Datasheet MCP9808 Datasheet

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Page 1

MCP9808

±0.5°C Maximum Accuracy Digital Temperature Sensor

Features

•Accuracy:

- ±0.25 (typical) from -40°C to +125°C

- ±0.5°C (maximum) from -20°C to 100°C

- ±1°C (maximum) from -40°C to +125°C

• User-Selectable Measurement Resolution:

- +0.5°C, +0.25°C, +0.125°C, +0.0625°C

• User-Programmable Temperature Limits:

- Temperature Window Limit

- Critical Temperature Limit

• User-Programmable Temperature Alert Output

• Operating Voltage Range: 2.7V to 5.5V

• Operating Current: 200 µA (typical)

• Shutdown Current: 0.1 µA (typical)

• 2-wire Interface: I

C™/SMBus Compatible

• Available Packages: 2x3 DFN-8, MSOP-8

Typical Applications

• General Purpose

• Industrial Applic atio ns

• Industrial Freezers and Refrigerators

• Food Processing

• Personal Computers and Servers

• PC Peripherals

• Consumer Electronics

• Handheld/Portable Devices

Temperature Accuracy

40%

TA= -20°C, 25°C, 85°C, 100°C

= 3.3V

854 units

30%

Description

Microchip Technology Inc.’s MCP9808 digital temperature sensor converts temperatures between

-20°C and +100°C to a digital word with ±0.25°C/±0.5°C (typical/maximum) accuracy.

The MCP9808 comes with user-programmable registers that provide flexibility for temperature sensing applications. The registers allow user-selectable settings such as Shutdown or Low-Power modes and the specification of temperature Alert window limits and critical output limits. When the temperature changes beyond the specified boundary limits, the MCP9808 outputs an Alert signal. The user has the option of setting the Alert output signal polarity as an active-low or activehigh comparator output for thermostat operation, or as a temperature Alert interrupt output for microprocessorbased systems. The Alert output can also be configured as a critical temperature output only.

This sensor has an industry standard 400 kHz, 2-wire, SMBus/I

C compatible se rial interfa ce, allowing up to eight or sixteen sensors to be controlled with a single serial bus (see Table 3-2 for available Address codes). These features make the MCP9808 ideal for sophisticated, multi-zone, temperature-monitoring applications.

Package Types

8-Pin 2x3 DFN*

SDA V

SCL

Alert

GND

* Includes Exposed Thermal Pad (EP); see Table 3-1 .

8-Pin MSOP

SDA

SCL

Alert

GND

A1 A2

20%

Occurrences

10%

0.0

0.1

0.2

0.3

0.4

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.5

Page 2

MCP9808

Functional Block Diagram

Hysteresis Shutdown Critical Trip Lock

Alarm Window Lock

Clear Alert Alert Status

Output Co ntrol Critical Alert only Alert Polarity Alert Comp./Int.

Configuration

Band Gap

Temperature

Sensor

Pointer

Temperature T

T T

Manufacturer ID

Device ID/Rev Resolution

UPPER LOWER CRITICAL

Alert

Limit

SMBus/Standard I2C™

Interface

SDA

SCL

ΔΣ ADC

+0.5°C

+0.25°C

+0.125°C

+0.0625°C

GND

Page 3

MCP9808

1.0 ELECTRICAL CHARACTERISTICS

†Notice: S tress es ab ove th ose li ste d under “Maxim um

ratings” may ca use permanen t damage to the de vice. This is a stress rating only and functional operation of the device at tho se or any oth er conditions ab ove those

Absolute Maximum Ratings †

VDD.................................................................................. 6.0V

Voltage at All Input/Output Pins .............. GND – 0.3V to 6.0V

Storage Temperature ....................................-65°C to +150°C

Ambient Temperature with Power Applied....-40°C to +125°C

Junction Temperature (T

ESD Protection on All Pins (HBM:MM) ................ (4 kV:400V)

Latch-up Cu rr e n t at Ea c h Pi n (+ 2 5 °C ) ................ ..... ±200 mA

) ..........................................+150°C

indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.

TEMPERATURE SENSOR DC CHARACTERISTICS

Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground and

= -40°C to +125°C.

Parameters Sym Min Typ Max Unit Conditions

Temperature Sensor Accuracy

-20°C < T

-40°C < TA ≤ +125°C -1.0 ±0.25 +1.0 °C VDD = 3.3V

Temperature Conversion Time

0.5°C/bit t

0.25°C/bit — 65 — ms 15s/sec (typical)

0.125°C/bit — 130 — ms 7s/sec (typical)

0.0625°C/bit — 250 — ms 4s/sec (typical)

Power Supply

Operating Voltage Range V Operating Current I Shutdown Current I Power-on Reset (POR) V Power Supply Rejection Δ°C/ΔV

Alert Output (open-drain output, external pull-up resistor required), see Section 5.2.3 “Alert Output Configuration”

High-Level Current (leakage) I Low-Level Voltage V

Thermal Response, from +25°C (air) to +125°C (oil bath)

8L-DFN t 8L-MSOP — 1.4 — s

≤ +100°C T

ACY

CONV

SHDN

POR

RES

-0.5 ±0.25 +0.5 °C VDD = 3.3V

— 30 — ms 33s/sec (typical)

2.7 — 5.5 V —200 400 µA —0.1 2 µA — 2.2 — V Threshold for falling V —-0.1 — °C/VVDD = 2.7V to 5.5V, TA = +25°C

—— 1 µAV

= VDD (Active-Low, Pull-up Resistor)

—— 0.4 VIOL= 3 mA (Active-Low, Pull-up Resistor)

— 0.7 — s Time to 63% (+89°C)

Page 4

MCP9808

DIGITAL INPUT/OUTPUT PIN CHARACTERISTICS

Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground and

= -40°C to +125°C.

Parameters Sym Min Typ Max Units Conditions

Serial Input/Output (SCL, SDA, A0, A1, A2)

Input

High-Level Voltage V Low-Level Voltage V Input Current I

Output (SDA)

Low-Level Voltage V High-Level Current (leakage) I Low-Level Current I

OL OH OL

SDA and SCL Inputs

Hysteresis V Spike Suppression t Capacitance C

HYST

GRAPHICAL SYMBOL DESCRIPTION

0.7 V

GND — 0.3 V

—VDDV

——±5µA

——0.4VI ——1µAV

6——mAV

—0.05 VDD—V ——50ns —5—pF

= 3 mA

OH OL

= 5.5V

= 0.6V

Volta ge

Current

INPUT

Vol tage

Current

time

TEMPERATURE CHARACTERISTICS

Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V and GND = Ground.

Parameters Sym Min Typ Max Units Conditions

Temperature Ranges

Specified Temperature Range T Operating Temperature Range T Storage Temperature Range T

A A A

Thermal Package Resistances

Thermal Resistance, 8L-DFN θ Thermal Resistance, 8L-MSOP θ

JA JA

Note 1: Operation in this range must not cause T

-40 — +125 °C (Note 1)

-40 — +125 °C

-65 — +150 °C

—68—°C/W —211—°C/W

to exceed Maximum Junction Temperature (+150°C).

OUTPUT

Page 5

MCP9808

SENSOR SERIAL INTERFACE TIMING SPECIFICATIONS

Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V, TA = -40°C to +125°C, GND = Ground

= 80 pF. (Note 1)

and C

Parameters Sym Min Max Units Conditions

2-Wire SMBus/Standard Mode I

Serial Port Clock Frequency f Low Clock t High Clock t Rise Time t Fall Time t Data in Setup Time t Data In Hold Time t Data Out Hol d Time t Start Condition Setup Time t Start Condition Hold Time t Stop Condition Setup Time t Bus Free t Time-out t Bus Capacitive Load C

Note 1: All values referred to V

2: If t

LOW

> t

OUT

or t

is required for communication.

3: This device can be used in a Standard mode I

be met. This device does not stretch the SCL Low time.

4: As a transmitter, the device provides internal minimum delay time, t

region (min. 200 ns) of the falling edge of SCL, t conditions.

5: As a receiver, SDA should not be sampled at the falling edge of SCL. SDA can transition t

SCL toggles Low.

C™ Compatible Interface (Note 1)

LOW

HIGH

F SU-DI HD-DI

HD-DO SU-START HD-START

SU-STOP

B-FREE

OUT

HIGH

and V

IL MAX

> t

, the temperature senso r I2C interface will time-out. A Repeat Start comm and

OUT

IH MIN

levels.

