TC1303A/TC1303B/
TC1303C/TC1304
500 mA Synchronous Buck Regulator,
+ 300 mA LDO with Power-Good Output
Features
• Dual-Output Regulator (500 mA Buck Regulator
and 300 mA Low-Dropout Regulator)
• Power-Good Output with 300 ms Delay
• Total Device Quiescent Current = 65 µA, Typ.
• Independent Shutdown for Buck and LDO
Outputs (TC1303)
• Both Outputs Internally Compensated
• Synchronous Buck Regulator:
- Over 90% Typical Efficiency
- 2.0 MHz Fixed-Frequency PWM
(Heavy Load)
- Low Output Noise
- Automatic PWM to PFM mode transition
- Adjustable (0.8V to 4.5V) and Standard
Fixed-Output Voltages (0.8V, 1.2V, 1.5V,
1.8V, 2.5V, 3.3V)
• Low-Dropout Regulator:
- Low-Dropout Voltage = 137 mV Typ. @
200 mA
- Standard Fixed-Output Voltages
(1.5V, 1.8V, 2.5V, 3.3V)
• Power-Good Function:
- Monitors Buck Output Function (TC1303A)
- Monitors LDO Output Function (TC1303B)
- Monitors Both Buck and LDO Output Func-
tions (TC1303C
and TC1304)
- 300 ms Delay Used for Processor Reset
• Sequenced Startup and Shutdown (TC1304)
• Small 10-pin 3X3 DFN or MSOP Package
Options
• Operating Junction Temperature Range:
- -40°C to +125°C
• Undervoltage Lockout (UVLO)
• Output Short Circuit Protection
• Overtemperature Protection
Description
The TC1303/TC1304 combines a 500 mA synchro-
nous buck regulator and 300 mA Low-Dropout Regula-
tor (LDO) with a power-good monitor to provide a highly
integrated solution for devices that require multiple
supply voltages. The unique combination of an
integrated buck switching regulator and low-dropout
linear regulator provides the lowest system cost for
dual-output voltage applications that require one lower
processor core voltage and one higher bias voltage.
The 500 mA synchronous buck regulator switches at a
fixed frequency of 2.0 MHz when the load is heavy,
providing a low noise, small-size solution. When the
load on the buck output is reduced to light levels, it
changes operation to a Pulse Frequency Modulation
(PFM) mode to minimize quiescent current draw from
the battery. No intervention is necessary for smooth
transition from one mode to another.
The LDO provides a 300 mA auxiliary output that
requires a single 1 µF ceramic output capacitor,
minimizing board area and cost. The typical dropout
voltage for the LDO output is 137 mV for a 200 mA
load.
For the TC1303/TC1304, the power-good output is
based on the regulation of the buck regulator output, the
LDO output or the combination of both. The TC1304
features start-up and shutdown output sequencing.
The TC1303/TC1304 is available in either the 10-pin
DFN or MSOP package.
Additional protection features include: UVLO,
overtemperature and overcurrent protection on both
outputs.
For a complete listing of TC1303/TC1304 standard
parts, consult your Microchip representative.
Applications
•
•
•
•
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Cellular Phones
Portable Computers
USB-Powered Devices
Handheld Medical Instruments
Organizers and PDAs
©
2005 Microchip Technology Inc.
DS21949B-page 1
Microcontroller MCU
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