RT9501AGF RICHTEK [Richtek Technology Corporation], RT9501AGF Datasheet - Page 8

• Manufacturer Part Number: RT9501AGF
• Description: Advanced Lithium-Ion Linear Battery Charger
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT9501A/B
Charge status indication
The RT9501 indicates the status of the charger on the 3-
state STAT pin. The following table shows the statuses of
this pin.
Selecting an External PNP Pass-Transistor or
P-Channel MOSFET:
The RT9501 drives an external PNP transistor or
Channel MOSFET to control the charging current. The
specifications must be concerned are the
current rating and package power dissipation. The external
switch is performed as a linear regulator. The maximum
power loss occurs when the constant current regulation
starts at the beginning, and it can be calculated
approximately from following equation:
I
The minimum voltage drop between the sense-resistor
is 100mV, and the minimum precharge threshold voltage
is 2.8V.
The external pass device with PCB heatsinking must be
rated for the maximum power dissipation.
www.richtek.com
8
V
(SNS)
IN
function disable or sleep mode
Temperature fault or charge
In battery charging cycle
Charge cycle completed
is the constant regulation current.
R
CS
P
D(MAX)
Condition
Figure 8. For FB pin Function
V
O(REG)
STAT
= I
FB
CS
VDD
(SNS)
= 2.1 (1+
R4
×
BATT
(V
×
GND
CC
TS
DD
Q1
- 0.1V - 2.8V)
R
R
FB2
FB1
High Impedance
) V
STAT Pin
High
Low
voltage and
R
R
FB1
FB2
Preliminary
Battery
P-
Selecting Input/Output Capacitor
In analog circuit applications, to place a high-frequency
decoupling capacitor nearby the controller IC between
input power source and ground is very important. A 0.1uF
ceramic is recommended. If a high ripple and noise input
power is chosen, it should have enough capacitance to
reduce the disturbance.
A 0.1uF to 1uF output capacitor is recommended to control
the output voltage and keep the output voltage ripple small
when the battery is disconnected.
DS9501A/B-07 March 2007