Introduction
The ＣＭＤ1408/9 is
a CMOS step-up switching DC/DC converter that mainly consists of a
reference voltage source, an oscillator, and a comparator. The
ＣＭＤ1408 allows the duty ratio to be automatically switched
according to the load (light load: 50%, high output current: 75%),
enabling products with a low ripple over a wide range, high
efficiency, and high output current. With the ＣＭＤ1408/9, a step-up
switching DC/DC converter can be configured by using an external
coil, capacitor, diode and NMOS or NPN. The built-in MOSFET is
turned off by a protection circuit when the voltage at the LX pin
exceeds the limit to prevent it from
being damaged. This feature, along with the mini package and low
current consumption, makes the ＣＭＤ1408 ideal for
applications such as the power supply unit of portable
equipment.
Features
• Low voltage operation: Startup at 0.9 V
min. (IOUT = 1 mA) guaranteed
• Duty ratio: 66/78%, builtin auto switching
• External parts: Coil, capacitor, diode,
NMOS
• High efficiency：±85%（typ.）
• Output voltage Adjustable
• Providing Flexibility for Using Internal
and ExternalPower Switches
• Zero Shutdown Mode Supply Current
• 6μA Quiescent (Switch-off) Supply
Current
• Small SOT23-5,SOT89-5 Package &
SOT-26(customer order）
Applications
• PDA
• DSC
• LCD Panel
• RF-Tags
• MP3
• Portable Instrument
• Wireless Equipment
