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FEATURES DESCRIPTION
L
O
A
D
SENSE (–)
SENSE (+)
PTQA430xxxN
52
7
Adjust
8
6
4
1
3
+VO
Sense(+)
−VO
Sense(−)
+VI
−VI
+VI
−VI
+VO
−VO
CI
(Optional) CO
(Optional)
Remote
On/Off
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
100-W 48-V INPUT ISOLATED DC/DC CONVERTER
•100-W Output
The PTQA series of power modules are single-outputisolated DC/DC converters, housed in an industry•Input Voltage Range: 36 V to 75 V
standard quarter-brick package. These modules are•92% Efficiency
rated up to 100W with a maximum load current of up•1500 Vdc Isolation
to 30 A.•Fast Transient Response
The PTQA series operates from a standard 48-V•On/Off Control
telecom central office (CO) supply and occupies only3.3 in
2
of PCB area. The modules offer OEMs a•Overcurrent Protection
compact and flexible high-output power source in an•Differential Remote Sense
industry standard footprint. They are suitable for•Adjustable Output Voltage
distributed power applications in both telecom and•Output Overvoltage Protection computing environments, and may be used forpowering high-end microprocessors, DSPs, general•Over-Temperature Shutdown
purpose logic and analog.•Undervoltage Lockout
Features include a remote On/Off control with•Standard 1/4-Brick Footprint
optional logic polarity, an undervoltage lockout•UL Safety Agency Approval
(UVLO), a differential remote sense, and an industrystandard output voltage adjustment using an externalresistor. Protection features include outputovercurrent protection (OCP), overvoltage protection(OVP), and thermal shutdown (OTP).
The modules are fully integrated for stand-aloneoperation, and require no additional components.
STANDARD APPLICATION
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Copyright © 2006, Texas Instruments IncorporatedProducts conform to specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.
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ABSOLUTE MAXIMUM RATING
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
For the most current package and ordering information, see the Package Option Addendum at the end of this datasheet, or see the TIwebsite at www.ti.com.
PART NUMBERING SCHEME
Input Output
Output Voltage Enable Electrical Options Pin StyleVoltage Current
PTQA 4 30 033 N 2 A D
4 = 48 V 30 = 30A 025 = 2.5 V N = Negative 2 = V
O
Adjust D = Through-hole, Pb-free20 = 20A 033 = 3.3 V P = Positive S = SMD, SnPb solder ball050 = 5.0 V Z = SMD, SnAgCu solder ball
UNIT
T
A
Operating Temperature Over V
I
Range –40 °C to 85 °C
(1)
Range
V
I,
Continuous voltage 80 VMaximum Input VoltageMAX
Peak voltage for 100 ms duration 100 VPTQA420050x2
100 WP
O,
Maximum Output Power PTQA430033x2MAX
PTQA430025x2 75 WT
S
Storage Temperature –40 °C to 125 °CAD Suffix 250 GPer Mil-STD-883, Method 2002.3 1 ms, 1/2Mechanical Shock
Sine, mounted
AS or AZ Suffix 175 GAD Suffix 15 GPer Mil-STD-883, Method 2007.2 20-2000 Hz,Mechanical Vibrarion
PCB mounted
AS or AZ Suffix 2.5 GWeight 30 gramsFlammability Meets UL 94V-O
(1) See SOA curves or consult factory for appropriate derating.
