ETC PT4124

PT4120 Series
20-W 48-V Input Isolated
DC/DC Converter
SLTS092B
(Revised 2/26/2002)
Features
• Input Voltage Range:
36V to 75V
• 20W Rated
• 82% Efficiency
• 1500 VDC Isolation
• Low Profile (8.5 mm)
• Small Footprint: 1.52in x 1.73in
• Remote On/Off
•
•
•
•
•
•
•
Short Circuit Protection
Over Temperature Shutdown
Under-Voltage Lockout
UL1950 Recognized
CSA 22.2 950 Certified
EN60950 Approved
4×106 Hrs MTBF
Description
Ordering Information
Pin-Out Information
The PT4120 power modules are a series
of isolated DC/DC converters housed a lowprofile package. Rated for 20 watts or 5A, the
series includes standard output voltages ranging from as low as 1.5VDC to 15VDC. The
output may be adjusted ±10% of nominal.
These converters are ideal for Telecom,
Industrial, Computer, and other distributed
power applications that require input-tooutput isolation.
Using multiple PT4120 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 PT4120 series requires no additional
components for proper operation.
PT4121H
PT4122H
PT4123H
PT4124H
PT4125H
PT4126H
PT4127H
PT4128H
PT4129H
Pin
= 3.3V/5A (16.5W)
= 5.0V/4A
= 12.0V/1⋅6A
= 15.0V/1⋅3A
= 5.2V/3·8A
= 1.5V/5A (7.5W)
= 1.8V/5A (9W)
= 2.5V/5A (12.5W)
= 1.65V/5A (8·25W)
Order
Suffix
Package
Code *
A
C
Horizontal
SMD
(EGD)
(EGE)
* Previously known as package style 710.
(Reference the applicable package code drawing for the dimensions and PC board layout)
Standard Application
+VIN
–VIN
3
+VOUT
4
–VOUT
PT4120
LOAD
2
1
Remote
On/Off
5
6
Q1
BSS138
For technical support and more information, see inside back cover or visit www.ti.com
VOAdj
Remote On/Off
2
–Vin
3
+Vin
4
–Vout
5
+Vout
6
Vout Adjust †
†
† For further information, see
application notes.
PT Series Suffix (PT1234x )
Case/Pin
Configuration
Function
1
PT4120 Series
20-W 48-V Input Isolated
DC/DC Converter
Specifications
(Unless otherwise stated, Ta =25°C, V in =48V, Cout =0µF, and Io =Io max)
Characteristic
Symbol
Output Current
Io
Conditions
Over Vin range
Input Voltage Range
Set Point Voltage Tolerance
Vin
Vo tol
Over Io Range
Temperature Variation
Line Regulation
Regtemp
Regline
–40° ≤Ta ≤ +85°C
Over Vin range
Load Regulation
Regload
Over Io range
Total Output Voltage Variation
∆Votot
Includes set-point, line load,
–40° ≤Ta ≤ +85°C
Efficiency
η
Min
Vo = 15V
Vo = 12V
Vo =5.0V
Vo ≤ 3.3V
Vo ≥5.0V
Vo ≤3.3V
Vo ≥5.0V
Vo ≤3.3V
Vo ≥5.0V
Vo ≤3.3V
Vo ≥5.0V
Vo ≤3.3V
Vo = 15V
Vo = 12V
Vo =5.0V
Vo =3.3V
Vo =1.8V
Vo ≥ 5.0V
Vo ≤ 3.3V
Vo Ripple (pk-pk)
Vr
20MHz bandwidth
Transient Response
ttr
0.1A/µs, load step 50% to 100% Iomax
Vo over/undershoot
Vo ≥ 5.0V
Vo ≤ 3.3V
∆Vtr
Short Circuit Current
Switching Frequency
Isc
ƒs
Under-Voltage Lockout
Remote On/Off (Pin 1)
Input High Voltage
Input Low Voltage
Input Low Current
UVLO
VIH
VIL
IIL
Over Vin range
Referenced to –Vin (pin 2)
Standby Input Current
Internal Input Capacitance
External Output Capacitance
Isolation Voltage
Capacitance
Resistance
Operating Temperature Range
Storage Temperature
Reliability
Iin standby
Cin
Cout
pins 1 & 2 connected
Ta
Ts
MTBF
Mechanical Shock
—
Mechanical Vibration
—
Weight
Flammability
—
—
Over Vin range
—
Per Bellcore TR-332
50% stress, Ta =40°C, ground benign
Per Mil-Std-883D, method 2002.3,
1mS, half-sine, mounted to a fixture
Per Mil-Std-883D, method 2007.2,
20-2000Hz, soldered in a PC board
—
Materials meet UL 94V-0
Between +Vo and –Vo
Input to output
Vo ≥ 12.0V
Vo ≤ 5.2V
PT4120 SERIES
Typ
Max
Units
0.1 (1)
0.1 (1)
0.1 (1)
0.1 (1)
36.0
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
600
800
—
—
—
—
—
48.0
±1
—
±0.5
±0.2
±7
±0.4
±13
±2
±67
86
83
82
78
67
0.5
15
100
±3.0
±150
2xIomax
650
850
31
1.3
1.6
4.0
5.0
75.0
±1.5
±50
—
±1.0
±33
±1.0
±33
—
—
—
—
—
—
—
—
—
—
—
—
—
700
900
—
2.5
–0.2
—
—
—
0
1500
—
10
-40
-40
—
—
–10
7
0.5
—
—
1100
—
—
—
7.0 (2)
+0.8
–
50
—
200
—
—
—
+85 (3)
+125
µA
mA
µF
µF
V
pF
MΩ
°C
°C
4.0
—
—
106 Hrs
—
500
—
G’s
—
15
—
G’s
—
23
—
grams
A
VDC
%Vo
mV
%Vo
%Vo
mV
%Vo
mV
%Vo
mV
%
%Vo
mVpp
µs
%Vo
mV
A
kHz
V
V
Notes: (1) The DC/DC converter will operate at no load with reduced specifications.
