User's Guide

LM940 HW Design Guide
1VV0301352 Rev. 2 Page 26 of 68 2017-07-19
4. POWER SUPPLY
The power supply circuitry and board layout are very important parts of the full product
design, with critical impact on the overall product performance. Read the following
requirements and guidelines carefully to ensure a good and proper design.
Power Supply Requirements
The LM940 power requirements are as follows:
Power Supply Requirements
Nominal supply voltage 3.3V
Supply voltage range 3.10V – 3.6V
Maximum ripple on module input supply 30 mV
Power Consumption
Below table provides typical current consumption values of LM940 for various operation
modes.
LM940 Current Consumption
Mode Average [Typ.] Mode Description
IDLE Mode
IDLE Mode 60.0 mA
No call connection
USB3.0 is connected to a host
Operative Mode (LTE)
LTE (22 dBm) 750 mA LTE data call (Non-CA BW 5MHz, RB=1)
1250 mA
LTE data call (CA_3A+7A+20A,
20MHz+20MHz+20MHz, Full RB, 256QAM
DL / 64QAM UL, FDD 600Mbps DL /
75Mbps UL)
Operative Mode (WCDMA)
WCDMA Voice 650 mA WCDMA voice call (Tx = 23 dBm)
WCDMA HSPA
(22 dBm)
650 mA
WCDMA data call (DC-HSDPA up to 42
Mbps, Max Throughput)
* Worst/best case current values depend on network configuration - not under module
control.
** Applied MPR –2dB 16-QAM full RB
*** 3.3 voltage / room temperature