TI PTH03000W

PTH03000W —3.3-V Input
6-A, 3.3-V Input Non-Isolated
Wide-Output Adjust Power Module
SLTS200C – MAY 2003 – REVISED DECEMBER 2003
Features
NOMINAL SIZE =
0.75 in x 0.5 in
(19,05 mm x 12,7 mm)
• Up to 6-A Output Current
• 3.3 V Input Voltage
• Wide-Output Voltage Adjust
(0.9 V to 2.5 V)
• Efficiencies up to 95 %
• 115 W/in³ Power Density
• On/Off Inhibit
• Under-Voltage Lockout
•
•
•
•
•
Output Current Limit
Over-Temperature Protection
Operating Temp: –40 to +85 °C
Surface Mount Package
Safety Agency Approvals (Pending):
UL 1950, CSA 22.2 950, EN60950
& VDE
Description
Pin Configuration
The PTH03000 series of non-isolated
power modules are small in size and high
on performance. Using double-sided surface mount construction and synchronous
rectification technology, these regulators
deliver up to 6 A of output current while
occupying a PCB area of about half the
size of a standard postage stamp. They
are an ideal choice for applications where
space, performance and cost are important design constraints.
The series operates from an input
voltage of 3.3 V to provide step-down
power conversion to any output voltage
over the range, 0.9 V to 2.5 V. The output voltage of the PTH03000W is set
within this range using a single resistor.
Operating features include an on/off
inhibit, output voltage adjust (trim), an
output current limit, and over-temperature
protection.
Target applications include telecom,
industrial, and general purpose circuits,
including low-power dual-voltage systems
that use a DSP, microprocessor, or ASIC.
Package options include both throughhole and surface mount configurations.
Pin
1
2
3
4
5
* Denotes negative logic:
Open
= Output On
Ground = Output Off
Standard Application
Rset = Required to set the output voltage to a value
higher than 0.9 V (see spec. table for values)
Cin = Required 100 µF capacitor
Cout = Optional 100 µF capacitor
1
VIN
2
PTH03000W
(Top View)
3
CIN
100 µF
(Required)
VOUT
5
4
RSET
1 %, 0.1 W
(Required)
COUT
100 µF
Electrolytic
(Optional)
Inhibit
GND
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Function
GND
Vin
Inhibit *
Vo Adjust
Vout
GND
PTH03000W —3.3-V Input
6-A, 3.3-V Input Non-Isolated
Wide-Output Adjust Power Module
SLTS200C – MAY 2003 – REVISED DECEMBER 2003
Ordering Information
Output Voltage (PTH03000Hxx)
Package Options (PTH03000xHH) (1)
Code
W
Code
Voltage
0.9 V – 2.5 V (Adjust)
AH
AS
Description
Pkg Ref.
Horiz. T/H
SMD, Standard (3)
(2)
(EUS)
(EUT)
Notes: (1) Add “T” to end of part number for tape and reel on SMD packages only.
(2) Reference the applicable package reference drawing for the dimensions and PC board layout
(3) “Standard” option specifies 63/37, Sn/Pb pin solder material.
Pin Descriptions
Vin: The positive input voltage power node to the module, which is referenced to common GND.
Vout: The regulated positive power output with respect
to the GND node.
GND: This is the common ground connection for the
‘Vin’ and ‘Vout’ power connections. It is also the 0 VDC
reference for the ‘Inhibit’ and ‘Vo Adjust’ control inputs.
Inhibit: The Inhibit pin is an open-collector/drain negative
logic input that is referenced to GND. Applying a lowlevel ground signal to this input disables the module’s
output and turns off the output voltage. When the Inhibit
control is active, the input current drawn by the regulator
is significantly reduced. If the Inhibit pin is left opencircuit, the module will produce an output whenever a
valid input source is applied.
Vo Adjust: A 0.1 W 1 % resistor must be directly connected
between this pin and the GND pin to set the output voltage
to a value higher than 0.9 V. The temperature stability
of the resistor should be 100 ppm/°C (or better). The set
point range for the output voltage is from 0.9 V to 2.5 V.
The resistor required for a given output voltage may be
calculated from the following formula. If left open circuit,
the output voltage will default to its lowest value. For
further information on output voltage adjustment, consult
the related application note.
