TNY278GN Power Integrations, TNY278GN Datasheet - Page 11
Manufacturer Part Number
IC OFFLINE SWIT OVP OTP HV 8SMD
Specifications of TNY278GN
124 ~ 140kHz
Voltage - Output
-40°C ~ 150°C
Package / Case
8-SMD Gull Wing, 7 Leads
Input / Supply Voltage (max)
Input / Supply Voltage (min)
Duty Cycle (max)
Operating Temperature Range
- 40 C to + 150 C
No. Of Outputs
Voltage Regulator Case Style
No. Of Pins
For Use With
596-1194 - KIT DESIGN REF TINYSWITCH-III
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
the BP/M pin solder pad preventing the design from starting up.
Designs that make use of the undervoltage lockout feature by
connecting a resistor from the high voltage rail to the EN/UV pin
are not affected.
If the contamination levels in the PC board assembly facility are
unknown, the application is open frame or operates in a high
pollution degree environment and the design does not make
use of the undervoltage lockout feature, then an optional
390 kΩ resistor should be added from EN/UV pin to SOURCE
pin to ensure that the parasitic leakage current into the EN/UV
pin is well below 1 μA.
Note that typical values for surface insulation resistance (SIR)
where no-clean ﬂ ux has been applied according to the
suppliers’ guidelines are >>10 MΩ and do not cause this issue.
Quick Design Checklist
As with any power supply design, all TinySwitch-III designs
should be veriﬁ ed on the bench to make sure that component
speciﬁ cations are not exceeded under worst case conditions.
The following minimum set of tests is strongly recommended:
Maximum drain voltage – Verify that V
650 V at highest input voltage and peak (overload) output
power. The 50 V margin to the 700 V BV
gives margin for design variation.
Recommended Circuit Board Layout for TinySwitch-III with Undervoltage Lock Out Resistor.
Input Filter Capacitor
does not exceed
Up-to-date information on design tools is available at the Power
Integrations website: www.powerint.com.
Maximum drain current – At maximum ambient temperature,
maximum input voltage and peak output (overload) power,
verify drain current waveforms for any signs of transformer
saturation and excessive leading edge current spikes at
startup. Repeat under steady state conditions and verify that
the leading edge current spike event is below I
end of the t
current should be below the speciﬁ ed absolute maximum
Thermal Check – At speciﬁ ed maximum output power,
minimum input voltage and maximum ambient temperature,
verify that the temperature speciﬁ cations are not exceeded
for TinySwitch-III, transformer, output diode, and output
capacitors. Enough thermal margin should be allowed for
part-to-part variation of the R
speciﬁ ed in the data sheet. Under low line, maximum power,
a maximum TinySwitch-III SOURCE pin temperature of
110 °C is recommended to allow for these variations.
. Under all conditions, the maximum drain
Maximize hatched copper
of TinySwitch-III as
) for optimum
Rev. I 01/09