MIC280-7BM6_技术文档

MIC280

Micrel

MIC280

Precision IttyBitty™ Thermal Supervisor

REV. 11/04

General Description

Features

TheMIC280isadigitalthermalsupervisorcapableofmeasur-

ing its own internal temperature and that of a remote PN junc-

tion. The remote junction may be an inexpensive commodity

transistor, e.g., 2N3906, or an embedded thermal diode such

as found in Intel Pentium* II/III/IV CPUs,AMDAthlon* CPUs,

and Xilinx Virtex* FPGA's. A 2-wire SMBus* 2.0 compatible

serial interface is provided for host communication. Remote

temperature is measured with ±1°C accuracy and 9-bit to

12-bitresolution(programmable).Independenthigh,low,and

over-temperature thresholds are provided for each zone.

• Measures local and remote temperature

• Highly accurate remote sensing

±1°C max., 60°C to 100°C

• Superior noise immunity for reduced temperature guard-

bands

• 9-bit to 12-bit temperature resolution for remote zone

• Fault queues to further reduce nuisance tripping

• Programmable high, low, and over-temperature thresh-

olds for each zone

• SMBus 2 compatible serial interface including device

timeout to prevent bus lockup

• Voltage tolerant I/O’s

• Open-drain interrupt output pin - supports SMBus Alert

Response Address protocol

• Low power shutdown mode

• Locking of critical functions to insure failsafe operation

• Failsafe response to diode faults

• Enables ACPI compliant thermal management

• 3.0V to 3.6V power supply range

• IttyBitty™ SOT23-6 package

TheadvancedintegratingA/Dconverterandanalogfront-end

reduce errors due to noise for maximum accuracy and mini-

mumguardbanding.Theinterruptoutputsignalstemperature

events to the host, including data-ready and diode faults.

Criticaldevicesettingscanbelockedtopreventchangesand

insure failsafe operation. The clock, data, and interrupt pins

are 5V-tolerant regardless of the value of V . They will not

DD

clamp the bus lines low even if the device is powered down.

Superior accuracy, failsafe operation, and small size make

the MIC280 an excellent choice for the most demanding

thermal management applications.

Applications

• Desktop, server and notebook computers

• Printers and copiers

• Test and measurement equipment

• Thermal supervision of Xilinx Virtex FPGA's

• Wireless/RF systems

• Intelligent power supplies

• Datacom/telecom cards

Typical Application

3V to 3.6V

0.1µF

ceramic

3 ×

10k

MIC280

5

4

6

1

3

DATA

CLK

VDD

T1

TO

SERIAL BUS

HOST

2

/INT

GND

2N3906/�

CPU DIODE

1800pF

MIC280 Typical Application

IttyBiity is a trademark of Micrel, Inc.

*All trademarks are the property of their respective owners.

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

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Ordering Information

Part Number

Slave Address Ambient Temp. Range

Package

Standard

Marking Pb-FREE

Marking

TA00

TA01

TA02

TA03

TA05

TA06

TA07

MIC280-0BM6 TA00

MIC280-1BM6 TA01

MIC280-2BM6 TA02

MIC280-3BM6 TA03

MIC280-4BM6 TA04

MIC280-5BM6 TA05

MIC280-6BM6 TA06

MIC280-7BM6 TA07

MIC280-0YM6

MIC280-1YM6

MIC280-2YM6

MIC280-3YM6

MIC280-4YM6

MIC280-5YM6

MIC280-6YM6

MIC280-7YM6

100 1000

100 1001

100 1010

100 1011

-55°C to +125°C

SOT23-6

b

100 1100

100 1101

100 1110

b

100 1111

Pin Conﬁguration

VDD

GND

T1

1

2

3

6

5

4

/INT

DATA

CLK

SOT23-6

Pin Description

Pin Number

Pin Name

VDD

Pin Function

Power Supply Input.

Ground.

1

2

3

4

5

6

GND

T1

Analog Input. Connection to remote diode junction.

Digital Input. Serial bit clock input.

CLK

DATA

/INT

Digital Input/Output. Open-drain. Serial data input/output.

Digital Output. Open-drain. Interrupt output.

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Absolute Maximum Ratings (Note 1)

Operating Ratings (Note 2)

Power Supply Voltage, V

3.8V

Power Supply Voltage, V ............................ +3V to +3.6V

DD.....................................................

DD

Voltage on T1 ........................................–0.3V to V +0.3V

Ambient Temperature Range (T ) .......... –55°C to +125°C

DD

A

Voltage on CLK, DATA, /INT..............................–0.3V to 6V

Current Into Any Pin ................................................. ±10mA

Junction Temperature................................................ 150°C

Package Thermal Resistance (θ )

JA

SOT23-6............................................................230°C/W

Power Dissipation, T = 125°C................................109mW

A

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

ESD Ratings, Note 3

Human Body Model................................................ 1.5kV

Machine Model ........................................................200V

Soldering (SOT23-6 Package)

+5

Vapor Phase (60s).....................................220°C /-0°C

Infrared (15s).............................................235°C /-0°C

Electrical Characteristics

For typical values T_A= 25°C, V_DD= 3.3V, unless otherwise noted.

Bold values indicate –55°C ≤ T_A≤ 125°C, 3.0V ≤ V_DD≤ 3.6V, unless otherwise noted. Note 2

Symbol

Power Supply

I_DD

Parameter

Conditions

Min.