Rset
= 10 kΩ ·
0.891 V
Vout – 0.9 V
– 4.99 kΩ
The specification table gives the preferred resistor values
for a number of standard output voltages.
For technical support and further information visit http://power.ti.com
PTH03000W —3.3-V Input
6-A, 3.3-V Input Non-Isolated
Wide-Output Adjust Power Module
SLTS200C– MAY 2003 – REVISED DECEMBER 2003
Environmental & Absolute Maximum Ratings
Characteristics
Symbols
Conditions
Min
Typ
Max
Units
Operating Temperature Range
Solder Reflow Temperature
Storage Temperature
Over Temperature Protection
Mechanical Shock
Ta
Treflow
Ts
OTP
Over Vin Range
Surface temperature of module body or pins
—
IC junction temperature
Per Mil-STD-883D, Method 2002.3
1 msec, ½ sine, mounted
Mil-STD-883D, Method 2007.2
20-2000 Hz
–40 (i)
—
–40
—
—
—
150
500
+85
235 (ii)
+125
—
—
°C
°C
°C
°C
G’s
—
20
—
G’s
—
2
—
grams
Mechanical Vibration
Weight
Flammability
—
—
Meets UL 94V-O
Notes: (i) During reflow of SMD package version do not elevate peak temperature of the module, pins or internal components above the stated maximum.
Electrical Specifications
Unless otherwise stated, T a =25 °C, V in =3.3 V, Vo =2 V, C in =100 µF, C out =0 µF, and Io =Iomax
Characteristics
Symbols
Conditions
Output Current
Io
0.9 V ≤ Vo ≤ 2.5 V,
Input Voltage Range
Set-Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Variation
Vin
Vo tol
∆Regtemp
∆Regline
∆Regload
∆Regtot
Over Io range
Efficiency
η
Vo Ripple (pk-pk)
Transient Response
Vr
Current Limit
Under-Voltage Lockout
ttr
∆Vtr
Ilim
UVLO
Inhibit Control (pin 3)
Input High Voltage
Input Low Voltage
Input Low Current
VIH
VIL
IIL
Standby Input Current
Switching Frequency
External Input Capacitance
External Output Capacitance
Iin inh
ƒs
Cin
Cout
Reliability
MTBF
Min
Ta =60 °C, 200 LFM airflow
Ta =25 °C, natural convection
–40 °C <Ta < +85 °C
Over Vin range
Over Io range
Includes set-point, line, load,
–40 °C ≤ T a ≤ +85 °C
Io =4 A
RSET = 576 Ω Vo = 2.5 V
RSET = 3.09 kΩ Vo = 2.0 V
RSET = 4.87 kΩ Vo = 1.8 V
RSET = 9.76 kΩ Vo = 1.5 V
RSET = 24.3 kΩ Vo = 1.2 V
RSET = 82.5 kΩ Vo = 1.0 V
20 MHz bandwidth
1 A/µs load step, 50 to 100 % Iomax,
Vo =1.8 V, C out =100 µF
Recovery time
Vo over/undershoot
∆Vo = –50 mV
Vin increasing
Vin decreasing
Referenced to GND
Pin 3 to GND
pins 1 & 3 connected
Over Vin and Io ranges
Capacitance value
non-ceramic
ceramic
Equiv. series resistance (non-ceramic)
Per Bellcore TR-332
50 % stress, Ta =40 °C, ground benign
PTH03000W
Typ
Max
Units
0
0
3
—
—
—
—
—
—
—
—
±0.5
±5
±5
6 (1)
6 (1)
3.6
±2 (2)
—
—
—
A
V
%Vo
%Vo
mV
mV
—
—
±3 (2)
%Vo
—
—
—
—
—
—
—
93
91
90
88
86
84
20
—
—
—
—
—
—
—
—
—
—
—
2.6
70
100
13
2.95
2.8
—
—
—
3
—
Vin –0.5
–0.2
—
—
—
100 (4)
0
0
4 (7)
—
—
–10
1
700
—
100
—
—
28
—
(5)
Open (3)
0.8
—
—
—
—
1,000 (6)
300
—
—
%
mVpp
µSec
mV
A
V
V
µA
mA
kHz
µF
µF
mΩ
106 Hrs
Notes: (1) See SOA curves or consult factory for appropriate derating.