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ELECTRICAL CHARACTERISTICS PTQA430025
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
(Unless otherwise stated, T
A
=25 °C, V
I
= 48 V, V
O
= 2.5 V, C
O
= 0 µF, and I
O
= I
O
max)
PTQA430025PARAMETER TEST CONDITIONS
MIN TYP MAX UNIT
I
O
Output Current Over V
I
range 0 30 AV
I
Input Voltage Range Over I
O
Range 36 48 75 VV
O
tol Set Point Voltage ±1
(1)
%V
OToleranceReg
temp
Temperature Variation –40 °C >T
A
> 85 °C±1.15 %V
O
Reg
line
Line Regulation Over V
I
range ±5 mVReg
load
Load Regulation Over I
O
range ±5 mV∆V
o
tot Total Output Voltage Includes set-point, line, load, –40 °C >T
A
> 85 °C±1.5 ±3 %V
OVariation∆V
ADJ
Output Adjust Range P
O
≤75 W –20 10 %V
O
ηEfficiency I
O
= 50% I
O
max 91%V
R
V
O
Ripple (pk-pk) 20 MHz bandwidth 50 100 mV
pp
t
tr
0.1 A/ µs slew rate, 50% to 75% I
O
max 150 µsTransient Response∆V
tr
V
O
over/undershoot 25 mVI
TRIP
Overcurrent Threshold Shutdown, followed by auto-recovery 41 AOVP Output Overvoltage Output shutdown and latch off 120 %V
OProtectionOTP Over Temperature Temperature Measurement at thermal sensor. Hysteresis = 10 °C 105 °CProtection nominal.f
s
Switching Frequency Over V
I
range 300 kHzV
OFF
V
I
decreasing, I
O
= 6 A 32.5UVLO Undervoltage Lockout VV
HYS
Hysteresis 1.5On/Off Input: Negative Enable
V
IH
Input High Voltage 2.4 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.3 mAOn/Off Input: Positive Enable
V
IH
Input High Voltage 4.5 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.5 mAI
ISB
Standby Input Current Output disabled (pin 2 status set to Off) 37 mAC
I
External Input Capacitance Between +V
I
and –V
I
100 µFC
O
External Output Between +V
O
and –V
O
0 30000 µFCapacitance
Isolation Voltage Input-to-output and input-to-case 1500 VdcIsolation Capacitance Input-to-output 1200 pFIsolation Resistance Input-to-output 10 M Ω
(1) If Sense(–) is not used, pin 5 must be connected to pin 4 for optimum output voltage accuracy.(2) The Remote On/Off input has an internal pull-up and may be controlled with an open collector (drain) interface. An open circuitcorrelates to a logic high. Consult the application notes for interface considerations.
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ELECTRICAL CHARACTERISTICS PTQA430033
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
(Unless otherwise stated, T
A
=25 °C, V
I
= 48 V, V
O
= 3.3 V, C
O
= 0 µF, and I
O
= I
O
max)
PTQA430033PARAMETER TEST CONDITIONS
MIN TYP MAX UNIT
I
O
Output Current Over V
I
range 0 30 AV
I
Input Voltage Range Over I
O
Range 36 48 75 VV
O
tol Set Point Voltage ±1
(1)
%V
OToleranceReg
temp
Temperature Variation –40 °C >T
A
> 85 °C±1.15 %V
O
Reg
line
Line Regulation Over V
I
range ±5 mVReg
load
Load Regulation Over I
O
range ±5 mV∆V
o
tot Total Output Voltage Includes set-point, line, load, –40 °C >T
A
> 85 °C±1.5 ±3 %V
OVariation∆V
ADJ
Output Adjust Range P
O
≤100 W –20 10 %V
O
ηEfficiency I
O
= 50% I
O
max 92%V
R
V
O
Ripple (pk-pk) 20 MHz bandwidth 50 100 mV
pp
t
tr
0.1 A/ µs slew rate, 50% to 75% I
O
max 150 µsTransient Response∆V
tr
V
O
over/undershoot 33 mVI
TRIP
Overcurrent Threshold Shutdown, followed by auto-recovery 41 AOVP Output Overvoltage Output shutdown and latch off 120 %V
OProtectionOTP Over Temperature Temperature Measurement at thermal sensor. Hysteresis = 10 °C 105 °CProtection nominal.f
s
Switching Frequency Over V
I
range 300 kHzV
OFF
V
I
decreasing, I
O
= 6 A 32.5UVLO Undervoltage Lockout VV
HYS
Hysteresis 1.5On/Off Input: Negative Enable
V
IH
Input High Voltage 2.4 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.3 mAOn/Off Input: Positive Enable
V
IH
Input High Voltage 4.5 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.5 mAI
Isb
Standby Input Current Output disabled (pin 2 status set to Off) 42 mAC
I
External Input Capacitance Between +V
I
and –V
I
100 µFC
O
External Output Between +V
O
and –V
O
0 30000 µFCapacitance
Isolation Voltage Input-to-output and input-to-case 1500 VdcIsolation Capacitance Input-to-output 1200 pFIsolation Resistance Input-to-output 10 M Ω
(1) If Sense(–) is not used, pin 5 must be connected to pin 4 for optimum output voltage accuracy.(2) The Remote On/Off input has an internal pull-up and may be controlled with an open collector (drain) interface. An open circuitcorrelates to a logic high. Consult the application notes for interface considerations.