0400kHz(Note 2, 4)

1300 — ns (Note 2)

600 — ns (Note 2)

20 300 ns 20 300 ns

100 — ns (Note 3)

0—ns(Note 5) 200 900 ns (Note 4) 600 — ns 600 — ns 600 — ns

1300 — ns

25 35 ms —400pf

C bus system, but the requirement, t

, to avoid unintended generation of Start or Stop

F MAX

HD-DO MIN

SU-DI

, to bridge the undefined

≥ 100 ns, must

0 ns after

HD-DI

TIMING DIAGRAM

HD-START

SU-START

HIGH

LOW

SCL

SDA

OUT

SU-DI

START Condition

HD-DI/tHD-DO

Data Transmission

tR, t

B-FREE

SU-STOP

STOP Condition

Page 6

MCP9808

NOTES:

Page 7

MCP9808

2.0 TYPICAL PERFORMANCE CURVES

Note: The graphs and t ables provid ed follo wing this no te are a st atis tical summa ry bas ed on a lim ited nu mber of

samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range.

Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD and T

= -40°C to +125°C.

1.0

0.5

= 3.3V

854 units at -20°C, 25°C, 85°C, 100°C 240 units at -40°C, 125°C

0.0

Temperature Accuracy (°C)

-0.5

-1.0

+Std. Dev.

Average

-Std. Dev.

+3 * Std. Dev.

-3 * Std. Dev.

-40 -20 0 20 40 60 80 100 120

TA(°C)

FIGURE 2-1: Temperature Accuracy.

40%

TA= -20°C

= 3.3V

827 units

30%

20%

Occurrences

10%

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.0

0.1

0.2

0.3

FIGURE 2-2: Temperature Accuracy Histogram, T

40%

30%

= -20°C.

TA= 25°C

= 3.3V

875 units

0.4

0.5

40%

TA= -20°C, 25°C, 85°C, 100°C

= 3.3V

854 units

30%

20%

Occurrences

10%

0.0

0.1

0.2

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.3

FIGURE 2-4: Temperature Accuracy Histogram.

40%

TA= 85°C

= 3.3V

859 units

30%

20%

Occurrences

10%

0.0

0.1

0.2

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.3

FIGURE 2-5: Temperature Accuracy Histogram, T

40%

30%

= +85°C.

TA= 100°C V

= 3.3V

856 units

0.4

0.5

20%

Occurrences

10%

0.0

0.1

0.2

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.3

FIGURE 2-3: Temperature Accuracy Histogram, T

= +25°C.

0.4

0.5

20%

Occurrences

10%

0.0

0.1

0.2

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.3

FIGURE 2-6: Temperature Accuracy Histogram, T

= +100°C.

0.4

0.5

Page 8

MCP9808

Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD and

= -40°C to +125°C.

40%

TA= -40°C

= 3.3V

240 units

30%

40%

TA= 125°C

= 3.3V

240 units

30%

20%

Occurrences

10%

0.0

0.1

0.2

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.3

FIGURE 2-7: Temperature Accuracy Histogram, T

400

350

300

250

(µA)

200

150

100

= -40°C.

-40-20 0 20406080100120

Temperature (°C)

FIGURE 2-8: Supply Current vs. Temperature.

0.4

0.5

20%

Occurrences

10%

0.0

0.1

0.2

0.3

-0.5

-0.4

-0.3

-0.2

Temperature Accuracy (°C)

-0.1

0.4

FIGURE 2-10: Temperature Accuracy Histogram, T

1.00

0.50

0.00

-0.50

Temperature Accuracy (°C)

-1.00

= +125°C.

VDD= 2.7V

= 3.3V

= 5.5V

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

∆°C/∆VDD = 0.1°C/V

FIGURE 2-11: Temperature Accuracy vs Supply Voltage.

0.5

2.5

(V)

POR

1.5

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

FIGURE 2-9: Power-on Reset Threshold Voltage vs. Temperature.

1000

0.0625°C

(ms)

CONV

0.125°C

100

0.25°C

0.5°C

-40-20 0 20406080100120

Temperature (°C)

FIGURE 2-12: Temperature Conversion Time vs. Temperature.

Page 9

MCP9808

Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD and

= -40°C to +125°C.

0.4

IOL = 3 mA

(V)

0.3

0.2

0.1

SDA V

Alert V

SDA & Alert Output V

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

FIGURE 2-13: SDA and Alert Output VOL vs. Temperature.

VOL = 0.6V

(mA)

SDA I

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

(ms)

OUT

C Bus t

SMBus/I

-40 -20 0 20 40 60 80 100 120

Temperature (°C)

FIGURE 2-16: SMBus Time-out vs. Temperature.

2.00

1.50

(µA)

1.00

SHDN

0.50

0.00

-40 -20 0 20 40 60 80 100 120

Temperature (°C )

FIGURE 2-14: SDA IOL vs. Temperature.

120%

100%

80%

60%

40%

20%

Thermal Response (%)

-2 0 2 4 6 8 10 12 14 16

MSOP-8 DFN-8

Room to +125°C (Oil bath)

Time (s)

FIGURE 2-15: Package Thermal Response.

FIGURE 2-17: Shutdown Current vs Temperature.

1.0

∆°C/∆VDD, VDD = 3.3V + 150 mV

0.5

0.0

-0.5

No decoupling capacit or

Normalized Temp. Error (°C)

-1.0

100 1,000 10,000 100,000 1,000,000

100 1k 10k 100k 1M

1k 10k 100k 1M100k 1M10k 100k 1M1k 10k 100k 1M

Frequency (Hz)

PP (AC)

TA = 25°C

TA = +25°C

FIGURE 2-18: Power Supply Rejection vs. Frequency.

Page 10

MCP9808

NOTES:

Page 11

3.0 PIN DESCRIPTION

The descriptions of the pins are listed in Table 3-1.

TABLE 3-1: PIN FUNCTION TABLE

DFN MSOP Symbol Pin Function

1 1 SDA Serial Data Line 2 2 SCL Serial Clock Line 3 3 Alert Temperature Alert Output 44 GNDGround 5 5 A2 Slave Address 6 6 A1 Slave Address 7 7 A0 Slave Address 88 V 9 — EP Exposed Thermal Pad (EP); must be connected to GND

Power Pin

MCP9808

3.1 Serial Data Line (SDA)

SDA is a bidirectional input/output pin, used to serially transmit data to/from the host controller. This pin requires a pull-up resistor. (See Section 4.0 “Serial

Communication”.)

3.2 Serial Clock Line (SCL)

The SCL is a clock input pin. All communication and timing is relative to the signal on this pin. The clock is generated by the host or master controller on the bus. (See Section 4.0 “Serial Communication”.)

3.3 Temperature Alert, Open-Drain Output (Alert)

The MCP9808 temperature Alert output pin is an open-drain output. The device outputs a signal when the ambient temperature goes beyond the user-programmed temperature limit. (See Section 5.2.3 “Alert Output

Configuration”).

3.4 Ground Pin (GND)

The GND pin is the system ground pin.

3.5 Address Pins (A0, A1, A2)

These pins are device address input pins. The address pins correspond to the Least Significant

bits (LSbs) of th e ad dre ss bi t s a nd the Mo st Significant bits (MSbs): A6, A5, A4, A3. This is illustrated in

Table 3-2.

TABLE 3-2: MCP9808 ADDRESS BYTE

Device Address Code Slave

Address

A6 A5 A4 A3 A2 A1 A0

(1)

MCP9808 0011x MCP9808

Note 1: User-selectable address is shown by ‘x’.

(2)

1001xxx

A2, A1 and A0 must match the corresponding device pin configuration.

2: Contact factory for this address code.

3.6 Power Pin (VDD)

VDD is the power pin. The operating voltage range, as specified in the DC electrical specification table, is applied on this pin.

3.7 Exposed Thermal Pad (EP)

There is an internal electrical connection between the Exposed Thermal Pad (EP) and the GND pin. The EP may be connected to the syst em gro und on the Pri nted Circuit Board (PCB).

Page 12

MCP9808

NOTES:

Page 13

MCP9808

4.0 SERIAL COMMUNICATION

4.1 2-Wire Standard Mode I2C™ Protocol Compatible Interface

The MCP9808 Serial Clock (SCL) input and the bidirectional Serial Data (SDA) line form a 2-wire bidirectional, Standard mode, I communicati on po rt (re fer t o the Digital Input/Output

Pin Characteristics and Sensor Serial Interface Timing Specifications tables).

The following bus protocol has been defined:

TABLE 4-1: MCP9808 SERIAL BUS

PROTOCOL DESCRIPTIONS

Term Description

Master The device that controls the serial bus,

typically a microcontroller.

Slave The device addressed by the master,

such as the MCP9808. Transmitter Device sending data to the bus. Receiver Device receiving data from the bus. START A unique signal from the master to

initiate serial interface with a slave. STOP A unique signal from the master to

terminate serial interface from a slave. Read/Write A read or write to the MCP9808

registers. ACK A receiver Acknowledges (ACK) the

reception of eac h byte by pol ling the bu s. NAK A receive r Not-Acknowledges (NAK) or

releases the bus to show End-of-Data

(EOD). Busy Communication is not possible

because the bus is in use. Not Busy The bus is in the Idle state; both SDA

and SCL remain high. Data Valid SDA must remain stable before SCL

becomes high in order for a data bit to

be considered valid. During normal

data transfers, SDA only cha nges st a te

while SCL is low.