Typ

Max

0.4

Units

Supply Current

/INT, T1 open; CLK=DATA=High;

Normal Mode

0.23

9

mA

µA

Shutdown Mode; /INT, T1 open; Note 5

CLK=100kHz, DATA=High

Shutdown Mode; /INT, T1 open;

CLK=DATA=High

6

[TBD]

t_POR

Power-on Reset Time, Note 5

V_DD> V_POR

200

µs

V_POR

Power-on Reset Voltage

All registers reset to default values;

A/D conversions initiated

2.65

2.95

V

V_HYST

Power-on Reset Hysteresis Voltage

Note 5

300

mV

Temperature-to-Digital Converter Characteristics

Accuracy, Remote Temperature

Notes 2, 7, 10, 11

60°C ≤ T_D≤ 100°C,

3.15V < V_DD< 3.45V, 25°C < T_A< 85°C

±0.25

±1

±2

°C

0°C ≤ T_D≤ 100°C,

3.15V < V_DD< 3.45V, 25°C < T_A< 85°C

–55°C ≤ T_D≤ 125°C,

3.15V < V_DD< 3.45V, 25°C < T_A< 85°C

±2

±4

Accuracy, Local Temperature

Note 2, 10

0°C ≤ T_A≤ 100°C, 3.15V < V_DD< 3.45V

±1

±2

–55°C ≤ T_A≤ 125°C, 3.15V < V_DD< 3.45V

±1.5

±2.5

t_CONV

Conversion Time, Notes 2, 8

RES[1:0]=00 (9 bits)

RES[1:0]=01 (10 bits)

RES[1:0]=10 (11 bits)

RES[1:0]=11 (12 bits)

200

330

240

390

ms

570

670

1000

1250

Remote Temperature Input, T1

I_FCurrent into External Diode

T1 forced to 1.0V, High level

192

400

µA

Note 5

Low level

7

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Symbol

Parameter

Condition

Min

2.1

Typ

Max

Units

Serial Data I/O Pin, DATA

V_OL

Low Output Voltage, Note 4

I_OL= 3mA

0.3

0.5

0.8

5.5

V

I_OL= 6mA

V_IL

Low Input Voltage

High Input Voltage

Input Capacitance

Input Current

3V ≤ V_DD≤ 3.6V

Note 5

V

V_IH

V

C_IN

I_LEAK

10

pF

µA

±1

Serial Clock Input, CLK

V_IL

Low Input Voltage

3V ≤ V_DD≤ 3.6V

Note 5

0.8

5.5

V

V_IH

High Input Voltage

Input Capacitance

Input Current

C_IN

I_LEAK

pF

µA

±1

Interrupt Output, /INT

V_OL

Low Output Voltage, Note 4

I_OL= 3mA

0.3

0.5

V

I_OL= 6mA

t_INT

Interrupt Propagation Delay

Notes 5, 6

from TEMPx < TLOWx or

TEMPx > THIGHx or TEMPx >

CRITx to /INT < V_OL; R_PULLUP= 10kΩ

[t_CONV

]

ms

t_nINT

Interrupt Reset Propagation Delay

Note 5, 9

from read of STATUS or A.R.A. to

/INT > V_OH; R_PULLUP= 10kΩ

1

µs

I_LEAK

±1

µA

Serial Interface Timing

t₁

t₂

t₃

t₄

t₅

CLK (Clock) Period

2.5

100

300

100

µs

ns

Data In Setup Time to CLK High

Data Out Stable after CLK Low

Data Low Setup Time to CLK Low

Start Condition

Stop Condition

Data High Hold Time after CLK

High

t_TO

Bus Timeout

25

30

35

ms

Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating range. Final test on outgoing product is performed at T_A= 25°C.

Note 3. Devices are ESD sensitive. Handling precautions recommended.

Note 4. Current into the /INT or DATA pins will result in self heating of the device. Sink current should be minimized for best accuracy.

Note 5. Guaranteed by design over the operating temperature range. Not 100% production tested.

Note 6. t_INTand t_CRITare equal to t_CONV

.

Note 7. T_Dis the temperature of the remote diode junction. Testing is performed using a single unit of one of the transistors listed in Table 8.

Note 8. t_CONV= t_CONV(local) + t_CONV(remote). Following the acquisition of either remote or local temperature data, the limit comparisons for that zone

are performed and the device status updated; Status bits will be set and /INT driven active, if applicable.

Note 9. The interrupt reset propogation delay is dominated by the capacitance on the bus.

Note 10. Accuracy speciﬁcation does not include quantization noise, which may be up to ±¹/₂LSB.

Note 11. Tested at 10-bit resolution.

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Timing Diagrams

t₁

CLK

DATA INPUT

t₄

t₂

t₅

t₃

DATA OUTPUT

Serial Interface Timing

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Typical Characteristics

V

= 3.3V; T = 25°C, unless otherwise noted.

DD

A

Accuracy vs .

Temperature, Internal S ens or

2.5

R emote Temperature

Meas urement E rror

S upply C urrent vs .

Temperature for V = 3.3V

DD

2

400

350

300

250

200

150

100

50

2

1.5

1

1.5

1

0.5

0

0.5

0

-0.5

-1

-0.5

-1

-1.5

-2

-1.5

-2.5

-2

0

-55 -35 -15

5

25 45 65 85 105 125

0

20

40

60

80

100

-55 -35 -15

5

25 45 65 85 105 125

JUNCTION TEMPERATURE (°C)

REMOTE DIODE TEMPERATURE (°C)

TEMPERATURE (°C)

Quies cent C urrent vs .

C lock Frequency in

S hutdown Mode

Quies cent C urrent vs .

Temperature in S hutdown Mode

S upply Voltage in S hutdown Mode

10

30

20

15

10

5

/INT, T1 open

C LK = DATA = HIG H

/INT, T1 open

DATA = HIG H

/INT, T1 open

C LK = DATA = HIG H

9

25

8

7

6

5

4

3

2

1

0

20

15

10

5

0

2.6

2.8

3.0

3.2

3.4

3.6

0

100

200

300

400

-55 -35 -15

5 25 45 65 85 105 125

SUPPLY VOLTAGE (V)

FREQUENCY (kHz)

TEMPERATURE (°C)

R es pons e to Immers ion

in 125°C Fluid B ath

Meas urement E rror vs .

R emote Temperature E rror vs .

C apacitance on T1

5

P C B L eakage to +3.3V/G ND

140

120

100

80

8

6

4

0

2

G ND

3.3V

-5

0

60

-10

-2

-4

-6

40

-15

-20

20

0

-8

1x10 ⁶

1x10 ⁷

1x10 ⁸

1x10 ⁹

0

1 2 3 4 5 6 7 8 9 10

TIME (sec)

RESISTANCE FROM T1 (Ω)

CAPACITANCE (pF)

Nois e Injected into the B as e of

R emote Trans is tor

7

Nois e Injected into the

C ollector of R emote Trans is tor

1.6

100mV_{P -P}

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

6

25mV_{P -P}

5

4

3

10mV_{P -P}

3mV_{P -P}

50mV_{P -P}

2

1

25mV_{P -P}

10M

100M

0

1k

10M

1k

10 100 10k100k 1M

1

10 100

10k100k 1M

FREQUENCY (Hz)

100M

1

FREQUENCY (Hz)

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initiate communication. The MIC280’s slave address is ﬁxed

at the time of manufacture. Eight different slave addresses

are available as determined by the part number. See Table

2 below and the Ordering Information table above.

