Quectel EC21 Series User Manual

LTE Standard Module Series
EC21_Series_Hardware_Design
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Figure 7: Power Supply Limits during Burst Transmission
To decrease voltage-drop, use bypass capacitors of at least 100 µF with low ESR, and reserve a multi-
layer ceramic chip capacitor (MLCC) array due to their low ESR. It is recommended to use at least three
ceramic capacitors (100 nF, 33 pF, 10 pF) for composing the MLCC array, and place these capacitors
close to VBAT_BB and VBAT_RF pins. The main power supply from an external application has to be a
single voltage source and can be expanded to two sub paths with star structure. The width of VBAT_BB
trace should be no less than 1 mm; and the width of VBAT_RF trace should be no less than 2 mm. In
principle, the longer the VBAT trace is, the wider it will be.
In addition, in order to avoid the damage caused by electric surge and ESD, it is suggested that a TVS
diode with suggested low reverse stand-off voltage V
RWM
4.5 V, low clamping voltage V
C
and high reverse
peak pulse current I
PP
should be used. The following figure shows the star structure of the power supply.
Figure 8: Star Structure of the Power Supply
3.6.3. Reference Design for Power Supply
The performance of the module largely depends on the power source. The power supply should be able

Quectel EC21 Series Specifications

General

Category	Control Unit
Form Factor	LCC
Operating Temperature	-40°C to +85°C
Storage Temperature	-45°C to +90°C
Power Consumption	TBD
Network Support (LTE TDD)	B38/B40/B41
Network Support (GSM)	850/900/1800/1900 MHz
Module Type	LTE Cat 1
Supply Voltage	3.3V
Interface	USB 2.0
SIM Interface	1.8V/3.0V
Data Rate (Downlink)	10 Mbps
Data Rate (Uplink)	5Mbps
Network Support (LTE FDD)	B1/B3/B5/B8/B20
GNSS	GPS/GLONASS/BeiDou
Certifications	CE, FCC, GCF, PTCRB

Summary

2 Product Overview

2.1. Frequency Bands and Functions

2.2. Key Features

Details key features of the EC21 series module, including power supply and transmission.

3 Application Interfaces

3.2. Pin Assignment

Visual representation of the EC21 series module's pin assignment (top view).

3.3. Pin Description

Detailed description of each pin's I/O type, function, and characteristics.

3.5. Power Saving

4 RF Specifications

4.1. Cellular Network

Details antenna interfaces, frequency bands, and operating frequencies for cellular network.

4.2. GNSS

Covers GNSS antenna interface, frequencies, and performance metrics.

4.4. Antenna Design Requirements

5 Electrical Characteristic and Reliability

5.1. Absolute Maximum Ratings

5.2. Power Supply Ratings

5.4. Power Consumption

Presents current consumption values for various operating states and conditions.

5.5. ESD

5.6. Thermal Dissipation

6 Mechanical Information

6.1. Mechanical Dimensions

Provides the physical dimensions and tolerances of the EC21 module.

6.2. Recommended Footprint

Offers a recommended PCB footprint for the EC21 series module.

7 Storage, Manufacturing and Packaging

7.2. Manufacturing and Soldering

Guides on manufacturing processes, soldering, and thermal profiles.