LT3575EFE#PBF Linear Technology, LT3575EFE#PBF Datasheet - Page 5

• Manufacturer Part Number: LT3575EFE#PBF
• Description: IC FLYBACK CONVERTER 16TSSOP
• Manufacturer: Linear Technology
• Type: Flyback, Isolatedr

Specifications of LT3575EFE#PBF

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: Adj to 60V
• Current - Output: 2.5A
• Frequency - Switching: 1MHz
• Voltage - Input: 3 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: *
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Voltage - Supply: 3 V ~ 40 V
• Frequency-max: 1MHz
• Pwm Type: Regulator
• Buck: No
• Boost: No
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Primary Input Voltage: 40V
• No. Of Outputs: 1
• Output Current: 3.5A
• No. Of Pins: 16
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 1 - Unlimited
• Peak Reflow Compatible (260 C): Yes
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Duty Cycle: -

PIN FUNCTIONS
NC (Pins 1, 15, 16): No Connect Pins. Can be left open
or connected to any ground plane.
V
the internal start-up circuitry and as a reference voltage
for the DCM comparator and feedback circuitry. This pin
must be locally bypassed with a capacitor.
SW (Pins 3, 4): Collector Node of the Output Switch. This
pin has large currents fl owing through it. Keep the traces to
the switching components as short as possible to minimize
electromagnetic radiation and voltage spikes.
BIAS (Pin 5): Bias Voltage. This pin supplies current to the
switch driver and internal circuitry of the LT3575. This pin
must be locally bypassed with a capacitor. This pin may
also be connected to V
V
be lower than the input voltage for proper operation.
SHDN/UVLO (Pin 6): Shutdown/Undervoltage Lockout.
A resistor divider connected to V
program the minimum input voltage at which the LT3575
will operate. At a voltage below ~0.7V, the part draws no
quiescent current. When below 1.22V and above ~0.7V,
the part will draw 7μA of current, but internal circuitry will
remain off. Above 1.22V, the internal circuitry will start
and a 7μA current will be fed into the SS pin. When this
pin falls below 1.22V, 2.8μA will be pulled from the pin to
provide programmable hysteresis for UVLO.
SS (Pin 7): Soft-Start Pin. Place a soft-start capacitor
here to limit start-up inrush current and output voltage
ramp rate. Switching starts when the voltage at this pin
reaches ~0.7V.
R
should be tied to this pin to ground to set the current
limit. Use a 10k resistor for the full current capabilities
IN
IN
ILIM
≤ 15V. If a third winding is used, the BIAS voltage should
(Pin 2): Input Voltage. This pin supplies current to
(Pin 8): Maximum Current Limit Adjust Pin. A resistor
IN
if a third winding is not used and if
IN
is tied to this pin to
of the switch.
V
Connect a series RC from this pin to ground to compensate
the switching regulator. A 100pF capacitor in parallel helps
eliminate noise.
R
pin is connected to the transformer primary (V
ratio of this resistor to the R
bandgap reference, determines the output voltage (plus
the effect of any non-unity transformer turns ratio). The
average current through this resistor during the fl yback
period should be approximately 200μA. For nonisolated
applications, this pin should be connected to V
R
Reference Resistor. This resistor should be in the range of
6k, but for convenience, need not be precisely this value.
For nonisolated applications, a traditional resistor voltage
divider may be connected to this pin.
TC (Pin 12): Output Voltage Temperature Compensation.
Connect a resistor to ground to produce a current
proportional to absolute temperature to be sourced into
the R
TEST (Pin 13): This pin is used for testing purposes only
and must be connected to ground for the part to operate
properly.
GND (Pin 14, Exposed Pad Pin 17): Ground. The exposed
pad of the package provides both electrical contact to
ground and good thermal contact to the printed circuit
board. The exposed pad must be soldered to the circuit
board for proper operation and should be well connected
with many vias to an internal ground plane.
C
FB
REF
(Pin 9): Compensation Pin for Internal Error Amplifi er.
(Pin 10): Input Pin for External Feedback Resistor. This
REF
(Pin 11): Input Pin for External Ground-Referred
node. I
TC
= 0.55V/R
REF
TC
resistor, times the internal
.
LT3575
IN
SW
.
). The
5
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