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CAT6095

Digital Output Temperature Sensor

ON Semiconductor 

CAT6095

REGISTER DATA FORMAT

The values used in the temperature data register and

the 3 temperature trip point registers are expressed in

two’s complement format. The measured temperature

value is expressed with 12-bit resolution, while the 3

trip temperature limits are set with 10-bit resolution. The

total temperature range is arbitrarily defined as 256°C,

thus yielding an LSB of 0.0625°C for the measured

temperature and 0.25°C for the 3 limit values. Bit B12 in

all temperature registers represents the sign, with a ‘0’

indicating a positive, and a ‘1’ a negative value. In two’s

complement format, negative values are obtained by

complementing their positive counterpart and adding a

‘1’, so that the sum of opposite signed numbers, but of

equal absolute value, adds up to zero.

Note that trailing ‘0’ bits, are ‘0’ irrespective of polarity.

Therefore the don’t care bits (B1 and B0) in the 10-bit

resolution temperature limit registers, are always ‘0’.

12-Bit Temperature Data Format

Binary (B12 to B0)

1 1100 1001 0000

1 1100 1110 0000

1 1110 0111 0000

1 1111 1111 1111

0 0000 0000 0000

0 0000 0000 0001

0 0001 1001 0000

0 0011 0010 0000

0 0111 1101 0000

Hex

1C90

1CE0

1E70

1FFF

000

001

190

320

7D0

Temperature

−55°C

−50°C

−25°C

−0.0625°C

0°C

+0.0625°C

+25°C

+50°C

+125°C

EVENT PIN FUNCTIONALITY

The E¯¯V¯E¯N¯T¯ output reacts to temperature changes as

illustrated in Figure 8, and according to the operating

mode defined by the Configuration register.

In Interrupt Mode, the enabled E¯¯V¯E¯N¯T¯ output will be

asserted every time the temperature crosses one of

the alarm window limits, and can be de-asserted by

writing a ‘1’ to the clear event bit (B5) in the

configuration register. When the temperature exceeds

the critical limit, the event remains asserted as long as

the temperature stays above the critical limit and can

not be cleared.

In Comparator Mode, the E¯¯V¯E¯N¯T¯ output is asserted

outside the alarm window limits, while in Critical

Temperature Mode, E¯¯V¯E¯N¯T¯ is asserted only above

the critical limit. The exact trip limits are determined by

the 3 temperature limit settings and the hystersis

offsets, as illustrated in Figure 9.

Following a TS shut-down request, the converter is

stopped and the most recently recorded temperature

value present in the TDR is frozen; the E¯¯V¯E¯N¯T¯ output

will continue to reflect the state immediatelly

preceding the shut-down command. Therefore, if the

state of the E¯¯V¯E¯N¯T¯ output creates an undesirable bus

condition, appropriate action must be taken either

before or after shutting down the TS. This may require

clearing the event, disabling the E¯¯V¯E¯N¯T¯ output or

perhaps changing the E¯¯V¯E¯N¯T¯ output polarity.

In normal use, events are triggered by a change in

recorded temperature, but the CAT6095 will also

respond to limit register changes. Whereas recorded

temperature values are updated at sampling rate

frequency, limits can be modified at any time. The

enabled E¯¯V¯E¯N¯T¯ output will react to limit changes as

soon as the respective registers are updated.This

feature may be useful during testing.

Doc. No. MD-1124 Rev. D

14

© 2009 SCILLC. All rights reserved.

Characteristics subject to change without notice

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