Functional Description

Serial Port Operation

The MIC280 uses standard SMBus Write_Byte, Read_Byte,

and Read_Word operations for communication with its host.

The SMBus Write_Byte operation involves sending the

device’s slave address (with the R/W bit low to signal a write

operation), followed by a command byte and the data byte.

The SMBus Read_Byte operation is a composite write and

readoperation:thehostﬁrstsendsthedevice’sslaveaddress

followed by the command byte, as in a write operation. A

new start bit must then be sent to the MIC280, followed by a

repeat of the slave address with the R/W bit (LSB) set to the

high (read) state. The data to be read from the part may then

be clocked out. A Read_Word is similar, but two successive

data bytes are clocked out rather than one. These protocols

are shown in Figure 1, Figure 2, and Figure 3.

Part Number

MIC280-0BM6

MIC280-1BM6

MIC280-2BM6

MIC280-3BM6

MIC280-4BM6

MIC280-5BM6

MIC280-6BM6

MIC280-7BM6

Slave Address

100 1000_b= 48_h

100 1001_b= 49_h

100 1010_b= 4A_h

100 1011_b= 4B_h

100 1100_b= 4C_h

100 1101_b= 4D_h

100 1110_b= 4E_h

100 1111_b= 4F_h

Table 2: MIC280 Slave Addresses

Alert Response Address

The Command byte is eight bits (one byte) wide. This byte

carries the address of the MIC280 register to be operated

upon. The command byte values corresponding to the vari-

ous MIC280 registers are shown in Table 1. Other command

byte values are reserved, and should not be used.

In addition to the Read_Byte, Write_Byte, and Read_Word

protocols, the MIC280 adheres to the SMBus protocol for

responsetotheAlertResponseAddress(ARA). TheMIC280

expects to be interrogated using the ARA when it has as-

serted its /INT output.

Slave Address

Temperature Data Format

The MIC280 will only respond to its own unique slave ad-

dress. A match between the MIC280’s address and the

address speciﬁed in the serial bit stream must be made to

The least-signiﬁcant bit of each temperature register (high

bytes) represents one degree Centigrade. The values are in

a two’s complement format, wherein the most signiﬁcant bit

Command Byte

Value

Power-on

Default

Target Register

Label

Description

Read

00_h

01_h

02_h

03_h

04_h

05_h

06_h

07_h

08_h

09_h

10_h

13_h

14_h

19_h

20_h

FE_h

FF_h

Write

n/a

TEMP0

TEMP1h

STATUS

CONFIG

IMASK

Local temperature result

00_h(0°C)

00_h

Remote temperature result, high byte

Status

n/a

Conﬁguration

03_h

04_h

05_h

06_h

07_h

08_h

09_h

n/a

80_h

Interrupt mask register

07_h

THIGH0

TLOW0

THIGH1h

TLOW1h

LOCK

Local temperature high limit

Local temperature low limit

Remote temperature high limit, high byte

Remote temperature low limit, high byte

Security register

3C_h(60°C)

00_h(0°C)

50_h(80°C)

00_h(0°C)

00_h

TEMP1l

THIGH1l

TLOW1l

CRIT1

Remote temperature result, low byte

Remote temperature high limit, low byte

Remote temperature low limit, low byte

Remote over-temperature limit

Local over-temperature limit

Manufacturer Identiﬁcation

Device and revision identiﬁcation

00_h

13_h

14_h

19_h

20_h

n/a

00_h

64_h(100°C)

46_h(70°C)

2A_h

CRIT0

MFG_ID

DEV_ID

n/a

0x_h*

* The lower nibble contains the die revision level, e.g., Rev 0 = 00h.

Table 1: MIC280 Register Addresses

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(D7) represents the sign: zero for positive temperatures and

one for negative temperatures. Table 3 shows examples of

the data format used by the MIC280 for temperatures:

register is shown in Table 5. Note: there is no fault queue

for over-temperature events (CRIT0 and CRIT1) or diode

faults. The fault queue applies only to high-temperature and

low-temperature events as determined by the THIGHx and

TLOWx registers. Any write to CONFIG will result in the fault

queues being purged and reset. Writes to any of the limit

registers, TLOWx or THIGHx, will result in the fault queue for

the corresponding zone being purged and reset.

Temperature

+127°C

+125°C

+25°C

Binary

Hex

7F

7D

19

0111 1111

0111 1101

0001 1001

0000 0001

0000 0000

1111 1111

1110 0111

1000 0011

1000 0000

+1°C

01

CONFIG[5:4]

FAULT QUEUE

DEPTH

0°C

00

–1°C

FF

E7

83

00

01

10

11

1 (Default)

–25°C

2

4

6

–125°C

–128°C

80

Table 3: Digital Temperature Format, High Bytes

Table 5: Fault Queue Depth Settings

Interrupt Generation

Extended temperature resolution is provided for the external

zone. The high and low temperature limits and the measured

temperatureforzoneonearereportedas12-bitvaluesstored

in a pair of 8-bit registers. The measured temperature, for

example,isreportedinregistersTEMP1h,thehigh-orderbyte,

and TEMP1l, the low-order byte. The values in the low-order

bytes are left-justiﬁed four-bit binary values representing

one-sixteenth degree increments. TheA-D converter resolu-

tion for zone 1 is selectable from nine to twelve bits via the

conﬁguration register. Low-order bits beyond the resolution

selected will be reported as zeroes. Examples of this format

are shown below in Table 4.

ThereareeightdifferentconditionsthatwillcausetheMIC280

to set one of the bits in STATUS and assert its /INT output,

if so enabled. These conditions are listed in Table 6. Unlike

previous generations of thermal supervisor IC’s, there are no

interdependencies between any of these conditions. That is,

if CONDITION is true, the MIC280 will respond accordingly,

regardless of any previous or currently pending events.

