LPC1112FHN24/2021 NXP Semiconductors, LPC1112FHN24/2021 Datasheet - Page 92

• Manufacturer Part Number: LPC1112FHN24/2021
• Description: ARM Microcontrollers - MCU
• Manufacturer: NXP Semiconductors

Specifications of LPC1112FHN24/2021

• Rohs: yes
• Core: ARM Cortex M0
• Processor Series: LPC1112
• Data Bus Width: 32 bit
• Maximum Clock Frequency: 50 MHz
• Program Memory Size: 16 KB
• Data Ram Size: 2 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 1.8 V to 3.6 V
• Package / Case: HVQFN-24
• Mounting Style: SMD/SMT
• Factory Pack Quantity: 2450

NXP Semiconductors
LPC111X
Product data sheet
11.8 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
The effective input impedance, R
parallel impedance of ((1/f
using
Under nominal operating condition V
frequency fs = 400 kHz, the parameters assume the following values:
The effective input impedance with these parameters is R
Fig 49. ADC input channel
f
C
R
R
C
C
R
R
C
s
ia
mux
sw
io
ia
mux
sw
io
= sampling frequency
= ADC analog input capacitance
= pin capacitance
= 1 pF (max)
= 7.1 pF (max)
Equation 1
= switch resistance
= 1.3 kΩ (max)
= analog mux resistance
= 2 kΩ (max)
COMPARATOR
ADC
All information provided in this document is subject to legal disclaimers.
with
Rev. 8 — 20 February 2013
ADC Block
R
C ia
s
V
in
SS
x C
=
<2 kΩ
R mux
ia


) + R
----------------- -
f
in
s
, seen by the external voltage source, V

1
C
DD
mux
ia
<1.3 kΩ
R sw
LPC1110/11/12/13/14/15
= 3.3 V and with the maximum sampling
+
+ R
R
mux
sw
) and (1/f
+
32-bit ARM Cortex-M0 microcontroller
R
sw





s
----------------- -
f
C io
s
x C
in

1
= 308 kΩ.
C
R in
Figure
io
io
), and can be calculated


R s
49.
Source
© NXP B.V. 2013. All rights reserved.
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