MCP1603
2.0 MHz, 500 mA Synchronous Buck Regulator
Features
•
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•
•
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•
•
•
•
•
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Over 90% Typical Efficiency
Output Current Up To 500 mA
Low Quiescent Current = 45 µA, typical
Low Shutdown Current = 0.1 µA, typical
Adjustable Output Voltage:
- 0.8V to 4.5V
Fixed Output Voltage:
- 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V
2.0 MHz Fixed-Frequency PWM (Heavy Load)
Automatic PWM to PFM Mode Transition
100% Duty Cycle Operation
Internally Compensated
Undervoltage Lockout (UVLO)
Overtemperature Protection
Space Saving Packages:
- 5-Lead TSOT
- 8-Lead 2X3 DFN
General Description
The MCP1603 is a high efficient, fully integrated
500 mA synchronous buck regulator whose 2.7V to
5.5V input voltage range makes it ideally suited for
applications powered from 1-cell Li-Ion or 2-cell/3-cell
NiMH/NiCd batteries.
At heavy loads, the MCP1603 operates in the 2.0 MHz
fixed frequency PWM mode which provides a low
noise, low output ripple, small-size solution. When the
load is reduced to light levels, the MCP1603
automatically changes operation to a PFM mode to
minimize quiescent current draw from the battery. No
intervention is necessary for a smooth transition from
one mode to another. These two modes of operation
allow the MCP1603 to achieve the highest efficiency
over the entire operating current range.
The MCP1603 is available with either an adjustable or
fixed output voltage. The available fixed output voltage
options are 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. When a
fixed option is used, only three additional small external
components are needed to form a complete solution.
Couple this with the low profile, small-foot print
packages and the entire system solution is achieved
with minimal size.
Additional protection features include:
overtemperature, and overcurrent protection.
UVLO,
Applications
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Cellular Telephones
Portable Computers
Organizers / PDAs
USB Powered Devices
Digital Cameras
Portable Equipment
+5V or +3.3V Distributed Systems
Package Types
5-Lead TSOT
V
IN
GND
SHDN
1
2
3
4
V
FB
/V
OUT
5
L
X
SHDN
GND
L
X
1
2
3
4
V
IN
5
V
FB
/V
OUT
8-Lead 2x3 DFN
L
X
1
NC 2
SHDN 3
V
FB
/V
OUT
4
8 GND
7 V
IN
6 NC
5 NC
MCP1603
MCP1603L
©
2007 Microchip Technology Inc.
DS22042A-page 1
MCP1603
Typical Application Circuit
V
IN
2.7V To 4.5V
V
IN
C
IN
4.7 µF
L
X
C
OUT
4.7 µF
L
1
4.7 µH
V
OUT
1.8V @ 500 mA
SHDN V
FB
GND
100
95
90
85
80
75
70
65
60
55
50
V
OUT
= 1.8V
V
IN
= 3.6V
V
IN
= 2.7V
Efficiency (%)
V
IN
= 4.5V
0.1
1
10
Output Current (mA)
100
1000
DS22042A-page 2
©
2007 Microchip Technology Inc.
MCP1603
Functional Block Diagram
V
IN
Band
Gap
Thermal
Shutdown
V
REF
UVLO
Soft Start
UVLO
SHDN
I
PK
Limit
ILIM
PWM
ILIM
PFM
TSD
IPEAK
PWM
IPEAK
PFM
Slope
Comp
OSC
-ILPK
S
R
Q
Q
POFF
NOFF
Switch Drive
Logic and timing
PWM/PFM
L
X
PFM Error Amp
PWM/PFM
Logic
GND
V
REF
PWM Error Amp
EA
IPEAK
PFM
IPEAK
PWM
-ILPK
-I
PK
Limit
V
REF
OV Threshold
Disable
Switcher
V
FB
/ V
OUT
UV Threshold
UVLO
TSD
©
2007 Microchip Technology Inc.
DS22042A-page 3
MCP1603
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 sections of this specification is not intended.
Exposure to maximum rating conditions for extended periods
may affect device reliability.
Absolute Maximum Ratings †
V
IN
- GND.......................................................................+6.0V
All Other I/O ...............................(GND - 0.3V) to (V
IN
+ 0.3V)
L
X
to GND .............................................. -0.3V to (V
IN
+ 0.3V)
Output Short Circuit Current..................................Continuous
Power Dissipation
(Note 5)
..........................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..............................................................................4 kV
MM...............................................................................300V
DC CHARACTERISTICS
Electrical Characteristics:
Unless otherwise indicated, V
IN
= SHDN = 3.6V, C
OUT
= C
IN
= 4.7 µF, L = 4.7 µH, V
OUT
(ADJ) = 1.8V,
I
OUT
= 100 mA, T
A
= +25°C.
