PCA8538UG(2014) View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

MFG CO.

PCA8538UG
(Rev.:2014)

Automotive 102 x 9 Chip-On-Glass LCD segment driver

NXP Semiconductors. 

NXP Semiconductors

PCA8538

Automotive 102 x 9 Chip-On-Glass LCD segment driver

8.10.4 Temperature measurement and temperature compensation of VLCD

8.10.4.1 Temperature readout

The PCA8538 has a built-in temperature sensor which provides an 8-bit digital value

(TD[7:0]) of the ambient temperature. This value can be read by command (see

Section 8.2.6 on page 12 and Section 8.2.7 on page 12). The actual temperature is

determined from TD[7:0] using Equation 3.

TC = 0.6275  TD7:0 – 40

(3)

TD[7:0] = FFh means that no temperature readout is available or was performed. FFh is

the default value after Power-On Reset (POR). The measurement needs about 8 ms to

complete. It is repeated periodically every second as long as bit TME is set logic 1 (see

Table 17 on page 15).

Due to the nature of a temperature sensor, oscillations may occur. To avoid this, a filter

has been implemented in PCA8538. A control bit, TMF, is implemented to enable or

disable the digital temperature filter (see Table 17 on page 15). The system is exemplified

in Figure 21.

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Fig 21. Temperature measurement block with digital temperature filter

The digital temperature filter introduces a certain delay in the measurement of the

temperature. This behavior is illustrated in Figure 22.

PCA8538

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 4 — 26 September 2014

© NXP Semiconductors N.V. 2014. All rights reserved.

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