C compatible

4.1.1 DATA TRANSFER

Data transfers are initiated by a Start condition (START), followed by a 7-bit device address and a read/write bit. An Acknowledge (ACK) from the slave confirms the receptio n of eac h byte . Each a ccess mus t be terminated by a Stop condition (STOP).

Repeated communication is initiated after t This device does not support sequential register

read/write. Each register needs to be addressed using the Register Pointer.

This device supports the receive protocol. The register can be spec ified using the pointer for the initi al read. Each repeated read or receive begins with a Start condition and address byte. The MCP9808 retains the previously selected register. Therefore, it outputs data from the previously spec ified re giste r (repeate d point er specification is not necessary).

B-FREE

4.1.2 MASTER/SLAVE

The bus is controlled by a master device (typically a microcontroller) that controls the bus access and generates the S tart and Stop co nditions. The M CP9808 is a slave device and does not control other devices in the bus. Both master and slave devices can operate as either transmitter or receiver. However, the master device determines which mode is activated.

4.1.3 START/STOP CONDITION

A high-to- low trans ition of t he SDA line (while S CL is high) is the Start condition. All data transfers must be preceded by a Start condition from the master. A low-to-high transition of the SDA line (while SCL is high) signifies a Stop condition.

If a Start or Stop condition is introduced during data transmission, the MCP9808 releases the bus. All data transfers are ended by a Stop condition from the master.

Page 14

MCP9808

4.1.4 ADDRESS BYTE

Following the Start condition, the host must transmit an 8-bit address byte to the MCP9808. The address for the MCP9808 temperature sensor is ‘0011,A2,A1,A0’ in binary, where the A2, A1 and A0 bits are set externally by connecting the corresponding pins to V

‘1’ or GND

‘0’. The 7-bit address, transmitted in the serial bit stream, must match the selected address for the MCP9808 to respond with an ACK. Bit 8 in the address byte is a read/write bit. Setting this bit to ‘1’ commands a read operation, while ‘0’ commands a write operation (see

Figure 4-1).

Address Byte

SCL

SDA

See Table 3-2.

123456789

011A2A1A0

Start

Address

Code

Slave

Address

R/W

MCP9808 Response

A C K

FIGURE 4-1: Device Addressing.

4.1.5 DATA VALID

After the Start condition, each bit of data in the transmission needs to be s ettled for a tim e specified b y t

SU-DATA

before SCL t ogg les from low -to- hig h (s ee t he

Sensor Serial Interface T iming Specifications sect ion).

4.1.6 ACKNOWLEDGE (ACK/NAK)

Each receiving device, when addressed, must generate an ACK bit after the reception of each byte. The master device must generate an extra clock pulse for ACK to be recognized.

The Acknowledging d ev ice pulls down the SDA l in e f or t

SU-DATA

before the low-to-high transition of SCL from the master. SDA also needs to remain pulled down for t

after a high-to-low transition of SCL.

H-DATA

During read, the master must signal an End-of-Data (EOD) to the slave, by not generating an ACK bit (NAK), once the last bit has been clocked out of the slave. In this case, the slave will leave the data line released to enable the master to generate the Stop condition.

4.1.7 TIME-OUT

If the SCL stays low or high for the time specified by t

, the MCP9808 temperature sensor resets the

OUT

serial interface. T his di ct ates th e min imum clock spee d as outlined in the specification.

Page 15

5.0 FUNCTIONAL DESCRIPTION

The MCP9808 temperature sensors consist of a bandgap-type temperature sensor , a Delt a-Sigma Analog-toDigital Converter (ΔΣ ADC), user-programmable

registers and a 2-wire SMBus/I

serial interface. Figure 5-1 shows a block diagram of the register structure.

C protocol compatible

Hysteresis Shutdown Critical Trip Lock Alarm Win. Lock Clear Alert Alert Status

Output Co ntrol Critical Alert Only Alert Polarity Alert Comp/Int

Configuration

MCP9808

Band Gap

Temperature

Sensor

Pointer

Temperature

T T T

Manufactu r er I D

Device ID/Rev Resolution

UPPER LOWER CRITICAL

Alert

Limit Limit

Limit

SMBus/Standard I2C™

Interface

SDA

SCL

ΔΣ

ADC

+0.5°C

+0.25°C

+0.125°C

+0.0625°C

GND

FIGURE 5-1: Functional Block Diagram.

Page 16

MCP9808

5.1 Registers

The MCP9808 has several registers that are user-accessible. These registers include the Temperature register, Configuration register, Temperature Alert Upper Boundary and Lower Boundary Limit registers, Critical Temperature Limit register, Manufacturer Identification reg ister and Device Ide ntification register .

The Te mperature register is read-only, used to access the ambient temperature data. This register is doublebuffered and it is updated every t Alert Upper Boundary and Lower Boundary Limit registers are read/write registers. If the ambient temperature drifts beyond the user-specified limits, the MCP9808 outputs a signal using the Alert pin (refer to

W-0 W-0 W-0 W-0 W-0 W-0 W-0 W-0

— — — — Pointer bits

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

. The T em perature

CONV

Section 5.2.3 “Alert Output Configuration”). In

addition, the Critical Temperature Limit register is used to provide an additional critical temperature limit.

The Configuration register provides access to configure the MCP9808 device’s various features. These registers are described in further detail in the following sections.

The registers are accessed by sending a Register Pointer to the MCP9808, using the serial interface. This is an 8-bit write-only po inter. However, the four Least Significant bit s are used as pointers and all u nused bit s (Register Pointer<7:4>) need to be cleared or set to ‘0’.

each register.

bit 7-4 W: Writable bits

Write ‘0’. Bits 7-4 must alway s be cleare d or wr itten to ‘ 0’. T his d evice ha s add itiona l regi ste rs tha t are re se rved

for test and calibration. If these registers are accessed, the device may not perform according to the specification.

bit 3-0 Pointer bits

0000 = RFU, Reserved for Future Use (Read-Only register) 0001 = Configuration register (CONFIG) 0010 = Alert Temperature Upper Boundary Trip register (T 0011 = Alert Temperature Lower Boundary Trip register (T 0100 = Critical Temperature Trip register (T 0101 = Temperature register (T 0110 = M anufacturer ID register 0111 = Device ID/Revision register 1000 = Resolution register 1xxx = Reserved

Note 1: Some registers contain calibration codes and should not be accessed.

(1)

)

CRIT

)

UPPER LOWER

)

Page 17

MCP9808

TABLE 5-1: BIT ASSIGNMENT SUMMARY FOR ALL REGISTERS

(See Section 5.3 “Summary of Power-on Default” for Power-on Defaults)

Pointer

(Hex)

0x00 MSB 0 0 0 0 0 0 0 0

0x01 MSB 00 000 Hysteresis SHDN

0x02 MSB 0 0 0 SIGN 27°C 26°C 25°C 24°C

0x03 MSB 00 0SIGN 2

0x04 MSB 0 0 0 SIGN 27°C 26°C 25°C 24°C

0x05 MSB T

0x06 MSB 0 0 0 0 0 0 0 0

0x07 MSB 00 000100

0x08 LSB 0 0 0 0 0 0 1 1

MSB/

LSB

LSB 0 0 0 1 1 1 1 1

LSB Crt Loc Win Loc Int Clr Alt Stat Alt Cnt Alt Sel Alt Pol Alt Mod

LSB 23°C 22°C 21°C 20°C 2-1°C 2-2°C 0 0

LSB 2

LSB 23°C 22°C 21°C 20°C 2-1°C 2-2°C 0 0

LSB 2

LSB 0 1 0 1 0 1 0 0

LSB 00 0 00000

76 5 43210

°C 22°C 21°C 20°C 2-1°C 2-2°C 00

≥ T

CRITTA

°C 22°C 21°C 20°C 2-1°C 2-2°C 2

> T

UPPERTA

< T

LOWER

Bit Assignment

°C 26°C 25°C 24°C

SIGN 27°C 26°C 25°C 24°C

°C 2

°C

Page 18

MCP9808

5.1.1 SENSOR CONFIGURATION REGISTER (CONFIG)

The MCP9808 has a 16-bit Configuration register (CONFIG) that allows the user to set various functions for a robust temperature monitoring system. Bits 10 through 0 are used to select the temperature alert output hysteresis, device shutdown or Low-Power mode, temperature bo un da ry an d c ritical temperatu re lock, and temperature Alert output enable/disable. In addition, Alert output condition (output set for T temperature boundary or T

only), Alert output status

CRIT

and Alert outp ut pol arity and mode (C omparator Outp ut or Interrupt Output mode) are user-configurable.