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ELECTRICAL CHARACTERISTICS PTQA420050
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
(Unless otherwise stated, T
A
=25 °C, V
I
= 48 V, V
O
= 5.0 V, C
O
= 0 µF, and I
O
= I
O
max)
PTQA420050PARAMETER TEST CONDITIONS
MIN TYP MAX UNIT
I
O
Output Current Over V
I
range 0 20 AV
I
Input Voltage Range Over I
O
Range 36 48 75 VV
O
tol Set Point Voltage ±1
(1)
%V
OToleranceReg
temp
Temperature Variation –40 °C >T
A
> 85 °C±1.15 %V
O
Reg
line
Line Regulation Over V
I
range ±5 mVReg
load
Load Regulation Over I
O
range ±5 mV∆V
o
tot Total Output Voltage Includes set-point, line, load, –40 °C >T
A
> 85 °C±1.5 ±3 %V
OVariation∆V
ADJ
Output Adjust Range P
O
≤100 W –20 10 %V
O
ηEfficiency I
O
= 50% I
O
max 92.5%V
R
V
O
Ripple (pk-pk) 20 MHz bandwidth 50 100 mV
pp
t
tr
0.1 A/ µs slew rate, 50% to 75% I
O
max 100 µsTransient Response∆V
tr
V
O
over/undershoot 50 mVI
TRIP
Overcurrent Threshold Shutdown, followed by auto-recovery 29 AOVP Output Overvoltage Output shutdown and latch off 120 %V
OProtectionOTP Over Temperature Temperature Measurement at thermal sensor. Hysteresis = 10 °C 105 °CProtection nominal.f
s
Switching Frequency Over V
I
range 300 kHzV
OFF
V
I
decreasing, I
O
= 6 A 32.5UVLO Undervoltage Lockout VV
HYS
Hysteresis 1.5On/Off Input: Negative Enable
V
IH
Input High Voltage 2.4 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.3 mAOn/Off Input: Positive Enable
V
IH
Input High Voltage 4.5 Open
(2)Referenced to –V
I
VV
IL
Input Low Voltage –0.2 0.8I
IL
Input Low Current –0.5 mAI
Isb
Standby Input Current Output disabled (pin 2 status set to Off) 58 mAC
I
External Input Capacitance Between +V
I
and –V
I
100 µFC
O
External Output Between +V
O
and –V
O
0 30000 µFCapacitance
Isolation Voltage Input-to-output and input-to-case 1500 VdcIsolation Capacitance Input-to-output 1200 pFIsolation Resistance Input-to-output 10 M Ω
(1) If Sense(–) is not used, pin 5 must be connected to pin 4 for optimum output voltage accuracy.(2) The Remote On/Off input has an internal pull-up and may be controlled with an open collector (drain) interface. An open circuitcorrelates to a logic high. Consult the application notes for interface considerations.
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PIN DESCRIPTIONS
Sense(+)
+VO
Adjust
Sense(−)
−VO
PTQA430xxxN
(Top View)
+VI
On/Off
1
2
3−VI5
6
7
4
8
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
+V
I
:The positive input for the module with respect to –V
I
. When powering the module from a –48-V telecomcentral office supply, this input is connected to the primary system ground.
–V
I
:The negative input supply for the module, and the 0 VDC reference for the Remote On/Off input. Whenpowering 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 (–V
I
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.
V
O
Adjust: Allows the output voltage to be trimmed by up or down between +10% and –20% of its nominalvalue. The adjustment method uses a single external resistor. Connecting the resistor between V
O
Adjust and–V
O
adjusts the output voltage lower, and placing it between V
O
Adjust and +V
O
adjusts the output higher. Thecalculations for the resistance value follows industry standard formulas. For further information consult theapplication note on output voltage adustment.