(2) The set-point voltage tolerance is affected by the tolerance and stability ofRSET. The stated limit is unconditionally met if RSET has a tolerance of 1 %
with 100 ppm/°C or better temperature stability.
(3) The Inhibit control (pin 3) has an internal pull-up to Vin, and if left open-circuit the module will operate when input power is applied. A small lowleakage (<100 nA) MOSFET is recommended to control this input. See application notes for more information.
(4) The regulator requires a minimum of 100 µF input capacitor with a minimum 300 mArms ripple current rating. For further information, consult the
related application note on Capacitor Recommendations.
(5) An external output capacitor is not required for basic operation. Adding 100 µF of distributed capacitance at the load will improve the transient response.
(6) This is the calculated maximum. The minimum ESR limitation will often result in a lower value. Consult the application notes for further guidance.
(7) This is the typical ESR for all the electrolytic (non-ceramic) output capacitance. Use 7 mΩ as the minimum when using max-ESR values to calculate.
For technical support and further information visit http://power.ti.com
PTH03000W —3.3-V Input
Typical Characteristics
6-A, 3.3-V Input Non-Isolated
Wide-Output Adjust Power Module
Characteristic Data; Vin =3.3V
SLTS200C – MAY 2003 – REVISED DECEMBER 2003
Safe Operating Area; Vin =3.3 V
(See Note A)
Efficiency vs Output Current
(See Note B)
All Output Voltages
100
90
Efficiency - %
VOUT
2.5 V
2.0 V
1.8 V
1.5V
1.2V
1.0 V
80
70
60
Ambient Temperature (°C)
80
90
70
Airflow
60
100LFM
Nat Conv
50
40
30
50
20
0
1
2
3
4
5
6
0
Iout - Amps
1
2
3
4
5
6
Iout (A)
Ripple vs Output Current
50
Ripple - mV
40
VOUT
1.0 V
1.2 V
1.5 V
1.8 V
2.0 V
2.5 V
30
20
10
0
0
1
2
3
4
5
6
Iout (A)
Power Dissipation vs Output Current
2
Pd - Watts
1.6
1.2
0.8
0.4
0
0
1
2
3
4
5
6
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. Derating limits apply to
modules soldered directly to a 4 in. × 4 in. double-sided PCB with 1 oz. copper.
For technical support and further information visit http://power.ti.com
Application Notes
PTH03000W
Capacitor Recommendations for the PTH03000W,
Wide-Output Adjust Power Modules
Input Capacitor
The recommended input capacitor(s) is determined by
the 100 µF minimum capacitance and 300 mArms minimum ripple current rating.
Ripple current, less than 300 mΩ equivalent series resistance (ESR), and temperature are the major considerations
when selecting input capacitors. Unlike polymer tantalum,
regular tantalum capacitors have a recommended minimum voltage rating of 2 × (maximum DC voltage + AC
ripple). This is standard practice to ensure reliability.
For improved ripple reduction on the input bus, ceramic
capacitors [2] may used to complement electrolytic types
and achieve the minimum required capacitance.
Output Capacitors (Optional)
For applications with load transients (sudden changes in
load current), regulator response will benefit from an
external output capacitance. The recommended output
capacitance of 100 µF will allow the module to meet
its transient response specification (see product data sheet).
For most applications, a high quality computer-grade
aluminum electrolytic capacitor is adequate. These capacitors provide decoupling over the frequency range, 2 kHz
to 150 kHz, and are suitable for ambient temperatures
above 0 °C. For operation below 0 °C tantalum, ceramic
or Os-Con type capacitors are recommended. When using
one or more non-ceramic capacitors, the calculated equivalent ESR should be no lower than 4 mΩ (7 mΩ using the
manufacturer’s maximum ESR for a single capacitor). A
list of preferred low-ESR type capacitors are identified
in Table 1-1.
Ceramic Capacitors
Above 150 kHz the performance of aluminum electrolytic
capacitors becomes less effective. To further improve the
reflected input ripple current [2] or the output transient
response, multilayer ceramic capacitors can also be added.
