TC1313
500 mA Synchronous Buck Regulator,
+ 300 mA LDO
Features
• Dual-Output Regulator (500 mA Buck Regulator
and 300 mA Low-Dropout Regulator (LDO))
• Total Device Quiescent Current = 57 µA (Typical)
• 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 Typical @
200 mA
- Standard Fixed-Output Voltages
(1.5V, 1.8V, 2.5V, 3.3V)
• 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 TC1313 device combines a 500 mA synchronous
buck regulator and 300 mA Low-Dropout Regulator
(LDO) 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.
The TC1313 device 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 TC1313 standard parts,
consult your Microchip representative.
Applications
•
•
•
•
•
Cellular Phones
Portable Computers
USB-Powered Devices
Handheld Medical Instruments
Organizers and PDAs
Package Type
10-Lead DFN *
SHDN2
1
V
IN2
2
V
OUT2
3
NC
4
A
GND
5
10
P
GND
EP
11
9
L
X
8
V
IN1
7
SHDN1
6
V
FB1
/V
OUT1
10
P
GND
9
8
7
10-Lead MSOP
SHDN2
1
V
IN2
2
V
OUT2
3
NC
4
A
GND
5
L
X
V
IN1
SHDN1
6
V
FB1
/V
OUT1
* Includes Exposed Thermal Pad (EP); see
Table 3-1.
©
2009 Microchip Technology Inc.
DS21974B-page 1
TC1313
1.0
ELECTRICAL
CHARACTERISTICS
† Notice:
Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied.
Exposure to maximum rating conditions for extended periods
may affect device reliability.
Absolute Maximum Ratings †
V
IN
- A
GND
......................................................................6.0V
All Other I/O ...............................(A
GND
- 0.3V) to (V
IN
+ 0.3V)
L
X
to P
GND
...............................................-0.3V to (V
IN
+ 0.3V)
P
GND
to A
GND
.................................................. -0.3V to +0.3V
Output Short Circuit Current ................................ Continuous
Power Dissipation (Note
7)
.......................... Internally Limited
Storage temperature .....................................-65°C to +150°C
Ambient Temp. with Power Applied ................-40°C to +85°C
Operating Junction Temperature...................-40°C to +125°C
ESD protection on all pins (HBM)
.......................................
3 kV
DC CHARACTERISTICS
Electrical Characteristics:
V
IN1
= V
IN2
= SHDN1,2 = 3.6V, C
OUT1
= C
IN
= 4.7 µF, C
OUT2
= 1µF, L = 4.7 µH, V
OUT1
(ADJ) = 1.8V,
I
OUT1
= 100 ma, I
OUT2
= 0.1 mA T
A
= +25°C.
Boldface
specifications apply over the T
A
range of
-40°C to +85°C.
Parameters
Input/Output Characteristics
Input Voltage
Maximum Output Current
Maximum Output Current
Shutdown Current
Combined V
IN1
and V
IN2
Current
Operating I
Q
Synchronous Buck I
Q
LDO I
Q
SHDN1,SHDN2,
Logic Input Voltage Low
SHDN1,SHDN2,
Logic Input Voltage High
SHDN1,SHDN2,
Input Leakage Current
Thermal Shutdown
Thermal Shutdown Hysteresis
Undervoltage Lockout
(V
OUT1
and V
OUT2
)
Undervoltage Lockout Hysteresis
Note 1:
2:
3:
4:
5:
6:
V
IL
V
IH
I
IN
V
IN
I
OUT1_MAX
I
OUT2_MAX
I
IN_SHDN
I
Q
2.7
500
300
—
—
—
—
—
45
-1.0
—
—
—
0.05
57
38
44
—
—
±0.01
5.5
—
—
1
100
—
—
15
—
1.0
V
mA
mA
µA
µA
µA
µA
%V
IN
%V
IN
µA
Note 1, Note 2, Note 8
Note 1
Note 1
SHDN1 = SHDN2 = GND
SHDN1 = SHDN2 = V
IN2
I
OUT1
= 0 mA, I
OUT2
= 0 mA
SHDN1 = V
IN
, SHDN2 = GND
SHDN1 = GND, SHDN2 = V
IN2
V
IN1
= V
IN2
= 2.7V to 5.5V
V
IN1
= V
IN2
= 2.7V to 5.5V
V
IN1
= V
IN2
= 2.7V to 5.5V
SHDNX = GND
SHDNY = V
IN
Note 6, Note 7
V
IN1
Falling
Sym
Min
Typ
Max
Units
Conditions
Shutdown/UVLO/Thermal Shutdown Characteristics
T
SHD
T
SHD-HYS
UVLO
UVLO
-
HYS
—
—
2.4
—
165
10
2.55
200
—
—
2.7
—
°C
°C
V
mV
7:
8:
The Minimum V
IN
has to meet two conditions: V
IN
≥
2.7V and V
IN
≥
V
RX
+ V
DROPOUT,
V
RX
= V
R1
or V
R2
.
V
RX
is the regulator output voltage setting.
TCV
OUT2
= ((V
OUT2max
– V
OUT2min
) * 10
6
)/(V
OUT2
* D
T
).
Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested
over a load range from 0.1 mA to the maximum specified output current.
Dropout voltage is defined as the input-to-output voltage differential at which the output voltage drops 2% below its
nominal value measured at a 1V differential.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e. T
A
, T
J
,
θ
JA
). Exceeding the maximum allowable power
dissipation causes the device to initiate thermal shutdown.
The integrated MOSFET switches have an integral diode from the L
X
pin to V
IN
, and from L
X
to P
GND
. In cases where
these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not
able to limit the junction temperature for these cases.
V
IN1
and V
IN2
are supplied by the same input source.
©
2009 Microchip Technology Inc.
DS21974B-page 5
PCB Design
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