Not Recommended for New Designs
PTEA404120
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SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
50-W, 48-V INPUT, 12-V OUTPUT, ISOLATED DC/DC CONVERTER
Check for Samples: PTEA404120
FEATURES
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DESCRIPTION
50-W Output
Input Voltage Range: 36 V to 75 V
91% Efficiency
1500 VDC Isolation
On/Off Control
Overcurrent Protection
Differential Remote Sense
Adjustable Output Voltage
Output Overvoltage Protection
Over-Temperature Shutdown
Undervoltage Lockout
Standard 1/8-Brick Footprint
UL Safety Agency Approval
The PTEA404120 power module is
isolated DC/DC converter, housed
standard one-eighth brick package.
rated up to 50 W with a maximum
4.2 A.
a single-output
in an industry
This module is
load current of
The PTEA404120 operates from a standard 48-V
telecom central office (CO) supply and occupies less
than 2.0 in2 of PCB area. The modules offer OEMs a
compact and flexible high-output power source in an
industry standard footprint. They are suitable for
distributed power applications in both telecom and
computing environments, and may be used for
intermediate bus converter architectures.
Features include a remote On/Off control with
optional logic polarity, an undervoltage lockout
(UVLO), a differential remote sense, and an industry
standard output voltage adjustment using an external
resistor.
Protection
features
include
output
overcurrent protection (OCP), overvoltage protection
(OVP), and thermal shutdown (OTP).
The modules are fully integrated for stand-alone
operation, and require no additional components.
STANDARD APPLICATION
SENSE (+)
+VO
7
+VI
Sense(+)
1 +V
I
CI
(Optional)
3
−VI
+VO
PTEA404120N
−VI
Remote
On/Off
2
Adjust
−VO
Sense(−)
8
6
CO
(Optional)
4
L
O
A
D
−VO
5
SENSE (–)
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006–2010, Texas Instruments Incorporated
Not Recommended for New Designs
PTEA404120
SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ORDERING INFORMATION
For the most current package and ordering information, see the Package Option Addendum at the end of this datasheet, or see the TI
website at www.ti.com.
Table 1. PART NUMBERING SCHEME
Input
Voltage
PTEA
4
4 = 48 V
Output
Current
Output Voltage
04
04 = 4A
Enable
120
Electrical Options
N
120 = 12 V
N = Negative
2
2 = VO Adjust
Pin Style
A
D
D = Through-hole, Pb-free
P = Positive
ABSOLUTE MAXIMUM RATING
UNIT
TA
Operating Temperature
Range
VI, MAX
Maximum Input Voltage
PO, MAX
Maximum Output Power
TS
Storage Temperature
Continuous voltage
75 V
Peak voltage for 100 ms duration
100 V
50 W
–40°C to 125°C
Mechanical Shock
Per Mil-STD-883, Method 2002.3 1 ms,
1/2 Sine, mounted
AD Suffix
250 G
Mechanical Vibrarion
Per Mil-STD-883, Method 2007.2 202000 Hz, PCB mounted
AD Suffix
15 G
Weight
Flammability
(1)
2
–40°C to 85°C (1)
Over VI Range
18 grams
Meets UL 94V-O
See SOA curves or consult factory for appropriate derating.
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PTEA404120
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SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
ELECTRICAL CHARACTERISTICS PTEA404120
(Unless otherwise stated, TA =25°C, VI = 48 V, VO = 12 V, CO = 0 μF, and IO = IOmax)
PARAMETER
TEST CONDITIONS
MIN
IO
Output Current
Over VI range
0
VI
Input Voltage Range
Over IO Range
35
VO tol
TYP
MAX
4.2
48
75
±1 (1)
Set Point Voltage Tolerance
11.88
12
UNIT
A
V
%VO
12.12
Regtemp
Temperature Variation
–40°C >TA > 85°C
Regline
Line Regulation
Over VI range
±5
mV
Regload
Load Regulation
Over IO range
±5
mV
ΔVotot
Total Output Voltage Variation
Includes set-point, line, load, –40°C >TA > 85°C
ΔVADJ
Output Adjust Range
PO ≤ 50 W and IO ≤ 4.2 A
η
Efficiency
IO = IOmax
VR
VO Ripple (pk-pk)
20 MHz bandwidth
ttr
Transient Response
ΔVtr
±1.15
V
±1.5
–40
%VO
±3
%VO
10
%VO
91%
50
mVpp
0.1 A/μs slew rate, 50% to 75% IOmax
500
μs
VO over/undershoot
200
mV
ITRIP
Overcurrent Threshold
Shutdown, followed by auto-recovery
OVP
Output Overvoltage Protection
Output shutdown and latch off
120
%VO
OTP
Over Temperature Protection
Temperature Measurement at thermal sensor. Hysteresis
= 10°C nominal.