Ceramic capacitors have very low ESR and their resonant
frequency is higher than the bandwidth of the regulator.
When used on the output their combined ESR is not
critical as long as the total value of ceramic capacitance
does not exceed 300 µF. Also, to prevent the formation of
local resonances, do not place more than five identical ceramic capacitors in parallel with values of 10 µF or greater.
Tantalum Capacitors
Tantalum type capacitors can be used at both the input
and output, and are recommended for applications where
the ambient operating temperature can be less than 0 °C.
The AVX TPS, Sprague 593D/594/595 and Kemet T495/
For technical support and further information visit http://power.ti.com
T510 capacitor series are suggested over many other
tantalum types due to their higher rated surge, power
dissipation, and ripple current capability. As a caution
many general purpose tantalum capacitors have considerably higher ESR, reduced power dissipation and lower
ripple current capability. These capacitors are also less
reliable as they have lower power dissipation and surge
current ratings. Tantalum capacitors that do not have a
stated ESR or surge current rating are not recommended
for power applications.
When specifying Os-Con and polymer tantalum capacitors
for the output, the minimum ESR limit will be encountered well before the maximum capacitance value is
reached.
Capacitor Table
Table 1-1 identifies the characteristics of capacitors from a
number of vendors with acceptable ESR and ripple current
(rms) ratings. The recommended number of capacitors
required at both the input and output buses is identified
for each capacitor type.
This is not an extensive capacitor list. Capacitors from other
vendors are available with comparable specifications. Those
listed are for guidance. The RMS ripple current rating and
ESR (at 100 kHz) are critical parameters necessary to insure
both optimum regulator performance and long capacitor life.
Designing for Very Fast Load Transients
The transient response of the DC/DC converter has been
characterized using a load transient with a di/dt of 1 A/µs.
The typical voltage deviation for this load transient is
given in the data sheet specification table using the
optional value of output capacitance. As the di/dt of a
transient is increased, the response of a converter’s regulation circuit ultimately depends on its output capacitor
decoupling network. This is an inherent limitation with
any DC/DC converter once the speed of the transient
exceeds its bandwidth capability. If the target application
specifies a higher di/dt or lower voltage deviation, the
requirement can only be met with additional output
capacitor decoupling. In these cases special attention
must be paid to the type, value and ESR of the capacitors
selected.
If the transient performance requirements exceed that
specified in the data sheet, the selection of output capacitors becomes more important. For further guidance
consult the separate application note, “Selecting Output
Capacitors for PTH Products in High-Performance Applications.”
Application Notes continued
PTH03000W
Table 1-1: Input/Output Capacitors
Capacitor Vendor, Type/
Series (Style)
Capacitor Characteristics
Quantity
Working
Voltage
Value (µF)
Max. (ESR)
at 100 kHz
Max. Ripple
at 85 °C
