For technical support and more information, see inside back cover or visit www.ti.com
Standard Application
Features
Input Voltage Range:
18V to 40V
20W Rated
Output Voltages: 1.2V to 15V
82% Efficiency
1500 VDC Isolation
Low Profile (8.5 mm)
Adjustable Output Voltage
PT4500 Series
20-W 24-V Input Isolated
DC/DC Converter
SLTS153B - JUNE 2000 - REVISED OCTOBER 2002
Ordering Information
PT4501
H = 3.3V/5A (16.5W)
PT4502
H = 5.0V/4A
PT4503
H = 12V/1.6A
PT4504
H = 15V/1.3A
PT4506
H = 1.5V/5A (7.5W)
PT4507
H = 1.8V/5A (9W)
PT4508
H = 2.5V/5A (12.5W)
PT4509
H = 1.2V/5A (6W)
Pin-Out Information
Pin
Function
1
Remote On/Off
*
2
Vin
3
Vin
4
+Vin
5
+Vin
6
Remote Sense ()
7
Vout
8
Vout
9
+Vout
10
+Vout
11
Remote Sense (+)
12
Vout Adjust
*
* For further information, see
application notes.
Description
The PT4500 ExcaliburTM power modules
are a series of isolated DC/DC converters
housed a new space-saving copper case. The
series includes a number of standard output
voltages ranging from as low as 1.2VDC to
15VDC, each adjustable by up to 10% of
nominal. The modules are ideal for Telecom,
Industrial, Computer, and other distributed
power applications that require input-to-output
isolation.
Using multiple modules, system designers
can implement a complete custom power supply
solution. The flexibility of full isolation also
allows the input or output to be configured for
negative voltage operation.
The PT4500 series is electrically equivalent
to the popular PT4140 series and requires no
additional components for proper operation.
On/Off Control
Differential Remote Sense
Short Circuit Protection
Over Temperature Shutdown
Space Saving Package:
1.0 sq. in. PCB Area (Suffix N)
410
6
Hrs MTBF
PT4500
LOAD
4, 5
2, 3
1
9, 10
7, 8
11
6
12
Remote Sense ()
Remote Sense (+)
+V
OUT
V
OUT
V
O
Adj
+V
IN
V
IN
Remote
On/Off
Q
1
BSS138
PT Series Suffix
(PT1234
x
)
Case/Pin
Order
Package
Configuration
Suffix
Code
Vertical
N
(ELJ)
Horizontal
A
(ELK)
SMD
C
(ELL)
(Reference the applicable package code draw-
ing for the dimensions and PC board layout)
For technical support and more information, see inside back cover or visit www.ti.com
PT4500 Series
20-W 24-V Input Isolated
DC/DC Converter
Specifications
(Unless otherwise stated, T
a
=25C, V
in
=24V, C
out
=0F, and I
o
=I
o
max)
PT4500 SERIES
Characteristic
Symbol
Conditions
Min
Typ
Max
Units
Output Current
I
o
Over V
in
range
V
o
= 15V
0.1
(1)
--
1.3
V
o
= 12V
0.1
(1)
--
1.6
A
V
o
=5.0V
0.1
(1)
--
4
V
o
3.3V
0.1
(1)
--
5
Input Voltage Range
V
in
Over I
o
Range
18
24
40
VDC
Set Point Voltage Tolerance
V
o
tol
--
1
1.5
(2)
%V
o
Temperature Variation
Reg
temp
40
T
a
+85C, I
o
=I
o
min
--
0.5
--
%V
o
Line Regulation
Reg
line
Over V
in
range
--
0.2
1
%V
o
Load Regulation
Reg
load
Over I
o
range
Vo
5.0V
--
0.4
1
(2)
%V
o
V
o
3.3V
--
13
33
mV
Total Output Voltage Variation
V
o
tot
Includes set-point, line, load,
--
2
3
(2)
%V
o
40
T
a
+85C
Efficiency
V
o
= 15V
--
86
--
V
o
= 12V
--
83
--
V
o
=5.0V
--
82
--
V
o
=3.3V
--
79
--
%
V
o
=1.8V
--
67
--
V
o
=1.5V
--
65
--
V
o
=1.2V
--
59
--
V
o
Ripple (pk-pk)
V
