MCP1603-150I/MC Microchip Technology, MCP1603-150I/MC Datasheet - Page 14

• Manufacturer Part Number: MCP1603-150I/MC
• Description: IC SYNC BUCK REG 0.5A 1.5V 8DFN
• Manufacturer: Microchip Technology
• Type: Step-Down (Buck)r

Specifications of MCP1603-150I/MC

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 1.5V
• Current - Output: 500mA
• Frequency - Switching: 2MHz
• Voltage - Input: 2.7 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• For Use With: MCP1603RD-TNY - REFERENCE DESIGN FOR MCP1603MCP1603EV - BOARD EVAL BUCK CONV MCP1603
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP1603
5.0
5.1
The MCP1603 500 mA synchronous buck regulator
operates over a wide input voltage range (2.7V to 5.5V)
and is ideal for single-cell Li-Ion battery powered
applications, USB powered applications, three cell
NiMH or NiCd applications and 3V or 5V regulated
input applications. The 5-lead TSOT and 8-lead 2x3
DFN packages provide a small footprint with minimal
external components.
5.2
Typical Application Circuit shows a fixed MCP1603
in an application used to convert three NiMH batteries
into a well regulated 1.8V @ 500 mA output. A 4.7 µF
input capacitor, 4.7 µF output capacitor, and a 4.7 µH
inductor make up the entire external component solu-
tion for this application. No external voltage divider or
compensation is necessary. In addition to the fixed
1.8V option, the MCP1603 is also available in 1.2V,
1.5V, 2.5V, or 3.3V fixed voltage options.
5.3
When the desired output for a particular application is
not covered by the fixed voltage options, an adjustable
MCP1603 can be used. The circuit listed in
shows an adjustable MCP1603 being used to convert a
5V rail to 1.0V @ 500 mA. The output voltage is adjust-
able by using two external resistors as a voltage
divider.
recommended that the top resistor divider value be
200 kΩ. The bottom resistor value can be calculated
using the following equation:
EQUATION 5-1:
DS22042A-page 14
Example:
R
R
R
V
BOT
BOT
OUT
V
TOP
FB
R
APPLICATION INFORMATION
Typical Applications
Fixed Output Voltage Applications
Adjustable Output Voltage
Applications
BOT
For
=
=
=
=
=
=
adjustable-output
R
200 kΩ
1.0V
0.8V
200 kΩ x (0.8V/(1.0V - 0.8V))
800 kΩ
(Standard Value = 787 kΩ)
TOP
×
⎛
⎝
---------------------------- -
V
OUT
V
voltages,
FB
–
V
FB
Figure 6-2
⎞
⎠
it
is
For adjustable output applications, an additional R-C
compensation network is necessary for control loop
stability. Recommended values for any output voltage
are:
Refer to
C
5.4
The input current to a buck converter, when operating
in continuous conduction mode, is a squarewave with
a duty cycle defined by the output voltage (V
input voltage (V
undesirable input voltage transients, the input capacitor
should be a low ESR type with an RMS current rating
given by
low ESR, ceramic capacitors are often used. Ceramic
material X5R or X7R are well suited since they have a
low temperature coefficient and acceptable ESR.
EQUATION 5-2:
Table 5-1
capacitor value.
5.5
The output capacitor helps provide a stable output
voltage during sudden load transients, smooths the
current that flows from the inductor to the load, and
reduces the output voltage ripple. Therefore, low ESR
capacitors are a desirable choice for the output capac-
itor. As with the input capacitor, X5R and X7R ceramic
capacitors are well suited for this application.
The output ripple voltage is often a design specifica-
tion. A buck converters’ output ripple voltage is a
function of the charging and discharging of the output
capacitor and the ESR of the capacitor. This ripple
voltage can be calculated by
EQUATION 5-3:
R
C
COMP
COMP
COMP
I
CIN RMS
Δ
.
,
Figure 6-2
V
Input Capacitor Selection
Equation
Output Capacitor Selection
contains the recommend range for the input
OUT
=
=
=
I
IN
OUT MAX
=
) relationship of V
5.5. Because of their small size and
4.99 kΩ
33 pF
for proper placement of R
,
Δ
I
L
© 2007 Microchip Technology Inc.
×
×
⎛
⎜
⎝
ESR
Equation
V
----------------------------------------------------- -
OUT
+
OUT
×
(
-------------------- -
8 f C
V
V
/V
5-3.
×
IN
IN
Δ
IN
–
I
. To prevent
L
×
V
COMP
OUT
OUT
)
⎞
⎟
⎠
and
) to