CS5212GD14 ONSEMI [ON Semiconductor], CS5212GD14 Datasheet - Page 12

• Manufacturer Part Number: CS5212GD14
• Description: Low Voltage Synchronous Buck Controller
• Manufacturer: ONSEMI [ON Semiconductor]

Rpullup Value Selection for Boost Circuit Startup
resistor, R7, into the boost circuitry. This resistor is essential
to achieving startup of the boost circuit. At startup, the
GATE(H) output may be limited to 0.8 V, due to internal Vbe
drops. Until the boost circuitry charges up, the GATE(H)
output cannot provide sufficient Vgs to turn on the MOSFET.
A resistor from GATE(H) to BST allows bypassing of the
GATE(H) driver until the boost circuitry is charged. The time
constant, set by the pullup resistor and the Cin of the top
MOSFET, must be fast enough to turn on the MOSFET
during the switching period. The following equation is used
to determine Rpullup:
where f
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
ORDERING INFORMATION
Specifications Brochure, BRD8011/D.
CS5212ED14
CS5212ED14G
CS5212EDR14
CS5212EDR14G
CS5212GD14
CS5212GD14G
CS5212GDR14
CS5212GDR14G
The CS5212 application circuit incorporates a pullup
SW
is the switching frequency.
Device
Rpullup t
(Cin
1
f SW )
Temperature Range
−40°C < T
0°C < T
Operating
A
A
< 70°C
< 85°C
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12
insure that approximately 63% of the boost voltage will be
applied to GATE(H) within one switching period. To start
charge pumping, the control MOSFET must pull up the
switching node above 0.6 V, two Schottky drops, which will
allow V
by GATE(H) must be 0.6 V greater than Vth of the top FET.
Both high− and low−side switches must be sublogic level
MOSFETs with R
ensure proper up.
Choosing components according to this equation will
(Pb−Free)
(Pb−Free)
(Pb−Free)
(Pb−Free)
SOIC−14
SOIC−14
SOIC−14
SOIC−14
SOIC−14
SOIC−14
SOIC−14
SOIC−14
Package
C
voltage to increase. Therefore, the voltage applied
DS(on)
specified at 2.5 Vgs in order to
2500 / Tape & Reel
2500 / Tape & Reel
2500 / Tape & Reel
2500 / Tape & Reel
55 Units / Rail
55 Units / Rail
55 Units / Rail
55 Units / Rail
Shipping
†