pth12050 Astec Powe, pth12050 Datasheet - Page 7

• Manufacturer Part Number: pth12050
• Description: Pth05020 5vin Single
• Manufacturer: Astec Powe

7. Feature Set
7.1 Adjusting the Output Voltage of the PTH05020
The V
product. The adjustment range is from 0.8V to 3.6V. The adjustment
method requires the addition of a single external resistor, R
must be connected directly between the Vo Adjust and GND pins
Table 4 gives the preferred value for the external resistor for a
number of standard voltages, along with the actual output voltage
that this resistance value provides.
For other output voltages the value of the required resistor can either
be calculated using the following formula, or simply selected from
the range of values given in Table 5. Figure 8 shows the placement of
the required resistor.
Table 4 - Preferred Values of R
V
out
o
GND
Standard
adjust control (pin 4) sets the output voltage of the PTH05020
3.3V
2.5V
2.0V
1.8V
1.5V
1.2V
1.0V
0.8V
10
1
PTH05020W
GND
Figure 8 - Adjust Resistor Placement
9
7
8
R SET
0.1 W, 1 %
R
set
(Preferred Value)
File Name: an_pth05020.pdf Rev (05): 21 Dec 2005
2.21kΩ
4.12kΩ
5.49kΩ
8.87kΩ
17.4kΩ
36.5kΩ
698kΩ
V
Open
o
V
set
o
Sense
Adj
V
5
4
for Standard Output Voltages
o
V
Sense (See Note 2)
out
6
C
330µF
out
V
out
3.309V
2.502V
2.010V
1.803V
1.504V
1.202V
1.005V
+
0.8V
(Actual)
set
GND
, that
V
out
1
.
Application Note 156
Notes:
1 Use a 0.1W resistor, with a tolerance of 1% (or better). Place the
2 Never connect capacitors from V
7.2 Output ON/OFF Inhibit
For applications requiring output voltage ON/OFF control,each series
of the PTH family incorporates an output Inhibit control pin. The
inhibit feature can be used wherever there is a requirement for the
output voltage from the regulator to be turned OFF.
The power modules function normally when the Inhibit pin is left
open-circuit, providing a regulated output whenever a valid source
voltage is connected to V
typical application of the inhibit function. Note the discrete transistor
(Q1). The Inhibit control has its own internal pull-up to +Vin potential.
An open-collector or open-drain device is recommended to control
this input.
Turning Q1 on applies a low voltage to the Inhibit control pin and
disables the output of the module. If Q1 is then turned off, the
module will execute a soft-start power-up sequence. A regulated
output voltage is produced within 20ms. Figure 9 shows the typical
rise in both the output voltage and input current, following the turn-
off of Q1. The turn off of Q1 corresponds to the rise in the waveform,
Q1 V
V
a
0.800
0.825
0.850
0.875
0.900
0.925
0.950
0.975
1.000
1.025
1.050
1.075
1.100
1.125
1.150
1.175
1.200
1.225
1.250
1.275
1.300
1.325
1.350
1.375
resistor as close to the regulator as possible. Connect the resistor
directly between pins 4 and 7 using dedicated PCB traces.
Any capacitance added to the V
of the regulator.
Req’d
www.artesyn.com
DS
. The waveforms were measured with a 5A load.
OUTPUT VOLTAGE SET-POINT RESISTOR VALUES
Table 5 - Output Voltage Set-point Resistor Values
77.5kΩ
61.5kΩ
50.8kΩ
43.2kΩ
37.5kΩ
33.1kΩ
29.5kΩ
26.6kΩ
24.2kΩ
22.1kΩ
20.4kΩ
18.8kΩ
17.5kΩ
16.3kΩ
15.3kΩ
14.4kΩ
13.5kΩ
12.7kΩ
12.1kΩ
11.4kΩ
318kΩ
158kΩ
104kΩ
Open
R
set
V
a
1.400
1.425
1.450
1.475
in
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
2.05
2.10
2.15
2.20
2.25
2.30
2.35
2.40
2.45
Req’d
with respect to GND. Figure 9 shows the
o
10.8kΩ
10.3kΩ
9.82kΩ
9.36kΩ
8.94kΩ
8.18kΩ
7.51kΩ
6.92kΩ
5.93kΩ
5.51kΩ
5.13kΩ
4.78kΩ
4.47kΩ
4.18kΩ
3.91kΩ
3.66kΩ
3.44kΩ
3.22kΩ
3.03kΩ
2.84kΩ
2.67kΩ
2.51kΩ
2.36kΩ
o
6.4kΩ
Adjust pin will affect the stability
R
Adjust to either GND or V
set
V
a
2.50
2.55
2.60
2.65
2.70
2.75
2.80
2.85
2.90
2.95
3.00
3.05
3.10
3.15
3.20
3.25
3.30
3.35
3.40
3.45
3.50
3.55
5.60
Req’d
2.22kΩ
2.08kΩ
1.95kΩ
1.83kΩ
1.72kΩ
1.61kΩ
1.51kΩ
1.41kΩ
1.32kΩ
1.23kΩ
1.15kΩ
1.07kΩ
914Ω
843Ω
419Ω
367Ω
988Ω
775Ω
710Ω
647Ω
587Ω
529Ω
473Ω
R
set
out
7
.