TS2596S
Taiwan Semiconductor
4 Version: C1602
APPLICATION INFORMATION
Pin Function Descriptions
V
CC
This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be presented
at this pin to minimize voltage transients and to supply the switching currents needed by the regulator.
Ground
Circuit ground
SW Output
Internal switch. The voltage at this pin switches between (+V
CC
– V
SAT
) and approximately – 0.5V, with a duty cycle
of approximately V
OUT
/ V
CC
. To minimize coupling to sensitive circuitry, the PC board copper area connected to this
pin should be minimized.
Feedback
Sense the regulated output voltage to complete the feedback loop.
Enable
Allow the switching regulator circuit to be shutdown using logic level signals, thus dropping the total input supply
current to approximately is 100µA. 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 V
CC
) shuts the regulator down. If this shutdown
feature is not needed, the EN pin can be wired to the ground pin.
Thermal Considerations
The SOP-8 package needs a heat sink under most conditions. The size of the heat sink depends on the input
voltage, the output voltage, the load current and the ambient temperature. The TS2596S junction temperature rises
above ambient temperature for a 2A load and different input and output voltages.
The data for these curves was taken with the TS2596S (SOP-8) package operating as a buck-switching regulator
in an ambient temperature of 25ºC (still air). These temperature increments are all approximate and are affected by
many factors. A higher ambient temperature requires more heat sinker.
For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper (need
connect to the Ground pin) should be used in the board layout, (one exception is the SW 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 thermal resistance and junction temperature increments are all approximate. The increments are affected
by a lot of factors. Some of these factors include board 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.