Current (Irms)
Physical Size
(mm)
Input
Bus
Output
Bus
Panasonic
FC, Aluminum (SMD)
WA, Poly-Aluminum (SMD)
25 V
10 V
100 µF
120 µF
0.300 Ω
0.035 Ω
450 mA
2800 mA
8×10
8.3×6.9
1
1
1
≤3
EEVFC1E101P
EEFWA1A121P
Panasonic, Aluminum
FC (Radial)
FK (SMD)
16 V
16 V
220 µF
330 µF
0.150 Ω
0.160 Ω
555 mA
600 mA
10×10.2
8×10.2
1
1
≤5
≤3
EEUFC1C221
EEVFK1C331P
United Chemi–Con
FS, Os-con (Radial)
PXA , Poly-Alum (SMD)
MVZ, Aluminum (SMD)
PS, Poly-Alum. (Radial)
10 V
10 V
16 V
10 V
100 µF
120 µF
220 µF
100 µF
0.040 Ω
0.027 Ω
0.170 Ω
0.024 Ω
2100 mA
2430 mA
450 mA
4420 mA
6.3×9.8
8×6.7
8×10
8×11.5
1
1
1
1
≤3
≤3
≤5
≤3
10FS100M
PXA10VC121MH80TP
MVZ25VC221MH10TP
10PS270MH11
Nichicon, Aluminum
WG, Aluminum (SMD)
PM, (Radial)
F55, Tantalum (SMD)
35 V
25 V
10 V
100 µF
150 µF
100 µF
0.150 Ω
0.160 Ω
0.055 Ω
670 mA
460 mA
2000 mA
10×10
10×11.5
7.7×4.3
1
1
1
1
≤5
≤3
UWG1V101MNR1GS
UPM1E151MPH
F551A107MN
Sanyo
SVP, Os-con (SMD)
SP, Os-con (Radial)
TPE, Poscap Polymer (SMD)
10 V
16 V
10 V
120 µF
100 µF
220 µF
0.040 Ω
0.025 Ω
0.025 Ω
>2500 mA
>2800 mA
>2400mA
7×8
6.3×9.8
7.3×5.7
1
1
1
≤3
≤2
≤2
10SVP120M
16SPS100M
10TPE220ML
10 V
10 V
100 µF
220 µF
0.100 Ω
0.100 Ω
>1090 mA
>1414 mA
7.3L
×4.3W ×4.1H
1
1
≤3
≤3
TPSD107M010R0100
TPSV227M010R0100
Kemet
T520, Poly-Alum (SMD)
T495,Tantalum (SMD)
A700-Poly-Alum. (SMD)
10 V
10 V
6.3 V
100 µF
100 µF
100 µF
0.080 Ω
0.100 Ω
0.018 Ω
1200 mA
>1100 mA
2900 mA
7.3L ×5.7W
×4.0H
1
1
1
≤4
≤4
≤2
T520D107M010AS
T495X107M010AS
A700D107M006AT
Vishay-Sprague
594D, Tantalum (SMD)
595D, Tantalum (SMD)
94SA, Os-con (Radial)
10 V
10 V
10 V
150 µF
120 µF
100 µF
0.090 Ω
0.140 Ω
0.030 Ω
1100 mA
>1000 mA
2670 mA
7.3L
×6.0W ×4.1H
8×10.5
1
1
1
≤4
≤4
≤2
594D157X0010C2T
595D127X0010D2T
94SA107X0010EBP
Kemet, Ceramic X5R (SMD)
16 V
6.3 V
10
47
0.002 Ω
0.002 Ω
—
1210 case
3225 mm
1
2 [1]
≤5
≤2
C1210C106M4PAC
C1210C476K9PAC
Murata, Ceramic X5R (SMD)
6.3 V
6.3 V
16 V
16 V
100
47
22
10
0.002 Ω
—
1210 case
3225 mm
1
2 [1]
5
1 [2]
≤1
≤2
≤3
≤5
GRM32ER60J107M
GRM32ER60J476M
GRM32ER61C226K
GRM32DR61C106K
TDK, Ceramic X5R (SMD)
6.3 V
6.3 V
16 V
16 V
100
47
22
10
0.002 Ω
—
1210 case
3225 mm
1
2 [1]
5
1 [2]
≤1
≤2
≤3
≤5
C3225X5R0J107MT
C3225X5R0J476MT
C3225X5R1C226MT
C3225X5R1C106MT
AVX, Tantalum
TPS (SMD)
Vendor Number
[1] A total capacitance of 94 µF is acceptable based on the combined ripple current rating.
[2] A ceramic capacitor may be used to complement electrolytic types at the input to further reduce high-frequency ripple current.
For technical support and further information visit http://power.ti.com
Application Notes
PTH03000W
Adjusting the Output Voltage of the PTH03000W
Wide-Output Adjust Power Modules
The Vo Adjust control (pin 4) sets the output voltage of
the PTH03000Wproduct. The adjustment range is
from 0.9 V to 2.5 V. The adjustment method requires
the addition of a single external resistor, Rset, that must
be connected directly between the Vo Adjust and GND
pins 1. Table 2-1 gives the preferred value of the external
resistor for a number of standard voltages, along with the
actual output voltage that this resistance value provides.
For other output voltages the value of the required resistor
can either be calculated using the following formula, or
simply selected from the range of values given in Table 2-2.
Figure 2-1 shows the placement of the required resistor.
