MIC3838BMM Micrel Inc, MIC3838BMM Datasheet - Page 3

• Manufacturer Part Number: MIC3838BMM
• Description: IC CTRLR DC/DC PUSH-PULL 10-MSOP
• Manufacturer: Micrel Inc

Specifications of MIC3838BMM

• Pwm Type: Voltage/Current Mode
• Number Of Outputs: 1
• Frequency - Max: 1MHz
• Duty Cycle: 50%
• Voltage - Supply: 2 V ~ 14 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Frequency-max: 1MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Pin Description
April 2005
MIC3838/3839
Pin Number
7, 8
10
9
OUTB, OUTA
Pin Name
VREF
VDD
Pin Function
Alternating high current output stages. Both stages are capable of driving
the gate of a power MOSFET. Each stage is capable of 500mA peak source
current, and 1A peak sink current.
The output stages switch at half the oscillator frequency, in a push/pull
configuration. When the voltage on the RC pin is rising, one of the two
outputs is high, but during fall time, both outputs are off. This “dead time”
between the two outputs, along with a slower output rise time than fall time,
insures that the two outputs can not be on at the same time. This dead time
is typically 60ns to 200ns and depends upon the values of the timing
capacitor and resistor.
The high-current output drivers consist of MOSFET output devices, which
switch from V
impedance to overshoot and undershoot. This means that in many cases,
external Schottky clamp diodes are not required.
The power input connection for this device. Total V
quiescent V
the operating frequency and the MOSFET gate charge (Qg), average OUT
current can be calculated from IOUT = Qg • F, where Qg is the total gate
change of all MOSFETs (OUTA and OUTB) and F is oscillator switching
frequency. To prevent noise problems, bypass VDD to GND with a ceramic
capacitor as close to the chip as possible. A 1µF decoupling capacitor is
recommended.
Internal 3V supply. Will source 1mA maximum.
3
DD
DD
current and the average gate drive (OUT) current. Knowing
to GND. Each output stage also provides a very low
DD
current is the sum of
MIC3838/3839
Micrel