r
20MHz bandwidth
V
o
5.0V
--
0.5
--
%V
o
V
o
3.3V
--
15
--
mV
pp
Transient Response
t
tr
0.1A/s load step, 50% to 100% I
o
max
--
100
--
s
V
tr
V
o
over/undershoot
V
o
5.0V
--
3
--
%V
o
V
o
3.3V
--
150
--
mV
Current Limit Threshold
I
lim
V
in
=18V,
V
o
= 1%
--
200
--
%I
o
max
Output Voltage Adjust
V
o
adj
--
10
--
%
Switching Frequency
s
Over V
in
range
V
o
5.0V
600
650
700
kHz
V
o
3.3V
800
850
900
Under-Voltage Lockout
UVLO
--
16.5
--
V
Remote On/Off (Pin 1)
Referenced to Vin (pin 2)
High-Level Input Voltage
V
IH
2.5
--
Open
(3)
V
Low-Level Input Voltage
V
IL
0.2
--
0.8
Low-Level Input Current
I
IL
--
10
A
Standby Input Current
I
in
standbypins 1 & 2 connected
--
7
10
mA
Internal Input Capacitance
C
in
--
0.5
--
F
External Output Capacitance
C
out
0
--
220
(4)
F
Isolation Voltage
Inputoutput/inputcase
1500
--
--
V
Capacitance
Input to output
--
1100
--
pF
Resistance
Input to output
10
--
--
M
Operating Temperature Range
T
a
Over V
in
range
40
--
85
(5)
C
Solder Reflow Temperature
T
reflow
Surface temperature of module pins or case
--
--
215
(6)
C
Storage Temperature
T
s
--
40
--
125
C
ReliabilityMTBF
Per Bellcore TR-332
4
--
--
10
6
Hrs
50% stress, T
a
=40C, ground benign
Mechanical Shock
--
Per Mil-Std-883D, method 2002.3,
--
500
--
G's
1mS, half-sine, mounted to a fixture
Mechanical Vibration
--
Mil-Std-883D, Method 2007.2
Suffix N
--
20
(7)
--
G's
20-2000Hz, soldered
Suffix A, C
--
20
(7)
--
Weight
--
--
--
23
--
grams
Flammability--
Materials meet UL 94V-0
Notes:
(1)The DC/DC converter will operate at no load with reduced specifications.
(2) For optimum voltage accuracy the `Remote Sense (+)' and `Remote Sense ()' pins must be connected to +V
out
and V
out
respectively.
(3)The Remote On/Off control (pin 1)
has an internal pull-up. If pin 1 is left open the PT4500 will operate when input power is applied. A small low-
leakage (<100nA) MOSFET must be used to control this input. The open-circuit voltage is less than 10V. See application notes for further information.
(4)External output capacitance is not required for proper operation. Capacitamce may be added to improve the response to load transients. The maximum
total capacitance (including the load circuit) must not exceed 220F, and the combined ESR of must not be less than 100m
.
(5)See Safe Operating Area curves or contact the factory for the appropriate derating.
(6)During solder reflow of SMD package version do not elevate the module case, pins, or internal component temperatures above a peak of 215C. For
further guidance refer to the application note, "Reflow Soldering Requirements for Plug-in Power Surface Mount Products," (SLTA051).
(7)The case pins on the through-hole package types (suffixes N & A)
must be soldered. For more information see the applicable package outline drawing.
SLTS153B - JUNE 2000 - REVISED OCTOBER 2002
For technical support and more information, see inside back cover or visit www.ti.com
Note A:
Characteristic data has been developed from actual products tested at 25C. This data is considered typical data for the Converter.
