Specifications
Table Of Contents
- Contents
- Tables
- Figures
- 1 Introduction
- 2 Interface Characteristics
- 2.1 Application Interface
- 2.2 RF Antenna Interface
- 2.3 Sample Application
- 3 Operating Characteristics
- 3.1 Operating Modes
- 3.2 Power Up/Power Down Scenarios
- 3.3 Power Saving
- 3.4 Power Supply
- 3.5 Operating Temperatures
- 3.6 Electrostatic Discharge
- 3.7 Blocking against RF on Interface Lines
- 3.8 Reliability Characteristics
- 4 Mechanical Dimensions, Mounting and Packaging
- 5 Regulatory and Type Approval Information
- 6 Document Information
- 7 Appendix
Cinterion
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ELS81-US Hardware Interface Description
3.2 Power Up/Power Down Scenarios
77
els81-us_hid_v01.004 2017-09-27
Confidential / Preliminary
Page 55 of 107
3.2 Power Up/Power Down Scenarios
In general, be sure not to turn on ELS81-US while it is beyond the safety limits of voltage and
temperature stated in Section 2.1.2.1. ELS81-US immediately switches off after having started
and detected these inappropriate conditions. In extreme cases this can cause permanent dam-
age to the module.
3.2.1 Turn on ELS81-US
ELS81-US can be turned on as described in the following sections:
• Connecting the operating voltage BATT+ (see Section 3.2.1.1).
• Hardware driven switch on by ON line: Starts Normal mode (see Section 3.2.1.2).
After startup or restart, the module will send the URC ^SYSSTART that notifies the host appli-
cation that the first AT command can be sent to the module (see also [1]).
3.2.1.1 Connecting ELS81-US BATT+ Lines
Figure 29 shows sample external application circuits that allow to connect (and also to tempo-
rarily disconnect) the module‘s BATT+ lines from the external application‘s power supply.
Figure 29 illustrates the application of power employing an externally controlled microcontrol-
ler. The voltage supervisory circuit ensures that the power is disconnected and applied again
depending on given thresholds.
The transistor T2 mentioned in Figure 29 should have an R
DS_ON
value < 50m in order to min-
imize voltage drops.
Such circuits could be useful to maximize power savings for battery driven applications or to
completely switch off and restart the module after a firmware update.
After connecting the BATT+ lines the module can then be (re-)started as described in Section
3.2.1.2 and Section 3.2.2.