response and ChipCap 2 Revision - 2 Bytes
Wait for
Slave ACK
Device Slave Address [6:0]
Master ACK
Status Diagnostics Response
[7:6]
[5:2]
[1:0]
Master ACK
EEPROM Data
High Byte [15:8]
Master NACK
EEPROM Data
Low Byte [7:0]
(3) I2C EEPROM DF - Command Status Response and EEPROM Data Fetch - 3 Bytes
Start Condition
Slave Address Bit
(Example: Bit 2)
Stop Condition
Acknowledge (ACK)
Not Acknowledge
(NACK)
Command or Data Bit
(Example: Bit 2)
Read/Write Bit
(Example: Read = 1)
Status Bits
(In Command Mode Always 10)
Figure 18: Command Mode Data Fetch
4.12 EEPROM
The EEPROM array contains the calibration coefficients for gain and offset, etc., and the configuration bits for the
analog front end, output modes, measurement modes, etc. The ChipCap 2 EEPROM is arranged as 10 16-bit words (see
Table 14 on page 25).
See section 4.9, “Command Mode” on page 21, for instructions on reading and writing to the EEPROM in Command
Mode via the I2C interface. When programming the EEPROM, an internal charge pump voltage is used; therefore, a
high voltage supply is not needed.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
EEPROM Word
Table 14: EEPROM Word Assignments
Bit Range
IC Default
Name
Description and Notes
16HEX
13:0
0x3FFF
PDM_Clip_High
PDM high clipping limit
17HEX
13:0
0x0000
PDM_Clip_Low
PDM low clipping limit
18HEX
13:0
0x3FFF
Alarm_High_On
High alarm on trip point
19HEX
13:0
0x3FFF
Alarm_High_Off
High alarm off trip point
1AHEX
13:0
0x0000
Alarm_Low_On
Low alarm on trip point
1BHEX
13:0
0x0000
Alarm_Low_Off
Low alarm off trip point
1CHEX
15:0
0x0028
Cust_Config
Customer Configuration
(see Table 16 on page 32)
1DHEX
15:0
0x0000
Reserved
Reserved Word: Do Not
Change; must leave at
factory settings
1EHEX
15:0
0x0000
Cust_ID2
Customer ID byte 2: For use
by customer
1FHEX
15:0
0x0000
Cust_ID3
Customer ID byte 3: For use
by customer
Application Guide
25
ChipCap 2 Humidity and Temperature Sensor
5.
Converting PDM to Analog Signal
5.1 PDM (Pulse Density Modulation)
Both corrected humidity and temperature are available in PDM output. Humidity PDM appears on PDM_H (2) pad and
Temperature PDM appears on the PDM_T (1) pad.
The PDM frequency is 231.25 kHz ±15% (i.e., the oscillator frequency 1.85 MHz ±15% divided by 8). Both PDMs
output 14-bit values for Humidity and Temperature.
In PDM Mode, ChipCap 2 is programmed to Update Mode. Every time a conversion cycle has finished, the PDM will
begin outputting the new value.
See Figure 19 below for the PDM Timing Diagram.
X = 10%
VDD
PDM_H/PDM_T
0V
X = 50%
VDD
PDM_H/PDM_T
0V
X = 90%
VDD
PDM_H/PDM_T
0V
Figure 19: PDM Signal Timing Diagram
5.2 Low Pass Filtering
An analog output value is created by low-pass filtering the PDM output; a simple first-order RC filter will work in this
application.
Select the time constant of the filter based on the requirements for setting time and/or peak-to-peak ripple.
IMPORTANT: The resistor of the RC filter must be >10 k
Table 15: Low Pass Filter Example for R=10 k
Filter Capacitance (nF)
26
Desired Analog Output
Resolution
PDM_H / PDM_T
Vpp Ripple (mV/V)
0 to 90% settling
time (ms)
100
4.3
2.3
8
400
1.0
9.2
10
1600
0.3
36.8
12
6400
0.1
147.2
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
5.2 Low Pass Filtering (cont.)
For a different (higher) resistor, the normalized ripple VPP (mV/V) can be calculated as:
VPP (mV/V) = 4324 / [R(k) * C(nF)]
Or the setting time tSETT for a 0% to 90% setting can be calculated as:
tSETT (ms) = 0.0023 * R(k) * C(nF)
5.3 Analog Output Characteristics
5.3.1
Polynomial Equation Humidity
PDM_H [mV]= %RH /100 * VDD[mV]
5.3.2
Polynomial Equation Temperature
PDM_T [mV] = ((T[°C] / 165) +0.2424)*VDD[mV]
Application Guide
27
ChipCap 2 Humidity and Temperature Sensor
6.