UPPER

and T

LOWER

user-specified temperature boundary (see

Section 5.2.2 “Temperature Hysteresis (T

HYST

The Continuous Conversion or Shutdown mode is selected using bit 8. In Shutdown mode, the band gap temperature sensor circuit stops converting temperature and the Ambient Temperature register

) holds the previous temperature data (see

Section 5.2.1 “Shutdown Mode”). Bits 7 and 6 are

used to lock the user-specified boundaries T T

LOWER

and T

to prevent an accidental rewrite.

CRIT

UPPER

The Lock bits a re cle ared by reset ting t he powe r. Bits 5 through 0 are used to configure the temperature Alert output pin. All functions are described in Register 5-2 (see Section 5.2.3 “Alert Output Configuration”).

The temperature hysteresis bits 10 and 9 can be used to prevent output chatter when the ambient temperature gradually changes beyond the

U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0

— — — — —T

HYST

SHDN

bit 15 bit 8

R/W-0 R/W-0 R/W-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0

Crit. Lock Win. Lock Int. Clear Alert Stat. Alert Cnt. Alert Sel. Alert Pol. Alert Mod.

bit 7 bit 0

)”.

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15-11 Unimplemented: Read as ‘0’ bit 10-9 T

HYST

: T

UPPER

and T

Limit Hysteresis bits

LOWER

00 = 0°C (power-up default) 01 =+1.5°C 10 =+3.0°C 11 =+6.0°C

(Refer to Section 5.2.3 “Alert Output Configuration”.) This bit can not be altered when either of the Lock bits are set (bit 6 and bit 7). This bit can b e programmed in Shutdown mode.

bit 8 SHDN: Shutdown Mode bit

0 = Continuous conversion (power-up default) 1 = Shutdown (Low-Power mode)

In shutdown, all power-consumin g activitie s are disab led, though all registers can be writ ten to or read. This bit cannot be set to ‘1’ when either of the Lock bits is set (bit 6 and bit 7). However, it can be

cleared to ‘0’ for continuous conversion while locked (refer to Section 5.2.1 “Shutdown Mode”).

Page 19

MCP9808

bit 7 Crit. Lock: T

0 = Unlocked. T 1 = Locked. T

Lock bit

CRIT

When enabled, this bit remains set to ‘1’ or locked until cleared by an internal Reset (Section 5.3

“Summary of Power-on Default”).

This bit can be programmed in Shutdown mode.

bit 6 Win. Lock: T

0 = Unlocked; T 1 = Locked; T

UPPER

and T

LOWER

When enabled, this bit remains set to ‘1’ or locked until cleared by a Power-on Reset (Section 5.3

“Summary of Power-on Default”).

This bit can be programmed in Shutdown mode.

bit 5 Int. Clear: Interrupt Clear bit

0 = No effect (power-up default) 1 = Clear interrupt output; when read, this bit returns to ‘0’

This bit can not be se t to ‘1’ i n Shutdo wn mode, but it can be c leared af ter the dev ice enters Shu tdown mode.

bit 4 Alert Stat.: Alert Output Status bit

0 = Alert output is not asserted by the device (power-up default) 1 = Alert output is asserted as a comparator/Interrupt or critical temperature output

This bit can not be set to ‘1’ or cleared to ‘0’ in Shutdown mo de. However , if the Alert outp ut i s co nfig ured as Interrupt mode, and if th e host con troller clea rs to ‘0’, t he interrupt, using b it 5 while the d evice is in Shutdown mode, then this bit will also be cleared ‘0’.

bit 3 Alert Cnt.: Alert Output Control bit

0 = Disabled (power-up default) 1 = Enabled

This bit can not be altered when either of the Lock bits are set (bit 6 and bit 7). This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.

bit 2 Alert Sel.: Alert Output Select bit

0 = Alert output for T 1 =T

> T

CRIT

only (T

UPPER

, T

LOWER

and T When the Alarm Window Lock bit is set, this bit cannot be altered until unlocked (bit 6). This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.

bit 1 Alert Pol.: Alert Output Polarity bit

0 = Active-low (power-up default; pull-up resistor required) 1 = A ctive-high

This bit cannot be altered when either of the Lock bits are set (bit 6 and bit 7). This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.

bit 0 Alert Mod.: Alert Output Mode bit

0 = Comparator output (power-up default) 1 = Interrupt output

This bit cannot be altered when either of the Lock bits are set (bit 6 and bit 7). This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.

Window Lock bit

registers can be written (power-u p default)

registers can not be written

and T

LOWER

(power-up default)

CRIT

temperature boundaries are disab led )

Page 20

MCP9808

Writing to the CONFIG Register to Enable the Event Output Pin <0000 0000 0000 1000>b:

SCL

12345678 12345678

SDA

0011

A 2A1A0

Address Byte

A C

0000

001

Configuration Pointer

A C K

MCP9808 MCP9808

12345678 12345678

00000

MSB Data

000 00001

C K

LSB Data

MCP9808

000

A C K

MCP9808

Note: This is an example routine (see Appendix A: “Source Code”).

i2c_start(); // send START command i2c_write(Addres sByte & 0xFE); //WRITE Com man d (see Section 4.1.4 “Address Byte”)

//also, make sure bit 0 is cleared ‘0’ i2c_write(0x01); // Write CONFIG Register i2c_write(0x00); // Write data i2c_write(0x08); // Write data i2c_stop(); // send STOP command

FIGURE 5-2: Timing Diagram for Writing to the Configuration Register (see Section 4.0 “Serial

Communication”).

Page 21

Reading the CONFIG Register:

12345678 12345678

SCL

SDA

0011

A 2A1A0

A C

0000

001

MCP9808

Note: It is not necessary to

select the Register

A C K

Pointer if it was set from the previous read/write.

Address Byte

Configuration Pointer

MCP9808 MCP9808

12345678 12345678 12345678

SCL

SDA

0011

S P

2A1A0

Address Byte LSB Data

A C

00000

000 00001

MSB Data

MCP9808

A C K

000

Master Master

Note: This is an example routine (see Appendix A: “Source Code”).

i2c_start(); // send START command i2c_ write(Add r essB y te & 0 xFE); //WRITE Command (see Section 4.1.4 “Address Byte”)

//also, make sure bit 0 is cleared ‘0’ i2c_write(0x01); // Write CONFIG Register i2c_start(); // send Repeat START command i2c_ write(Add r essB y te | 0 x01); //READ Command

//also, make sure bit 0 is set ‘1’ UpperByte = i2c_read(ACK); // READ 8 bits

//and Send ACK bit LowerByte = i2c_read(NAK); // READ 8 bits

//and Send NAK bit i2c_stop(); // send STOP command

N A K

FIGURE 5-3: Timing Diagram for Reading from the Configuration Register (see Section 4.0 “Serial

Communication”).

Page 22

MCP9808

5.1.2 UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTERS (T

UPPER/TLOWER/TCRIT

The MCP9808 has a 16-bit read/write Alert Output Temperat ure Uppe r Boundary register (T Lower Bounda ry regi ster (T Boundary register (T

LOWER

) that contain 11-bit data in

CRIT

two’s complement format (0.25°C). This data repres ents

UPPER/TLOWER/TCRIT

)

), a 16-bit

UPPER

) and a 16-bit Critical

UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTER

(→ ADDRESS ‘0000 0010’b/‘0000 0011’b/‘0000 0100’b)

the maximum and minimum temperature boundary or temperature window that can be used to monitor ambient temperature. If this feature is enabled (Section 5.1.1 “Sensor Configuration Register

(CONFIG)”) and the ambient temperature exceeds the

specified boundary or window , the MCP9808 ass erts an Alert output. (Refer to Section 5.2.3 “Alert Output

Configuration”).

(1)

U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— — —Sign2

°C 26°C 25°C 24°C

bit 15 bit 8

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0

°C 22°C 21°C 20°C 2-1°C 2-2°C — —

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15-13 Unimplemented: Read as ‘0’ bit 12 Sign: Sign bit

≥ 0°C

0 =T

< 0°C

1 =T

bit 11-2 T

UPPER/TLOWER/TCRIT

: Temperature Boundary bits

Temperature boundary trip data in two’s complement format.

bit 1-0 Unimplemented: Read as ‘0’ Note 1: This table shows two 16-bit registers for T

‘0000 0011b’ and ‘0000 0100b’, respectively.