115
°C
fs
Switching Frequency
Over VI range
250
kHz
UVLO
Undervoltage Lockout
7
VOFF
VI decreasing, IO = 1 A
32.5
VHYS
Hysteresis
1.5
A
V
On/Off Input: Negative Enable
VIH
Input High Voltage
VIL
Input Low Voltage
IIL
Input Low Current
Referenced to –VI
2.4
Open (2)
–0.2
0.8
–0.3
V
mA
On/Off Input: Positive Enable
4.5
Open (2)
–0.2
0.8
VIH
Input High Voltage
VIL
Input Low Voltage
IIL
Input Low Current
IISB
Standby Input Current
Output disabled (pin 2 status set to Off)
CI
External Input Capacitance
Between +VI and –VI
0
Between +VO and –VO
0
CO
(1)
(2)
External Output Capacitance
Referenced to –VI
–0.3
Equivalent Series Resistance
V
mA
10
mA
μF
100
1000
10
μF
mΩ
Isolation Voltage
Input-to-output and input-to-case
1500
Vdc
Isolation Capacitance
Input-to-output
1200
pF
Isolation Resistance
Input-to-output
10
MΩ
If Sense(–) is not used, pin 5 must be connected to pin 4 for optimum output voltage accuracy.
The Remote On/Off input has an internal pull-up and may be controlled with an open collector (or open drain) interface. An open circuit
correlates to a logic high. Consult the application notes for interface considerations.
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PTEA404120
SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
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PIN DESCRIPTIONS
+VI: The positive input for the module with respect to –VI. When powering the module from a –48-V telecom
central office supply, this input is connected to the primary system ground.
–VI: The negative input supply for the module, and the 0 VDC reference for the Remote On/Off input. When
powering the module from a +48-V supply, this input is connected to the 48-V return.
Remote On/Off: This input controls the On/Off status of the output voltage. It is either driven low (–VI potential),
or left open-circuit. For units identified with the NEN option, applying a logic low to this pin will enable the output.
And for units identified with the PEN option, the output will be disabled.
VO Adjust: Allows the output voltage to be trimmed by up or down between +10% and –40% of its nominal
value. The adjustment method uses a single external resistor. Connecting the resistor between VO Adjust and
–VO adjusts the output voltage lower, and placing it between VO Adjust and +VO adjusts the output higher. The
calculations for the resistance value follows industry standard formulas. For further information consult the
application note on output voltage adustment.
+VO: The positive power output with respect to –VO, which is DC isolated from the input supply pins. If a negative
output voltage is desired, +VO should be connected to the secondary circuit common and the output taken from
–VO.
–VO: The negative power output with respect to +VO, which is DC isolated from the input supply pins. This output
is normally connected to the secondary circuit common when a positive output voltage is desired.
Sense(+): Provides the converter with an output sense capability to regulate the set-point voltage directly at the
load. When used with Sense(-), the regulation circuitry will compensate for voltage drop between the converter
and the load. The pin may be left open circuit, but connecting it to +VO will improve load regulation. If a series
inductor is used for filtering between the module output and load, this pin must be connected directly to the
module output to ensure good control design stability.
Sense(–): Provides the converter with an output sense capability when used in conjunction with Sense(+) input.
For optimum output voltage accuracy this pin should always be connected to –VO.