Normallywhenatemperatureeventoccurs,thecorresponding

status bit will be set in STATUS, the corresponding interrupt

mask bit will be cleared, and /INT will be asserted. Clearing

the interrupt mask bit(s) prohibits continuous interrupt gen-

eration while the device is being serviced. (It is possible to

prevent events from clearing interrupt mask bits by setting

bits in the lock register. See Table 7 for Lockbit function-

ality.) A temperature event will only set bits in the status

register if it is speciﬁcally enabled by the corresponding bit

in the interrupt mask register. An interrupt signal will only

be generated on /INT if interrupts are also globally enabled

(IE =1 in CONFIG).

FAULT QUEUE

A set of fault queues (programmable digital ﬁlters) are pro-

vided in the MIC280 to prevent false tripping due to thermal

or electrical noise. Two bits, CONFIG[5:4], set the depth of

the fault queues. The fault queue setting then determines

the number of consecutive temperature events (TEMPx >

THIGHx or TEMPx < TLOWx) which must occur in order for

the condition to be considered valid. As an example, as-

sume CONFIG[5:4] is programmed with 10b. The measured

temperature for a given zone would have to exceed THIGHx

for four consecutive A/D conversions before /INT would be

asserted or the status bit set.

The MIC280 expects to be interrogated using the Alert Re-

sponseAddress once it has asserted its interrupt output. Fol-

lowing an interrupt, a successful response to the A.R.A. or a

read operation on STATUS will cause /INTto be de-asserted.

STATUS will also be cleared by the read operation. Reading

STATUS following an interrupt is an acceptable substitute for

Like any ﬁlter, the fault queue function also has the effect

of delaying the detection of temperature events. In this ex-

ample, it would take 4 x t

to detect a temperature event.

CONV

The fault queue depth vs. CONFIG[5:4] of the conﬁguration

Extended Temperature,

Resolution

Low Byte

9 BITS

10 BITS

Binary

11 BITS

Binary

12 BITS

Binary

Hex

00

80

Hex

00

Hex

00

Hex

00

10

20

40

90

F0

0.0000

0.0625

0.1250

0.2500

0.5625

0.9375

0000 0000

1000 0000

0000 0000

0100 0000

1000 0000

1100 0000

0000 0000

0010 0000

0100 0000

1000 0000

1110 0000

0000 0000

0001 0000

0010 0000

0100 0000

1001 0000

1111 0000

00

20

40

80

C0

E0

Table 4: Digital Temperature Format, Low Bytes

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using the A.R.A. if the host system does not implement the

A.R.A protocol. Figure 4 and Figure 5 illustrate these two

methods of responding to MIC280 interrupts.

to the host. For polled systems, the global interrupt enable

bit should be clear (IE = 0). This will disable interrupts from

the MIC280 (prevents the /INT pin from sinking current).

For interrupt-driven systems, IE must be set to enable the

/INT output.

Sincetemperature-to-digital conversionscontinuewhile/INT

isasserted,themeasuredtemperaturecouldchangebetween

the MIC280’s assertion of /INT and the host’s response. It

is good practice for the interrupt service routine to read the

value in TEMPx, to verify that the over-temperature or under-

temperature condition still exists. In addition, more than one

temperature event may have occurred simultaneously or in

rapid succession between the assertion of /INT and servic-

ing of the MIC280 by the host. The interrupt service routine

should allow for this eventuality. At the end of the interrupt

service routine, the interrupt enable bits should be reset to

permit future interrupts.

Shutdown Mode

Puttingthedeviceintoshutdownmodebysettingtheshutdown

bit in the conﬁguration register will unconditionally deassert

/INT, clear STATUS, and purge the fault queues. Therefore,

this should not be done before completing the appropriate

interruptserviceroutine(s). Nootherregisterswillbeaffected

by entering shutdown mode. The last temperature readings

will persist in the TEMPx registers.

The MIC280 can be prevented from entering shutdown

mode using the shutdown lockout bit in the lock register. If

L3 in LOCK is set while the MIC280 is in shutdown mode,

it will immediately exit shutdown mode and resume normal

operation. It will not be possible to subsequently re-enter

shutdown mode. If the reset bit is set while the MIC280 is

shut down, normal operation resumes from the reset state.

(see below)

Reading the Result Registers

AllMIC280registersareeightbitswideandmaybeaccessed

using the standard Read_Byte protocol. The temperature

result for the local zone, zone 0, is a single 8-bit value in

register TEMP0. A single Read_Byte operation by the host

is sufﬁcient for retrieving this value. The temperature result

for the remote zone is a twelve-bit value split across two

eight-bit registers, TEMP1h and TEMP1l. A series of two

Read_Byteoperationsareneededtoobtaintheentiretwelve-

bit temperature result for zone 1. It is possible under certain

conditions that the temperature result for zone 1 could be

updated between the time TEMP1l or TEMP1h is read and

the companion register is read. In order to insure coherency,

TEMP1h supports the use of the Read_Word protocol for ac-

cessing both TEMP1h and TEMP1l with a single operation.

This insures that the values in both result registers are from

the same ADC cycle. This is illustrated in Figure 3 above.

Read_Word operations are only supported for TEMP1h:

TEMP1l, i.e., only for command byte values of 01h.

Warm Resets

The MIC280 can be reset to its power-on default state during

operation by setting the RST bit in the conﬁguration register.

When this bit is set, /INT will be deasserted, the fault queues

willbepurged,thelimitregisterswillberestoredtotheirnormal

power-on default values, and anyA/D conversion in progress

will be halted and the results discarded. This includes reset-

ting bits L3 - L0 in the security register, LOCK. The state of

the MIC280 following this operation is indistinguishable from

a power-on reset. If the reset bit is set while the MIC280 is

shut down, the shutdown bit is cleared and normal operation

resumes from the reset state.

If bit 4 of LOCK, the Warm Reset Lockout Bit, is set, warm

resets cannot be initiated, and writes to the RST bit will be

completely ignored. Setting L4 while the MIC280 is shut

down will result in the device exiting shutdown mode and

resuming normal operation, just as if the shutdown bit had

been cleared.

