PCF85263ATLSLASHAX datasheet(39/92 Pages) NXP

39 / 92 page

NXP Semiconductors

PCF85263A

Tiny Real-Time Clock/calendar with alarm function, battery switch-over, time stamp input, and I2C-bus

Bit

Symbol

Value

Description

0 [1]

normal

reduced CLK output jitter; increase IDD

Table 32. LOWJ bit - oscillator control register (address 25h)...continued

[1]

Default value.

Oscillator circuits suffer from jitter. In particular, ultra low-power oscillators like the one

used in the PCF85263A are optimized for power and not jitter. By setting the LOWJ bit,

the jitter performance can be improved at the cost of power consumption.

7.10.5 OSCD[1:0]: quartz oscillator drive control

Bit

Symbol

Value

Description

oscillator drive bits

00 [1]

normal drive; RS(max): 100 kΩ

low drive; RS(max): 60 kΩ; reduced IDD

3 to 2

OSCD[1:0]

10, 11

high drive; RS(max): 500 kΩ; increased IDD

Table 33. OSCD[1:0] bits - oscillator control register (address 25h)

[1]

Default value.

The oscillator is designed to be used with quartz with a series resistance up to 100 kΩ.

This covers the typical range of 32.768 kHz quartz crystals. Series resistance is also

referred to as: ESR, motional resistance, or RS.

A low drive mode is available for low series resistance quartz. This reduces the current

consumption.

For very high series resistance quartz, there is a high drive mode. Current consumption

increases substantially in this mode.

7.10.6 CL[1:0]: quartz oscillator load capacitance

Bit

Symbol

Value

Description

internal oscillator capacitor selection for

quartz crystals with the corresponding load

capacitance of CL:

00 [1]

7.0 pF

6.0 pF

12.5 pF

1 to 0

CL[1:0]

12.5 pF

Table 34. CL[1:0] bits - oscillator control register (address 25h)

[1]

Default value.

CL refers to the load capacitance of the oscillator circuit and allows for a certain amount

of package and PCB parasitic capacitance. When the oscillator circuit matches the CL

parameter of the quartz, then the frequency offset is zero.

PCF85263A

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

Product data sheet

Rev. 5 — 1 February 2021

39 / 92

PCF85263ATL/AX Datasheet(PDF) 39 Page - NXP Semiconductors

PCF85263ATL/AX Datasheet(HTML) 39 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 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

Datasheet Download

Link URL