Buck Controller. MIC2198 Datasheet
500kHz 4mm × 4mm Synchronous Buck Controller
The MIC2198 is a high-power 500kHz synchronous buck
DC-to-DC controller housed in a small 4mm × 4mm MLF™
12-pin package. The MIC2198 operates from a wide 4.5V
to 32V input and can be programmed for output voltages
from 0.8V to 6V. The wide input voltage capability makes
the MIC2198 an ideal solution for point-of-load DC-to-DC
conversion in 5V, 12V and higher systems.
The 500kHz switching frequency allows the use of a small
inductor and small output capacitors. The current mode PWM
control along with the external COMP pin allows for ease of
stability compensation and fast transient response across a
wide range of applications.
An all N-Channel synchronous architecture and powerful
output drivers allow up to 20A of output current capability.
For higher efﬁciency at higher input voltages, refer to the
The MIC2198 is available in a 12-pin 4mm × 4mm MLF™
package with a junction temperature range from –40°C to
• 4.5V to 32V input range
• 4mm × 4mm MLF™ package
• 500kHz PWM operation
• >90% efﬁciency
• Output voltage adjustable down to 0.8V
• 20A output current capability
• Drives all N-Channel MOSFETs
• Logic controlled micropower shutdown
• Cycle-by-cycle current limiting
• Adjustable undervoltage lockout
• Frequency foldback overcurrent protection
• Point-of-load DC-to-DC conversion from 5V, 12V
and higher supplies
• Telecom equipment
• Wireless modems
• Base stations
5.5V to 24V
5.5V–24V to 3.3V/7A Converter
vs. Load Current
60 VIN = 5.5V
55 VOUT = 3.3V
500 2 4 6
MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
–40ºC to +125ºC
12-Pin 4x4 MLF™
12-Pin 4×4 MLF (ML)
Compensation (Output): Internal error ampliﬁer output. Connect to capacitor
or series RC network to compensate the regulator control loop.
Enable/Undervoltage Lockout (Input): Low-level signal powers down the
controller. Input below the 2.5V threshold disables switching and functions as
an accurate undervoltage lockout (UVLO). Input below the threshold forces
complete micropower (<0.1µA) shutdown.
Feedback (Input): Regulates FB pin to 0.8V. See “Applications Information”
for resistor divider calculations.
Current-Sense High (Input): Current limit comparator non-inverting input. A
built-in offset of 75mV between CSH and VOUT pins in conjunction with the
current-sense resistor set the current limit threshold level. This is also the
non-inverting input to the current sense ampliﬁer.
Current-Sense Low (Input): Output voltage feedback input and inverting
input for the current limit comparator and the current sense ampliﬁer.
Unregulated Input (Input): +4.5V to +32V supply input.
5V Internal Linear-Regulator (Output): VDD is the external MOSFET gate
drive supply voltage and internal supply bus for the IC. Bypass to GND with
Low-Side Drive (Output): High-current driver output for low-side N-Channel
MOSFET. Voltage swing is between ground and VDD.
Boost (Input): Provides drive voltage for the high-side MOSFET driver. The
drive voltage is higher than the input voltage by VDD minus a diode drop.
Switch (Return): High-side MOSFET driver return.
High-Side Drive (Output): High-current driver output for high-side MOSFET.
This node voltage swing is between ground and VIN +5V minus a diode drop.
2 October 2005