LPC11E36 Datasheet, PDF(53/66 Page) NXP Semiconductors – 32-bit ARM Cortex-M0 microcontroller up to 128 kB flash up to 12 kB SRAM and 4 kB EEPROM USART

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LPC11E36 Datasheet, PDF (53/66 Pages) NXP Semiconductors – 32-bit ARM Cortex-M0 microcontroller up to 128 kB flash up to 12 kB SRAM and 4 kB EEPROM USART

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NXP Semiconductors

LPC11E3x

32-bit ARM Cortex-M0 microcontroller

11.4 Reset pad configuration

VDD

Rpu

VDD

ESD

reset

20 ns RC

GLITCH FILTER

ESD

Fig 28. Reset pad configuration

VSS

002aaf274

11.5 ADC effective input impedance

A simplified diagram of the ADC input channels can be used to determine the effective

input impedance seen from an external voltage source. See Figure 29.

LPC11E3X

Product data sheet

ADC Block

ADC

COMPARATOR

Rmux

<2 kÎ©

Cia

Rsw

<1.3 kÎ©

Source

Rin

Cio

VEXT

VSS

002aah615

Fig 29. ADC input channel

The effective input impedance, Rin, seen by the external voltage source, VEXT, is the

parallel impedance of ((1/fs x Cia) + Rmux + Rsw) and (1/fs x Cio), and can be calculated

using Equation 1 with

fs = sampling frequency

Cia = ADC analog input capacitance

Rmux = analog mux resistance

Rsw = switch resistance

Cio = pin capacitance

Rin

ï¦

ï¨

--------1---------

fs ï´ Cia

Rmu

ï¶

wï¸

ï¼ï¼

ï¦

ï¨

f--s----ï´--1--C-----i-o-ï¸ï¶

(1)

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

Rev. 2 â 21 November 2013

53 of 66

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