MIC2204BMM Micrel Inc, MIC2204BMM Datasheet - Page 10

• Manufacturer Part Number: MIC2204BMM
• Description: IC CONV SYNC BUCK PWM HE 10MSOP
• Manufacturer: Micrel Inc
• Type: Step-Down (Buck)r

Specifications of MIC2204BMM

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: Adj to 1V
• Current - Output: 600mA
• Frequency - Switching: 2MHz
• Voltage - Input: 2.3 ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

MIC2204
PWM Operation
The MIC2204 is a pulsewidth modulation (PWM) controller.
By controlling the ratio of on-to-off time, or duty cycle, a
regulated DC output voltage is achieved. As load or supply
voltage changes, so does the duty cycle to maintain a
constant output voltage. In cases where the input supply runs
into a dropout condition, the MIC2204 will run at 100% duty
cycle.
The MIC2204 provides constant switching at 2MHz with
synchronous internal MOSFETs. The internal MOSFETs
include a high-side P-Channel MOSFET from the input
supply to the switch pin and an N-Channel MOSFET from the
switch pin to ground. Since the low-side N-Channel MOSFET
provides the current during the off cycle, a free wheeling
Schottky diode from the switch node to ground is not required.
PWM control provides fixed frequency operation. By main-
taining a constant switching frequency, predictable funda-
mental and harmonic frequencies are achieved. Other meth-
ods of regulation, such as burst and skip modes, have
frequency spectrums that change with load and can interfere
with sensitive communication equipment.
M9999-042205
10
Synchronization
SYNC_IN allows the user to change the frequency from
2MHz up to 2.5MHz or down to 1.8MHz. This controls the
fundamental frequency and all the resultant harmonics. Main-
taining a predictable frequency creates the ability to either
shift the harmonics away from sensitive carrier and IF fre-
quency bands, or to accurately filter out specific harmonic
frequencies.
Connecting the SYNC_OUT function pin to the SYNC_IN of
other MIC2204s will synchronize multiple MIC2204s in a
daisy-chain. Synchronizing multiple MIC2204s means that
regulators will run at the same fundamental frequency, result-
ing in matched harmonic frequencies and simplifying design
for sensitive communication equipment.
Micrel, Inc.
April 2005