Polling

The MIC280 may either be polled by the host, or request

the host’s attention via the /INT pin. In the case of polled

operation, the host periodically reads the contents of STA-

TUS to check the state of the status bits. The act of reading

STATUS clears it. If more than one event that sets a given

status bit occurs before the host polls STATUS, only the fact

that at least one such event has occurred will be apparent

EVENT

CONDITION

MIC280 RESPONSE*

Data ready

A/D conversions complete for both zones; result

registers updated; state of /INT updated

Set S7, clear IM7, assert /INT

Over-temperature, remote

Over-temperature, local

High temperature, remote

High temperature, local

Low temperature, remote

Low temperature, local

Diode fault

([TEMP1h:TEMP1l]) > CRIT1

TEMP0 > CRIT0

Set S1, assert /INT

Set S0, assert /INT

([TEMP1h:TEMP1l]) > THIGH1h:THIGH1l]**

TEMP0 > THIGH0**

Set S4, clear IM4, assert /INT

Set S6, clear IM6, assert /INT

Set S3, clear IM3, assert /INT

Set S5, clear IM5, assert /INT

Set S2, clear IM2, assert /INT

( [TEMP1h:TEMP1l]) < TLOW1h:TLOW1l]**

TEMP0 < TLOW0**

T1 open or T1 shorted to VDD or GND

* Assumes interrupts enabled. **CONDITION must be true for Fault_Queue conversions to be recognized.

Table 6: MIC280 Temperature Events

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Conﬁguration Locking

mask bit. Similarly, setting L2 will ﬁx the state of IM2, allow-

ing the system to permanently enable or disable diode fault

interrupts. Adiode fault will generate an interrupt regardless

of the setting of IE or its interrupt mask bit.

The security register, LOCK, provides the ability to disable

conﬁguration changes as they apply to the MIC280’s most

critical functions: shutdown mode, and reporting diode faults

andover-temperatureevents. LOCKprovidesawaytoprevent

malicious or accidental changes to the MIC280 registers that

might prevent a system from responding properly to critical

events. Once L0, L1, or L2 has been set, the global interrupt

enable bit, IE, will be set and ﬁxed. It cannot subsequently be

cleared. Itsstatewillbereﬂectedintheconﬁgurationregister.

The bits in LOCK can only be set once. That is, once a bit is

set, it cannot be reset until the MIC280 is power-cycled or a

warm reset is performed by setting RST in the conﬁguration

register. The warm reset function can be disabled by setting

L4 in LOCK. If L4 is set, locked settings cannot be changed

during operation and warm resets cannot be performed; only

a power-cycle will reset the locked state(s).

L3 can be used to lock out shutdown mode. If L3 is set, the

MIC280willnotshutdownunderanycircumstances. Attempts

to set the SHDN bit will be ignored and all chip functions will

remainoperational.IfL3issetwhiletheMIC280isinshutdown

mode, it will immediately exit shutdown mode and resume

normal operation. It will not be possible to subsequently re-

enter shutdown mode.

Setting L4 disables the RST bit in the conﬁguration register,

preventing the host from initiating a warm reset. Writes to

RST will be completely ignored if L4 is set.

If L0 is set, the values of IM0 and CRIT0 become ﬁxed and

unchangeable.Thatis,writestoCRIT0andthecorresponding

interrupt enable bit are locked out. A local over-temperature

event will generate an interrupt regardless of the setting of

IE or its interrupt mask bit.

If L1 is set, the values of IM1 and CRIT1 become ﬁxed and

unchangeable. A remote over-temperature event will gener-

ate an interrupt regardless of the setting of IE or its interrupt

LOCK BIT

FUNCTION LOCKED

Local over-temperature detection

Remote over-temperature detection

Diode fault interrupts locked on or off

Shutdown mode

RESPONSE WHEN SET

L0

L1

L2

L3

L4

IM0 ﬁxed at 1, writes to CRIT0 locked-out; IE permanently set

IM1 ﬁxed at 1; writes to CRIT1 locked-out; IE permanently set

IM2 ﬁxed at current state; IE permanently set if IM2=1

SHDN ﬁxed at 0; exit shutdown if SHDN=1 when L3 is set

RST bit disabled; cannot initiate Warm resets

Warm resets

Table 7: Lock bit functionality

MIC280

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MIC280

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Detailed Register Descriptions

Local Temperature Result Register (TEMP0)

8-bits, read-only

Local Temperature Result Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read-only

Temperature Data from ADC

Bit

Function

Measured temperature data for the local zone.

Operation

Read only

D[7:0]

Power-up default value:

Read command byte:

0000 0000 = 00 (0°C)**

b

h

0000 0000 = 00

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . See Temperature Data Format (above) for more details.

b

**TEMP0 will contain measured temperature data after the completion of one conversion.

Remote Temperature Result High-Byte Register (TEMP1h)

8-bits, read only

Remote Temperature Result High-Byte Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read-only

Temperature Data from ADC

Bit

Function

Measured temperature data for the remote zone, most signiﬁcant byte.

Operation

Read only

D[7:0]

Power-up default value:

Read command byte:

0000 0000 = 00 (0°C)**

b

h

0000 0001 = 01

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000b. See Temperature Data Format (above) for more details.

TEMP1h can be read using either a Read_Byte operation or a Read_Word operation. Using Read_Byte will yield the 8-bit

value in TEMP1h. The complete remote temperature result in both TEMP1h and TEMP1l may be obtained by performing a

Read_Word operation on TEMP1h. The MIC280 will respond to a Read_Word with a command byte of 01h (TEMP1h) by

returning the value in TEMP1h followed by the value in TEMP1l. This guarantees that the data in both registers is from the

same temperature-to-digital conversion cycle. The Read_Word operation is diagramed in Figure 3. This is the only MIC280

register that supports Read_Word.