Note B:
SOA curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures
Efficiency vs Output Current
Ripple vs Output Current
Power Dissipation vs Output Current
PT4501, 3.3 VDC
(See Note A)
Safe Operating Area, V
in
=24V
(See Note B)
Typical Characteristics
PT4500 Series
20-W 24-V Input Isolated
DC/DC Converter
50
60
70
80
90
0
0.4
0.8
1.2
1.6
Iout (A)
Efficiency - %
18.0V
24.0V
30.0V
36.0V
V
IN
0
10
20
30
40
50
0
0.4
0.8
1.2
1.6
Iout (A)
Ripple - mV
36.0V
30.0V
24.0V
18.0V
V
IN
0
1
2
3
4
5
6
0
0.4
0.8
1.2
1.6
Iout (A)
Pd - Watts
18.0V
24.0V
30.0V
36.0V
V
IN
50
60
70
80
90
0
1
2
3
4
Iout (A)
Efficiency - %
18.0V
24.0V
30.0V
36.0V
V
IN
0
10
20
30
40
50
0
1
2
3
4
Iout (A)
Ripple - mV
36.0V
30.0V
24.0V
18.0V
V
IN
0
1
2
3
4
5
6
0
1
2
3
4
Iout (A)
Pd - Watts
36.0V
30.0V
24.0V
18.0V
V
IN
50
60
70
80
90
0
1
2
3
4
5
Iout (A)
Efficiency - %
18.0V
24.0V
30.0V
36.0V
V
IN
0
10
20
30
40
50
0
1
2
3
4
5
Iout (A)
Ripple - mV
36.0V
30.0V
24.0V
18.0V
V
IN
0
1
2
3
4
5
6
0
1
2
3
4
5
Iout (A)
Pd - Watts
36.0V
30.0V
24.0V
18.0V
V
IN
Efficiency vs Output Current
Ripple vs Output Current
Power Dissipation vs Output Current
PT4502, 5 VDC
(See Note A)
Efficiency vs Output Current
Ripple vs Output Current
Power Dissipation vs Output Current
PT4503, 12 VDC
(See Note A)
20
30
40
50
60
70
80
90
0
1
2
3
4
5
Iout (A)
Ambient Temperature (C)
300LFM
200LFM
100LFM
Nat conv
Airflow
Safe Operating Area, V
in
=24V
(See Note B)
Safe Operating Area, V
in
=24V
(See Note B)
20
30
40
50
60
70
80
90
0
1
2
3
4
Iout (A)
Ambient Temperature (
C)
300LFM
200LFM
100LFM
Nat conv
Airflow
SLTS153B - JUNE 2000 - REVISED OCTOBER 2002
20
30
40
50
60
70
80
90
0
0.3
0.6
0.9
1.2
1.5
Iout (A)
Ambient Temperature (
C)
300LFM
200LFM
100LFM
Nat conv
Airflow
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT4500/PT4520 Series
Operating Features and System Considerations for
the PT4500/PT4520 DC/DC Converters
Output Current Limit
The PT4500 and PT4520 series of DC/DC converters
incorporate an output current limit. This protects both the
module and upstream source against load faults. Applying
a load, in excess of the current limit threshold, will sim-
ply cause the output voltage to drop. The output current
remains limited, but continues to flow in the fault. The
drop in output voltage will vary according to the severity
of the fault. Applying a short circuit to the output will
result in an output voltage of zero, and the fault current
will be limited to a value slightly higher than the current
limit threshold. Upon the removal of the load fault, the
output voltage of the module will fully recover to its
normal regulated output voltage.
Primary-Secondary Isolation
The PT4500 and PT4520 series of DC/DC converters
incorporate electrical isolation between the input termi-
nals (primary) and the output terminals (secondary). All
converters are production tested to a withstand voltage
of 1500VDC. The isolation complies with UL60950 and
EN60950, and the requirements for operational isolation.
This allows the converter to be configured for either a
positive or negative input voltage source.
Output Voltage Adjustment
The output voltage is typcially adjustable over a range of
10% of nominal. Consult the separate application note,
"Ajusting the Output Voltage of the PT4500/PT4520
Series of Isolated DC/DC Converters."
Remote On/Off Function
The output voltage from the converter can be turned off
from the primary side using the Remote On/Off control
(pin 1). Consult the separate application note, "Using
the Remote On/Off Function on the PT4500/PT4520
Series of Isolated DC/DC Converters."
Under-Voltage Lock-Out
The Under-Voltage Lock-Out (UVLO) circuit prevents
operation of the converter whenever the input voltage to
the module is insufficient to maintain output regulation.
Below the UVLO threshold the module is off and the
Remote On/Off control (pin 1) is inoperative. Table 1-2
gives the applicable UVLO thresholds.
Table 1-2; UVLO Thresholds
Series
UVLO Threshold
V
in
Range
PT4520
31V Typical
36 75V
PT4500
16.5V Typical
18 40V
Turn-On Time
The typical turn-on time is typically 35 milliseconds at
V
in
=48V. This is from application of input power, or the
removal of a low-voltage signal from the Remote On/Off
(pin 1). This includes about about 510ms of delay time
before the output voltage begins to rise. Turn-on time
will vary slightly with input voltage, output load, and the
total amount of capacitance connected to the output.