+V
O
:The positive power output with respect to –V
O
, which is DC isolated from the input supply pins. If anegative output voltage is desired, +V
O
should be connected to the secondary circuit common and the outputtaken from –V
O
.
–V
O
:The negative power output with respect to +V
O
, which is DC isolated from the input supply pins. Thisoutput 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 theload. When used with Sense(-), the regulation circuitry will compensate for voltage drop between the converterand the load. The pin may be left open circuit, but connecting it to +V
O
will improve load regulation.
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 –V
O
.
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TYPICAL CHARACTERISTICS
PTQA430025, V
O
= 2.5 V
00 5 10 15 20 25 30
15
10
30
20
25
5
35
40
45
50
IO − Output Current − A
VO − Output Voltage Ripple − mVPP
VI= 36 V
VI= 48 V
VI= 60 V
VI= 75 V
0
0
5 10 15 20 25 30
6
4
12
8
10
2
P − PowerDiddipation − W
D
I − OutputCurrent − A
O
VI=75V
VI=60V
VI=48V
VI=36V
90
80
85
95
70
60
65
75
50
40
45
55
0 5 10 15 20 25 30
I − OutputCurrent − A
O
VI=36V
VI=75V
η− Efficiency − %
VI=60V
VI=48V
20
0 5 10 15 20 25 30
50
40
80
60
70
30
90
I − OutputCurrent − A
O
LFM=200
Natural
Convection
T − AmbientT
Aemperature −C
o
LFM=400
LFM=100
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
All data listed in the graphs below have been developed from actual products tested at 25 °C. This data is considered typicaldata for the DC-DC Converter. SOA curves represent operating conditions at which internal components are at or belowmanufacturer's maximum rated operating temperature. For Figure 4 Safe Operating Area, V
I
= 48 V.
EFFICIENCY OUTPUT RIPPLE POWER DISSIPATIONvs vs vsLOAD CURRENT LOAD CURRENT LOAD CURRENT
Figure 1. Figure 2. Figure 3.
AMBIENT TEMPERATURE
vsLOAD CURRENT
Figure 4.
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TYPICAL CHARACTERISTICS
PTQA430033, V
O
= 3.3 V
90
80
85
95
70
60
65
75
50
40
45
55
0 5 10 15 20 25 30
IO− OutputCurrent − A
V =36V
I
VI=48V VI=60V
VI=75V
η− Efficiency − %
00 5 10 15 20 25 30
15
10
30
20
25
5
35
40
IO − Output Current − A
VI= 36 V
VI= 48 V
VI= 60 V
VI= 75 V
VO − Output Voltage Ripple − mVPP
0
05 10 15 20 25 30
6
4
12
8
10
2
14
IO − Output Current − A
VI= 36 V
VI= 48 V
VI= 60 V
VI= 75 V
PD − Power Diddipation − W
20 0 5 10 15 20 25 30
50
40
80
60
70
30
90
IO − Output Current − A
LFM = 200
Natural
Convection
TA − Ambient Temperature − °C
LFM = 400
LFM = 100
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
All data listed in the graphs below have been developed from actual products tested at 25 °C. This data is considered typicaldata for the DC-DC Converter. SOA curves represent operating conditions at which internal components are at or belowmanufacturer's maximum rated operating temperature. For Figure 8 Safe Operating Area, V
I
= 48 V.
EFFICIENCY OUTPUT RIPPLE POWER DISSIPATIONvs vs vsLOAD CURRENT LOAD CURRENT LOAD CURRENT
Figure 5. Figure 6. Figure 7.
AMBIENT TEMPERATURE
vsLOAD CURRENT
Figure 8.
