AAT4620
PCMCIA Current Limit Interface
and Capacitor Charger
General Description
The AAT4620 SmartSwitch is a current limited P-
channel MOSFET power switch designed for high-
side load-switching applications in PCMCIA
GSM/GPRS/3G modem cards. Used in conjunc-
tion with a super capacitor, the AAT4620 will
ensure that the power ratings of the PCMCIA host
are not exceeded at any time. Featuring two inde-
pendent, programmable current limits and a power
loop, the AAT4620 can ensure that the super
capacitor can be charged without exceeding PCM-
CIA 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 AAT4620
also incorporates a System READY function which
can advise the system that the super capacitor is
fully charged and ready for use. Adjustable hys-
teresis 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 AAT4620 is available in a thermally enhanced,
Pb-free, 12-pin TSOPJW package and is specified
over the -40°C to 85°C temperature range.
Features
•
•
SmartSwitch
™
•
•
•
•
•
•
•
•
•
V
IN
Range: 3.0V to 5.5V
Dual Independent Current Limits
— 100mA to 1200mA
— ±10% Current Accuracy
— 20°C Temperature Band
Reverse Current Blocking Protection
Power Loop
Low Quiescent Current
— 40µA Typical
— 1.0µA Max with Switch Off
65mΩ Typical R
DS(ON)
at 3V
Only 1.4V Needed for Enable Control Pin
System READY Output with Externally
Programmable Hysteresis
Under-Voltage Lockout
Temperature Range: -40 to 85°C
12-Pin TSOPJW Package
Applications
•
•
•
•
•
CF Card Port Power Protection
Express Card GSM/GPRS/3G Modems
Hot Swap Supplies
PCMCIA Card GSM/GPRS/3G Modems
Personal Communication Devices
Typical Application
Reverse
Blocking
100kΩ
OUT
Over-Temp
Protection
Under-
Voltage
Lockout
EN IL
EN
SUPERCAP
EN
OPERATION
EN IU
1.2V
Reference
Current
Limit
Control
ISETL
To Load
VCC
V
CC
Power
Loop
RDY
To μC
ISETU
GND
SuperCap
R
HYS
R
SETU
R
SETL
4620.2007.04.1.1
1
AAT4620
PCMCIA Current Limit Interface
and Capacitor Charger
Pin Descriptions
Pin #
1
Symbol
EN IU
Function
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 and EN IU are enabled, I
SETU
will be selected.
Enable input. Active low enable with internal pull up. Also switches in the lower current limit
initiating the super capacitor to start charging.
Device ground connection.
Input pins to the P-channel MOSFET source. Connect 1µF capacitor from VCC to GND.
P-channel MOSFET drain connection. Connect to super capacitor from OUT to GND.
Lower current-limit set input. A resistor from ISETL to ground sets the maximum lower cur-
rent limit for the switch. Current limit can be set between 100mA and 1200mA.
Upper current limit set input. A resistor from ISETU to ground sets the maximum upper cur-
rent limit for the switch. Current limits can be set between 100mA and 1200mA. Connect to
ground to disable current limit.
System READY hysteresis. Connect a resistor to ground to set the System Ready com-
parator hysteresis.
System ready pin. Open drain, active low, initiated when the capacitor is 98% charged.
2
3
4, 5, 6
7, 8
9
10
EN IL
GND
VCC
OUT
ISETL
ISETU
11
12
RHYS
RDY
Pin Configuration
TSOPJW-12
(Top View)
EN IU
EN IL
GND
VCC
VCC
VCC
1
2
3
4
5
6
12
11
10
9
8
7
RDY
RHYS
ISETU
ISETL
OUT
OUT
2
4620.2007.04.1.1
AAT4620
PCMCIA Current Limit Interface
and Capacitor Charger
Absolute Maximum Ratings
1
Symbol
V
CC
V
EN
V
SET
, V
OUT
I
MAX
Description
VCC to GND
EN to GND
SET, OUT to GND
Maximum Continuous Switch Current
Value
-0.3 to 6
-0.3 to V
CC
+ 0.3
-0.3 to V
CC
+ 0.3
2.5
Units
V
V
V
A
Thermal Characteristics
Symbol
θ
JA
P
D
T
J
Description
Maximum Thermal Resistance
2
Maximum Power Dissipation
2
Operating Junction Temperature Range
Value
160
625
-40 to 150
Units
°C/W
mW
°C
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 board.