**TEMP1h will contain measured temperature data after the completion of one conversion.

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MIC280

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Status Register (STATUS)

8-bits, read-only

Status Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read-only

S7

S6

S5

S4

S3

S2

S1

S0

Bit(s)

Function

Operation*

S7

Data ready

1 = data available

0 = ADC busy

S6

S5

S4

S3

S2

S1

S0

Local high temperature event

Local low temperature event

Remote high temperature event

Remote low temperature event

Diode fault

1 = event occurred, 0 = none

1 = fault, 0 = none

Remote over-temperature event

Local over-temperature event

1 = event occurred, 0 = none

* All status bits are cleared after any read operation is performed on STATUS.

Power-up default value:

Read command byte:

0000 0000 = 00 (no events pending)

b

h

0000 0010 = 02

b

h

The power-up default value is 00h. Following the ﬁrst conversion, however, any of the status bits may be set depending on

the measured temperature results or the existence of a diode fault.

Conﬁguration Register (CONFIG)

8-bits, read/write

Conﬁguration Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

reserved

Interrupt

Enable

(IE)

Shut-down

Fault Queue

Resolution

Reserved

Reset

(SHDN)

(FQ[1:0])

(RES[1:0])

(RST)

Bits(s)

Function

Operation*

IE

Interrupt enable

1 = interrupts enabled,

0 = disabled

SHDN

FQ[1:0]

RES[1:0]

Selects operating mode: normal/shutdown

Depth of fault queue*

1 = shutdown, 0 = normal

[00]=1, [01]=2, [10]=4, [11]=6

A/D converter resolution for external zone - affects conversion rate

[00]=9-bits, [01]=10-bits,

[10]=11-bits, [11]=12-bits

D[1]

RST

Reserved

always write as zero!

Resets all MIC280 functions and restores the power-up default state

write only; 1 = reset, 0 =

normal

operation; disabled by

setting L4

Power-up default value:

1000 0000 = 80 (Not in shutdown mode; Interrupts enabled;

b h

Fault queue depth=1; Resolution = 9 bits)

Read/Write command byte:

0000 0011 = 03

b

h

* Any write to CONFIG will result in the fault queues being purged and reset and any A/D conversion in progress being aborted and the result

discarded. The A/D will begin a new conversion sequence once the write operation is complete.

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Interrupt Mask Register (IMASK)

8-bits, read/write

Interrupt Mask Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

IM7

IM6

IM 5

IM 4

IM 3

IM 2

IM 1

IM0

Bit(s)

IM7

IM6

IM5

IM4

IM3

IM2

IM1

IM0

Function

Operation*

Data ready event mask

1 = enabled, 0 = disabled

Local high temperature event mask

Local low temperature event mask

Remote high temperature event mask

Remote low temperature event mask

Diode fault mask

Remote over-temperature event mask

Local over-temperature event mask

Power-up default value:

0000 0111 = 07 (Over-temp. and diode faults enabled)

b h

Read/Write command byte:

0000 0100 = 04

b h

Local Temperature High Limit Register (THIGH0)

8-bits, read/write

Local Temperature High Limit Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

High temperature limit for local zone.

Bit

Function

Operation

D[7:0]

High temperature limit for the local zone.

Read/write

Power-up default value:

0011 1100 = 3C (60°C)

b

h

Read/Write command byte:

0000 0101 = 05

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . See Temperature Data Format (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

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MIC280

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Local Temperature Low Limit Register (TLOW0)

8-bits, read/write

Local Temperature Low Limit Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

Low temperature limit for local zone

Bit

Function

Operation

D[7:0]

Low temperature limit for the local zone

Read/write

Power-up default value:

0000 0000 = 00 (0°C)

b

h

Read/Write command byte:

0000 0110 = 06

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . See TEMPERATURE DATA FORMAT (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

Remote Temperature High Limit High-Byte Register (THIGH1h)

8-bits, read/write

Remote Temperature High Limit High-Byte Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

High temperature limit for remote zone, most signiﬁcant byte.

Bit

Function

Operation

D[7:0]

High temperature limit for the remote zone, most signiﬁcant byte.

Read/write

Power-up default value:

0101 0000 = 50 (80°C)

b

h

Read/Write command byte:

0000 0111 = 07

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . See TEMPERATURE DATA FORMAT (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

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MIC280

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Remote Temperature Low Limit High-Byte Register (TLOW1h)

8-bits, read/write

Remote Temperature Low Limit High-Byte Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

Low temperature limit for remote zone, most signiﬁcant byte.

Bit

Function

Operation

D[7:0]

Low temperature limit for the remote zone, most signiﬁcant byte.

Read/write

Power-up default value:

0000 0000 = 00 (0°C)

b

h

Read/Write command byte:

0000 1000 = 08

b

h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000b. See Temperature Data Format (above) for more details.

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

Security Register (LOCK)

8-bits, write once

Security Register

D[7]

reserved

D[6]

reserved

D[5]

reserved

D[4]

read/

D[3]

read/

D[2]

read/

D[1]

read/

D[0]

read/

write-once

Reserved

L4

L3

L2

L1

L0

Bit

D[7:5]

L4

Function

Operation*

Reserved

Always write as zero

Warm reset lockout bit

1 = RST bit disabled;

0 = unlocked

L3

Shutdown mode lockout bit*

1= shutdown disabled;

0 = unlocked

L2

L1

L0

Diode fault event lock bit

1 = locked, 0 = unlocked

Remote over-temperature event lock bit

Local over-temperature event lock bit

Power-up default value:

0000 0000 = 00 (All events unlocked)

b

h

Read/Write command byte:

0000 1001 = 09

b

h

* If the chip is shutdown when L3 is set, the chip will exit shutdown mode and resume normal operation. It will not be possible to subsequently

re-enter shutdown mode.

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Remote Temperature Result Low-Byte Register (TEMP1l)

8-bits, read only

Remote Temperature Result Low-Byte Register

D[7]

read-only

D[6]

read-only

D[5]

read-only

D[4]

read-only

D[3]

reserved

D[2]

reserved

D[1]

reserved

D[0]

reserved

Temperature data from ADC, least signiﬁcant bits

Reserved - always reads zero

Bit

Function

Operation

D[7:4]

D[3:0]

Measured temperature data for the remote zone, least signiﬁcant bits.

