ILC6376 Datasheet, PDF (1/12 Pages) Fairchild Semiconductor – 0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with Shutdown

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ILC6376/77
0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with
Shutdown
Features
• ±2.5% accurate output voltages
• Guaranteed 500mA output current
• 95% efficiency
• 55µA no load battery input current (ILC6377)
• 1.5µA shutdown current
• Built in short circuit and overcurrent protection
• Undervoltage lockout and soft-start
• External transistor drive available for higher I_OUT
• 300kHz operation
• Automatic switchover to PFM mode at low currents for
longest battery life (ILC6377)
• Fixed 3.3V or 5V or adjustable output
• SO-8 package
Applications
• Cellular Phones
• Palmtops and PDAs
• Portable Instrumentation
• Buck Converter for Industrial / Networking Applications
Typical Applications
Description
The ILC6376/77 is a 95% efficient, 300kHz step-down DC-
DC converter in an SO-8 package; capable of delivering
500mA output current. The device is also capable of driving
an external FET for higher output current applications.
The ILC6376/77 uses a unique p-channel architecture with
built-in charge pump to maintain low on-resistance, even at
low input voltages. The ILC6376 operates in PWM mode
with 300kHz switching frequency. The ILC6377 does the
same at high and medium load currents. When the load
current drops and the device hits approximately 25% duty
cycle, ILC6377 automatically switches over to PFM or pulse
skipping mode. PFM (pulse frequency modulation) mode of
operation extends efficiency at light loads.
Start-up is controlled via an external soft-start capacitor. The
device will automatically re-enter start-up mode when an
output current overload condition is sensed; thus providing
automatic short-circuit protection. Voltage lockout prevents
faulty operation below the minimum operating voltage level.
In shutdown, the ILC6376/77 consumes only 1.5µA current.
The ILC6376/77SOXX offers fixed 3.3V or 5V output while
ILC6376/77SOADJ allows adjustable output. Both versions
of ILC6376/77 are available in an SO-8 surface mount
package.
V_IN
S/D
*C_IN ⁺
10µF
1
8
2 _ILC6376/77 7
3
6
(TOP VIEW)
4
5
C_SS
SD1
L
22µH
V_OUT
+
C_L
47µF
Fig 1. Typical step-down DC-DC
converter application
SD1: SS12 Schottky Diode (FAIRCHILD)
C_L: 10V/47µF Tantalum Capacitor (NICHICON, F93)
C_SS: 4700pF Ceramic Capacitor
C_IN: 16V / 10µF Tantalum Capacitor (NICHICON, F93)
Rev. 1.5 November 2001
©2001 Fairchild Semiconductor Corporation