Datasheet

© 2007 Microchip Technology Inc. DS22061A-page 11
MCP1602
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN FUNCTION TABLE
3.1 Shutdown Control Input Pin
(SHDN
)
The SHDN pin is a logic-level input used to enable or
disable the device. A logic high (>45% of V
IN
) will
enable the regulator output. A logic-low (<15% of V
IN
)
will ensure that the regulator is disabled.
3.2 Analog Input Supply Voltage Pin
(V
CC
)
The V
CC
pin provides bias for internal analog functions.
This voltage is derived by filtering the V
IN
supply.
3.3 Power-Good Output Pin (PG)
PG is an output level indicating that the output voltage
is within 94% of regulation. The PG output is configured
as an open-drain output.
3.4 Analog Ground Pin (A
GND
)
A
GND
is the analog ground connection. Tie A
GND
to the
analog portion of the ground plane (A
GND
). See the
physical layout information in the Section 5.8 “PCB
Layout Information” section for ground recommenda-
tions.
3.5 Output Voltage Sense Pin (V
FB
/
V
OUT
)
For the adjustable output voltage options, connect the
center of the output voltage divider to the V
FB
pin. For
fixed-output voltage options, connect the output of the
buck regulator to this pin (V
OUT
).
3.6 Power Supply Input Voltage Pin
(V
IN
)
V
IN
is the buck regulator power input supply pin.
Connect a variable input voltage source to V
IN
.
3.7 Buck Inductor Output Pin (L
X
)
Connect L
X
directly to the buck inductor. This pin
carries large signal-level current; all connections
should be made as short as possible.
3.8 Power Ground Pin (P
GND
)
Connect all large signal level ground returns to P
GND
.
These large signal level ground traces should have a
small loop area and length to prevent coupling of
switching noise to sensitive traces.
3.9 Exposed Metal Pad (EP)
For the DFN package, connect the Exposed Pad to
A
GND
, with vias into the A
GND
plane. This connection to
the A
GND
plane will aid in heat removal from the
package.
MSOP DFN Sym Description
1 1 SHDN
Shutdown Input Pin
22V
CC
Analog Input Supply Voltage Pin
3 3 PG Power Good Output Pin
44A
GND
Analog Ground Pin
55V
FB
/V
OUT
Feedback Voltage (Adjustable Version) / Output Voltage (Fixed Version) Pin
66V
IN
Input Supply Voltage Pin
77L
X
Buck Inductor Output Pin
88P
GND
Power Ground Pin
— Exposed
Pad
EP For the DFN package, the center exposed pad is a thermal path to remove
heat from the device. Electrically this pad is at ground potential and should
be connected to A
GND