SR086DB1 Supertex, SR086DB1 Datasheet - Page 3

• Manufacturer Part Number: SR086DB1
• Description: Power Management IC Development Tools ADJUSTABLE OFF-LINE INDUCTORLESS SWITCHING REGULATOR DEMOBOARD
• Manufacturer: Supertex
• Type: AC/DC Convertersr

Specifications of SR086DB1

• Product: Power Management Modules
• Tool Is For Evaluation Of: SR086
• Input Voltage: 90 V to 270 V
• Output Voltage: 3.3 V, 12.6 V
• Factory Pack Quantity: 1

Modifications
Output Voltage
V
ing feedback resistor R
Keep in mind that the peak output voltage is regulated, not
the average, therefore the average output voltage will de-
crease (and ripple increase) with increased loads.
Leave R
quired for the proper operation of the SR086. Change R
and R
replace C
rating. For C
ripple current rating (800mArms). Use ceramic for C
Since V
mum current available from V
creased due to power considerations.
or 60mA, whichever is less.
Output Ripple
Storage capacitor C
at 100mA combined load (I
may be reduced. Conversely, C
er ripple. Use a low ESR capacitor with an adequate ripple
current rating (measure using a current probe). Efficiency
and output current capability may drop with increased ca-
pacitance because of a smaller conduction angle associated
with lower ripple. Due to feedback hysteresis, ripple cannot
be reduced below 4%.
Input Voltage
To reduce standby power for 230VAC-only applications, or
for supply voltages less than 90Vrms, R
changed according to equation 4 below. R
main at 400kΩ.
Note:
OUT
1. V
may be adjusted in the range of 9.0 to 50V
REG
4
according to the equation 4. It may be necessary to
REG
R
I
V
6
requires at least 4.0V of headroom to provide 3.3V. Therefore V
REG(MAX)
RIPPLE (P - P)
5
2
at 12.4kΩ - it assures a minimum 100µA load re-
= R
is a linear regulator supplied from V
and C
Supertex inc.
3
, use a low ESR capacitor with an adequate
6
• [(V
=
3
V
≈
with capacitors having a higher voltage
OUT
3
OUT
1.5W
was sized to provide about 2V
I
OUT
5
- 3.3V
2f
/1.25V) - 1]
according to the following equation.
IN
+ I
C
OUT
3
REG
REG
+ I
3
may be increased for low-
REG
is reduced as V
●
). For lighter loads, C
1235 Bordeaux Drive, Sunnyvale, CA 94089
1
and R
1
+ R
OUT
1
2
4
, the maxi-
should re-
by chang-
should be
OUT
P-P
2
.
EQ. 1
EQ. 2
EQ. 3
ripple
is in-
3
3
OUT
3
, including ripple and tolerance, must not fall below 7.3V.
R
tances and resistor voltage ratings for 230VAC operation.
For 120VAC-only applications they may be omitted (replaced
with shorts), with R
Conducted EMI
As supplied, the SR086DB1 meets 47CFR Part 15 Class B
and CISPR 14-1 requirements for conducted emissions at
combined load currents (I
higher load currents, an RC network (R
before the IGBT gate to slow down the falling edge. This has
the effect of reducing harmonics, lowering conducted EMI.
Suggested values of 22kΩ and 390pF allow the SR086DB1
to meet EMI requirements at combined load currents of
60mA for 120VAC and 40mA for 230VAC.
Slowing down the falling edge results in the output voltage
overshooting the intended regulation point, causing the peak
V
pensated for by entering a slightly lower value for V
equation 1 when selecting feedback resistors. Slowing down
the falling edge also increases switching losses, resulting in
slightly decreased efficiency.
R
Use the minimum anticipated RMS value for V
sistor tolerance into account, selecting the next lower stan-
dard value. Choosing a lower value has no effect other than
slightly higher standby power.
OUT
2
3
+ R
and R
voltage to be higher than expected. This may be com-
4
(R3 + R4) <
where V
Equation
4
are employed to ensure adequate creepage dis-
●
Tel: [phone]
X
= V
1
√ 2V
OUT
= 1.0MΩ and R
+ 15V
IN
OUT
2
- V
●
+ I
X
www.supertex.com
2
π • 25µA
REG
- V
) of less than 20mA. For
3
X
= 430kΩ.
cos
8
& C
SR086DB1
-1
√2 V
5
) can be used
V
IN
X
IN
. Take re-
OUT
Eq. 4
into