Datasheet

MCP73123/223
DS22191E-page 10  2009-2013 Microchip Technology Inc.
3.0 PIN DESCRIPTION
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN FUNCTION TABLE
3.1 Battery Management Input Supply
(V
DD
)
A supply voltage of [V
REG
(Typical) + 0.3V] to 6.0V is
recommended for MCP73123, while a supply voltage
of [V
REG
(Typical) + 0.3V] to 12.0V is recommended for
MCP73223. Bypass to V
SS
with a minimum of 1 µF.
The V
DD
pin is rated 18V absolute maximum to prevent
sudden rise of input voltage from spikes or low cost
AC-DC wall adapter.
3.2 Battery Charge Control Output
(V
BAT
)
Connect to the positive terminal of the battery. Bypass
to V
SS
with a minimum of 1 µF to ensure loop stability
when the battery is disconnected. The MCP73123 is
designed to provide 3.6V battery regulation voltage for
LiFePO
4
batteries. Undercharge may occur if a typical
Li-Ion or Li-Poly battery is used.
3.3 No Connect (NC)
No connect.
3.4 Status Output (STAT)
STAT is an open-drain logic output for connection to an
LED for charge status indication in stand-alone
applications. Alternatively, a pull-up resistor can be
applied for interfacing to a host microcontroller. Refer to
Table 5-1 for a summary of the status output during a
charge cycle.
3.5 Battery Management 0V Reference
(V
SS
)
Connect to the negative terminal of the battery and
input supply.
3.6 Current Regulation Set (PROG)
The fast charge current is set by placing a resistor from
PROG to V
SS
during constant current (CC) mode.
The PROG pin also serves as a charge control enable
pin. Allowing the PROG pin to float or connecting the
pin to an impedance greater than 200 k will disable
the MCP73123/223 charger. Refer to
Section 5.5,
"Constant Current Mode – Fast Charge", for details.
3.7 Exposed Pad (EP)
The Exposed Thermal Pad (EP) shall be connected to
the exposed copper area on the Printed Circuit Board
(PCB) to enhance thermal power dissipation.
Additional vias on the copper area under the
MCP73123/223 device will improve the performance of
heat dissipation and simplify the assembly process.
Connecting EP to V
SS
is recommended.
MCP73123/223
Symbol I/O Description
DFN-10
1, 2 V
DD
I Battery Management Input Supply
3, 4 V
BAT
I/O Battery Charge Control Output
5, 6 NC — No Connection
7 STAT O Battery Charge Status Output
8, 9 V
SS
— Battery Management 0V Reference
10 PROG I/O Battery Charge Current Regulation Program and Charge Control Enable
11 EP — Exposed Pad