PT6300 Datasheet, PDF (3/8 Pages) Texas Instruments – 3 AMP ADJUSTABLE POSITIVE STEP-DOWN INTEGRATED SWITCHING REGULATORS

Application Notes
PT6100/6210/6300 Series
Adjusting the Output Voltage of Power Trends’
Wide Input Range Bus ISRs
The output voltage of the Power Trends’ Wide Input
Range Series ISRs may be adjusted higher or lower than
the factory trimmed pre-set voltage with the addition of a
single external resistor. Table 1 accordingly gives the
allowable adjustment range for each model for either
series as V_a (min) and V_a (max).
Adjust Up: An increase in the output voltage is obtained by
adding a resistor R2, between pin 12 (V_o adjust) and pins 5-8
(GND).
Adjust Down: Add a resistor (R1), between pin 12 (V_o adjust)
and pins 9-11(V_out).
Figure 1
Vin
C1
1µF Ceramic
(Optional)
COM
PT6100/6200/6300
2,3,4
9,10,11
Vin
Vo
GND
Vo(adj)
5,6,7,8
12
(R1)
Adj Down
R2
Adjust
Up
C2
+
1 0 0 µF
(Req'd)
Vo
COM
Notes:
1. Use only a single 1% resistor in either the (R1) or R2
location. Place the resistor as close to the ISR as possible.
2. Never connect capacitors from V_o adjust to either GND
or V_out. Any capacitance added to the V_o adjust pin will
affect the stability of the ISR.
3. Adjustments to the output voltage may place additional
limits on the maximum and minimum input voltage for
the part. The revised maximum and minimum input
voltage limits must comply with the following
requirements. The limits are model dependant.
PT6216/PT6314:
V_in (max) = (10 x V_a)V or 17V, whichever is less.
V_in (min) = 9.0V
All other models:
V_in (max) = (8 x V_a)V or as specified.
V_in (min) = (V_a + 4)V or 9V, whichever is greater.
The values of (R1) [adjust down], and R2 [adjust up], can
also be calculated using the following formulas. Refer to
Figure 1 and Table 2 for both the placement and value of the
required resistor; either (R1) or R2 as appropriate.
(R1)
=
R_o (V_a – 1.25)
V_o – V_a
kΩ
R2
=
1.25 R_o
V_a – V_o
kΩ
Where: V_o = Original output voltage
V_a = Adjusted output voltage
R_o = The resistance value fromTable 1
Table 1
ISR ADJUSTMENT RANGE AND FORMULA PARAMETERS
1Adc Rated
2Adc Rated
3Adc Rated
PT6216
PT6314
PT6102
PT6213
PT6303
PT6101
Vo (nom)
1.5
Va (min)
1.3
Va (max)
1.9
Ro (kΩ)
8.25
3.3
5.0
1.8
1.88
6.07
11.25
66.5
150.0
PT6212
PT6302
5.0
2.18
8.5
90.9
PT6103
PT6214
PT6304
12.0
2.43
22.12
243.0
For technical support and more information, see inside back cover or visit www.ti.com/powertrends