UPPER

, T

LOWER

and T

, located at ‘0000 0010b’,

CRIT

Page 23

MCP9808

Writing +90°C to the T

12345678 12345678

SCL

0011

SDA

Address Byte

UPPER

A 2A1A0

A C

0000

UPPER

010

Pointer

A C K

MCP9808 MCP9808

12345678 12345678

00000

MSB Data

101 10100

C K

LSB Data

MCP9808 MCP9808

000

A C

Reading from the T

12345678 12345678

UPPER

SCL

SDA

0011

2A1A0

Address Byte

A C

0000

UPPER

Pointer

010

MCP9808

12345678 12345678 12345678

A C K

MCP9808

SCL

SDA

0011

S P

2A1A0

Address Byte LSB Data

A C

00000

101 10100

MSB Data

MCP9808

A C K

Master Master

FIGURE 5-4: Timing Diagram for Writing and Reading from the T

“Serial Communication”).

Note: It is not necessary to

select the Register Pointer if it was set from the previous read/write.

000

UPPER

A K

Page 24

MCP9808

5.1.3 AMBIENT TEMPERATURE REGISTER (T

The MCP9808 uses a band gap temperature sensor circuit to output anal og voltage proportiona l to absolu te temperature. An intern al ΔΣ ADC is use d to convert th e analog voltage to a digital word. The digital word is loaded to a 16-bit read-only Ambient Temperature register two’s complemen t format.

(TA) that contains 13-bit temperature data in

)

In addition, the T to reflect the Alert pin state. This allows the user to identify the cause of the Alert output trigger (see

Section 5.2.3 “Alert Output Configuration”); bit 15 is

set to ‘1’ if T set to ‘1’ if T

is less than T

‘1’ if T

The T

conditions are described in Register 5-4.

is greater than or eq ua l to T

is greater than T

LOWER

and bit 13 is set to

UPPER

CRIT

, bit 14 is

The TA register bits (TA<12:0>) are double-buffered. Therefore, the user can ac cess the register , while in the background, the MCP9808 performs an Analog-toDigital conversion. The temperature data from the ΔΣ ADC is loaded in parallel to the T

CONV

refresh rate.

: AMBIENT TEMPERATURE REGISTER (→ ADDRESS ‘0000 0101’b)

(1)

R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0

vs. T

CRIT

(1)

TA vs. T

UPPER

(1)

TA vs. T

LOWER

(1)

SIGN 27 °C 26 °C 25 °C 24 °C

bit 15 bit 8

R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0

°C 22 °C 21 °C 20 °C 2

-1

°C 2

-2

°C

(2)

-3

(2)

°C

-4

(2)

°C

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15 T

bit 14 T

bit 13 T

vs. T

0 =TA < T 1 =TA ≥ T

vs. T

0 =T

≤ T

1 =TA > T

vs. T

0 =TA ≥ T 1 =TA < T

bit

CRIT

CRIT CRIT

UPPER

UPPER UPPER

LOWER

LOWER LOWER

(1)

bit

(1)

bit 12 SIGN bit

≥ 0°C

0 =T

< 0°C

1 =T

bit 11-0 T

: Ambient Temperature bits

(2)

12-bit ambient temperature data in two’s complement format.

Note 1: Bits 15, 14 and 13 are not affected by the status of the Alert Output Configuration (CONFIG<5:0> bits,

2: Bits 2, 1 and 0 may remain clear at ‘0’ dependi ng on the status of the Resolutio n regis ter (Register 5-7).

The power-up default is 0.25°C/bit; bits 1 and 0 remain clear ‘0’.

Page 25

MCP9808

5.1.3.1 TA Bits to Temperature Conversion

To convert the TA bits to decimal temperature, the upper three boundary bits (T

<15:13>) must be

masked out. Then, determine the SIGN bit (bit 12) to check positive or negative temperature, shift the bits accordingly, and combine the upper and lowe r b yte s of the 16-bit register. The upper byte contains data for temperatures greater than +32°C while the lower byte contains data fo r t e mp era t ure l es s t h an +3 2° C, i n cl uding fractional data. When combining the upper and lower bytes, the upper byte must be right-shifted by 4 bits (or multiply by 2 shifted by 4 bi ts (o r m ul t ip l y b y 2

) and the lower byte must be lef t-

-4

). Adding the results of the shifted values provides the temperature data in decimal format (see Equation 5-1).

The temperature bits are in two’s compliment format, therefore, positiv e te mpe rature data and ne gat ive tem perature data are computed differently. Equation 5-1 shows the temperature computation. The example

EXAMPLE 5-1: SAMPLE INSTRUCTION CODE

This example routine assumes the variables and I (see Appendix A: “Source Code”):

i2c_start(); // send START command i2c_write (AddressByte & 0xFE); //WRITE Command (see Section 4.1.4 “Address Byte”)

//also, make sure bit 0 is cleared ‘0’ i2c_write(0x05); // Write T i2c_start(); //Repeat START i2c_write(AddressByte | 0x01); // READ Command (see Section 4.1.4 “Address Byte”)

//also, make sure bit 0 is Set ‘1’ UpperByte = i2c_read(ACK); // READ 8 bits

//and Send ACK bit LowerByte = i2c_read(NAK); // READ 8 bits

//and Send NAK bit i2c_stop(); // send STOP command

//Convert the temperature data

//First Check flag bits if ((UpperByte & 0x80) == 0x80){ //T } if ((UpperByte & 0x40) == 0x40){ //T } if ((UpperByte & 0x20) == 0x20){ //T } UpperByte = UpperByte & 0x1F; //Clear flag bits if ((UpperByte & 0x10) == 0x10){ //T

UpperByte = UpperByte & 0x0F; //Clear SIGN

Temperature = 256 - (UpperByte x 16 + LowerByte / 16);

}else //T

Temperature = (UpperByte x 16 + LowerByte / 16);

//Temperature = Ambient Temperature (°C)

instruction code, outlined in Example 5-1, shows the communicat ion f l ow; al so see Figure 5-5 for the timing diagram.

EQUATION 5-1: BYTES TO

TEMPERATURE CONVERSION

Temperature T

Temperature < 0°C

Where:

UpperByte = TA bit 15 to bit 8 LowerByte = T

C™ communication subroutines are predefined

³ T

CRIT

> T

UPPER

< T

LOWER

< 0°C

³ 0°C

≥ 0°C

UpperByte 24LowerByte 2

()=

()–=

256 UpperByte 24LowerByte 2

TA= Ambient Temperature (°C)

bit 7 to bit 0

4–

Page 26

MCP9808

12345678 12345678

SCL

0011

SDA

A 2A1A0

A C

0000

101

Note: It is not necessary to

select the Register

A C K

Pointer if it was set from the previous read/write.

Address Byte

TA Pointer

MCP9808 MCP9808

12345678 12345678 12345678

SCL

SDA

0011

S P

A 2A1A0

Address Byte LSB Data

A C

00000

001 10010

MSB Data

MCP9808

A C K

Master

100

Master

FIGURE 5-5: Timing Diagram for Reading +25.25°C Temperature from the TA Register (see Section 4.0 “Serial Communication”).

N A K

Page 27

MCP9808

5.1.4 MANUFACTURER ID REGISTER

This register is used to ide nti fy the manufacturer of the device in order to perform manufacturer-specific operation. The Manufacturer ID for the MCP9808 is 0x0054 (hexadecimal).

R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0

Manufac turer ID

bit 15 bit 8

R-0 R-1 R-0 R-1 R-0 R-1 R-0 R-0

Manufac turer ID

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15-0 Device Manufacturer Identification bits

12345678 12345678

SCL

SDA

0011

A 2A1A0

Address Byte

A C

0000

Manufacturer ID Point er

MCP9808 MCP9808

12345678 12345678 12345678

SCL

SDA

0011

S P

2A1A0

Address Byte LSB Data

A C

00000

MSB Data

MCP9808

Note: It is not necessary to

110

000 01010

C K

A C K

Master Master

select the Register Pointer if it was set from the previous read/write.

100

N A K

FIGURE 5-6: Timing Diagram for Reading the Manufacturer ID Register (see Section 4.0 “Serial

Communication”).

Page 28

MCP9808

5.1.5 DEVICE ID AND REVISION REGISTER

The upper byte of this register is used to specify the device identification and the lower byte is used to specify the device revision. The Device ID for the MCP9808 is 0x04 (hex).

The revision begins with 0x 00 (hex) for the first release, with the number being inc remented as revised v ersions are released.

R-0 R-0 R-0 R-0 R-0 R-1 R-0 R-0

Device ID

bit 15 bit 8

R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0

Device Revision

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 15-8 Device ID: Bit 15 to bit 8 are used for device ID bit 7-0 Device Revision: Bit 7 to bit 0 are used for device revision

12345678 12345678

SCL

SDA

0011

A 2A1A0

Address Byte

A C

0000

Device ID Pointer

111

MCP9808 MCP9808

12345678 12345678 12345678

SCL

SDA

0011

S P

A 2A1A0

Address Byte LSB Data

A C

00000

MCP9808

100

MSB Data

Master Master

Note: It is not necessary to

A C K

A C

00000

select the Register Pointer if it was set from the previous read/write.

