MIC2128 Datasheet, PDF (1/32 Pages) Microchip Technology – 75V, Synchronous Buck Controller Featuring Adaptive On-Time Control with External Soft Start

MIC2128
75V, Synchronous Buck Controller Featuring Adaptive
On-Time Control with External Soft Start
Features
• Hyper Speed Control^® Architecture Enables:
- High Input to Output Voltage Conversion
Ratio Capability
- Any Capacitor™ Stable
- Ultra-Fast Load Transient Response
• Wide 4.5V to 75V Input Voltage Range
• Adjustable Output Voltage from 0.6V to 30V
• 270 kHz to 800 kHz Programmable Switching
Frequency
• Built-in 5V Regulator for Single-Supply Operation
• Auxiliary Bootstrap LDO for Improving System
Efficiency
• Internal Bootstrap Diode
• Adjustable Soft-Start Time
• Enable Input and Power Good Output
• Programmable Current Limit
• Hiccup Mode Short-Circuit Protection
• Internal Compensation and Thermal Shutdown
• Supports Safe Start-Up into a Prebiased Output
Applications
• Networking/Telecom Equipment
• Base Station, Servers
• Distributed Power Systems
• Industrial Power Supplies
General Description
The MIC2128 is a constant-frequency synchronous
buck controller featuring a unique adaptive on-time
control architecture with external soft start. The
MIC2128 operates over an input voltage range from
4.5V to 75V.The output voltage is adjustable down to
0.6V with a guaranteed accuracy of ±1%. The device
operates with programmable switching frequency from
270 kHz to 800 kHz.
The MIC2128 features an external soft-start pin (SS)
which allows the user to adjust output soft-start time to
reduce inrush current from mains during start-up. The
MIC2128 features an auxiliary bootstrap LDO which
improves the system efficiency by supplying the
MIC2128 internal circuit bias power and gate drivers
from output of the converter. A logic level enable (EN)
signal can be used to enable or disable the
controller.The MIC2128 can start-up monotonically into
a prebiased output. The MIC2128 features an open
drain power good signal (PG) which signals when the
output is in regulation and can be used for simple
power supply sequencing purpose.
The MIC2128 offers a full suite of protection features to
ensure protection of the IC during Fault conditions.
These include undervoltage lockout to ensure proper
operation under power-sag conditions, “hiccup” mode
short-circuit protection and thermal shutdown.
The MIC2128 is available in a 16-pin 3 mm x 3 mm
QFN package, with an operating junction temperature
range from -40°C to +125°C.
Package Types
MIC2128
3 x 3 QFN*
(Top View)
16 15 14 13
PG 1
I_{LIM 2}
SW 3
BST 4
12 SS
11 _FREQ
EP
10 EN
9 EXTVDD
567 8
* Includes Exposed Thermal Pad (EP); see Table 3-1.
 2016 Microchip Technology Inc.
DS20005620A-page 1