(2) The Remote On/Off (pin 1) has an internal pull-up, and if it is left open circuit the PT4120 will operate when input power is applied. Refer to the
application notes for interface considerations.
(3) See Safe Operating Area curves or contact the factory for the appropriate derating.
For technical support and more information, see inside back cover or visit www.ti.com
Typical Characteristics
PT4120 Series
20-W 48-V Input Isolated
DC/DC Converter
PT4121, 3.3 VDC
PT4122, 5.0 VDC
(See Note A)
PT4123, 12.0 VDC
(See Note A)
Efficiency vs Output Current
Efficiency vs Output Current
90
Efficiency vs Output Current
90
90
36.0V
48.0V
75.0V
70
60
85
80
Vin
75
36.0V
48.0V
75.0V
70
65
60
Efficiency - %
Vin
Efficiency - %
Efficiency - %
85
80
55
50
1
2
3
4
5
0.5
1
1.5
2.5
3
3.5
0
75.0V
48.0V
36.0V
6
4
0
4
Vin
10
75.0V
48.0V
36.0V
8
6
5
1
1.5
3
3.5
3
2
0
0
3
4
5
0.4
75.0V
48.0V
36.0V
60
50
40
30
20
1
1.5
2
2.5
3
3.5
5
1.6
Vin
75.0V
48.0V
36.0V
2
4
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Iout (A)
Safe Operating Area, Vin =48V (See Note B)
90
80
Airflow
70
200LFM
120LFM
60LFM
Nat conv
60
50
40
30
20
4
1.4
0
0.5
Ambient Temperature (°C)
200LFM
120LFM
60LFM
Nat conv
1.2
3
Safe Operating Area, Vin =48V (See Note B)
Ambient Temperature (°C)
Airflow
70
1
1
90
80
0.8
4
Iout (A)
Safe Operating Area, Vin =48V (See Note B)
0.6
5
Vin
0
90
Iout (A)
0.2
Power Dissipation vs Output Current
2
0
3
20
6
3
1
2
75.0V
48.0V
36.0V
30
Iout (A)
4
1
1
Vin
4
Pd - Watts
75.0V
48.0V
36.0V
Pd - Watts
Pd - Watts
2.5
5
Vin
1.6
40
Power Dissipation vs Output Current
Iout (A)
Ambient Temperature (°C)
2
6
4
1.4
50
Iout (A)
5
1.2
0
0.5
Iout (A)
Power Dissipation vs Output Current
1
10
0
6
0.8
60
12
0
3
0.6
Ripple vs Output Current
2
0
0.4
70
4
2
2
0.2
Iout (A)
Ripple - mV
8
Ripple - mV
Vin
1
60
4
14
10
Ripple - mV
2
16
0
65
Ripple vs Output Current
Ripple vs Output Current
2
36.0V
48.0V
75.0V
70
Iout (A)
12
1
Vin
75
50
0
Iout (A)
0
80
55
50
0
(See Note A)
80
Airflow
70
200LFM
120LFM
60LFM
Nat conv
60
50
40
30
20
0
1
2
3
4
Iout (A)
0
0.25
0.5
0.75
1
Iout (A)
Note A: Characteristic data has been developed from actual products tested at 25°C. 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
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1.25
1.5
1.75
Application Notes
PT4120/4140 Series
Using the Remote On/Off Function on the PT4120/
PT4140 Series of Isolated DC/DC Converters
For applications requiring output voltage on/off control,
the PT4120/4140 series of DC/DC converters incorporate
a remote on/off function. This function may be used in
applications that require battery conservation, power-up/
shutdown sequencing, and/or to co-ordinate the powerup of the regulator for active in-rush current control. (See
the related application note, AN21).
