User's Manual
Table Of Contents
- 1 Introduction
- 2 General Product Description
- 3 Application Interface
- 3.1 Power Supply
- 3.2 Reset
- 3.3 Serial Interface
- 3.4 GPIO Interface
- 3.5 I2C Interface 0F
- 3.6 SPI Serial Peripheral Interface
- 3.7 Bluetooth Radio Interface
- 1.1
- 3.8 NFC Function
- 3.9 Slow Clock Interface
- 3.10 Test Mode
- 3.11 Operating in a Power-Switched Environment
- 3.12 Serial Wire Debug Interface
- 3.13 DC/DC Converter
- 4 Module Pins
- 5 Electrical Characteristics
- 6 Mechanical Characteristics
- 7 Application Diagram
- 8 Compliances
- 9 Packing
- 10 Ordering Information
- 11 Safety Recommendations
- 12 Document History
BlueMod+S42 Hardware User Guide
1VV0301303 Rev.3 – 2016-08-22
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 41 of 62
5.4.5 Analog ADC Input AIN
When the ADC is not sampling the AIN input pin has very high impedance and can be
regarded as open circuit.
Table 14 shows the internal impedance for AIN during
sampling for different prescaler settings.
This impedance has to be taken into account when using additional external voltage dividers.
Prescaler
Impedance R
AIN
Unit
min. typ. Max.
1 / 1 120 130 140 kΩ
2 / 3 180 195 210 kΩ
1 / 3 365 390 415 kΩ
Table 14: Input Impedance for AIN
Maximum allowed input voltage at AIN:
(Both of the following rules have to be fulfilled)
• The ADC may not be exposed to voltages >2,4V after the AIN prescaler
and
• The AIN pin must not be exposed to voltages >VDD + 0,3V