PCA9620 datasheet(37/71 Pages) NXP

37 / 71 page

PCA9620

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

Product data sheet

Rev. 1 — 9 December 2010

37 of 71

NXP Semiconductors

PCA9620

Universal LCD driver for low multiplex rates

[1]

The relationship between the temperature coefficients MA to MD and the slope factor is derived from the

following equation:

[2]

Default value.

The slope factors imply a linear correction, however the implementation is set in steps of

30 mV (parameter n in Table 27 on page 31).

Remark: After reset, VLCD is fixed because the VPR[7:0] bit field is reset logic 0. The

value of VT[7:0] is generated by the reset value of TD[7:0] (40h, representing 20

°C).

Temperature compensation is implemented by adding an offset VT[7:0] to the VPR[7:0]

value. VT[7:0] is a two’s complement number that equals 0h at 20

°C. The final result for

VLCD calculation is an 8-bit positive number (see Equation 6 on page 31).

Remark: Care must be taken that the ranges of VPR[7:0] and VT[7:0] don’t cause clipping

and hence undesired results. The device will not permit overflow or underflow and will

clamp results to either end of the range.

Table 29.

Temperature coefficients

SLA[2:0] to SLD[2:0] value

Corresponding slope factor

(mV/

°C)

Temperature coefficients

MA, MB, MC, MD[1]

000[2]

00.00

001

−4

−0.125

010

−8

−0.25

011

−16

−0.5

100

−40

−1.25

101

0.125

110

0.25

111

+16

0.5

Fig 29. Example of segmented temperature coefficients

0.9375

0.03

----------------

slope

1000

--------------

Temperature (

°C)

−40

−10

013aaa261

TD[7:0]

60h

20h

zero offset

at 20

°C

7Fh

40h

SLA

SLB

SLC

SLD

PCA9620 датащи(PDF) 37 Page - NXP Semiconductors

PCA9620 датащи(HTML) 37 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71

датащи скачать

ссылки URL