Alarm Function (Optional)
6.1 Alarm Output
The alarm output can be used to monitor whether the Humidity reading has exceeded or fallen below pre-programmed
values. The alarm can be used to drive an open-drain load connected to VDD as shown in Figure 22 on page 30 or it
can function as a full push-pull driver. If a high voltage application is required, external devices can be controlled with
the Alarm pads, as demonstrated in Figure 20 on page 29 and Figure 21 on page 30.
In standard ChipCap 2 PDM mode, only the High Alarm can be used.
6.2 Alarm Registers
Four registers are associated with the alarm functions: Alarm_High_On, Alarm_High_Off, Alarm_Low_On, and
Alarm_Low_Off (see Table 14 on page 25 for EEPROM addresses). Each of these four registers is a 14-bit value that
determines where the alarms turn on or off. The two high alarm registers form the output with hysteresis for the
Alarm_High pin, and the two low alarm registers form the output with hysteresis for the Alarm_Low pin. Each of the
two alarm pins can be configured independently using Alarm_Low_Cfg and Alarm_High_Cfg located in EEPROM
word Cust_Config (see Table 16 on page 32 for bit assignments).
Note: If two high alarms or two low alarms are needed, see the section Alarm Polarity on the next page.
6.3 Alarm Operation
As shown in Figure 23 on page 31, the Alarm_High_On register determines where the high alarm trip point is and the
Alarm_High_Off register determines where the high alarm turns off if the high alarm has been activated. The high
alarm hysteresis value is equal to Alarm_High_On - Alarm_High_Off. The same is true for the low alarm where
Alarm_Low_On is the low alarm trip point with Alarm_Low_Off determining the alarm shut off point. The low alarm
hysteresis value is equal to Alarm_Low_Off - Alarm_Low_On. Figure 24 on page 31 shows output operation
flowcharts for both the Alarm_High and Alarm_Low pins.
6.4
Alarm Output Configuration
The user can select the output driver configuration for each alarm using the Output Configuration bit in the
Alarm_High_Cfg and Alarm_Low_Cfg registers in EEPROM word Cust_Config (see Table 16 on page 32 for bit
assignments). For applications, such as interfacing with a microcontroller or controlling an external device, select the
full push-pull driver for the alarm output type. For an application that directly drives a load connected to VDD, the
typical selection is the open-drain output type. An advantage of making an alarm output open drain is that in a system
with multiple devices, the alarm outputs of each ChipCap 2 can be connected together with a single pull-up resistance
so that one can detect an alarm on any device with a single wire.
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Application Guide
ChipCap 2 Humidity and Temperature Sensor
6.5
Alarm Polarity
For both alarm pins, the polarity of the alarm output is selected using the Alarm Polarity bit in the Alarm_High_Cfg
and Alarm_Low_Cfg registers in EEPROM word Cust_Config (see Table 16 on page 32 for bit assignments). Another
feature of the polarity bits is the ability to create two high alarms or two low alarms. For example, with applications
requiring two high alarms, flip the polarity bit of the Alarm_Low pin, and it will act as a high alarm.
However, in this case, the effect of the alarm low registers is also changed: the Alarm_Low_On register would act like
the Alarm_High_Off register and the Alarm_Low_Off register would act like the Alarm_High_On register. The same
can be done to achieve two low alarms: the Alarm_High pin would have the polarity bit flipped, and the two
Alarm_High registers would have opposite meanings.
