AAT4621_12 Datasheet, PDF (2/17 Pages) Skyworks Solutions Inc. – PC Card Current Limit Interface and Capacitor Charger

DATA SHEET
AAT4621
PC Card Current Limit Interface and Capacitor Charger
Pin Descriptions
Pin #
1
2
3
4
5, 6, 7
8, 9, 10, 11
12
13
14
EP
Symbol
RDY
RHYS
ISETU
ISETL
OUT
VCC
GND
EN IL
EN IU
EP
Function
System ready pin. Open drain, active low, initiated when the capacitor is 98% charged.
System READY hysteresis. Connect a resistor to ground to set the System Ready comparator hysteresis.
Upper current limit set input. A resistor from I_SETL to ground sets the maximum upper current limit for
the switch. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current
limit range from 150mA to 2400mA. Connect to ground to disable current limit.
Lower current-limit set input. A resistor from I_SETU to ground sets the maximum lower current limit for
the switch. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current
limit range from 150mA to 2400mA. Connect to ground to disable current limit.
P-channel MOSFET drain connection. Connect to super capacitor from OUT to GND.
Input pins to the P-channel MOSFET source. Connect 1μF capacitor from VCC to GND.
Device ground connection.
Enable input. Active low enable with internal pull up. Also switches in the lower current limit initiating
the super capacitor to start charging.
Enable input. Active low enable with internal pull up. Also switches in the higher current limit to allow the
System to start functioning. Can be directly connected to System Ready for automatic enabling. When
both EN IL B and EN IU B are enabled, I_SETU will be selected.
The exposed thermal pad (EP) must be connected to the board ground plane and Pin 12. The ground
plane should include a large exposed copper pad under the package for thermal dissipation (see pack-
age outline).
Pin Configuration
TDFN33-14
(Top View)
RDY ¹
RHYS ²
ISETU ³
ISETL ⁴
OUT ⁵
OUT ⁶
OUT ⁷
14 _ENIU
13 _ENIL
12 _GND
EP
11 _VCC
10 _VCC
9 _VCC
8 _VCC
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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201944A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 15, 2012