MAX6690MEE+【PDF 14/16 页】IC TEMP SENSOR SMBUS 16-QSOP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录44

10页 11页 12页 13页 [14页]15页 16页

2癈 Accurate Remote/Local Temperature

Sensor with SMBus Serial Interface

14 ______________________________________________________________________________________

The MAX6690 incorporates collision avoidance so that

completely asynchronous operation is allowed between

SMBus operations and temperature conversions.

When autoconverting, if the T

HIGH

and T

LOW

limits are

close together, its possible for both high-temp and low-

temp status bits to be set, depending on the amount of

time between status read operations (especially when

converting at the fastest rate). In these circumstances,

it is best not to rely on the status bits to indicate rever-

sals in long-term temperature changes. Instead, use a

current temperature reading to establish the trend

direction.

Conversion Rate Byte

The conversion rate register (Table 8) programs the

time interval between conversions in free-running auto-

convert mode. This variable rate control can be used to

reduce the supply current in portable-equipment appli-

cations. The conversion rate bytes POR state is 02h

(0.25Hz). The MAX6690 looks only at the 3LSB bits of

this register, so the upper 5 bits are dont care bits,

which should be set to zero. The conversion rate toler-

ance is ?5% at any rate setting.

Valid A/D conversion results for both channels are

available one total conversion time (125ms nominal,

156ms maximum) after initiating a conversion, whether

conversion is initiated through the RUN/STOP bit, hard-

ware STBY/pin, one-shot command, or initial power-up.

Extended resolution and the parasitic resistance can-

cellation mode are available at conversion rates of 1Hz

or lower.

Slave Addresses

The MAX6690s device address can be set to one of

nine different values by pin strapping ADD0 and ADD1

so that more than one MAX6690 can reside on the

same bus without address conflicts (Table 9).

The address pin states are checked at POR only, and

the address data stays latched to reduce quiescent

supply current due to the bias current needed for high-

Z state detection.

The MAX6690 also responds to the SMBus Alert

Response slave address (see the Alert Response

Address section).

POR and UVLO

The MAX6690 has a volatile memory. To prevent

ambiguous power-supply conditions from corrupting

the data in memory and causing erratic behavior, a

POR voltage detector monitors V

and clears the

memory if V

falls below 2V (typ, see Electrical

Characteristics). When power is first applied and V

rises above 2.0V (typ), the logic blocks begin operat-

ing, although reads and writes at V

levels below 3V

are not recommended. A second V

comparator, the

ADC undervoltage lockout (UVLO) comparator, pre-

vents the ADC from converting until there is sufficient

headroom (V

= 2.8V typ).

BIT

NAME

POR

STATE

FUNCTION

7 (MSB)

BUSY

ADC is busy converting when high.

LHIGH

Internal high-temperature alarm has tripped when high; cleared by POR or readout

of the entire status byte if the fault condition no longer exists.

LLOW

Internal low-temperature alarm has tripped when high; cleared by POR or readout of

the entire status byte if the fault condition no longer exists.

RHIGH

External high-temperature alarm has tripped when high; cleared by POR or readout

of the entire status byte if the fault condition no longer exists.

RLOW

External low-temperature alarm has tripped when high; cleared by POR or readout

of the entire status byte if the fault condition no longer exists.

OPEN

A high indicates an external diode is open; cleared by POR or readout of the entire

status byte if the fault condition no longer exists.

1 or 0

RFU

Reserved.

Table 7. Status Byte Bit Assignments

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式