Reserved

Read only

Always reads as zeroes

Power-up default value:

Read command byte:

0000 0000 = 00 (0°C)**

b

h

0001 0000 = 10

b

h

Each LSB represents one-sixteenth degree centigrade. The values are in a binary format such that 1/16th°C (0.0625°C) is

reported as 0001 0000 . See Temperature Data Format (above) for more details.

b

TEMP1l can be accessed using a Read_Byte operation. However, the complete remote temperature result in both TEMP1h

and TEMP1l may be obtained by performing a Read_Word operation on TEMP1h. The MIC280 will respond to a Read_Word

with a command byte of 01h (TEMP1h) by returning the value in TEMP1h followed by the value in TEMP1l. This guaran-

tees that the data in both registers is from the same temperature-to-digital conversion cycle. The Read_Word operation is

diagramed in Figure 3. TEMP1h is the only MIC280 register that supports Read_Word.

**TEMP1l will contain measured temperature data after the completion of one conversion.

Remote Temperature High Limit Low-Byte Register (THIGH1l)

8-bits, read/write

Remote Temperature High Limit Low-Byte Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

reserved

High temperature limit for remote zone, least signiﬁcant bits.

Reserved - always reads zero

Bit

Function

Operation

D[7:4]

D[3:0]

High temperature limit for the remote zone, least signiﬁcant bits.

Reserved.

Read/write

Always reads as zeros

Power-up default value:

0000 0000 = 00 (0°C)

b

h

Read/Write command byte:

0001 0011 = 13

b

h

Each LSB represents one-sixteenth degree centigrade. The values are in a binary format such that 1/16th°C (0.0625°C) is

reported as 0001 0000 . See Temperature Data Format (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

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Remote Temperature Low Limit Low-Byte Register (TLOW1l)

8-bits, read/write

Remote Temperature Low Limit Low-Byte Register

D[7]

read/write

D[6]

read/write

D[5]

read/write

D[4]

read/write

D[3]

reserved

D[2]

reserved

D[1]

reserved

D[0]

reserved

Low temperature limit for remote zone, least signiﬁcant bits.

Reserved - always reads zero.

Bit

Function

Operation

D[7:4]

D[3:0]

Low temperature limit for the remote zone, least signiﬁcant bits.

Reserved

Read/write

Always reads as zeros.

Power-up default value:

0000 0000 = 00 (0°C)

b

h

Read/Write command byte:

0001 0100 = 14

b

h

Each LSB represents one-sixteenth degree centigrade. The values are in a binary format such that 1/16th°C (0.0625°C) is

reported as 0001 0000 . See Temperature Data Format (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

Remote Over-Temperature Limit Register (CRIT1)

8-bit, read/write

Remote Over-Temperature Limit Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

Over-temperature limit for remote zone.

Bit

Function

Operation

D[7:0]

Over-temperature limit for the remote zone.

Read/write

Power-up default value:

0110 0100 = 64 (100°C)

b h

Read/Write command byte:

0001 1001 = 19

b h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . SeeTemperature Data Format (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

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MIC280

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Local Over-Temperature Limit Register (CRIT0)

8-bits, read/write

Local Over-Temperature Limit Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read/write

Over-temperature limit for local zone.

Bit

Function

Operation

D[7:0]

Over-temperature limit for the local zone.

Read/write

Power-up default value:

0100 0110 = 46 (70°C)

b h

Read/Write command byte:

0010 0000 = 20

b h

Each LSB represents one degree centigrade. The values are in a two’s complement binary format such that 0°C is reported

as 0000 0000 . SeeTemperature Data Format (above) for more details.

b

Any writes to a temperature limit register will result in the corresponding fault queue being purged and reset.

Manufacturer ID Register (MFG_ID)

8-bits, read only

Manufacturer ID Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read only

0

1

0

1

0

1

0

BIT(S)

FUNCTION

Operation*

D[7:0]

Identiﬁes Micrel as the manufacturer of the device. Always returns 2A_h.

Read only. Always returns

2A_h

Power-up default value:

Read command byte:

0010 1010 = 2A

b

h

1111 1110 = FE

b

h

Die Revision Register (DIE_REV)

8-bits, read only

Die Revision Register

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

read-only

reserved

MIC280 DIE REVISION NUMBER

Bit(s)

Function

Operation*

D[7:0]

Identiﬁes the device revision number

Read only.

Power-up default value:

Read command byte:

[Device revision number]

h

1111 1111 = FF

b

h

MIC280

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MIC280

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Series Resistance

Application Information

Remote Diode Selection

TheoperationoftheMIC280dependsuponsensingtheV

CB-E

of a diode-connected PNP transistor (“diode “) at two differ-

ent current levels. For remote temperature measurements,

this is done using an external diode connected between T1

and ground. Since this technique relies upon measuring the

relatively small voltage difference resulting from two levels of

current through the external diode, any resistance in series

with the external diode will cause an error in the temperature

reading from the MIC280. A good rule of thumb is this: for

each ohm in series with the external transistor, there will be

a0.8°CerrorintheMIC280’stemperaturemeasurement. Itis

not difﬁcult to keep the series resistance well below an ohm

(typically <0.1), so this will rarely be an issue.

Mostsmall-signalPNPtransistorswithcharacteristicssimilar

totheJEDEC2N3906willperformwellasremote temperature

sensors. Table 8 lists several examples of such parts that

Micrel has tested for use with the MIC280. Other transistors

equivalent to these should also work well.

Vendor

Part Number

MMBT3906

MMBT3906L

PMBT3906

Package

SOT-23

Fairchild Semiconductor

On Semiconductor

Philips Semiconductor

Samsung Semiconductor

KST3906-TF

Table 8: Transistors suitable for use as remote diodes

Filter Capacitor Selection

Minimizing Errors

It is usually desirable to employ a ﬁlter capacitor between the

T1 and GND pins of the MIC280. The use of this capacitor is

recommended in environments with a lot of high frequency

noise (such as digital switching noise), or if long wires are

used to conect to the remote diode. The maximum recom-

mended total capacitance from the T1 pin to GND is 2200pF.

This typically suggests the use of a 1800pF NP0 or C0G

ceramic capacitor with a 10% tolerance. If the remote diode

is to be at a distance of more than 6"-12" from the MIC280,

using twisted pair wiring or shielded microphone cable for

the connections to the diode can signiﬁcantly reduce noise

pickup. If using a long run of shielded cable, remember to

subtractthecable'sconductor-to-shieldcapacitancefromthe

2200pF maximum total capacitance.

