MIC2178_05 Datasheet, PDF (2/15 Pages) Micrel Semiconductor – 2.5A Synchronous Buck Regulator

MIC2178
Ordering Information
Part Number
Standard*
Pb-Free
Voltage Junction Temp.
MIC2178BWM
MIC2178YWM
ADJ
–40°C to +85°C
MIC2178-3.3BWM
MIC2178-3.3YWM
3.3V
–40°C to +85°C
MIC2178-5.0BWM
MIC2178-5.0YWM
5.0V
–40°C to +85°C
* Standard product will be supported as Pb-Free IAW PPCN #040004 effective 1-1-2005.
Micrel, Inc.
Package
20-lead WSOIC
20-lead WSOIC
20-lead WSOIC
Pin Configuration
VIN 1
VIN 2
SW 3
PGND 4
PGND 5
PGND 6
PGND 7
SW 8
VIN 9
PWM 10
20 EN
19 BIAS
18 SYNC
17 SGND
16 SGND
15 SGND
14 SGND
13 COMP
12 FB
11 PWRGD
20-Lead Wide Power SOIC
Pin Description
Pin Number
1, 2, 9
3, 8
4, 5, 6, 7
10
11
12
13
14, 15, 16, 17
18
19
20
Pin Name
VIN
SW
PGND
PWM
PWRGD
FB
COMP
SGND
SYNC
BIAS
EN
Pin Function
Supply Voltage (Input): Requires bypass capacitor to PGND. All three pins
must be connected to V_IN.
Switch (Output): Internal power MOSFET output switches. Both pins must
be externally connected together.
Power Ground: Connect all pins to central ground point.
PWM/Skip-Mode Control (Input): Logic-level input. Controls regulator
operating mode. Logic low enables PWM mode. Logic high enables skip
mode. Do not allow pin to float.
Error Flag (Output): Open-drain output. Active low when FB input is 10%
below the reference voltage (V_REF).
Feedback (Input): Connect to output voltage divider resistors.
Compensation: Output of internal error amplifier. Connect capacitor or
series RC network to compensate the regulator control loop.
Signal Ground: Connect all pins to ground, PGND*.
Frequency Synchronization (Input): Optional. Connect an external clock
signal to synchronize the oscillator. Leading edge of signal above 1.7V
terminates switching cycle. Connect to SGND if not used.
Internal 3.3V Bias Supply: Decouple with 0.01µF bypass capacitor to
SGND. Do not apply any external load.
Enable (Input): Logic high enables operation. Logic low shuts down
regulator. Do not allow pin to float.
M9999-031805
2
March 2005