000

A K

FIGURE 5-7: Timing Diagram for Reading Device ID and Device Revision Register (see

Section 4.0 “Serial Communication”).

Page 29

MCP9808

5.1.6 RESOLUTION REGISTER

This register allows the user to change the sensor resolution (see Section 5.2.4 “Temperature

Resolution”). The POR default resolution is

+0.0625°C. The selected resolution is also reflected in the Capability register (see Register 5-2).

U-0 U-0 U-0 U-0 U-0 U-0 R/W-1 R/W-1

— — — — — — Resolution

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘ 1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-2 Unimplemented: Read as ‘0’ bit 1-0 Resolution bits

00 = +0.5°C (t 01 = +0.25°C (t 10 = +0.125°C (t 11 = +0.0625°C (power-up default, t

= 30 ms typical)

CONV

= 65 ms typical)

CONV

= 130 ms typical)

CONV

= 250 ms typical)

CONV

12345678 12345678

12345678

SCL

SDA

0011

A 2A1A0

Address Byte

A C

00001

000 00000

MCP9808 MCP9808

A C K

011

A C

DataResolution Pointer

MCP9808

FIGURE 5-8: Timing Diagram for Changing TA Resolution to +0.0625°C <0000 0011>b (see

Section 4.0 “Serial Communication”).

Page 30

MCP9808

5.2 SENSOR FEATURE DESCRIPTION

5.2.1 SHUTDOWN MODE

Shutdown mode disables all power consuming activities (including temperature sampling operations) while leaving the serial interface active. This mode is selected by setting bit 8 of CONFIG to ‘1’. In this mode, the device consumes I until bit 8 is cleared to ‘0’ to enable Continuous Conversion mode or until power is recycled.

The Shutdown bit (bit 8) cannot be set to ‘1’ while the CONFIG<7:6> bits (Lock bi ts) are set to ‘1’. However, it can be cleared to ‘0’ or returned to Continuous Conversion mode while locked.

In Shutdown mode, all registe rs can be read or writte n. However, the serial bus activity increases the shutdown current. In addition, if the device is in shutdown while the Alert pin is asserted, t he device will ret ain the ac tive state during shutdown. This increases the shutdown current due to the additional Alert output current.

5.2.2 TEMPERATURE HYSTERESIS (T

A hysteresis of 0°C, +1.5°C, +3°C or +6°C can be selected for the T boundaries, using bits 10 and 9 of CONFIG. The hysteresis applies for decreasi ng temperature only (hot to cold) or as temperature drifts below the specified limit.

The Hysteresis bits can not be changed if either of the Lock bits (CONFIG<7:6) are se t to ‘1’.

The T

UPPER

are described graphically in Figure 5-10.

, T

HYST

UPPER

LOWER

)

5.2.3 ALERT OUTPUT CONFIGURATION

The Alert output can be enabled by using bit 3 of the CONFIG register (Alert Output Control bit) and can be configured as either a comparator output or as an Interrupt Output mode using bit 0 of CONFIG (Alert Output Mode bi t). T he pol ari ty can also be spe ci fied as active-high or active-low using bit 1 of CONFIG (Alert Polarity bit). This is an open-drain output and requires a pull-up r esistor.

When the ambient temperature increases above the critical temperature limit, the Alert output is forced to a comparator output (regardless of CONFIG<0>). When the temperature drifts below the critical temperature limit minus hysteresis, the Alert output automatically returns to the state specified by CONFIG<0> bit.

. It remains in this mode

SHDN

, T

and T

LOWER

boundary conditions

CRIT

temperate

CRIT

MCP9808

Alert Output

FIGURE 5-9: Active-Low Alert Output Configuration.

The status of the Alert output can be read using CONFIG<4> (Alert Output Status bit). This bit can not be set to ‘1’ in Shutdown mode.

Bits 7 and 6 of the CONFIG register c an be used to lock the T

UPPER

, T

LOWER

and T

registers. These bits

CRIT

prevent false triggers at the Alert output due to an accidental rewrite to these registers.

The Alert output can also be used as a critical temperature output using bit 2 of CON FIG (Alert Output Selec t bit). When this feature is selected, the Alert output becomes a comparator output. In this mode, the interrupt output configuration (Alert Output Mode bit, CONFIG<0>) is ignored.

5.2.3.1 Comparator Mode

Comparator mode is selected using bit 0 of CONFIG. In this mode, the Alert output is asserted as active-high or active-low, using bit 1 of CONFIG. Figure 5-10 shows the conditions that toggle the Alert output.

If the device enters Shutdown mode with asserted Alert output, the o utput remains as serted during S hutdown mode. The device must be operating in Continuous Conversion mode for t T

LOWER

and T

boundary conditions need to be

CRIT

satisfied in order for the Alert output to deassert. Comparator mode is useful for thermostat type

applications, such as turning on a cooling fan or triggering a system shutdown when the temperature exceeds a safe operating range.

. The TA vs. T

CONV

UPPER

Page 31

MCP9808

5.2.3.2 Interrupt Mode

In Interrupt mode, the Alert output is asserted as activehigh or active-low (depending on the polarity configuration) when T and T bit 5 (Interrupt Clear bit) of CONFIG. Shutting down the device will not res et or deassert the Aler t output. This mode can not be selected when the Alert output is used as a critical temperature output only, using bit 2 of CONFIG.

This mode is designed for interrupt driven microcontroller-based systems. The microcontroller receiving the interrupt will have to Acknowledge the interrupt by setting bit 5 of the CONFIG register from the MCP9808.

limits. The output is de asserted by setting

LOWER

drifts above or below T

UPPER

5.2.4 TEMPERATURE RESOLUTION

The MCP9808 is capable of providing temperature data with +0.5°C to +0.0625°C resolution. The resolution can be selected using the Resolution register (Register 5-7). It is located at address, ‘00001000’b, and it provides measurement flexibility. A +0.0625°C resolution is set as a POR default by the factory.

TABLE 5-2: TEMPERATURE

CONVERSION TIME

Resolution

+0.5°C 30 33

+0.25°C 65 15

+0.125°C 130 7

+0.0625°C

(Power-up Default)

CONV

(ms)

250 4

Samples/sec

(typical)

Page 32

MCP9808

CRIT

UPPER

– T

HYST

CRIT

– T

UPPER

HYST

– T

HYST

LOWER

Alert Output

(Active-Low)

Alert Output

(Active-High)

Comparator

Interrupt

S/w Int. Clear

Critical Only

Comparator

Interrupt

S/w Int. Clear

LOWER

– T

HYST

LOWER

– T

HYST

Critical Only

123457

Notes

1 T 2 T 3 T 4 T 5 T 6 When T

Alert Output Boundary

Conditions

≥ T

LOWER A A

A A

< T

> T

≤ T ≥ T

LOWER

UPPER

UPPER CRIT

≥ T

– T

HYST

– T

HYST

, the Alert output is forced t o Comp arator mode and the CONFIG<0> (Alert Output

CRIT

Mode bit) is ignored until T

< T

CRIT

(bit 5 of CONFIG), as shown in the diagram at Note 6, then Alert will remain asserted at Note 7 until the interrupt is cleared by the controller.

7 T

< T

CRIT

– T

HYST

FIGURE 5-10: Alert Output Conditions.

1342Notes: 6

Comparator Interrupt Critical T

Bits

Alert Output (Active-Low/High) 15 14 13

High/Low Low/High High/Low 000 Low/High Low/High High/Low 001 Low/High Low/High High/Low 010 High/Low Low/High High/Low 000 Low/High Low/High Low/High 110

– T

. In the Interrupt mode, if the interrupt is not cleared

HYST

Low/High High/Low High/Low 010

Page 33

5.3 Summary of Power-on Default

The MCP9808 has an internal Power-on Reset (POR) circuit. If the pow er supply volt age , V the V the power-on default settings.

Table 5-3 shows the power-on default summary for the

Temperature Sensor registers.

threshold, the devic e resets th e registe rs to

POR

TABLE 5-3: POWER-ON RESET DEFAULTS

Registers

Address

(Hexadecimal)

0x01 CONFIG 0x0000 Comparator Mode

0x02 T 0x03 T 0x04 T 0x05 T 0x06 Manufacturer ID 0x0054 0x0054 (hex) 0x07 Device ID/Device Revision 0x0400 0x0400 (hex) 0x08 Resolution 0x03 0x03 (hex)

UPPER LOWER CRIT

, glitches below

Default Register

Data (Hexadecimal)

0x0000 0°C 0x0000 0°C 0x0000 0°C 0x0000 0°C

MCP9808

Power-Up Default

Active-Low Output Alert and Critical Output Output Disabled Alert Not Asserted Interrupt Cleared Alert Limits Unlocked Critical Limit Unlocked Continuous Conversion 0°C Hysteresis

Page 34

MCP9808

NOTES:

Page 35

MCP9808

6.0 APPLICATIONS INFORMATION

6.1 Layout Considerations

The MCP9808 does not require any additional components besides the master controller in order to measure temperature. However, it is recommended that a decou pling capac itor of 0 .1 µF to 1 µF be used between the V ceramic capaci t or is re co mm en ded . It i s nece s sa ry f o r the capacitor to be located as close as possible to the power and ground pins of the device in order to provide effective noise protec tion.

