C8051T633-GM Silicon Laboratories Inc, C8051T633-GM Datasheet - Page 108
![IC MCU 4KB 20PIN QFN](/photos/12/25/122567/silicon_laboratories_inc-20-qfn_sml.jpg)
C8051T633-GM
Manufacturer Part Number
C8051T633-GM
Description
IC MCU 4KB 20PIN QFN
Manufacturer
Silicon Laboratories Inc
Series
C8051T63xr
Specifications of C8051T633-GM
Core Processor
8051
Core Size
8-Bit
Speed
25MHz
Connectivity
SMBus (2-Wire/I²C), SPI, UART/USART
Peripherals
POR, PWM, WDT
Number Of I /o
17
Program Memory Size
4KB (4K x 8)
Program Memory Type
OTP
Ram Size
768 x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 3.6 V
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
20-QFN
Processor Series
C8051T6x
Core
8051
Data Bus Width
8 bit
Data Ram Size
768 B
Interface Type
UART, SPI, SMBus
Maximum Clock Frequency
25 MHz
Number Of Programmable I/os
17
Number Of Timers
4 x 16-bit
Operating Supply Voltage
1.8 V to 3.6 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
3rd Party Development Tools
PK51, CA51, A51, ULINK2
Development Tools By Supplier
C8051T630DK
Minimum Operating Temperature
- 40 C
For Use With
336-1464 - KIT DEV FOR C8051T630 FAMILY
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Data Converters
-
Lead Free Status / Rohs Status
Details
Other names
336-1461-5
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
C8051T633-GM
Manufacturer:
Silicon
Quantity:
270
C8051T630/1/2/3/4/5
19.4.1. External RC Example
If an RC network is used as an external oscillator source for the MCU, the circuit should be configured as
shown in Figure 19.1, “RC Mode”. The capacitor should be no greater than 100 pF; however for very small
capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To deter-
mine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first
select the RC network value to produce the desired frequency of oscillation, according to Equation 19.1,
where f = the frequency of oscillation in MHz, C = the capacitor value in pF, and R = the pull-up resistor
value in k.
For example: If the frequency desired is 100 kHz, let R = 246 k and C = 50 pF:
f = 1.23( 10
Referring to the table in SFR Definition 19.5, the required XFCN setting is 010b.
19.4.2. External Capacitor Example
If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in
Figure 19.1, “C Mode”. The capacitor should be no greater than 100 pF; however for very small capacitors,
the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the
required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the capaci-
tor to be used and find the frequency of oscillation according to Equation 19.2, where f = the frequency of
oscillation in MHz, C = the capacitor value in pF, and V
For example: Assume V
f = KF / (C x VDD)
0.150 MHz = KF / (C x 3.0)
Since the frequency of roughly 150 kHz is desired, select the K Factor from the table in SFR Definition 19.5
(OSCXCN) as KF = 22:
0.150 MHz = 22 / (C x 3.0)
C x 3.0 = 22 / 0.150 MHz
C = 146.6 / 3.0 pF = 48.8 pF
Therefore, the XFCN value to use in this example is 011b and C = 50 pF.
108
3
) / RC = 1.23 ( 10
Equation 19.1. RC Mode Oscillator Frequency
DD
Equation 19.2. C Mode Oscillator Frequency
= 3.0 V and f = 150 kHz:
3
) / [ 246 x 50 ] = 0.1 MHz = 100 kHz
f
f
=
=
1.23 10
KF
Rev. 1.0
R V
3
DD
R C
= the MCU power supply in Volts.
DD