4620.2007.04.1.1
3
AAT4620
PCMCIA Current Limit Interface
and Capacitor Charger
Electrical Characteristics
1
V
CC
= 3.0V to 5.5V, T
A
= -40°C to 85°C unless otherwise noted. Typical values are at T
A
= 25°C.
Symbol
V
CC
I
Q
I
QU0
I
Q(OFF)
I
SD(OFF)
V
UVLO
R
DS(ON)
I
LIMLACC
I
LIMUACC
I
LIM(MIN)
V
EN(L)
V
EN(H)
I
EN(SINK)
T
DEL(OFF)
V
RDY
V
RDYHYS
V
RDY(L)
I
RDY
OTMP
Description
Operation Voltage
Quiescent Current
Quiescent Current U
0
Off Supply Current
Off Switch Current
Under-Voltage Lockout
On-Resistance
Lower Current Limit Accuracy
Upper Current Limit Accuracy
Lower Minimum Current Limit
EN Input Low Voltage
EN Input High Voltage
EN Input Leakage
Turn-Off Delay Time
System READY Trip Threshold
System READY Hysteresis
System READY Voltage Low
RDY Leakage Current
Shutdown Temperature
Conditions
EN IL or EN IU = V
CC
, I
OUT
= 0,
R
HYS
= 200kΩ
EN IL = V
CC
, EN IU = GND, I
OUT
= 0,
I
SET
= GND, R
HYS
= 200kΩ
EN IL = EN IU = V
CC
EN IL = EN IU = V
CC
, V
SUPERCAP
= 0
Rising edge, 1% hysteresis
V
CC
=4.75V, R
SETL
= R
SETU
= 0k
V
CC
=3.0V, R
SETL
= R
SETU
= 0k
R
SETL
= 249kΩ;
ΔT
A
≤
20°C
R
SETL
= 249kΩ
R
SETU
= 1.24MΩ;
ΔT
A
≤
20°C
R
SETU
= 1.24MΩ
V
CC
=3.0V to 5.5V
V
CC
= 3.0V to 5.5V
2
V
EN
= 5.5V
V
CC
= 5V
V
OUT
rising, T
A
= 25°C
R
HYS
= 200kΩ
I
SINK
= 1mA
V
RDY
< 5.5V, V
OUT
< 98% of V
OUT
2
Min
3.0
Typ
Max
5.5
Units
V
µA
µA
µA
µA
V
mΩ
mA
mA
mA
V
V
µA
µs
% of
V
OUT
mV
V
µA
°C
40
40
0.4
0.4
2.7
50
65
200
200
1000
1000
75
75
75
1.0
10
3.0
100
120
220
230
1100
1150
0.4
180
170
900
850
1.4
0.4
98
200
0.4
1.0
145
1.0
1.0
1. The AAT4620 is guaranteed to meet performance specification over the -40°C to 85°C operating temperature range and is assured by
design, characterization and correlation with statistical process controls.
2. For V
IN
outside this range consult the Typical EN Threshold curve.
4
4620.2007.04.1.1
AAT4620
PCMCIA Current Limit Interface
and Capacitor Charger
Typical Characteristics
Output Current vs. Output Voltage
(R
SETU
= 383kΩ, 25°C)
Ω
0.40
R
SET
vs. I
LIM
(25°C)
°
1.40
Output Current (A)
V
IN
= 3.3V
0.30
1.20
1.00
I
LIM
(A)
V
IN
= 3.3V
0.20
0.80
0.60
0.40
0.20
0.10
V
IN
= 5V
V
IN
= 5V
0.00
0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
3
3.3
0.00
0
200
400
600
800
1000
1200
1400
1600
Output Voltage (V)
R
SET
(kΩ)
Reverse Off-Switch Current vs. Temperature
(E
NUB
= E
NLB
= V
CC
; V
IN
= 0V)
100
100
Off-Switch Current vs. Temperature
(E
NUB
= E
NLB
= V
CC
; V
OUT
= 0V)
I
RSD(OFF)
(µA)
10
I
SD(OFF)
(µA)
V
OUT
= 5V
10
V
IN
= 5V
1
1
0.1
V
OUT
= 3.3V
0.1
V
IN
= 3.3V
0.01
-40
-20
0
20
40
60
80
100
120
0.01
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
°
Temperature (°C)
°
Off-Supply Current vs. Temperature
(E
NUB
= E
NLB
= V
CC
; V
OUT
= Open)
10
V
IN
= 5V
I
Q(OFF)
(µA)
1
0.1
V
IN
= 3.3V
0.01
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
°
4620.2007.04.1.1
5
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