PTEA404120
(Top View)
+VO
1
+VI
Sense(+)
2
On/Off
3
−VI
Adjust
Sense(−)
−VO
4
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8
7
6
5
4
Copyright © 2006–2010, Texas Instruments Incorporated
Product Folder Links: PTEA404120
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PTEA404120
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SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
TYPICAL CHARACTERISTICS
PTEA404120, VO = 12 V
(1) (2)
EFFICIENCY
vs
LOAD CURRENT
OUTPUT RIPPLE
vs
LOAD CURRENT
POWER DISSIPATION
vs
LOAD CURRENT
60
95
7
VI = 75 V
VI = 35 V
h - Efficiency - %
85
80
VI = 48 V
75
VI = 75 V
70
65
VI
60
75 V
48 V
35 V
55
50
0
0.6
1.2
1.8
2.4
3.0
IO - Output Current - A
3.6
50
6
VI = 48 V
PD - Power Dissipation - W
VO - Output Voltage Ripple - mVP-P
90
40
VI = 35 V
30
20
VI
4
3
2
1
VI = 35 V
0
4.2
VI = 75 V
VI = 48 V
VI
75 V
48 V
35 V
10
5
0
0.6
1.2
1.8
2.4
3.0
IO - Output Current - A
Figure 1.
3.6
75 V
48 V
35 V
0
4.2
0
Figure 2.
0.6
1.2
1.8
2.4
3.0
IO - Output Current - A
3.6
4.2
Figure 3.
AMBIENT TEMPERATURE
vs
LOAD CURRENT
90
300/400
TA - Ambient Temperature - °C
80
200
70
100
60
Natural Convection
50
40
LFM
300/400
200
100
Natural Convection
30
VI = 48 V
20
0
0.6
1.2
1.8
2.4
3.0
3.6
4.2
Figure 4.
(1)
(2)
All data listed in Figure 1, Figure 2, and Figure 3 have been developed from actual products tested at 25°C. This data is considered
typical data for the dc-dc converter.
The temperature derating curves represent operating conditions at which internal components are at or below manufacturer's maximum
rated operating temperature. Derating limits apply to modules soldered directly to a 100–mm × 100–mm, double-sided PCB with 2 oz.
copper. For surface mount packages, multiple vias (plated through holes) are required to add thermal paths around the power pins.
Please refer to the mechanical specification for more information. Applies to Figure 4.
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PTEA404120
SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
www.ti.com
APPLICATION INFORMATION
Operating Features and System Considerations for the PTEA404120 DC/DC Converter
Overcurrent Protection
To protect against load faults, these converters incorporate output overcurrent protection. Applying a load to the
output that exceeds the converter's overcurrent threshold (see applicable specification) will cause the output
voltage to momentarily fold back, and then shut down. Following shutdown the module will periodically attempt to
automatically recover by initiating a soft-start power-up. This is often described as a hiccup mode of operation,
whereby the module continues in the cycle of successive shutdown and power up until the load fault is removed.
Once the fault is removed, the converter automatically recovers and returns to normal operation.
Output Overvoltage Protection
Each converter incorporates protection circuitry that continually senses for an output overvoltage (OV) condition.
The OV threshold is set approximately 20% higher than the nominal output voltage. If the converter output
voltage exceeds this threshold, the converter is immediately shut down and remains in a latched-off state. To
resume normal operation the converter must be actively reset. This can only be done by momentarily removing
the input power to the converter. For fail-safe operation and redundancy, the OV protection uses circuitry that is
independent of the converter’s internal feedback loop.
Overtemperature Protection
Overtemperature protection is provided by an internal temperature sensor, which closely monitors the
temperature of the converter’s printed circuit board (PCB). If the sensor exceeds a temperature of approximately
115°C, the converter will shut down. The converter will then automatically restart when the sensed temperature
drops back to approximately 105°C. When operated outside its recommended thermal derating envelope (see
data sheet SOA curves), the converter will typcially cycle on and off at intervals from a few seconds to one or two
minutes. This is to ensure that the internal components are not permanently damaged from excessive thermal
stress.
Undervoltage Lockout
The Undervoltage lockout (UVLO) is designed to prevent the operation of the converter until the input voltage is
at the minimum input voltage. This prevents high start-up current during normal power-up of the converter, and
minimizes the current drain from the input source during low input voltage conditions. The UVLO circuitry also
overrides the operation of the Remote On/Off control.
Primary-Secondary Isolation
These converters incorporate electrical isolation between the input terminals (primary) and the output terminals
(secondary). All converters are production tested to a withstand voltage of 1500 VDC. This specification complies
with UL60950 and EN60950 requirements. This allows the converter to be configured for either a positive or
negative input voltage source. The data sheet Pin Descriptions section provides guidance as to the correct
reference that must be used for the external control signals.
