TMP512 datasheet(20/62 Pages) TI2

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TMP512

TMP513

SBOS491A

– JUNE 2010 – REVISED MAY 2011

www.ti.com

HIGH-SPEED MODE

SENSOR FAULT

In order for the two-wire bus to operate at frequencies

The

TMP512/13

can

sense

open

circuit.

above 400kHz, the master device must issue a

Short-circuit conditions return a value of

–256°C. The

High-Speed mode (Hs-mode) master code (0000

detection circuitry consists of a voltage comparator

1xxx) as the first byte after a START condition to

that trips when the voltage at DXP exceeds (V+)

–

switch

the

bus

high-speed

operation.

The

0.6V (typical). The comparator output is continuously

TMP512/13 do not acknowledge this byte, but switch

checked during a conversion. If a fault is detected,

the input filters on SDA and SCL and the output filter

the OPEN bit (bit 0) in the temperature result register

on SDA to operate in Hs-mode, allowing transfers at

is set to '1' and the rest of the register bits should be

up to 3.4MHz. After the Hs-mode master code has

ignored.

been issued, the master transmits a START condition

When

not

using

the

remote

sensor

with

the

to a two-wire slave address that initiates a data

TMP512/13, the DXP and DXN inputs must be

transfer operation. The bus continues to operate in

connected together to prevent meaningless fault

Hs-mode until a STOP condition occurs on the bus.

warnings.

Upon receiving the STOP condition, the TMP512/13

switch the input and output filters back to Fast mode

UNDERVOLTAGE LOCKOUT

operation.

The

TMP512/13

sense

when

the

power-supply

POWER-UP CONDITIONS

voltage has reached a minimum voltage level for the

ADC to function. The detection circuitry consists of a

Power-up conditions apply to a software reset via the

voltage comparator that enables the ADC after the

RST bit (bit 15) in the Configuration Register, or the

power supply (V+) exceeds 2.7V (typical). The

two-wire bus General Call Reset. At device power up,

comparator output is continuously checked during a

all Status bits are masked, and the SMBus Alert

conversion. The TMP512/13 do not perform a

function is disabled. All watchdog outputs default to

temperature conversion if the power supply is not

active low and transparent (non-latched) modes.

valid. The PVLD bit (see Status Register; Local

Temperature Reset Register; Remote Temperature

SHUTDOWN MODE

Reset 1, 2 and 3 Registers) of the individual

Local/Remote Temperature Result Registers are set

The TMP512/13 shutdown mode of operation allows

to '1' and the temperature result may be incorrect.

the user flexibility to shut down the shunt/bus voltage

measurement and the temperature measurement

functions individually.

TEMPERATURE AVERAGING

To shut down the shunt/bus voltage measurement

The TMP512/13 average the input diode voltages

function

immediately,

set

bits

through

that determine the remote temperature by sampling

Configuration Register 1 (00h) to '000' respectively.

multiple

times

throughout

conversion.

The

To shut down the shunt/bus voltage measurement

temperature

result

can

extracted

from

four

after the end of the current conversion, set bits 2

different VBE readings and is sampled 600 times in

through 0 in Configuration Resister 1 (00h) to '100'

130ms (max). Each VBE voltage is sampled 150 times

respectively.

through

integration

capacitors

that

average

the

results throughout the conversion time. A delta-sigma

To shut down the temperature measurement function

(

ΔΣ) modulator and digital filter integrate the VBE

immediately, set bits 15 through 11 in Configuration

voltages and create a sync filter averaging system. In

addition, a low-pass filter is present at the input of the

down the temperature measurement after the end of

converter with a cutoff frequency of 65kHz. This

the current conversion, set bit 15 in Configuration

integrating topology offers superior noise immunity.

FILTERING

ONE-SHOT COMMAND

Remote junction temperature sensors are usually

For the TMP512/13, when the temperature core is in

implemented in a noisy environment. Noise is

shutdown and the voltage core is in triggered mode, a

frequently generated by fast digital signals and if not

single conversion is started on all enabled channels

filtered properly will induce errors that can corrupt

by writing a '1' to the OS bit in Configuration Register

temperature measurements. The TMP512/13 have a

1. This write operation starts one conversion; the

built-in 65kHz filter on the inputs of DXP and DXN to

TMP512/13 returns to shutdown mode when that

minimize the effects of noise. However, a bypass

conversion completes. At the end of the conversion,

capacitor placed differentially across the inputs of the

the Conversion Ready flags (bit 6 and bit 5) in the

remote temperature sensor is recommended to make

Status Register are set to indicate end of conversion.

the

application

robust

against

unwanted

coupled signals. The value of this capacitor should be

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