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TYPICAL CHARACTERISTICS
PTQA420050, V
O
= 5.0 V
0 5 10 15 20
VI36 V
48 V
60 V
75 V
90
80
85
95
70
60
65
75
IO − Output Current − A
VI = 36 V
η − Efficiency − %
VI = 48 V VI = 60 V
VI = 75 V
0
0
1
3
9
8
2
10
VI36 V
48 V
60 V
75 V
5 10 15 20
4
5
7
6
IO − Output Current − A
PD − Power Dissipation − W
VI = 36 V
VI = 48 V
VI = 60 V
VI = 75 V
VO = 5 V
20 0
50
40
80
60
70
30
90
5 10 15 20
IO − Output Current − A
TA − Ambient T emperature − °C
VO = 5 V
Natural Convection
400 LFM
100 LFM
200 LFM
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
All data listed in the graphs below have been developed from actual products tested at 25 °C. This data is considered typicaldata for the DC-DC Converter. SOA curves represent operating conditions at which internal components are at or belowmanufacturer's maximum rated operating temperature. For Figure 12 Safe Operating Area, V
I
= 48 V.
EFFICIENCY OUTPUT RIPPLE POWER DISSIPATIONvs vs vsLOAD CURRENT LOAD CURRENT LOAD CURRENT
Figure 9. Figure 10. Figure 11.
AMBIENT TEMPERATURE
vsLOAD CURRENT
Figure 12.
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APPLICATION INFORMATION
Operating Features and System Considerations for the PTQA Series of DC/DC Converters
Overcurrent Protection
Output Overvoltage Protection
Overtemperature Protection
Undervoltage Lockout
Primary-Secondary Isolation
Input Current Limiting
Thermal Considerations
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
To protect against load faults, these converters incorporate output overcurrent protection. Applying a load to theoutput that exceeds the converter's overcurrent threshold (see applicable specification) will cause the outputvoltage to momentarily fold back, and then shut down. Following shutdown the module will periodically attemptto automatically recover by initiating a soft-start power-up. This is often described as a hiccup mode ofoperation, whereby the module continues in the cycle of successive shutdown and power up until the load faultis removed. Once the fault is removed, the converter automatically recovers and returns to normal operation.
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 outputvoltage exceeds this threshold, the converter is immediately shut down and remains in a latched-off state. Toresume normal operation the converter must be actively reset. This can only be done by momentarily removingthe input power to the converter. For fail-safe operation and redundancy, the OV protection uses circuitry that isindependent of the converter’s internal feedback loop.
Overtemperature protection is provided by an internal temperature sensor, which closely monitors thetemperature of the converter’s printed circuit board (PCB). If the sensor exceeds a temperature of approximately105 °C, the converter will shut down. The converter will then automatically restart when the sensed temperaturedrops back to approximately 95 °C. When operated outside its recommended thermal derating envelope (seedata sheet SOA curves), the converter will typcially cycle on and off at intervals from a few seconds to one ortwo minutes. This is to ensure that the internal components are not permanently damaged from excessivethermal stress.
The Undervoltage lockout (UVLO) is designed to prevent the operation of the converter until the input voltage isat the minimum input voltage. This prevents high start-up current during normal power-up of the converter, andminimizes the current drain from the input source during low input voltage conditions. The UVLO circuitry alsooverrides the operation of the Remote On/Off control.
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 specificationcomplies with UL60950 and EN60950 and the requirements for operational isolation. This allows the converter tobe configured for either a positive or negative input voltage source. The data sheet Pin Descriptions sectionprovides guidance as to the correct reference that must be used for the external control signals.
The converter is not internally fused. For safety and overall system protection, the maximum input current to theconverter must be limited. Active or passive current limiting can be used. Passive current limiting can be a fastacting fuse. A 125-V fuse, rated no more than 10 A, is recommended. Active current limiting can beimplemented with a current limited Hot-Swap controller.
Airflow may be necessary to ensure that the module can supply the desired load current in environments withelevated ambient temperatures. The required airflow rate may be determined from the Safe Operating Area(SOA) thermal derating chart (see typical characteristics).
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Differential Remote Sense
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
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 +V
O
, andSense(–) to –V
O
will improve output voltage accuracy. In the event that the sense pins are left open-circuit, aninternal 10- Ωresistor between each sense pin and its corresponding output prevents an excessive rise in theoutput voltage. For practical reasons, the amount of IR voltage compensation should be limited to 0.5 Vmaximum.
The remote sense feature is designed to compensate for limited amounts of IR voltage drop. It is not intended tocompensate for the forward drop of a non-linear or frequency dependent components that may be placed inseries with the converter output. Examples of such components include OR-ing diodes, filter inductors, ferritebeads, and fuses. Enclosing these components with the remote sense connections effectively places theminside the regulation control loop, which can affect the stability of the regulator.
