EFM8 Sleepy Bee Family
EFM8SB2 Data Sheet
The EFM8SB2, part of the Sleepy Bee family of MCUs, is the
world’s most energy friendly 8-bit microcontrollers with a compre-
hensive feature set in small packages.
These devices offer lowest power consumption by combining innovative low energy tech-
niques and short wakeup times from energy saving modes into small packages, making
them well-suited for any battery operated applications. With an efficient 8051 core, 6-bit
current reference, and precision analog, the EFM8SB2 family is also optimal for embed-
ded applications.
EFM8SB2 applications include the following:
• Hand-held devices
• Industrial controls
• Battery-operated consumer electronics
• Sensor interfaces
ENERGY FRIENDLY FEATURES
• Lowest MCU sleep current with supply
brownout detection (50 nA)
• Lowest MCU active current with these
features (170 μA / MHz at 24.5 MHz clock
rate)
• Lowest MCU sleep current using internal
RTC operating and supply brownout
detection (<300 nA)
• Ultra-fast wake up for digital and analog
peripherals (< 2 μs)
• Integrated low drop out (LDO) voltage
regulator to maintain ultra-low active
current at all voltages
Core / Memory
CIP-51 8051 Core
(25 MHz)
Flash Program
Memory
(up to 64 KB)
Clock Management
External
Oscillator
Low Power 20
MHz RC
Oscillator
High Frequency
24.5 MHz RC
Oscillator
Energy Management
Internal LDO
Regulator
Power-On Reset
RAM Memory
(4352 bytes)
Debug Interface
with C2
External 32 kHz
RTC Oscillator
Brown-Out Detector
8-bit SFR bus
Serial Interfaces
UART
2 x SPI
I/O Ports
External
Interrupts
General
Purpose I/O
Timers and Triggers
Timers
0/1/2/3
Watchdog
Timer
PCA/PWM
Real Time
Clock
Analog Interfaces
ADC
Comparator 1
Comparator 0
Internal Voltage
Reference
Security
16/32-bit CRC
Pin Reset
I
2
C / SMBus
Pin Wakeup
Internal Current Reference
Lowest power mode with peripheral operational:
Normal
Idle
Suspend
Sleep
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Rev. 1.1
EFM8SB2 Data Sheet
Feature List
1. Feature List
The EFM8SB2 highlighted features are listed below.
• Core:
• Pipelined CIP-51 Core
• Fully compatible with standard 8051 instruction set
• 70% of instructions execute in 1-2 clock cycles
• 25 MHz maximum operating frequency
• Memory:
• Up to 64 kB flash memory, in-system re-programmable
from firmware.
• Up to 4352 bytes RAM (including 256 bytes standard 8051
RAM and 4096 bytes on-chip XRAM)
• Power:
• Internal LDO regulator for CPU core voltage
• Power-on reset circuit and brownout detectors
• I/O: Up to 24 total multifunction I/O pins:
• Flexible peripheral crossbar for peripheral routing
• 5 mA source, 12.5 mA sink allows direct drive of LEDs
• Clock Sources:
• Internal 20 MHz low power oscillator with ±10% accuracy
• Internal 24.5 MHz precision oscillator with ±2% accuracy
• External RTC 32 kHz crystal
• External crystal, RC, C, and CMOS clock options
• Timers/Counters and PWM:
• 32-bit Real Time Clock (RTC)
• 6-channel programmable counter array (PCA) supporting
PWM, capture/compare, and frequency output modes with
watchdog timer function
• 4 x 16-bit general-purpose timers
• Communications and Digital Peripherals:
• UART
• 2 x SPI™ Master / Slave
• SMBus™/I2C™ Master / Slave
• External Memory Interface (EMIF)
• 16-bit/32-bit CRC unit, supporting automatic CRC of flash at
1024-byte boundaries
• Analog:
• Programmable current reference (IREF0)
• 10-Bit Analog-to-Digital Converter (ADC0)
• 2 x Low-current analog comparators
• On-Chip, Non-Intrusive Debugging
• Full memory and register inspection
• Four hardware breakpoints, single-stepping
• Pre-loaded UART bootloader
• Temperature range -40 to 85 ºC
• Single power supply 1.8 to 3.6 V
• QFP32, QFN32, and QFN24 packages
With on-chip power-on reset, voltage supply monitor, watchdog timer, and clock oscillator, the EFM8SB2 devices are truly standalone
system-on-a-chip solutions. The flash memory is reprogrammable in-circuit, providing non-volatile data storage and allowing field up-
grades of the firmware. The on-chip debugging interface (C2) allows non-intrusive (uses no on-chip resources), full speed, in-circuit
debugging using the production MCU installed in the final application. This debug logic supports inspection and modification of memory
and registers, setting breakpoints, single stepping, and run and halt commands. All analog and digital peripherals are fully functional
while debugging. Each device is specified for 1.8 to 3.6 V operation and is available in 24-pin QFN, 32-pin QFN, or 32-pin QFP pack-
ages. All package options are lead-free and RoHS compliant.
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Rev. 1.1 | 1
EFM8SB2 Data Sheet
Ordering Information
2. Ordering Information
EFM8 SB2 0 F 64 G
–
A
–
QFN32 R
Tape and Reel (Optional)
Package Type
Revision
Temperature Grade G (-40 to +85)
Flash Memory Size – 64 KB
Memory Type (Flash)
Family Feature Set
Sleepy Bee 2 Family
Silicon Labs EFM8 Product Line
Figure 2.1. EFM8SB2 Part Numbering
All EFM8SB2 family members have the following features:
• CIP-51 Core running up to 25 MHz
• Three Internal Oscillators (24.5 MHz, 20 MHz, and 16 kHz)
• SMBus / I2C
• 2 x SPI
• UART
• 6-Channel Programmable Counter Array (PWM, Clock Generation, Capture/Compare)
• 4 16-bit Timers
• 2 Analog Comparators
• 6-bit programmable current reference
• 10-bit Analog-to-Digital Converter with integrated multiplexer, voltage reference, and temperature sensor
• Low-current 32 kHz oscillator and Real Time Clock
• 16-bit CRC Unit
• Pre-loaded UART bootloader
In addition to these features, each part number in the EFM8SB2 family has a set of features that vary across the product line. The
product selection guide shows the features available on each family member.
Table 2.1. Product Selection Guide
(RoHS Compliant)
Ordering Part
ADC Channels
Memory (kB)
RAM (Bytes)
Digital Port
I/Os (Total)
Temperature
Comparator
Number
EFM8SB20F64G-A-QFN32
EFM8SB20F64G-A-QFP32
EFM8SB20F64G-A-QFN24
EFM8SB20F32G-A-QFN32
EFM8SB20F32G-A-QFP32
EFM8SB20F32G-A-QFN24
Flash
64
64
64
32
32
32
4352
4352
4352
4352
4352
4352
24
24
16
24
24
16
23
23
15
23
23
15
12
12
8
12
12
8
Yes
Yes
Yes
Yes
Yes
Yes
-40 to +85 C
-40 to +85 C
-40 to +85 C
-40 to +85 C
-40 to +85 C
-40 to +85 C
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Package
QFN32
QFP32
QFN24
QFN32
QFP32
QFN24
Rev. 1.1 | 2
Pb-free
Range
Inputs