VDD
2.7V < VDD < 5.5V
VCORE
100nF
SCL
SDA
GND
VDD
220nF
PDM_H
PDM_T
ALARM_HIGH
(10k:
CC2 A
DEHUMIDIFIER
6400nF
(slave)
uC
(master)
(10k:
6400nF
GND
Figure 20: Bang-Bang Humidity Control (High Voltage Application):
ChipCap 2 PDM: 1 Alarm/Humidity Output (Optional)
Application Guide
29
ChipCap 2 Humidity and Temperature Sensor
6.5 Alarm Polarity (cont.)
VDD
12V
12V
HUMIDIFIER
CC2 D
100nF
VCORE
DEHUMIDIFIER
SCL
SDA
GND
220nF
VDD
ALARM_HIGH
PDM_H
ALARM_LOW
GND
GND
Figure 21: Bang-Bang Humidity Control (High Voltage Application):
ChipCap 2 I2C:2 Alarms / Humidity Output (Optional)
ChipCap 2 also can be directly installed to a device without MCU interface when only a switch on/off function is
required at the desired humidity level (e.g., bathroom vent fan, humidifiers, dehumidifiers).
VDD
VCORE
2.7V < VDD < 5.5 V
100nF
SCL
SDA
GND
VDD
220nF
PDM_H
PDM_T
ALARM_HIGH
(10k:
CC2 A
6400nF
(slave)
(10k:
LED
6400nF
Figure 22: LED control with Alarm Function
ChipCap 2 PDM: 1 Alarm/ Humidity Output (Optional)
30
Application Guide
ChipCap 2 Humidity and Temperature Sensor
6.5 Alarm Polarity (cont.)
Hi Alarm Pin On
Alarm_Hi_On
Hi Alarm Pin Off
Hysteresis
Humidity (RH)
Alarm_Hi_Off
Lo Alarm Pin OffG
Alarm_Low_Off
Hysteresis
Alarm_Low_On
Lo Alarm Pin OnG
Time
Figure 23: Example of Alarm Function
HIGH ALARM PIN
Alarm = Off
No
Measurement >
Alarm_High_On?
Yes
Alarm = On
No
Yes
No
LOW ALARM PIN
Alarm = Off
Measurement <
Alarm_High_Off?
Measurement<
Alarm_Low_On?
Yes
Alarm = On
No
Measurement >
Alarm_Low_Off?
Yes
Figure 24: Alarm Output Flow Chart
Application Guide
31
ChipCap 2 Humidity and Temperature Sensor
6.5 Alarm Polarity (cont.)
Bit Range
Table 16: Cust_Config Bit Assignments
IC Default
Name
Description and Notes
6:0
0101000
Device_ID
8:7
00
Alarm_Low_Cfg
10:9
00
Alarm_High_Cfg
*12
0
*13
0
Fast_Startup
15:14
00
Reserved
I2C slave address
Configure the Alarm_Low output pin:
Bits
Description
7
Alarm Polarity
0 = Active High
1 = Active Low
8
Output Configuration
0 = Full push-pull
1 = Open Drain
Configure the Alarm_High output pin:
Bits
Description
9
Alarm Polarity
0 = Active High
1 = Active Low
10
Output Configuration
0 = Full push-pull
1 = Open Drain
Ready_Open_Drain Ready pin is
0 = Full push-pull
1 = Open drain
Sets the Command Window length:
0 = 10 ms Command Window
1 = 3 ms Command Window
Do Not Change - must leave at factory settings
* Only applies to I2C output.
32
Application Guide
ChipCap 2 Humidity and Temperature Sensor
7.
Part Number List
Table 17: Part Number List
GE part no.
Description
Application Guide
CC2A25
ChipCap2, analog, 2%, 5v
CC2A23
ChipCap2, analog, 2%, 3.3v
CC2D23S
ChipCap2, digital, sleep mode, 2%, 3.3v
CC2D25S
ChipCap2, digital, sleep mode, 2%, 5v
CC2D23
ChipCap2, digital, 2%, 3.3v
CC2D25
ChipCap2, digital, 2%, 5v
CC2D35
ChipCap2, digital, 3%, 5v
CC2A33
ChipCap2, analog, 3%, 3.3v
CC2D33S
ChipCap2, digital, sleep mode, 3%, 3.3v
CC2D35S
ChipCap2, digital, sleep mode, 3%, 5v
CC2D33
ChipCap2, digital, 3%, 3.3v
CC2A35
ChipCap2, analog, 3%, 5v
33
ChipCap 2 Humidity and Temperature Sensor
34
Application Guide
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916-127 Rev. A