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Using the Remote On/Off Function on the PTQA Series of DC/DC Converters
Negative Output Enable (NEN)
Positive Output Enable (PEN)
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
For applications requiring output voltage On/Off control, the PTQA series of DC/DC converters incorporate aRemote On/Off control (pin 2). This feature can be used to switch the module off without removing the appliedinput source voltage. When placed in the Off state, the standby current drawn from the input source is typicallyreduced to 3 mA.
Models using the negative enable option, the Remote On/Off (pin 2) control must be driven to a logic low voltagefor the converter to produce an output. This is accomplished by either permanently connecting pin 2 to –V
I
(pin3), or driving it low with an external control signal. Table 1 shows the input requirements of pin 2 for thosemodules with the NEN option.
Table 1. On/Off Control Requirementsfor Negative Enable
PARAMETER MIN TYP MAX
V
IH
Disable 2.4 V 20 VV
IL
Enable –0.2 V 0.8 VV
o/c
Open-Circuit 9 V 15 VI
I
Pin 2 at –V
I
–0.75 mA
For those models with the positive enable (PEN) option, leaving pin 2 open circuit, (or driving it to an equivalentlogic high voltage), will enable the converter output. This allows the module to produce an output voltagewhenever a valid input source voltage is applied to +V
I
with respect to –V
I
. If a logic-low signal is then applied topin 2 the converter output is disabled. Table 2 gives the input requirements of pin 2 for modules with the PENoption.
Table 2. On/Off Control Requirementsfor Positive Enable
PARAMETER MIN TYP MAX
V
IH
Enable 4.5 V 20 VV
IL
Disable –0.2 V 0.8 VV
o/c
Open-Circuit 5 V 7 VI
I
Pin 2 at –V
I
–0.5 mA
Notes:
1. The Remote On/Off control uses –V
I
(pin 3) as its ground reference. All voltages are with respect to –V
I
.2. An open-collector device (preferably a discrete transistor) is recommended. A pull-up resistor is notrequired. If one is added the pull-up voltage should not exceed 20 V.
Caution:Do not use a pull-resistor to +V
I
(pin 1). The remote On/Off control has a maximum input voltage of20 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 theoutput high level voltage (V
OH
) meets the module's minimum V
IH
specified in Table 1 . If a TTL gate isused, 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 theinput voltage is close to the minimum specified operating voltage. This is regardless of the state of theRemote On/Off control. Consult the product specification for the UVLO input voltage thresholds.
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PTQA430xxxP
1 = Disable
−VI
Q1
BSS138
2
3−VI
Remote
On/Off
t − Time − 100 µs/div
Voltage
Undershoot
VO (1 V/div)
< 300 mV
Delay Time
VO (1 V/div)
II (1 A/div)
Q1 VGS (10 V/div)
t − Time − 5 ms/div
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
Figure 13. Recommended Control or Remote On/Off Input
Turn-On: With a valid input source voltage applied, the converter produces a regulated output voltage within 75ms of the output being enabled. Figure 14 shows the output response of the PTQA430033P following theremoval of the logic-low signal from the Remote On/Off (pin 2); see Figure 13 . This corresponds to the drop inQ1 V
GS
in Figure 14 . Although the rise-time of the output voltage is short (<10 ms), the indicated delay time willvary depending upon the input voltage and the module’s internal timing. The waveforms were measured with 48VDC input voltage, and a 10-A resistive load.
Turn-Off Time: When a valid input source is removed or if the Remote On/Off (pin 2) is used to disable theoutput, with no external output capacitance, the module powers down within 200 µs. Figure 15 shows that,during power down, there is a small undershoot, typically less than 300 mV (or less than a diode drop). If usedto supply processor I/O voltages, the low undershoot ensures the parasitic diodes do not conduct current andpotentially cause damage to external circuitry.
