AAT4620ITP-T1 Analogic Tech, AAT4620ITP-T1 Datasheet - Page 10

• Manufacturer Part Number: AAT4620ITP-T1
• Description: Other Power Management Crnt Limit Intrface/ Capacitor Charger
• Manufacturer: Analogic Tech
• Type: Power Switchr

Specifications of AAT4620ITP-T1

• Power Dissipation: 625 mW
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TSOPJW-12
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

nal resistors connected between the two SET pins
and ground. The minimum current limit threshold is
specified by I
the device in current limit and the chip temperature
reaches a critical point, then an internal power loop
will reduce the current to a safe level. Connecting
ISETU to ground disables the current limit protec-
tion allowing a low impedance path to the host V
The load switch is turned off by applying a logic
high level to both of the EN pins. When both EN IL
and EN IU are selected ISETU will be selected.
The EN function has logic level thresholds that
allow the AAT4620 to be TTL compatible and may
also be controlled by 2.5V to 5.0V CMOS circuits.
The voltage level applied to the EN pins should not
exceed the input supply level present on the VCC
pin. The AAT4620 typically consumes 40µA when
operating, when off, the device draws less then
1µA. In the off state, current is prevented from flow-
ing between the input and output.
Under-voltage lockout circuitry ensures that the
V
the IC. Also included is a System Ready function
which will be activated when the capacitor voltage
is charged and the load is permitted to take current.
For automatic functionality, this pin can be directly
connected to the EN IU pin. An external resistor is
provided to add hysteresis to this function.
10
CC
supply is high enough for correct operation of
1.5Meg - 750k
187.5 - 93.75k
375k - 187.5k
R
750k - 375k
SET
Range
LIM(MIN)
. If the load condition maintains
I
ISET
1
2
4
8
(µA)
I
LIM
/V
Table 1: R
ISET
0.8
0.4
0.2
0.1
CC
(A/V)
.
SET
Application Information
ISETU and ISETL Current Limit Set
The AAT4620 current limit is set at two different lev-
els. Resistors from ISETL and ISETU set the lower
and upper current limit levels respectively.
The ISETL and ISETU nodes operate within a win-
dow of 0.75V to 1.5V for resistor values ranging from
93.75Ω to 1.5MΩ. Resistor values outside this range
are not recommended. The ISETL and ISETU
source current varies with the resistor value used
according to Table 1. To determine the resulting cur-
rent limit multiply the R
times the gain in Table 1. Note that the voltage at the
node varies from 0.75V to 1.5V and the current limit
gain varies depending on the resistor value used.
If the set pin is open circuit or allowed to exceed
2V, all power devices are disabled and the input is
disconnected from the output. Shorting the set pin
to GND enables all power devices and shorts the
V
To activate the upper current level (R
low. To activate the lower current level (R
EN IL low. If both EN IU and EN IL are pulled low the
EN IU current limit level (R
Current Limit Range (A)
Table.
CC
PCMCIA Current Limit Interface
to the output pin with no current limit.
0.15-0.075
V
0.3-0.15
1.2-0.6
0.6-0.3
ISET
= R
and Capacitor Charger
SET
· I
ISET
SETU
SETU
= 0.75V to 1.5V
or R
) will be selected.
Current Limit
SETL
R
R
R
R
AAT4620
SET
SET
SET
SET
SETU
*1µA*0.8
*2µA*0.4
*4µA*0.2
*8µA*0.1
node voltage
4620.2007.04.1.1
) pull EN IU
SETL
) pull