Self-Heating

Oneconcernwhenusingapartwiththetemperatureaccuracy

and resolution of the MIC280 is to avoid errors induced by

self-heating (V × I ) + (V × I ). In order to understand

what level of error this might represent, and how to reduce

that error, the dissipation in the MIC280 must be calculated

and its effects reduced to a temperature offset. The worst-

case operating condition for the MIC280 is when V = 3.6V.

The maximum power dissipated in the part is given in the

following equation:

DD

OL

DD

P_D= [(I_DD×V_DD)+(I_OL(DATA)×V_OL(DATA))+(I_OL(/INT)×V_OL(/INT)

P_D= [(0.4mA×3.6V)+(6mA×0.5V)+(6mA×0.5V)]

P_D= 7.44mW

]

Layout Considerations

R

of SOT23-6 package is 230°C/W

θ(J-A)

Thefollowingguidelinesshouldbekeptinmindwhendesign-

ing and laying out circuits using the MIC280:

Theoretical Maximum ∆T due to self-heating is:

J

7.44mW×230°C/W = 1.7112°C

1. Place the MIC280 as close to the remote diode

as possible, while taking care to avoid severe

noise sources such as high frequency power

transformers, CRTs, memory and data busses,

and the like.

Worst-case self-heating

In most applications, the /INT output will be low for at most

a few milliseconds before the host resets it back to the high

state, making its duty cycle low enough that its contribution to

self-heating of the MIC280 is negligible. Similarly, the DATA

pinwillinalllikelihoodhaveadutycycleofsubstantiallybelow

25% in the low state. These considerations, combined with

more typical device and application parameters, give a better

system-level view of device self-heating in interrupt-mode

usage given in the following equation:

2. Since any conductance from the various volt-

ages on the PC Board and the T1 line can in-

duce serious errors, it is good practice to guard

the remote diode's emitter trace with a pair of

ground traces. These ground traces should be

returned to the MIC280's own ground pin. They

should not be grounded at any other part of their

run. However, it is highly desirable to use these

guard traces to carry the diode's own ground

return back to the ground pin of the MIC280,

thereby providing a Kelvin connection for the

base of the diode. See Figure 6.

(0.23mA I_DD(typ)×3.3V)+(25%×1.5mA I_OL(DATA)×0.15V)

+ (1%×1.5mA I_OL(/INT)×0.15V) = 0.817mW

∆T_J= (0.8175mW×230°C/W) = 0.188°C

Real-world self-heating example

In any application, the best test is to verify performance

against calculation in the ﬁnal application environment. This

is especially true when dealing with systems for which tem-

perature data may be poorly deﬁned or unobtainable except

by empirical means.

3. When using the MIC280 to sense the tempera-

ture of a processor or other device which has an

integral thermal diode, e.g., Intel's Pentium II, III,

IV, AMD Athlon CPU, Xilinx Virtex FPGAs, con-

nect the emitter and base of the remote sensor

to the MIC280 using the guard traces and Kelvin

return shown in Figure 6. The collector of the

remote diode is typically inaccessible to the user

November 2004

21

MIC280

on these devices. To allow for this, the MIC280

Micrel

6. Always place a good quality power supply

has superb rejection of noise appearing from

collector to GND.

bypass capacitor directly adjacent to, or under-

neath, the MIC280. This should be a 0.1 µF ce-

ramic capacitor. Surface-mount parts provide the

best bypassing because of their low inductance.

4. Due to the small currents involved in the mea-

surement of the remote diode’s ∆V , it is

BE

important to adequately clean the PC board after

soldering to prevent current leakage. This is

most likely to show up as an issue in situations

where water-soluble soldering ﬂuxes are used.

7. When the MIC280 is being powered from par-

ticularly noisy power supplies, or from supplies

which may have sudden high-amplitude spikes

appearing on them, it can be helpful to add ad-

ditional power supply ﬁltering. This should be

implemented as a 100Ω resistor in series with

5. In general, wider traces for the ground and T1

lines will help reduce susceptibility to radiated

noise (wider traces are less inductive). Use trace

widths and spacing of 10 mils wherever possible

and provide a ground plane under the MIC280

and under the connections from the MIC280 to

the remote diode. This will help guard against

stray noise pickup.

the part’s V pin, and a 4.7 µF, 6.3V electrolytic

DD

capacitor from V to GND. See Figure 7.

DD

MIC280

VDD

GND

T1

/INT

DATA

CLK

1

2

3

6

5

4

GUARD/RETURN

REMOTE DIODE (T1)

GUARD/RETURN

Figure 6. Guard Traces/Kelvin Ground Returns

3V to 3.6V

100Ω

3 ×

10k

MIC280

DATA

0.1µF

ceramic

4.7µF

5

4

6

1

3

2

VDD

T1

TO

CLK

/INT

SERIAL BUS

HOST

GND

2N3906/�

CPU DIODE

1800pF

Figure 7. V Decoupling for Very Noisy Supplies

DD

MIC280

22

November 2004

MIC280

Micrel

Package Information

1.90 (0.075) REF

0.95 (0.037) REF

1.75 (0.069) 3.00 (0.118)

1.50 (0.059) 2.60 (0.102)

DIMENSIONS:

MM (INCH)

1.30 (0.051)

0.90 (0.035)

3.00 (0.118)

2.80 (0.110)

0.20 (0.008)

0.09 (0.004)

10°

0°

0.15 (0.006)

0.00 (0.000)

0.50 (0.020)

0.35 (0.014)

0.60 (0.024)

0.10 (0.004)

6-Lead SOT23 (M6)

MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com

This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use.

Micrel reserves the right to change circuitry and speciﬁcations at any time without notiﬁcation to the customer.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can

reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into

the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a signiﬁcant injury to the user. A Purchaser's

use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify

Micrel for any damages resulting from such use or sale.

November 2004

23

MIC280


型号：	MIC280-7BM6
厂家：	MICREL SEMICONDUCTOR
描述：	Precision IttyBitty Thermal Supervisor 精密IttyBitty热监事
文件：	总23页 (文件大小：228K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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