MIC2203 Micrel Semiconductor, MIC2203 Datasheet - Page 2

• Manufacturer Part Number: MIC2203
• Description: High Efficiency 1MHz Synchronous Buck Regulator
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
Output Voltage
The output voltage on the MIC2203 evaluation board
is adjustable. The output voltage is controlled by the
feedback resistors (R1 and R2) and can be calculated
as follows:
The evaluation board is initially adjusted to 1.8V, but
can easily be modified by removing R2 and replacing
it with the value that yields the desired output voltage.
(Removing R2 sets the output to 0.5V.)
March 2005
V
OUT
R2 =
= 0.5V x
(
V
0.5V
OUT
(
R1
R2
- 1
)
+ 1
)
2
SYNC_IN
SYNC_IN is an input that allows the MIC2203 to
synchronize its internal switching frequency to an
external frequency source. The source must have
sufficient amplitude (down below 0.7V and above
1.7V). Again, careful attention should be paid to
avoid driving this pin above 5.5V. The range of
synchronization is around 20% of the fundamental
frequency. This pin can be tied high (to V
reduce the oscillator to its minimum frequency.
When not in use, this pin should be tied to ground.
The evaluation board accomplishes this through a
10kΩ resistor (R4).
SYNC_OUT
SYNC_OUT is an open collector output that tracks
the internal oscillator. A 10kΩ pull-up resistor is
required to use the SYNC_OUT function. The R3
location is reserved for this option. Applying the
SYNC_OUT signal to the SYNC_IN pin of another
MIC2203 converter allows both devices to run at the
same frequency.
MIC2203 Evaluation Board
[phone]
M9999-032305
IN
) to