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| ILC6390 Datasheet, PDF (1/10 Pages) Impala Linear Corporation – SOT-89 STEP-UP PFM SWITCHER WITH AUTO-LOAD SENSE | |||
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www.fairchildsemi.com
ILC6390/91
SOT-89 Step-Up PFM Switcher with Auto-Load Sense
Features
⢠85% conversion efficiency at 50mA out
⢠Start-up voltages as low as 900mV
⢠±2.5% accurate outputs
⢠Complete switch design with only 3 external components
⢠Automatically senses load variations to select the optimal
duty cycle and extend conversion efficiency over a wide
range
⢠External transistor configuration to run as switcher
controller
⢠Shutdown to 0.5µA
Applications
⢠Cellular phones, pagers
⢠Cameras, video recorders
⢠Palmtops and PDAs
Description
50 mA boost converter using Pulse Frequency Modulation, or
PFM, technique, in 5-lead SOT-89 or a 5-lead SOT-23
package. Only 3 external components are needed to complete
the switcher design.
The ILC6390 automatically senses load variations to choose
between 55% and 75% duty cycles. Normal operation is 55%
duty at 155kHz; when load currents exceed the internal
comparator trip point, a âturbo modeâ kicks in to provide
extended on-time switching (75% duty at 100kHz
oscillation).
Requiring only 30µA of supply current, the ILC6390
achieves efficiencies as high as 85% at 5V yet shuts down to
0.5µA max.
Standard voltages offered are 2.5, 3.3, and 5.0V and is
available in both a 5 lead SOT-23 and 5 lead SOT-89 package
for small footprint applications.
In addition, the ILC6391 is configured to drive an external
transistor to achieve higher power levels.
Typical Applications
L
V IN
CE
3
1
ILC6390CM
1
2
3
+
SD
CL
GND
Figures 1 & 2
L: 100µH (SUMIDA, CD-54)
SD: Diode (Schottky diode;
MATSUSHITA MA 735) VIN
CL: 16V 47µF (Tantalum
V Capacitor; NICHICON, f93)
OUT
Figures 3 & 4
CE
SD
V OUT L: 47µH (SUMIDA, CD-54)
L
V IN
3
2
1
+
ILC6391CM
CL
4
5
SD: Diode (Schottky diode;
MATSUSHITA MA735)
V IN
CL: 16V 47µF (Tantalum
Capacitor; NICHICON, F93)
Tr
R
RB: 1kâ¦
GND
CB: 3300pF
Tr: 2SC3279, 2SDI628G
SD
CE
V OUT
3
2
1
L
+
ILC6390CP
CL
4
5
GND
L
Tr
SD
3
2
1
ILC6391CP
CB
4
5
RB
GND
CE
V OUT
+
CL
Rev.1.2
©2001 Fairchild Semiconductor Corporation
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