DATA SHEET
AAT4621
PC Card Current Limit Interface and Capacitor Charger
General Description
The AAT4621 SmartSwitch family is a current limited P-channel MOSFET power switch designed for high-side load-switching applications in PC Card GSM/GPRS/3G modem cards. Used in conjunction with a super capacitor, the AAT4621 will ensure that the power ratings of the PCMCIA host are not exceeded at any time. Featuring two independent, programmable current limits and a power loop, the AAT4621 can ensure that the super capacitor can be charged without exceeding PCMCIA specifications. The current limit is set by two external resistors allowing a ±10% current limit accuracy over the normal operating temperature range. The switch can be controlled from either of the two enable inputs and in the off condition will block currents in both directions. The AAT4621 also incorporates a System READY function which can advise the system that the super capacitor is fully charged and ready for use. Adjustable hysteresis is provided with the addition of an external resistor. The quiescent supply current is typically a low 40μA. In shutdown mode, the supply current decreases to less than 1μA. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current limit range from 150mA to 2400mA.
The AAT4621 is available in a thermally enhanced, Pb-free 14-pin TDFN33 package and is specified over the -40°C to 85°C temperature range.
Features
• Operating Voltage Range: 3.0V to 5.5V • Dual Independent Current Limits
▪ AAT4621: 75mA to 1200mA ▪ AAT4621-1: 150mA to 2400mA ▪ ±10% Current Accuracy
• Reverse Current Blocking Protection • Power Loop • Low Quiescent Current
▪ 40μA Typical ▪ 1.0μA Max with Switch Off
• 65m Typical RDS(ON) at 3V • System READY Output with Externally Programmable
Hysteresis • Only 1.4V Needed for Enable Control Pin • Under-Voltage Lockout • Over-Temperature Protection • Temperature Range: -40 to 85°C • 14-Pin TDFN33 Package
Applications
• Capacitor Charger • CF Card Port Power Protection • Express Card GSM/GPRS/3G Modems • PC Card GSM/GPRS Class 10/12 Modems • WiMAX Cards
Typical Application
VCC
ENIL ENIU
VCC
EN IL
UnderVoltage Lockout
Reverse Blocking
Over-Temp Protection
Power Loop
EN IU
1.2V Reference
GND
Current Limit
Control
RHYS
OUT RDY
100k
To Load To μC
ISETL ISETU
RSETU
RSETL
SuperCap
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 •
[email protected] • www.skyworksinc.com 201944A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 15, 2012
1
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 ISETL 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 ISETU 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, ISETU 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 package 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 •
[email protected] • www.skyworksinc.com
2 201944A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 15, 2012
DATA SHEET
AAT4621
PC Card Current Limit Interface and Capacitor Charger
Absolute Maximum Ratings1
Symbol
VCC VEN VSET, VOUT IMAX TJ TLEAD TSTG
Description
VCC to GND ENIL, ENIU to GND ISETL, ISETU, OUT to GND Maximum Co.