FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27218-4E
ASSP For Power Supply Applications
Pentium
®
II DC/DC Converter IC
MB3870
s
DESCRIPTION
The FUJITSU MB3870 is a pulse width modulation (PWM) DC/DC converter IC chip that provides a selection of
1.3 V to 3.5 V output voltages for Pentium
®
* CPU’s, using a 5-bit input signal information.
The MB3870 utilizes synchronous rectification for high efficiency and features a soft-start/discharge control
function for ease in designing power supplies in multi-supply systems, making it ideal for Pentium
®
II power supply
systems.
* : Pentium is the registered trademark of Intel Corporation.
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FEATURES
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Highly efficient for using synchronous rectification scheme
On-chip soft-start/discharge control circuit
High precision output voltage:
±1.2%
5-bit, 32-step DAC: 3.5 V to 2.1 V in 100 mV steps
2.05 V to 1.3 V in 50 mV steps
Frequency range: 100 kHz to 500 kHz using variable resistance (on-chip frequency setting capacitance)
Standby current: 0
µA
TYP
On-chip PWRGOOD circuit for output voltage state detection
Timer-latch short-circuit protection circuit, and overvoltage protection circuit for output protection
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PACKAGE
24-pin Plastic SSOP
(FPT-24P-M03)
FUJITSU [ FUJITSU COMPONENT LIMITED. ]
