PT6510_08 Datasheet, PDF (9/11 Pages) Texas Instruments – 8-A Rated Output Current

Application Notes
PT6510 Series
Adjusting the Output Voltage of the
PT6510 5V/3.3V Bus Converters
The output voltage of the PT6510 series switching regula-
tors may be adjusted higher or lower than the factory
trimmed pre-set voltage with the addition of a single
external resistor. Table 4-1 gives the allowable adjust-
ment range for each model in the 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 V_o Adjust (pin 14) and
GND (pins 7-10).
Adjust Down: Add a resistor (R₁), between V_o Adjust
(pin 14) and V_out (pins 11-13).
Refer to Figure 4-1 and Table 4-2 for both the placement and
value of the required resistor, either (R₁) or R₂ as appropriate.
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, V_out, or the V_o Sense pin. Any capacitance
added to the V_o Adjust pin will affect the stability of
the ISR.
3. If the remote sense feature is used, connecting the
resistor (R₁) between V_o Adjust (pin 14) and V_o Sense
(pin 1) can benefit load regulation.
4. The minimum input voltage required by the part is
V_out + 1.2 or V_in(min) from Table 4-1, whichever is
higher.
Figure 4-1
1
V_o(Sense)
Vin
4–6 _Vin
PT6510
11–13
V_out
+
C_in
STBY
3
GND V_o(adj)
7–10 14
(R1)
Adj Down
COM
R2
Adjust Up
V_out
L
+
C_out
O
A
D
COM
The values of (R₁) [adjust down], and R₂ [adjust up], can
also be calculated using the following formulae.
(R₁)
=
R_o (V_a – 1.0)
(V_o – V_a)
– R_s kΩ
R₂
=
R_o
V_a - V_o
– R_s
kΩ
Where: V_o = Original output voltage
V_a = Adjusted output voltage
R_o = The resistance value in Table 4-1
R_s = The series resistance from Table 4-1
Table 4-1
PT6510 ADJUSTMENT AND FORMULA PARAMETERS
Series Pt #
PT6515
PT6512
PT6516
Vo (nom)
1.2
1.5
1.8
Va (min)
1.14
1.27
1.4
Va (max)
2.35
2.65
2.95
Ro (kΩ)
2.49
2.49
2.49
Rs (kΩ)
2
2
2
Vin(min)
3.1
3.1
3.1
PT6513
2.5
1.8
3.5
4.99
4.22
4.5
PT6511
3.3
2.25
4.2
12.1
12.1
4.5
PT6514
3.6
2.5
4.3
10
12.1
4.5
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