AP1551SL-13 Diodes Inc, AP1551SL-13 Datasheet - Page 7

• Manufacturer Part Number: AP1551SL-13
• Description: IC CONV DC-DC PWM 2CH 2A 16-SOIC
• Manufacturer: Diodes Inc
• Type: Step-Down (Buck)r

Specifications of AP1551SL-13

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 2
• Voltage - Output: 1.23 ~ 18 V
• Current - Output: 2A
• Frequency - Switching: 150kHz
• Voltage - Input: 4.5 ~ 22 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Output Voltage: + 1.23 V to + 18 V
• Switching Frequency: 150 KHz
• Operating Temperature Range: - 40 C to + 125 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 0 % to 100 %
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: AP1551SLDITR

150KHz, Dual Channel 2A PWM Buck DC/DC Converter
Pin Functions
+V
This is the positive input supply for the IC switching
regulator. A suitable input bypass capacitor must be
present at this pin to minimize voltage transients
and to supply the switching currents needed by the
regulator.
Ground1/2
Circuit ground.
Output
Internal switch. The voltage at this pin switches
between (+V
with a duty cycle of approximately V
minimize coupling to sensitive circuitry, the PC
board copper area connected to this pin should be
kept a minimum.
Feedback1/2
Senses the regulated output voltage to complete
the feedback loop.
SD1/2
Allows the switching regulator circuit to be
shutdown using logic level signals thus dropping
the total input supply current to approximately
150uA. Pulling this pin below a threshold voltage of
approximately 1.3V turns the regulator on, and
pulling this pin above 1.3V (up to a maximum of
18V) shuts the regulator down. If this shutdown
feature is not needed, the SD pin can be wired to
the ground pin or it can be left open, in either case
the regulator will be in the ON condition.
Anachip Corp.
www.anachip.com.tw
IN1/2
Function Description
Not Recommended for New Design
IN
– V
SAT
) and approximately – 0.5V,
OUT
/ V
IN
. To
7/8
Thermal Considerations
The SOP-16 package needs a heat sink under
most conditions. The size of the heatsink depends
on the input voltage, the output voltage, the load
current and the ambient temperature. The AP1551
junction
temperature for each channel with a 2A load and
different input and output voltages. The data for
these curves was taken with the AP1551 (SOP-16
package) operating as a buck-switching regulator in
an ambient temperature of 25
temperature rise numbers are all approximate and
there are many factors that can affect these
temperatures. Higher ambient temperatures require
more heat sinking.
For the best thermal performance, wide copper
traces and generous amounts of printed circuit
board copper should be used in the board layout.
(Once exception to this is the output (switch) pin,
which should not have large areas of copper.)
Large areas of copper provide the best transfer of
heat (lower thermal resistance) to the surrounding
air, and moving air lowers the thermal resistance
even further.
Package
temperature rise numbers are all approximate, and
there are many factors that will affect these
numbers.
size, shape, thickness, position, location, and even
board temperature. Other factors are, trace width,
total printed circuit copper area, copper thickness,
single or double-sided, multi-layer board and the
amount of solder on the board.
The effectiveness of the PC board to dissipate heat
also depends on the size, quantity and spacing of
other components on the board, as well as whether
the surrounding air is still or moving. Furthermore,
some of these components such as the catch diode
will add heat to the PC board and the heat can vary
as the input voltage changes. For the inductor,
depending on the physical size, type of core
material and the DC resistance, it could either act
as a heat sink taking heat away from the board, or it
could add heat to the board.
temperature
Some of these factors include board
thermal
resistance
rises
o
C (still air). These
Rev. 1.0 Nov 17, 2004
above
AP1551
and
ambient
junction