PT6600 Datasheet, PDF (3/5 Pages) Texas Instruments – 9 AMP ADJUSTABLE INTEGRATED SWITCHING REGULATOR

Application Notes
For assistance or to order, call [phone]
PT6500/PT6600 Series
Adjusting the Output Voltage of the PT6500 and
PT6600 5V Bus Converters
The output voltage of the Power Trends PT6500/PT6600
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 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 pin 14 (V_o adjust) and pins 7-10
(GND).
Adjust Down: Add a resistor (R1), between pin 14 (V_o adjust)
and pins 11-13 (V_out).
Refer to Figure 1 and Table 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 loca-
tion. 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 Remote 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 being used, connecting the
resistor (R1) between pin 14 (V_o adjust) and pin 1 (Remote
Sense) can benefit load regulation.
4. The minimum input voltage required by the part is
V_out + 1.2 or 3.1V, whichever is higher.
Figure 1
More Application Notes
1
Vo(sense)
Vin
C _in
330 µF
4,5,6
+
PT6500/6600
Vin
11,12,13
Vo
STBY
3
GND
Vo(adj)
7,8,9,10 14
(R1)
Adj Down
R2
Adjust Up
C _out
+
330 µF
COM
Vo
L
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 1
R_s = The series resistance from Table 1
Table 1
PT6500/6600 ADJUSTMENT AND FORMULA PARAMETERS
Series Pt #
PT6505
PT6507
PT6502
PT6605
PT6607
PT6602
Vo (nom)
1.2
1.3
1.5
Va (min)
1.14
1.19
1.27
Va (max)
2.35
2.45
2.65
Ro (kΩ)
2.49
2.49
2.49
Rs (kΩ)
2.0
2.0
2.0
PT6508
PT6608
1.7
1.36
2.85
2.49
2.0
PT6506
PT6606
1.8
1.4
2.95
2.49
2.0
PT6503
PT6603
2.5
1.8
3.5
4.99
4.22
PT6501
PT6601
3.3
2.25
4.2
12.1
12.1
PT6504
PT6604
3.6
2.5
4.3
10.0
12.1
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com
3