MCP1650REUN MICROCHIP [Microchip Technology], MCP1650REUN Datasheet - Page 19

• Manufacturer Part Number: MCP1650REUN
• Description: 750 kHz Boost Controller
• Manufacturer: MICROCHIP [Microchip Technology]

5.2.4
There are no special requirements on the input or
output capacitor. For most applications, ceramic
capacitors or low effective series resistance (ESR) tan-
talum capacitors will provide lower output ripple voltage
than aluminum electrolytic. Care must be taken not to
exceed the manufacturer’s rated voltage or ripple cur-
rent specifications. Low-value capacitors are desired
because of cost and size, but typically result in higher
output ripple voltage.
The input capacitor size is dependant on the source
impedance
architecture of the MCP1650/51/52/53 boost converter
can draw relatively high input current peaks at certain
line and load conditions. Small input capacitors can
produce a large ripple voltage at the input of the
converter, resulting in unsatisfactory performance.
The output capacitor plays a very important role in the
performance
converter. In some cases, using ceramic capacitors
can result in higher output ripple voltage. This is a
result of the low ESR that ceramic capacitors exhibit.
As shown in the application schematics, 100 milli-ohms
of ESR in series with the ceramic capacitor will actually
reduce the output ripple voltage and peak input cur-
rents for some applications. The selection of the capac-
itor and ESR will largely determine the output ripple
voltage.
5.2.5
For low battery detection, the MCP1651 or MCP1653
device should be used. The low-battery detect feature
compares the low battery input (LBI) pin to the internal
1.22V reference. If the LBI input is below the LBI
threshold voltage, the low battery output (LBO) pin will
sink current (up to 10 mA) through the internal open-
drain MOSFET. If the LBI input voltage is above the LBI
threshold, the LBO output pin will be open or high
impedance.
5.2.6
For power good detection, the MCP1652 or MCP1653
device is ideal. The power good feature compares the
voltage on FB pin to the internal reference (±15%). If
the FB pin is more than 15% above or below the power
good threshold, the PG output will sink current through
the internal open-drain MOSFET. If the output of the
regulator is within ±15% of the output voltage, the PG
pin will be open or high-impedance.
2004 Microchip Technology Inc.
INPUT/OUTPUT CAPACITOR
SELECTION
LOW BATTERY DETECTION
POWER GOOD OUTPUT
of
of
the
the
application.
hysteretic
gated
The
hysteretic
oscillator
5.2.7
Inductors:
Sumida
Corporation
Coilcraft
BH Electronics
Pulse
Engineering
Coiltronics
Capacitors
MuRata
Kemet
Taiyo-Yuden
AVX
MOSFETs and Diodes:
International
Rectifier
Vishay
ON
Semiconductor
Fairchild
Semiconductor
®
MCP1650/51/52/53
®
®
®
®
/Siliconix
®
®
EXTERNAL COMPONENT
MANUFACTURES
®
®
®
®
http://www.sumida.com/
http://www.coilcraft.com
http://www.bhelectronics.com
http://www.pulseeng.com/
http://www.cooperet.com/
http://www.murata.com/
http://www.kemet.com/
http://www.taiyo-yuden.com/
http://www.avx.com/
http://www.irf.com/
http://www.vishay.com/com-
pany/brands/siliconix/
http://www.onsemi.com/
http://www.fairchildsemi.com/
DS21876A-page 19