Figure 14. Power Up Figure 15. Power Down
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Adjusting the Output Voltage of the 100-W Rated PTQA Series of Isolated DC/DC Converters
R1 +5.11 VO(100 )D%)
1.225 D%*511
D%*10.22 (kW)
(1)
(R2) +5.11100
D%*10.22 (kW)
(2)
IO(max) +VO IO(rated)
VA
(3)
L
O
A
D
Sense (–)
Sense (+)
+
(R2)
Adjust
Down
PTQA430xxxN
Sense(+)
Sense(–)
52
7
Adjust
8
6
4
1
3
+VI
−VI
+VI
−VI
CO
330 µF
+VO
−VO
+VO
−VO
Remote
On/Off
R1
Adjust
Up
PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
The output voltage adjustment of the PTQA series of isolated DC/DC converters follows the standard adoptedby popular 1/4-brick DC/DC converters. Adjustment is accomplished with a single external resistor that canadjust the output voltage from –20% to +10% of the nominal set-point voltage. The placement of the resistordetermines the direction of adjustment, up or down, and the value of the magnitude of adjustment.
Adjust Up: To increase the output voltage add a resistor, R1, between V
O
Adjust (pin 6) and Sense(+) (pin 7).
Adjust Down: Add a resistor, (R2), between V
O
Adjust (pin 6) and Sense(–) (pin 5).
Refer to Figure 16 for the placement of the required resistor, R1 or (R2).
The values of R1 [adjust up], and (R2) [adjust down], can be calculated using the following formulas.
Where:
∆% = Amount of adjustment in %V
O
= Original set-point voltage
Notes:
1. Use only a single 1% resistor in either the R1 or (R2) location. Place the resistor as close to the converteras possible.
2. If the output voltage is increased, the maximum load current must be derated according to the followingequation.
Where:
V
O
= Original set-point voltageV
A
= Adjusted output voltage (measured between pins 8 and 4)
In any instance, the load current must not exceed the converter's maximum rated output current of 30 A.3. The overvoltage threshold is fixed, and is set approximately 20% above the nominal output voltage.Adjusting the output voltage higher reduces the voltage margin between the adjusted output voltage andthe overvoltage (OV) protection threshold. This could make the module sensitive to OV fault detection, asa result of random noise and load transients.
Figure 16.
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PTQA430025 , PTQA430033 , PTQA420050
SLTS261A – MAY 2006 – REVISED DECEMBER 2006
Table 3. Adjustment Resistor Values
Adjusted Output Voltage (V) Trim-Up R
ADJ
Trim-Down R
ADJ
V
O
(nom) 3.3 V 2.5 V 3.3 V 2.5 V 3.3 V 2.5 V% Adjust (V) R1 (k Ω) R1 (k Ω) R2 (k Ω) R2 (k Ω)
+10 3.630 2.750 90.9 53.6 - -+ 9 3.597 2.725 100 59.0 - -+ 8 3.564 2.700 113 66.5 - -+ 7 3.531 2.675 127 76.8 - -+ 6 3.498 2.650 147 88.7 - -+ 5 3.465 2.625 178 107 - -+ 4 3.432 2.600 221 133 - -+ 3 3.399 2.575 294 178 - -+ 2 3.366 2.550 432 267 - -+ 1 3.333 2.525 866 536 - -0 3.300 2.500 Open Open - -–1 3.267 2.475 - - 499 499–2 3.234 2.450 - - 243 243–3 3.201 2.425 - - 158 158–4 3.168 2.400 - - 118 118–5 3.135 2.375 - - 90.9 90.9–6 3.102 2.350 - - 75 75–7 3.069 2.325 - - 63.4 63.4–8 3.036 2.300 - - 53.6 53.6–9 3.003 2.275 - - 46.4 46.4–10 2.970 2.250 - - 41.2 41.2–11 2.937 2.225 - - 36.5 36.5–12 2.904 2.200 - - 32.4 32.4–13 2.871 2.175 - - 28.7 28.7–14 2.838 2.150 - - 26.1 26.1–15 2.805 2.125 - - 23.7 23.7–16 2.772 2.100 - - 21.5 21.5–17 2.739 2.075 - - 19.6 19.6–18 2.706 2.050 - - 18.2 18.2–19 2.673 2.025 - - 16.5 16.5–20 2.640 2.000 - - 15.4 15.4
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