TC1303B Datasheet, PDF (1/30 Pages) Microchip Technology – 500 mA Synchronous Buck Regulator, + 300 mA LDO with Power-Good Output

TC1303B
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
• 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 LDO Output Function (TC1303B)
- 300 ms Delay Used for Processor Reset
• 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
Applications
• Cellular Phones
• Portable Computers
• USB Powered Devices
• Handheld Medical Instruments
• Organizers and PDAs
Description
The TC1303B combines a 500 mA synchronous buck
regulator and 300 mA Low-Dropout Regulator (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 TC1303B, the power-good output logic level is
based on the regulation of the LDO output only. The
buck regulator can be turned on and off without affecting
the power-good signal.
The TC1303B 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 TC1303B standard parts, con-
sult your Microchip representative.
Package Type
10-Lead DFN
10-Lead MSOP
SHDN2 1
V_{IN2 2}
V_{OUT2 3}
PG 4
A_{GND 5}
10 P_GND
SHDN2 1
9 LX
V_IN2 2
8 V_IN1
V_OUT2 3
7 SHDN1
PG 4
6 V_FB1/V_OUT1 ^{AGND 5}
10 PGND
9 L_X
8 VIN1
7 SHDN1
6 ^VFB1^/VOUT1
© 2005 Microchip Technology Inc.
DS21949A-page 1