SI7005EVB-UDP View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

Manufacturer

SI7005EVB-UDP

DIGITAL I2C HUMIDITY AND TEMPERATURE SENSOR

Silicon Laboratories 

Si7005

5.1.3. Fast Conversion Mode

The time needed to perform a temperature or RH measurement can be reduced from 35 ms (typical) to 18 ms

(typical) by setting FAST (D5) in CONFIG (register 0x03). Fast mode reduces the total power consumed during a

conversion or the average power consumed by the Si7005 when making periodic conversions. It also reduces the

resolution of the measurements. Table 18 is a comparison of the normal and fast modes.

Table 18. Normal vs. Fast Mode

Parameter

tCONV (typical)

Temperature resolution

RH resolution

Value

Normal Mode Fast Mode

35 ms

18 ms

14-bit

13-bit

12-bit

11-bit

5.1.4. Heater

The Si7005 relative humidity sensor contains an integrated, resistive heating element that may be used to raise the

temperature of the humidity sensor. This element can be used to drive off condensation or to implement dew-point

measurement when the Si7005 is used in conjunction with a separate temperature sensor such as another Si7005.

The heater can be activated by setting HEAT (D1) in CONFIG (register 0x03). Turning on the heater will reduce the

tendency of the humidity sensor to accumulate an offset due to “memory” of sustained high humidity conditions.

When the heater is enabled, the reading of the on-chip temperature sensor will be affected (increased).

5.1.5. Device Identification

The Si7005 device and its revision level can be determined by reading ID (register 0x11). Table 19 lists the values

for the various device revisions and may include revisions not yet in existence.

Table 19. Device ID Revision Values

Device ID Value

D[7:4]

D[3:0]

0101

0000

Device Revision

Type

Level

Si7005

B

22

Rev. 1.3

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