MIC2202_07 Datasheet, PDF (6/19 Pages) Micrel Semiconductor – High Efficiency 2MHz Synchronous Buck Converter 1μF Stable PWM Regulator

Micrel, Inc.
Functional Description
VIN
VIN provides power to the output and to the internal bias
supply. The supply voltage range is from 2.3V to 5.5V. A
minimum 1µF ceramic is recommended for bypassing
the input supply.
Enable
The enable pin provides a logic level control of the
output. In the off state, supply current of the device is
greatly reduced (typically <1µA). Also, in the off state,
the output drive is placed in a “tri-stated” condition,
where both the high side P-Channel MOSFET and the
low-side N-Channel are in an off or non-conducting
state. Do not drive the enable pin above the supply
voltage.
Sync_In
Sync_In pin enables the ability to change the funda-
mental switching frequency. The Sync_In frequency has
a minimum frequency of 1.6MHz and a maximum sync
frequency of 2.5MHz.
Careful attention should be paid to not driving the
Sync_In pin greater than the supply voltage. While this
will not damage the device, it can cause improper
operation.
MIC2202
Sync_Out
Sync_Out is an open collector output that provides a
signal equal to the internal oscillator frequency. This
creates the ability for multiple MIC2202s to be connected
together in a master-slave configuration for frequency
matching of the converters. A typical 10kΩ is
recommended for a pull-up resistor.
Bias
The bias supply is an internal 2.3V linear regulator that
supplies the internal biasing voltage to the MIC2202. A
10nF ceramic capacitor is required on this pin for
bypassing. Do not use the bias pin as a supply. The bias
pin was designed to supply internal power only.
Feedback
The feedback pin provides the control path to control the
output. A resistor divider connecting the feedback to the
output is used to adjust the desired output voltage. Refer
to the feedback section in the “Applications Information”
for more detail.
MIC2202
“Master”
VIN
SW
BIAS
SYNC_IN
SYNC_OUT
FB
MIC2202
“Slave”
VIN
SW
BIAS
SYNC_IN
SYNC_OUT
FB
Figure 1. Master-Slave Operation
March 2007
6
M9999-031907