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

n = 2 for 1:2 multiplex

n = 4 for 1:4 multiplex

n = 6 for 1:6 multiplex

n = 8 for 1:8 multiplex

n = 9 for 1:9 multiplex

The RMS off-state voltage (Voff(RMS)) for the LCD is calculated with Equation 5:

VoffRMS

=

VLCD

--a---2----–----2----a----+-----n---

n  1 + a2

(5)

Discrimination is the ratio of Von(RMS) to Voff(RMS) and is determined from Equation 6:

D = -V----o---n----R---M----S--- = a----2---+-----2----a----+-----n--

(6)

VoffRMS

a2 – 2a + n

VLCD is sometimes referred as the LCD operating voltage.

8.10.5.1 Electro-optical performance

Suitable values for Von(RMS) and Voff(RMS) are dependent on the LCD liquid used. The

RMS voltage, at which a pixel is switched on or off, determine the transmissibility of the

pixel.

For any given liquid, there are two threshold values defined. One point is at 10 % relative

transmission (at Vth(off)) and the other at 90 % relative transmission (at Vth(on)), see

Figure 24.

For a good contrast performance, the following rules should be followed:

VonRMS  Vthon

(7)

VoffRMS  Vthoff

(8)

Von(RMS) and Voff(RMS) are properties of the display driver and are affected by the selection

of a, n (see Equation 4 to Equation 6) and the VLCD voltage.

Vth(off) and Vth(on) are properties of the LCD liquid and can be provided by the module

manufacturer. Vth(off) is sometimes named Vth. Vth(on) is sometimes named saturation

voltage Vsat.

It is important to match the module properties to those of the driver in order to achieve

optimum performance.

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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