Si501/2/3/4
LVCMOS CMEMS Programmable Oscillator Series
Applications Circuits
VDD
R
UP
FS/OE
®
VDD
VDD
VDD
~50K
FS/OE
R
DOWN
CLK
1
Si501/2
4
VDD
0.1uF
VDD
R
UP
1
Si503
4
VDD
0.1uF
Z
0
= 50
GND
2
3
CLK
R
S
Z
0
= 50
GND
2
3
CLK
CLK
R
S
Si501/2 Apps Circuit w/ Optional Series Resistor
Si503 Apps Circuit w/ Configurable Options
Notes:
1. Dotted line boxes show optional components depending on configuration options. See data sheet for additional information and for
applications using a microcontroller. Data sheet is available at
2. Recommended series termination resistor (R
S
) = 24.9
for Z
0
= 50
.
Si502 FS/OE States and Resistor Values
FS/OE State
R
UP
Strong High
0
≤ R
UP
≤ 1 k
Weak High
20 k ≤ R
UP
≤ 200 k
Low
—
Clock Output
Frequency 1
Frequency 2
Hi-Z
Si503 FS States and Resistor Values
FS/OE State
R
UP
R
DOWN
Clock Output
No pop
Strong High
Frequency 1
0
≤ R
UP
≤ 1 k
No pop
Weak High 20 k ≤ R
UP
≤ 200 k
Frequency 2
Weak Low
No pop
20 k ≤ R
DOWN
≤ 200 k Frequency 3
Low
No pop
Frequency 4
0
≤ R
DOWN
≤ 1 k
Notes for both FS/OE tables above:
1. If the internal pull-up resistor order option is NOT selected, an MCU internal pull-up resistor or an external pull-up resistor should be used.
See data sheet for more information.
2. The parallel combination of all pull-up resistors on the FS/OE pin including the optional internal pull-up resistor must be > 20 k to select
Weak High.
3. If the Si50x internal pull-up resistor is enabled with no other external OE connections, the OE state will be detected as “Weak High”,
selecting Frequency 2 by default.
4
Revision 0.72
SILABS [ SILICON LABORATORIES ]