This function is provided by the Remote On/Off control,
pin1. If pin 1 is left open-circuit, the converter provides a
regulated output whenever a valid source voltage3 is applied between +Vin(pin 3), and –Vin (pin 2). Applying a
low-level ground signal 1 to pin 1 will disable the regulator output 5.
Table 1 provides details of the threshold requirements for
the Remote On/Off pin. Figure 1 shows how a discrete
MOSFET (Q1) 4, may be referenced to the negative input
voltage rail and used with this control input.
Table 1 Inhibit Control Thresholds
Parameter
min
max
Enable (VIH)
2.5V
(Open Circuit) 2, 4
Disable (VIL)
–0.3V
0.8V
Notes:
1. The on/off control uses -Vin (pin 2), the primary side of
the converter as its ground reference. All voltages specified
are with respect to -Vin.
2. The on/off control internal circuitry is a high impedance
10µA current source. The open-circuit voltage may be as
high as 8.3Vdc.
3. The PT4120/40 series incorporates an “Under Voltage
Lockout” (UVLO) function. This function automatically
inhibits the converter output until there is sufficient input
voltage for the converter to produce a regulated output.
Table 2 gives the applicable UVLO thresholds.
Table 2 UVLO Thresholds
Series
UVLO Threshold
PT4120
PT4140
31V Typical
15V Typical
6. Keep the on/off transition to less than 1ms. This prevents
erratic operation of the ISR, whereby the output voltage
may drift un-regulated between 0V and the rated output
during power-up.
Figure 1
+V o
3
+V in
+V in
+Vout
5
PT4121
2
–V in
–V out
Remote
On/Off
1
4
V o (adj)
6
–V o
Q1
BSS138
Inh
Note 2
–V in
Turn-On Time: The converter typically produces a fully
regulated output voltage within 50ms after the application of power, or the removal of the low voltage signal 6
from the Remote On/Off pin. The actual turn-on time
will vary with the input voltage, output load, and the
total amount of capacitance connected to the output.
Using the circuit of Figure 1, Figure 2 shows the output
voltage and input current waveforms of a PT4121 after
Q1 is turned off. The turn off of Q1 corresponds to the
drop in Q1 Vgs voltage. The waveforms were measured
with a 48Vdc input voltage, and 2.75-A resistive load.
Figure 2
Vout (2V/Div)
Vin Range
36 – 75V
18 – 40V
Iin (0.2A/Div)
4. The Remote On/Off input of the PT4120/40 series regulators
must be controlled with an open-collector (or open-drain)
discrete transistor or MOSFET. Do not use a pull-up resistor.
5. When the converter output is disabled, the current drawn
from the input supply is typically reduced to 8mA (16mA
maximum).
Q1 Vgs (10V/Div)
HORIZ. SCALE: 5ms/Div
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Application Notes
PT4120/4140 Series
Adjusting the Output Voltage of the PT4120/
PT4140 Series of Isolated DC/DC Converters
The factory pre-set output voltage of Power Trends’
PT4120 and PT4140 series of isolated DC/DC converters
may be adjusted within ±10% of nominal. Adjustment is
made from the secondary side of the regulator1 with a
single external resistor. For the input voltage range
specified in the data sheet Table 1 gives the allowable
adjustment range for each model, as Vo (min) and Vo (max).
Adjust Up: An increase in the output voltage is obtained
by adding a resistor, R2 between pin 6 (Vo adjust), and pin
4 (-Vout).
4. Never connect capacitors to Vo adjust. Any capacitance
added to the Vo adjust control pin will affect the stability of
the ISR.
The values of (R1) [adjust down], and R2 [adjust up], can also
be calculated using the following formulas.
(R1)
=
Ko (Va – Vr)
Vr (Vo – Va)
– Rs
kΩ
R2
=
Ko
(Va – Vo)
– Rs
kΩ
Adjust Down: Add a resistor (R1), between pin 6 (Vo adjust) and pin 5 (+Vout).
Refer to Figure 1 and Table 2 for both the placement
and value of the required resistor, (R1) or R2.
Notes:
1. The PT4120 and PT4140 series of DC/DC converters
incorporate isolation between the Vin and Vo 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 1). The revised maximum
output current must be determined as follows:Io(max)
=
20
A,
Va
= Original output voltage
= Adjusted output voltage
= Reference voltage (Table 1)
= Multiplier constant (Table 1)
= Internal series resistance (Table 1)
Where Vo
Va
Vr
Ko
Rs
Figure 1
+ Vo
+ V in
(R1)
Adj Down
3
+V in
+V out
PT4120/40
2
–V in
–V out
Remote
On/Off
or 5A, whichever is less.