Boldface
specifications apply over the T
A
range of -40°C to +85°C.
Parameters
Input Characteristics
Input Voltage
Maximum Output Current
Shutdown Current
Quiescent Current
SHDN, Logic Input Voltage Low
SHDN, Logic Input Voltage High
SHDN, Input Leakage Current
Undervoltage Lockout
Thermal Shutdown
Thermal Shutdown Hysteresis
Note 1:
2:
3:
4:
Sym
V
IN
I
OUT
I
IN_SHDN
I
Q
V
IL
V
IH
I
L_SHDN
UVLO
T
SHD
T
SHD-HYS
Min
2.7
500
—
—
—
45
-1.0
2.12
—
—
—
Typ
—
—
0.1
45
—
—
±0.1
2.28
140
150
10
Max
5.5
—
1
60
15
—
1.0
2.43
—
—
—
Units
V
mA
µA
µA
Note 1
Note 1
Conditions
SHDN = GND
SHDN = V
IN
, I
OUT
= 0 mA
Shutdown/UVLO/Thermal Shutdown Characteristics
%V
IN
V
IN
= 2.7V to 5.5V
%V
IN
V
IN
= 2.7V to 5.5V
µA
V
mV
°C
°C
Note 4, Note 5
Note 4, Note 5
V
IN
= 2.7V to 5.5V
V
IN
Falling
Undervoltage Lockout Hysteresis UVLO
HYS
5:
6:
The minimum V
IN
has to meet two conditions: V
IN
≥
2.7V and V
IN
≥
V
OUT
+ 0.5V.
Reference Feedback Voltage Tolerance applies to adjustable output voltage setting.
V
R
is the output voltage setting.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable
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 internal MOSFET switches have an integral diode from the L
X
pin to the V
IN
pin, and from the L
X
pin
to the GND pin. 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.
The current limit threshold is a cycle-by-cycle peak current limit.
DS22042A-page 4
©
2007 Microchip Technology Inc.
MCP1603
DC CHARACTERISTICS (CONTINUED)
Electrical Characteristics:
Unless otherwise indicated, V
IN
= SHDN = 3.6V, C
OUT
= C
IN
= 4.7 µF, L = 4.7 µH, V
OUT
(ADJ) = 1.8V,
I
OUT
= 100 mA, T
A
= +25°C.
Boldface
specifications apply over the T
A
range of -40°C to +85°C.
Parameters
Output Characteristics
Adjustable Output Voltage Range
Reference Feedback Voltage
Reference Feedback Voltage
Tolerance
Feedback Input Bias Current
Output Voltage Tolerance Fixed
Line Regulation
Load Regulation
Internal Oscillator Frequency
Start Up Time
R
DSon
P-Channel
R
DSon
N-Channel
L
X
Pin Leakage Current
Positive Current Limit Threshold
Note 1:
2:
3:
4:
Sym
V
OUT
V
FB
Min
0.8
—
-3.0
-2.5
Typ
—
0.8
—
—
0.1
V
R
V
R
0.3
0.35
2.0
0.6
500
500
±0.1
860
Max
4.5
—
+3.0
+2.5
—
+3.0%
+2.5
—
—
2.8
—
—
—
1.0
—
Units
V
V
%
%
nA
%
%
%/V
%
MHz
ms
mΩ
mΩ
µA
mA
Note 2
Conditions
T
A
= -40°C to +25°C
T
A
= +25°C to +85°C
T
A
= -40°C to +25°C,
Note 3
T
A
= +25°C to +85°C,
Note 3
V
IN
= V
R
+ 1V to 5.5V,
I
OUT
= 100 mA
V
IN
= V
R
+1.5V,
I
LOAD
= 100 mA to 500 mA
T
R
= 10% to 90%
I
P
= 100 mA
I
N
= 100 mA
SHDN = 0V, V
IN
= 5.5V,
L
X
= 0V, L
X
= 5.5V
Note 6
I
VFB
V
OUT
V
OUT
V
LINE-
REG
—
-3.0%
-2.5
—
—
1.5
—
—
—
-1.0
—
V
LOAD-
REG
F
OSC
T
SS
R
DSon-P
R
DSon-N
I
LX
+I
LX(MAX)
5:
6:
The minimum V
IN
has to meet two conditions: V
IN
≥
2.7V and V
IN
≥
V
OUT
+ 0.5V.
Reference Feedback Voltage Tolerance applies to adjustable output voltage setting.
V
R
is the output voltage setting.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable
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 internal MOSFET switches have an integral diode from the L
X
pin to the V
IN
pin, and from the L
X
pin
to the GND pin. 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.
The current limit threshold is a cycle-by-cycle peak current limit.
©
2007 Microchip Technology Inc.
DS22042A-page 5
PCB Design
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