AP2553W6-7 Diodes Inc., AP2553W6-7 Datasheet - Page 9

• Manufacturer Part Number: AP2553W6-7
• Description: Power Switch ICs - USB 2.1A Precision ADJ 5.5V 2.1A 210kOhm
• Manufacturer: Diodes Inc.

Specifications of AP2553W6-7

• Rohs: yes
• Supply Voltage - Min: 2.7 V
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 150 C
• Minimum Operating Temperature: - 40 C
• Package / Case: SOT26
• Mounting Style: SMD/SMT
• Number Of Switches: Single
• Off Time (max): 0.5 ms
• On Resistance (max): 70 mOhms
• On Time (max): 1.5 ms
• Operating Temperature Range: - 40 C to + 150 C
• Supply Current: 2.1 A
• Switch Configuration: Single

Application Note
The AP2552/53 AND AP2552A/53A are integrated high-side power switches optimized for Universal Serial Bus (USB) that requires protection
functions. The power switches are equipped with a driver that controls the gate voltage and incorporates slew-rate limitation. This, along with the
various protection features and special functions, makes these power switches ideal for hot-swap or hot-plug applications.
Protection Features:
Under-Voltage Lockout (UVLO)
Whenever the input voltage falls below UVLO threshold (~2.5V), the power switch is turned off. This facilitates the design of hot-insertion
systems where it is not possible to turn off the power switch before input power is removed.
Over-Current and Short-Circuit Protection
An internal sensing FET is employed to check for over-current conditions. Unlike current-sense resistors, sense FETs do not increase the series
resistance of the current path. When an overcurrent condition is detected, the device maintains a constant output current and reduces the output
voltage accordingly. Complete shutdown occurs only if the fault stays long enough to activate thermal limiting.
The different overload conditions and the corresponding response of the AP2552/53 AND AP2552A/53A are outlined below:
Note that when the output has been shorted to GND at extremely low temperature (< -30°C), a minimum 120-μF electrolytic capacitor on the
output pin is recommended. A correct capacitor type with capacitor voltage rating and temperature characteristics must be properly chosen so
that capacitance value does not drop too low at the extremely low temperature operation. A recommended capacitor should have temperature
characteristics of less than 10% variation of capacitance change when operated at extremely low temp. Our recommended aluminum electrolytic
capacitor type is Panasonic FC series.
Current-Limit Threshold Programming
The current-limit threshold can be programmed using an external resistor. The current-limit threshold is proportional to the current sourced out of
I
The recommended 1% resistor range for R
temperature and process. This graph does not include the external resistor tolerance. The traces routing the RLIM resistor to the AP2552/53 and
AP2552A/53A should be as short as possible to reduce parasitic effects on the current-limit accuracy.
To design below a maximum current-limit threshold, find the intersection of R
curve and choose a value of R
limiting upstream power supplies causing the input voltage bus to droop. The resulting minimum current-limit threshold is the intersection of the
selected value of R
AP2552/AP2553/AP2552A/AP2553A
Document number: DS35404 Rev. 6 - 2
LIM
S.NO
.
1
2
3
Short-circuit condition at
start-up
Short-circuit or overcurrent
condition
Gradual increase from
nominal operating current to
I
LIMIT
LIM
Conditions
and the I
OS(min)
LIM
above this value. Programming the current limit below a maximum threshold is important to avoid current
(I
LIM
) curve.
Output is shorted before input
voltage is applied or before the
part is enabled
Short-Circuit or Overload
condition that occurs when the
part is enabled.
Load increases gradually until
the current-limit threshold.(I
LIM
is 10kΩ ≤R
Explanation
LIM
≤210kΩ. Figure 15 includes current-limit tolerance due to variations caused by
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TRIG
)
The IC senses the short circuit and immediately clamps output
current to a certain safe level namely I
The current rises until I
has been reached, the device switches into its current limiting
mode and is set at I
 At the instance the overload occurs, higher current may flow
 After the current limit function has tripped (reached the over-
LIM
for a very short period of time before the current limit function
can react.
current trip threshold), the device switches into current
limiting mode and the current is clamped at I
and the maximum desired load current on the I
AP2552/ AP2553/ AP2552A/ AP2553A
Behavior of the AP2552/53 AND AP2552A/53A
LIMIT
LIMIT
.
or thermal limit. Once the threshold
SHORT.
SHORT
© Diodes Incorporated
OS(max)
/I
LIMIT
April 2013
.
(I
LIM
)