For technical support and more information, see inside back cover or visit www.ti.com
PT4841
—
48V
65-W Triple Output Isolated DC/DC
Converter for DSL Applications
PT4841 Electrical Specifications
(Unless otherwise stated, the operating conditions are:- T
a
=25°C, V
in
=48V, and Io
n
=0.5Io
n
max)
PT4841
Typ
Characteristics
Symbols
Conditions
Min
Max
Units
Output Power
P
o
Each output:
Vo
1
( 15V)
Vo
2
(3.3V)
Vo
3
(1.5V)
—
—
—
—
0
0
0
—
36
—
—
—
—
—
—
—
—
15
3.2
1.45
—
—
—
—
—
—
±10
—
—
—
450
—
—
—
—
—
—
—
—
—
—
—
15.2
3.3
1.5
±0.5
±0.8
0.1
0.2
—
—
—
—
85
50
20
20
30
5
—
4
16
200
(5)
500
34
32
41
20
10.5
(1)
65
2.7
6
7
11
75
—
—
—
—
—
0.5
0.5
1.0
15.75
(3)
3.4
1.55
—
100
(4)
50
50
—
—
—
—
—
—
550
—
—
(1)
(1)
W
Total (all three outputs)
(1)
W
Output Current
I
o
Io
1
( 15V)
Io
2
(3.3V)
Io
3
(1.5V)
(2)
(2)
A
Maximum (Io
2
+ Io
3
)
(2)
A
V
Input Voltage Range
Set-Point Voltage
V
in
V
o
Vo
1
Vo
2
Vo
3
Vo
1
V
Temperature Variation
Reg
temp
–40°C
≤
T
a
≤
+85°C, I
o
=I
o
min
%V
o
Vo
2
/Vo
3
Line Regulation
Load Regulation
Cross Regulation
Total Output Voltage Variation
Reg
line
Reg
load
Reg
cross
V
o
tol
All outputs, Over V
in
range
All outputs, 0
≤
I
o
≤
I
o
max
Any one output vs. other outputs
Includes set-point, line, load,
–40°C
≤
T
a
≤
+85°C
%V
o
%V
o
%V
o
Vo
1
Vo
2
Vo
3
(3)
(3)
V
Efficiency
V
Ripple/Noise
(0 to 20MHz bandwidth)
η
V
n
P
o
=P
o
max
Co
1
/Co
2
/Co
3
=10μF
%
Vo
1
Vo
2
Vo
3
(4)
(4)
mV
pp
Transient Response
t
tr
V
os
V
o
adj
I
LIM
0.1A/μs load step, 50% to 75% I
o
max
V
o
over/undershoot
μSec
%V
o
%V
o
A
Output Adjust Range
Current Limit Threshold
Vo
2
/ Vo
3
Io
1
Io
2
+ Io
3
Over Current Shutdown Delay
Switching Frequency
Under Voltage Lockout
t
sd
s
V
on
V
off
Time period prior to latched shutdown
Over V
in
and I
o
ranges
V
in
increasing
V
in
decreasing
Referenced to –V
in
(pin 2)
ms
kHz
V
Enable Control (pins 2 & 3)
High-Level Input Voltage
Low-Level Input Voltage
Low-Level Input Current
Standby Input Current
Internal Input Capacitance
External Output Capacitance
V
IH
V
IL
I
IL
I
in
standby
C
int
Co
1
Co
2
Co
3
V
temp
4.0
–0.2
—
—
—
0
0
0
—
—
1500
—
10
—
—
0.16
8
2
—
—
—
0.1
(8)
1.5
(8)
—
1500
—
70
(6)
0.8
(6)
0.25
10
(3)
—
330
5,000
10,000
(7)
—
—
—
—
—
V
V
in
=75V
pins 2 & 4 connected
mA
mA
μF
(7)
(7)
μF
Temperature Sense
Output voltage at temperatures:-
–40°C
100°C
V
Primary/Secondary Isolation
V
iso
C
iso
R
iso
V
pF
M
Notes:
(1) The sum total power delivered from all three regulated outputs, Vo
, Vo
2
, and Vo
3
, cannot exceed 65 watts.
(2) The sum-total current from outputs Vo
2
, and Vo
3
cannot exceed 11ADC.
(3) Limits are guaranteed by design.
(4) The ripple and noise is measured with a 10μF tantalum capacitor across each output.
(5) After latched shutdown, the module may be reset cycling the input power.
(6) The Enable inputs (pins 3 & 4) have internal pull-ups. Leaving pin 4 open-circuit and connecting pin 3 to –V
in
allows the the converter to operate when
input power is applied. The maximum open-circuit voltage is 5.1V.
(7) Ultra-low ESR capacitors, such as organic or polymer aluminum electrolytic types, may cause instability. For more information refer to the application
note regarding capacitor selection.
(8) Voltage output at “TEMP” pin is defined by the equation:- V
TEMP
= 0.5 + 0.01·T, where T is the sensed temperature in degrees centigrade. See pin
descriptions for more information.
SLTS142C - DECEMBER 2000 -REVISED SEPTEMBER 2002