In addition , good PCB layout is key for be tter ther mal conduction from the PCB temperature to the sensor die. For good temperature sensitivity, add a ground layer under the device pins, as shown in Figure 6-1.

6.2 Thermal Considerations

A potential for self-heating errors can exist if the MCP9808 SDA, SCL and Event lines are heavily loaded with pull-ups (high current). Typically, the self-heating error is n egl igi bl e because of the relativ el y small current co nsu mp tion of the MCP9808. A te mper-

and GND pins. A high-frequency

ature accuracy error of approximately +0.5°C could result from self-heating if the communication pins sink/source the maximum curre nt speci fied.

For example, if the event output is loade d to ma xim um

, Equation 6-1 can be used to determine the effect

of self-heating.

EQUATION 6-1: EFFECT OF

SELF-HEATING

()=

JAVDDIDD

Where:

OL_Alert, SDA

At room temperature (TA=+25°C) with maximum

= 500 µA and VDD= 3.6V, the self-heating due to

power diss ipat io n T and +0.5°C for the TSSOP-8 package.

•

=TJ – T

•

OL_AlertIOL_Alert

TJ= Junction Temperature

TA= Ambient Temperature

= Package Thermal Resistance

= Alert and SDA Output V

(0.4 V

max

)

= Alert and SDA Output I

(3 mA

is +0.2°C for the DFN-8 package

max

)

•

OL_SDAIOL_SDA

SDA

SCL

EP9

Alert

GND

FIGURE 6-1: DFN Package Layout (Top View).

Page 36

MCP9808

NOTES:

Page 37

7.0 PACKAGING INFORMATION

7.1 Package Marking Information

8-Lead DFN (2x3x0.9 mm) Example

8-Lead MSOP (3 x3 mm) Example

MCP9808

ALP

141

9808E

141256

Legend: XX...X Customer-specific information

Y Year code (last digit of calendar year) YY Year code (last 2 digits of calendar year) WW Week code (week of January 1 is week ‘01’) NNN Alphanumeric traceability code

Pb-free JEDEC designator for Matte Tin (Sn) * This package is Pb-free. The Pb-free JEDEC designator ( )

can be found on the outer packaging for this package.

Note: In the event the full Microc hip p art numb er cann ot be mark ed on one line, it wil l

be carried over to the next line, thus limiting the number of available characters for customer-specific information.

Page 38

MCP9808

 !""#$%&

' )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW

KWWSZZZPLFURFKLSFRPSDFNDJLQJ

EXPOSED PAD

NOTE 1

TOP VIEW

A3 A1

1XPEHURI3LQV 1 

3LWFK H %6&

2YHUDOO+HLJKW $   

6WDQGRII $   

&RQWDFW7KLFNQHVV $ 5()

2YHUDOO/HQJWK ' %6&

2YHUDOO:LGWK ( %6&

([SRVHG3DG/HQJWK '  ± 

([SRVHG3DG:LGWK (  ± 

&RQWDFW:LGWK E   

&RQWDFW/HQJWK /   

&RQWDFWWR([SRVHG3DG .  ± ±

'

 3LQYLVXDOLQGH[IHDWXUHPD\YDU\EXWPXVWEHORFDWHGZLWKLQWKHKDWFKHGDUHD  3DFNDJHPD\KDYHRQHRUPRUHH[SRVHGWLHEDUVDWHQGV  3DFNDJHLVVDZVLQJXODWHG  'LPHQVLRQLQJDQGWROHUDQFLQJSHU$60(<0

%6& %DVLF'LPHQVLRQ7KHRUHWLFDOO\H[DFWYDOXHVKRZQZLWKRXWWROHUDQFHV 5() 5HIHUHQFH'LPHQVLRQXVXDOO\ZLWKRXWWROHUDQFHIRULQIRUPDWLRQSXUSRVHVRQO\

NOTE 2

8QLWV 0,//,0(7(56

'LPHQVLRQ/LPLWV 0,1 120 0$;

BOTTOM VIEW

0LFURFKLS 7HFKQRORJ\ 'UDZLQJ &&

NOTE 1

Page 39

MCP9808

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

Page 40

MCP9808

()"*+)%)*&

' )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW

KWWSZZZPLFURFKLSFRPSDFNDJLQJ

NOTE 1

1XPEHURI3LQV 1 

3LWFK H %6&

2YHUDOO+HLJKW $ ± ± 

0ROGHG3DFNDJH7KLFNQHVV $   

6WDQGRII $  ± 

2YHUDOO:LGWK ( %6&

0ROGHG3DFNDJH:LGWK ( %6&

2YHUDOO/HQJWK ' %6&

)RRW/HQJWK /   

)RRWSULQW / 5()

)RRW$QJOH   ± 

/HDG7KLFNQHVV F  ± 

/HDG:LGWK E  ± 

'

 3LQYLVXDOLQGH[IHDWXUHPD\YDU\EXWPXVWEHORFDWHGZLWKLQWKHKDWFKHGDUHD  'LPHQVLRQV'DQG(GRQRWLQFOXGHPROGIODVKRUSURWUXVLRQV0ROGIODVKRUSURWUXVLRQVVKDOOQRWH[FHHGPPSHUVLGH  'LPHQVLRQLQJDQGWROHUDQFLQJSHU$60(<0

'LPHQVLRQ/LPLWV 0,1 120 0$;

8QLWV 0,//,0(7(56

0LFURFKLS 7HFKQRORJ\ 'UDZLQJ &%

Page 41

MCP9808

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

Page 42

MCP9808

NOTES:

Page 43

MCP9808

Software License Agreement

The software supplied herewith by Microchip Technology Incorporated (the “Company”) is intended and supplied to you, the Company’s customer, for use solely and exclusively with products manufactured by the Company.

The software is owned by the Company and/or its supplier, and is protected under applicable copyright laws. All rights are reserved. Any use in violation of the foregoing restrictions may subject the user to criminal sanctions under applicable laws, as well as to civil liability for the breach of the terms and conditions of this license.

THIS SOFTWARE IS PROVIDED IN AN “AS IS” CONDITION. NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.

APPENDIX A: SOURCE CODE

/******************************************************************** FileName: I2C.c Processor: PIC18 Microcontrollers Complier: Microchip C18 (for PIC18) or C30 (for PIC24) Company: Micr oc hi p Te ch no lo gy , In c.

#include <p18cxxx.h> // This code is developed for PIC18F2550 //It can be modified to be used with any PICmicro with MSSP module

/** PRIVATE PROTOTYPES *********************************************/ void i2c_init(void); void i2c_start(void); void i2c_repStart(void); void i2c_stop(void); unsigned char i2c_write( unsigned char i2cWriteData ); unsigned char i2 c_ re ad ( un si gn ed cha r ac k );

/******************************************************************** * Function Name: i2c_init * Return Value: void * Parameters: Enable SSP * Description: This fun ct io n se ts up th e SS P1 mod ul e on a * PIC18CXXX device for use wit h a Mi cr oc hi p I2 C ********************************************************************/ void i2c_init(void) {

TRISBbits.TRISB0 = 1; // Digital Output (make it input only when reading data) TRISBbits.TRISB1 = 1; // Digital Output

SSPCON1 = 0x28; // enable I2C Master mode SSPCON2 = 0x00; // clear control bits SSPSTAT = 0x80; // disable slew rate control ; di sa bl e SM Bu s

SSPADD = 19; // set baud rate to 100 kH z (F os c = 48 MHz )

PIR1bits.SSPIF = 0; PIR2bits.BCLIF = 0;

SSPCON2bits.SEN = 0; // force idle cond it io n

}

Page 44

MCP9808

/******************************************************************** * Function Name: i2c_start * Return Value: void * Parameters: void * Description: Send I2C Start Command ********************************************************************/ void i2c_start(void) {

PIR1bits.SSPIF = 0; //clear flag while (SSPSTATbits .B F ); // wait for idl e co nd it io n

SSPCON2bits.SEN = 1; // initiate ST AR T co nd it io n

while (!PIR1bits.S SP IF ) ; // wai t fo r a fl ag to be set PIR1bits.SSPIF = 0; // clear flag }

/******************************************************************** * Function Name: i2c_repStart * Return Value: void * Parameters: void * Description: Resend I2C Start Command * ********************************************************************/ void i2c_repStart(void) {