Input Current Limiting
The converter is not internally fused. For safety and
overall system protection, the maximum input current to
the converter must be limited. Active or passive current
limiting can be used. Passive current limiting can be a
fast acting fuse. A 125-V fuse, rated no more than 5A, is
recommended. Active current limiting can be imple-
mented with a current limited "Hot-Swap" controller.
Thermal Considerations
Airflow may be necessary to ensure that the module can
supply the desired load current in environments with
elevated ambient temperatures. The required airflow
rate may be determined from the Safe Operating Area
(SOA) thermal derating curves. These are provided in
the "Typical Characteristics" section of the converter
specifications.
Application Notes
For technical support and more information, see inside back cover or visit www.ti.com
Adjusting the Output Voltage of the PT4500/
PT4520 Series of Isolated DC/DC Converters
The factory pre-set output voltage of TI's PT4500 and
PT4520 series of isolated DC/DC converters may be
adjusted within a nominal 10% range. Adjustment is made
from the secondary side of the regulator
1
with a single
external resistor. For the input voltage range specified in
the data sheet Table 2-1 gives the allowable adjustment
range for each model, as V
o
(min) and V
o
(max).
Adjust Up:
An increase in the output voltage is obtained
by adding a resistor, R
2
between V
o
Adjust (pin 12), and
V
out
(pin 7, 8).
Adjust Down:
Add a resistor
(R
1
)
, between V
o
Adjust (pin 12),
and +V
out
(pin 9, 10).
Refer to Figure 2-1 and Table 2-2 for both the placement
and value of the required resistor,
(R
1
)
or R
2
.
Notes:
1. The PT4500 and PT4520 series of DC/DC converters
incorporate isolation between the V
in
and V
o
terminals. Adjustment of the output voltage is made
to the regulation circuit on the secondary or output
side of the converter.
2. The maximum rated output power for this series is
20W. An increase in the output voltage may therefore
require a corresponding reduction in the maximum
output current (
see Table 2-1
). The revised maximum
output current must be determined as follows.
I
o
(max) =
20
A,
or 5A, whichever is less.
V
a
Where V
a
is the adjusted ouput voltage.
3. Use only a single 1% resistor in either the
(R
1
)
or R
2
location. Place the resistor as close to the module as
possible.
Table 2-1
DC/DC CONVERTER ADJUSTMENT RANGE AND FORMULA PARAMETERS
Series Pt #
48V Bus
PT4529
PT4526
PT4527
PT4528
PT4521
PT4522
PT4523
PT4524
24V Bus
PT4509
PT4506
PT4507
PT4508
PT4501
PT4502
PT4503
PT4504
Max Current
2
5A
5A
5A
5A
5A
4A
1.6A
1.3A
V
o
(nom)
1.2
1.5
1.8
2.5
3.3
5.0
12.0
15.0
Va(min)
1.05
1.35
1.62
2.25
2.95
4.5
10.8
13.5
Va(max)
1.35
1.65
1.98
2.75
3.65
5.5
13.2
16.5
V
r
0.6125
1.225
1.225
1.225
1.225
2.5
2.5
2.5
K
o
(Vk
)
34.66
67.07
69.7
64.2
69.3
125.2
139.8
137.6
R
s
(k
)
150.0
43.2
110.0
187.0
187.0
187.0
110.0
90.9
Figure 2-1
(R1)
Adj Down
R2
Adjust Up
+ V
in
V
in
+ V
o
V
o
P T 4 5 0 0 / 4 5 2 0
+ Vout
Vout
+ Vin
Vin
Remote
On/Off
V
o
(adj)
1
2, 3
4, 5
9,10
7, 8
12
4. Never connect capacitors to V
o
adjust. Any
capacitance added to the V
o
adjust control pin will
affect the stability of the converter.
The values of
(R
1
)
[adjust down], and R
2
[adjust up], can
also be calculated using the following formulas.
(R
1
)
=
K
o
(V
a
V
r
) R
s
k
V
r
(V
o
V
a
)
R
2
=
K
o
R
s
k
(V
a
V
o
)
Where V
o
= Original output voltage
V
a
= Adjusted output voltage
V
r
= Reference voltage (Table 2-1)
K
o
= Multiplier constant (Table 2-1)
R
s
= Internal series resistance (Table 2-1)
PT4500/4520 Series
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