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 10 A, is recommended. Active current limiting can be implemented
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 chart (see typical characteristics).
6
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SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
Differential Remote Sense
The remote sense pins allows the converter to precisely regulate the DC output voltage at a remote location.
This might be a power plane on an inner layer of the host PCB. Connecting Sense(+) directly to +VO , and
Sense(–) to –VO will improve output voltage accuracy. In the event that the sense pins are left open-circuit, an
internal 10-Ω resistor between each sense pin and its corresponding output prevents an excessive rise in the
output voltage. For practical reasons, the amount of IR voltage compensation should be limited to 0.5 V
maximum.
The remote sense feature is designed to compensate for limited amounts of IR voltage drop. It is not intended to
compensate for the forward drop of a non-linear or frequency dependent components that may be placed in
series with the converter output. Examples of such components include OR-ing diodes, filter inductors, ferrite
beads, and fuses. Enclosing these components with the remote sense connections effectively places them inside
the regulation control loop, which can affect the stability of the regulator.
Using the Remote On/Off Function on the PTEA404120 DC/DC Converter
For applications requiring output voltage On/Off control, the PTEA404120 DC/DC converter incorporate a
Remote On/Off control (pin 2). This feature can be used to switch the module off without removing the applied
input source voltage. When placed in the Off state, the standby current drawn from the input source is typically
reduced to 3 mA.
Negative Output Enable (NEN)
Models using the negative enable option, the Remote On/Off (pin 2) control must be driven to a logic low voltage
for the converter to produce an output. This is accomplished by either permanently connecting pin 2 to –VI (pin
3), or driving it low with an external control signal. Table 2 shows the input requirements of pin 2 for those
modules with the NEN option.
Table 2. On/Off Control Requirements
for Negative Enable
PARAMETER
MIN
TYP
MAX
UNITS
V
VIH
Disable
2.4
20
VIL
Enable
–0.2
0.8
Vo/c
Open-Circuit
II
Pin 2 at –VI
9
15
–0.75
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Positive Output Enable (PEN)
For those models with the positive enable (PEN) option, leaving pin 2 open circuit, (or driving it to an equivalent
logic high voltage), will enable the converter output. This allows the module to produce an output voltage
whenever a valid input source voltage is applied to +VI with respect to –VI. If a logic-low signal is then applied to
pin 2 the converter output is disabled. Table 3 gives the input requirements of pin 2 for modules with the PEN
option.
Table 3. On/Off Control Requirements
for Positive Enable
PARAMETER
MIN
VIH
Enable
4.5
VIL
Disable
–0.2
Vo/c
Open-Circuit
II
Pin 2 at –VI
TYP
MAX
UNITS
20
V
0.8
5
7
–0.5
mA
Notes:
1. The Remote On/Off control uses –VI (pin 3) as its ground reference. All voltages are with respect to –VI.
2. An open-collector device (preferably a discrete transistor) is recommended. A pull-up resistor is not required.
If one is added the pull-up voltage should not exceed 20 V.
Caution: Do not use a pull-resistor to +VI (pin 1). The remote On/Off control has a maximum input voltage of
20 V. Exceeding this voltage will overstress, and possibly damage, the converter.
3. The Remote On/Off pin may be controlled with devices that have a totem-pole output. This is provided the
output high level voltage (VOH) meets the module's minimum VIH specified in Table 2. If a TTL gate is used, a
pull-up resistor may be required to the logic supply voltage.
4. The converter incorporates an undervoltage lockout (UVLO). The UVLO keeps the converter off until the
input voltage is close to the minimum specified operating voltage. This is regardless of the state of the
Remote On/Off control. Consult the product specification for the UVLO input voltage thresholds.
8
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SLTS274C – DECEMBER 2006 – REVISED NOVEMBER 2010
PTEA404120P
2
1=Disable
−VI
Remote On/Off
Q1
BSS138
3
−VI
Figure 5. Recommended Control or Remote On/Off Input
Turn-On: With a valid input source voltage applied, the converter produces a regulated output voltage within 10
ms of the output being enabled. Figure 6 shows the output response of the PTEA following the removal of the
logic-low signal from the Remote On/Off (pin 2); see Figure 5. This corresponds to the drop in Q1 VGS in
Figure 6. Although the rise-time of the output voltage is short (