PIR1bits.SSPIF = 0; // clear flag while ( SSPSTATbits. BF ) ; // wai t fo r id le con di ti on

SSPCON2bits.RSEN = 1; // initiate Repeated START condition

while (!PIR1bits.S SP IF ) ; // wa it for a fla g to be se t PIR1bits.SSPIF = 0; // clear flag

}

/******************************************************************** * Function Name: i2c_stop * Return Value: void * Parameters: void * Description: Send I2C Stop command * ********************************************************************/ void i2c_stop(void) {

PIR1bits.SSPIF = 0; // clear flag while ( SSPSTATbits. BF ) ; // wai t fo r id le con di ti on

SSPCON2bits.PEN = 1; // Initiate STO P co nd it io n

while (!PIR1bits.S SP IF ) ; // wa it for a fla g to be se t PIR1bits.SSPIF = 0; // clear flag

}

Page 45

MCP9808

/******************************************************************** * Function Name: i2c_write * Return Value: Status byte fo r WC OL det ec ti on . * Parameters: Single data byte for I2C 2 bu s. * Description: This routine writes a single byte to the * I2C2 bus. ********************************************************************/ unsigned char i2c_write( unsigned char i2cWriteData ) {

PIR1bits.SSPIF = 0; // clear interrupt while ( SSPSTATbits. BF ) ; // wai t fo r id le con di ti on

SSPBUF = i2cWriteData; // Load SSPBUF with i2cWriteData (the value to be transmitted)

while (!PIR1bits.S SP IF ) ; // wa it for a fla g to be se t PIR1bits.SSPIF = 0; // clear flag

return ( !SSPCON2bi ts .A CK ST AT ); // func ti on re tu rns '1 ' i f t ra ns mi ss io n i s a ck no wl ed ge d

}

/******************************************************************** * Function Name: i2c_read * Return Value: contents of SS P2 BU F re gi st er * Parameters: ack = 1 and nak = 0 * Description: Read a byte from I2C bus and ACK/NAK device ********************************************************************/ unsigned char i2 c_ re ad ( un si gn ed cha r ac k ) {

unsigned char i2cReadData;

PIR1bits.SSPIF = 0;// clear interrupt

while ( SSPSTATbits.BF ) ; // wait for idle condition SSPCON2bits.RCEN = 1; // enable receive mode

while (!PIR1bits.S SP IF ) ; // wai t fo r a fl ag to be set PIR1bits.SSPIF = 0;// clear flag

i2cReadData = SSPBUF ; // Read SSPB UF and put it in i2c Re ad Da ta

if ( ack ) { // if ack=1 SSPCON2bits.ACKDT = 0; // then tr an sm it an Ac kn ow le dg e } else { SSPCON2bits.ACKDT = 1; // other wi se tra ns mi t a No t Ac kn ow le dg e }

SSPCON2bits.ACKE N = 1; // send ackn ow le dg e se qu en ce

while (!PIR1bits.S SP IF ) ; // wai t fo r a fl ag to be set PIR1bits.SSPIF = 0;// clear flag

return( i2cReadDat a ); // return th e va lu e re ad fro m SS PB UF

}

Page 46

MCP9808

NOTES:

Page 47

APPENDIX B: REVISION HISTORY

Revision A (October 2011)

• Original Release of this Document.

MCP9808

Page 48

MCP9808

NOTES:

Page 49

PRODUCT IDENTIFICATION SYSTEM

To order or obtain information, e.g., on pricing or delivery , refer to the factory or the listed sales office.

PART NO. -X /XX

Device

Device: MCP98 08: Digital Temperature Sensor

Temperature Range: E = -40°C to +125°C

Package: MC = Plastic Dual Flat No-Lead (DFN) 2x3, 8-lead

Tape and Reel

and/or

Alternate Pinout

MCP9808T: Digital Temperature Sensor (Tape and Reel)

MS = Plastic Micro Small Outline (MSOP), 8-lead

Range

PackageTemperature

Examples:

a) MCP9808-E/MC: Extended Temperature

b) MCP9808-E/MS: Extended Temperature

c) MCP9808T-E/MC: Tape and Reel,

d) MCP9808T-E/MS: Tape and Reel,

MCP9808

8LD DFN package.

8LD MSOP package.

Extended Temperature 8LD DFN package.

Extended Temperature 8LD MSOP package.

Page 50

MCP9808

NOTES:

Page 51

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are com mitted to continuously improving the c ode prot ection f eatures of our products. Attempts to break Microchip’s code protection feature may be a violation of t he Digit al Mill ennium Copyright Act. If such act s allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Information contained in this publication regarding device

applications and t he lik e is provided only f or your convenience

and may be su perseded by updates. It is you r r es ponsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR

WARRANTIES OF ANY KIND WHETHER EXPRESS OR

IMPLIED, WRITTEN OR ORAL, STATUTORY OR

OTHERWISE, RELATED TO THE INFORMATION,

INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip

devices in life supp ort and/or safety ap plications is entir ely at

the buyer’s risk, and the buyer agrees to defend, indemnify and

hold harmless M icrochip from any and all dama ges, claims,

suits, or expenses re sulting from such use. No licens es are

conveyed, implicitly or otherwise, under any Microchip intellectual property rights.

Trademarks

The Microchip name and logo, the Microchip logo, dsPIC, K

EELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,

logo, rfPIC and UNI/O are registered trademarks of

PIC Microchip Technology Incorporated in the U.S.A. and other countries.

FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A.

Analog-for-the-Digital Age, Application Maestro, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.

SQTP is a service mark of Microchip T echnology Incorporated in the U.S.A.

All other trademarks mentioned herein are property of their respective companies.

Printed on recycled paper.

ISBN: 978-1-61341-739-3

Microchip received ISO/TS-16949:2009 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified.

MCUs and dsPIC® DSCs, KEELOQ

code hopping

Page 52

Worldwide Sales and Service

AMERICAS

Corporate Office

2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support:

http://www.microchip.com/ support

Web Address:

www.microchip.com

Atlanta

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Boston

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Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445

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ASIA/PACIFIC

Asia Pacific Office

Suites 3707-14, 37th Floor Tower 6, The Gateway Harbour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431

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Tel: 86-10-8569-7000 Fax: 86-10-8528-2104

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Tel: 86-571-2819-3187 Fax: 86-571-2819-3189

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Tel: 86-25-8473-2460 Fax: 86-25-8473-2470

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08/02/11

Datasheet MCP9808 Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual

1.0 ELECTRICAL CHARACTERISTICS

2.0 TYPICAL PERFORMANCE CURVES

FIGURE 2-1: Temperature Accuracy.

FIGURE 2-4: Temperature Accuracy Histogram.

FIGURE 2-8: Supply Current vs. Temperature.

FIGURE 2-11: Temperature Accuracy vs Supply Voltage.

FIGURE 2-9: Power-on Reset Threshold Voltage vs. Temperature.

FIGURE 2-12: Temperature Conversion Time vs. Temperature.

FIGURE 2-13: SDA and Alert Output VOL vs. Temperature.

FIGURE 2-16: SMBus Time-out vs. Temperature.

FIGURE 2-14: SDA IOL vs. Temperature.

FIGURE 2-15: Package Thermal Response.

FIGURE 2-17: Shutdown Current vs Temperature.

FIGURE 2-18: Power Supply Rejection vs. Frequency.

3.0 PIN DESCRIPTION

TABLE 3-1: PIN FUNCTION TABLE

3.1 Serial Data Line (SDA)

3.2 Serial Clock Line (SCL)

3.3 Temperature Alert, Open-Drain Output (Alert)

3.4 Ground Pin (GND)

3.5 Address Pins (A0, A1, A2)

TABLE 3-2: MCP9808 ADDRESS BYTE

3.6 Power Pin (VDD)

3.7 Exposed Thermal Pad (EP)

4.0 SERIAL COMMUNICATION

4.1 2-Wire Standard Mode I2C™ Protocol Compatible Interface

FIGURE 4-1: Device Addressing.

5.0 FUNCTIONAL DESCRIPTION

FIGURE 5-1: Functional Block Diagram.

5.1 Registers

FIGURE 5-5: Timing Diagram for Reading +25.25°C Temperature from the TA Register (see Section 4.0 “Serial Communication”).

5.2 SENSOR FEATURE DESCRIPTION

FIGURE 5-9: Active-Low Alert Output Configuration.

FIGURE 5-10: Alert Output Conditions.

5.3 Summary of Power-on Default

TABLE 5-3: POWER-ON RESET DEFAULTS

6.0 APPLICATIONS INFORMATION

6.1 Layout Considerations

6.2 Thermal Considerations

FIGURE 6-1: DFN Package Layout (Top View).

7.0 PACKAGING INFORMATION

7.1 Package Marking Information

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