5
1
–V in
4
R2
Adj
Up
V o (adj)
6
–V o
Where Va is the adjusted ouput voltage.
3. Use only a single 1% resistor in either the (R1) or R2
location. Place the resistor as close to the ISR as possible.
Table 1
DC/DC CONVERTER ADJUSTMENT RANGE AND FORMULA PARAMETERS
Series Pt #
48V Bus
24V Bus
Max Current 2
Vo(nom)
Va(min)
Va(max)
Vr
Ω)
Ko (V·kΩ
Ω)
Rs (kΩ
PT4126
PT4146
5A
1.5
1.35
1.65
1.225
67.07
43.2
PT4129
5A
1.65
1.49
1.81
1.225
63.9
66.5
PT4127
PT4147
5A
1.8
1.62
1.98
1.225
69.7
110.0
PT4128
PT4148
5A
2.5
2.25
2.75
1.225
64.2
187.0
PT4121
PT4141
5A
3.3
2.95
3.65
1.225
69.3
187.0
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PT4122
PT4142
4A
5.0
4.5
5.5
2.5
125.2
187.0
PT4125
3.8A
5.2V
4.75
5.75
2.5
134.7
243.0
PT4123
PT4143
1.6A
12.0
10.8
13.2
2.5
139.8
110.0
PT4124
PT4144
1.3A
15.0
13.5
16.5
2.5
137.6
90.9
Application Notes continued
PT4120/4140 Series
Table 2
DC/DC CONVERTER SERIES ADJUSTMENT RESISTOR VALUES
Series Pt #
48V Bus
24V Bus
Vo(nom)
Va(req’d)
1.35
1.4
1.45
1.5
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
1.95
2.25
2.3
2.35
2.4
2.45
2.5
2.55
2.6
2.65
2.7
2.75
2.95
3.0
3.05
3.1
3.15
3.2
3.25
3.3
3.35
3.4
3.45
3.5
3.55
3.6
3.65
R1 = (Blue)
PT4126
PT4146
1.5Vdc
PT4127
PT4147
1.8Vdc
PT4128
PT4148
2.5Vdc
PT4121
PT4141
3.3Vdc
PT4122
PT4142
5.0Vdc
Va(req’d)
(2.8)kΩ
(53.2)kΩ
(204.0)kΩ
1.3MΩ
627.0kΩ
404.0kΩ
4.5
4.55
4.6
4.65
4.7
4.75
4.8
4.85
4.9
4.95
5.0
5.05
5.1
5.15
5.2
5.25
5.3
5.35
5.4
5.45
5.5
(51.7)kΩ
(161.0)kΩ
(489.0)kΩ
1.28MΩ
587.0kΩ
355.0kΩ
(26.5)kΩ
(92.9)kΩ
(203.0)kΩ
(425.0)kΩ
(1.09)MΩ
1.09MΩ
450.0kΩ
237.0kΩ
131.0kΩ
67.7kΩ
(90.7)kΩ
(146.0)kΩ
(224.0)kΩ
(341.0)kΩ
(536.0)kΩ
(926.0)kΩ
(2.09)MΩ
PT4123
PT4143
12.0Vdc
PT4124
PT4144
15.0Vdc
Va(req’d)
(12.6)kΩ
(40.3)kΩ
(75.0)kΩ
(120.0)kΩ
(179.0)kΩ
(262.0)kΩ
(387.0)kΩ
(595.0)kΩ
(1.01)MΩ
1.06MΩ
645.0kΩ
437.0kΩ
312.0kΩ
229.0kΩ
169.0kΩ
125.0kΩ
90.2kΩ
62.4kΩ
10.8
11.0
11.2
11.4
11.6
11.8
12.0
12.2
12.4
12.6
12.8
13.0
13.2
13.5
13.6
13.8
14.0
14.2
14.4
14.6
14.8
15.0
15.2
15.4
15.6
15.8
16.0
16.5
(276.0)kΩ
(365.0)kΩ
(497.0)kΩ
(719.0)kΩ
(1.16)MΩ
588.0kΩ
239.0kΩ
123.0kΩ
64.6kΩ
29.7kΩ
6.4kΩ
(312.0)kΩ
(345.0)kΩ
(427.0)kΩ
(542.0)kΩ
(713.0)kΩ
(1.0)MΩ
(1.57)MΩ
597.0kΩ
253.0kΩ
138.0kΩ
81.0kΩ
46.6kΩ
0.8kΩ
1.19MΩ
502.0kΩ
272.0kΩ
158.0kΩ
88.7kΩ
42.7kΩ
9.9kΩ
R2 = Black
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