UPMU-M3L1X-B-EK Silicon Labs, UPMU-M3L1X-B-EK Datasheet - Page 33

• Manufacturer Part Number: UPMU-M3L1X-B-EK
• Description: Daughter Cards & OEM Boards UDP SiM3L1xx MCU Card (no LCD)
• Manufacturer: Silicon Labs

Specifications of UPMU-M3L1X-B-EK

• Product: MCU Cards
• Core: ARM Cortex M3
• Data Bus Width: 32 bit
• Description/function: MCU Card (No LCD) to use with UDP Motherboard
• Interface Type: I2C, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Tool Is For Evaluation Of: SiM3L1xx
• For Use With: SiM3L1xx

4.1. Power
The SiM3L1xx devices include a dc-dc buck converter that can take an input from 1.8–3.8 V and create an output
from 1.25–3.8 V. In addition, SiM3L1xx devices include three low dropout regulators as part of the LDO0 module:
one LDO powers the analog subsystems, one LDO powers the flash and SRAM memory at 1.8 V, and one LDO
powers the digital and core circuitry. Each of these regulators can be independently powered from the dc-dc
converter or directly from the battery voltage, and their outputs are adjustable to conserve system power. SiM3L1xx
devices also include a low power charge pump in the PMU module for use in low power modes (PM8) to further
reduce the power consumption of the device.
Figure 4.2 shows the power system configuration of these devices.
4.1.1. DC-DC Buck Converter (DCDC0)
SiM3L1xx devices include an on-chip step-down dc-dc converter to efficiently utilize the energy stored in the
battery, thus extending the operational life time. The dc-dc converter is a switching buck converter with a
programmable output voltage that should be at least 0.45 V lower than the input battery voltage; if this criteria is not
met and the converter can no longer operate, the output of the dc-dc converter automatically connects to the
battery. The dc-dc converter can supply up to 100 mA and can be used to power the MCU and/or external devices
in the system.
The dc-dc converter has a built in voltage reference and oscillator and will automatically limit or turn off the
switching activity in case the peak inductor current rises beyond a safe limit or the output voltage rises above the
programmed target value. This allows the dc-dc converter output to be safely overdriven by a secondary power
source (when available) in order to preserve battery life. When enabled, the dc-dc converter can source current
into the output capacitor, but cannot sink current.
The dc-dc converter includes the following features:





Efficiently utilizes the energy stored in a battery, extending its operational lifetime.
Input range: 1.8 to 3.8 V.
Output range: 1.25 to 3.8 V in 50 mV (1.25–1.8 V) or 100 mV (1.8–3.8 V) steps.
Supplies up to 100 mA.
Includes a voltage reference and an oscillator.
VBAT/VBATDC
LDO0
Figure 4.2. SiM3L1xx Power
Converter
SiM3L1xx Device
DC-DC
Mode Charge
Low Power
Memory LDO
Analog LDO
Digital LDO
Pump
Rev 0.5
to digital
and core
to memory
to analog
to PM8
peripherals
IND
VDC
VSSDC
VSS
VDRV
SiM3L1xx
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