Rset
= 10 kΩ ·
0.891 V
Vout – 0.9 V
– 4.99 kΩ
Table 2-1; Preferred Values of Rset for Standard Output Voltages
Vout (Standard)
Rset (Pref’d Value)
2.5 V
2V
1.8 V
1.5 V
1.2 V
1V
0.9 V
576 Ω
3.09 kΩ
4.87 kΩ
9.76 kΩ
24.3 kΩ
82.5 kΩ
Open
Vout (Actual)
2.501V
2.003 V
1.804 V
1.504 V
1.204 V
1.002 V
0.9 V
4
PTH03000W
Inhibit
CIN
100µF
(Required)
3
VO
5
VOUT
GND
1
RSET
0.1 W, 1 %
+
VIN
0.900
0.925
0.950
0.975
1.000
1.025
1.050
1.075
1.100
1.125
1.150
1.175
1.200
1.225
1.250
1.275
1.300
1.325
1.350
1.375
1.400
1.425
1.450
1.475
Rset
Open
351 kΩ
173 kΩ
114 kΩ
84.1 kΩ
66.3 kΩ
54.4 kΩ
45.9 kΩ
39.6 kΩ
34.6 kΩ
30.7 kΩ
27.4 kΩ
24.7 kΩ
22.4 kΩ
20.5 kΩ
18.8 kΩ
17.3 kΩ
16.0 kΩ
14.8 kΩ
13.8 kΩ
12.8 kΩ
12.0 kΩ
11.2 kΩ
10.5 kΩ
Va Req’d
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
2.05
2.10
2.15
2.20
2.25
2.30
2.35
2.40
2.45
2.50
Rset
9.86 kΩ
8.72 kΩ
7.74 kΩ
6.89 kΩ
6.15 kΩ
5.49 kΩ
4.91 kΩ
4.39 kΩ
3.92 kΩ
3.50 kΩ
3.11 kΩ
2.76 kΩ
2.44 kΩ
2.14 kΩ
1.86 kΩ
1.61 kΩ
1.37 kΩ
1.15 kΩ
950 Ω
758 Ω
579 Ω
2. Never connect capacitors from Vo Adjust to either GND or
Vout. Any capacitance added to the Vo Adjust pin will affect
the stability of the regulator.
V O Adj
2
Va Req’d
Notes:
1. Use a 0.1 W resistor. The tolerance should be 1 %,
with a temperature stability of 100 ppm/°C (or better).
Place the resistor as close to the regulator as possible.
Connect the resistor directly between pins 4 and 1
using dedicated PCB traces.
Figure 2-1; Vo Adjust Resistor Placement
VIN
Table 2-2; Output Voltage Set-Point Resistor Values
COUT
100µF
(Optional)
+
Inhibit
GND
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GND
Application Notes
PTH03000 & PTH05000 Series
Power-Up Characteristics
When configured per their standard application, the
PTH03000 and PTH05000 series of power modules will
produce a regulated output voltage following the application of a valid input source voltage. During power up,
internal soft-start circuitry slows the rate that the output
voltage rises, thereby limiting the amount of in-rush
current that can be drawn from the input source. The
soft-start circuitry introduces a short time delay (typically 10 ms) into the power-up characteristic. This is
from the point that a valid input source is recognized.
Figure 3-1 shows the power-up waveforms for a PTH05000W
(5-V input), with the output voltage set point adjusted for a
2-V output. The waveforms were measured with a 5-A
resistive load. The initial rise in input current when the
input voltage first starts to rise is the charge current drawn
by the input capacitors.
Figure 3-1
Vin (2 V/Div)
Output On/Off Inhibit
For applications requiring output voltage on/off control,
the PTH03000W & PTH05000W power modules incorporate an output on/off Inhibit control (pin 3). The
inhibit feature can be used wherever there is a requirement for the output voltage from the regulator to be
turned off.
The power module functions normally when the Inhibit
pin is left open-circuit, providing a regulated output
whenever a valid source voltage is connected to Vin with
respect to GND.
Figure 3-2 shows the typical application of the inhibit
function. Note the discrete transistor (Q1). The Inhibit
control has its own internal pull-up to Vin potential. An
open-collector or open-drain device is recommended to
control this input.
Turning Q1 on applies a low voltage to the Inhibit control
pin and disables the output of the module. If Q1 is then
turned off, the module will execute a soft-start power-up
sequence. A regulated output voltage is produced within
20 msec. Figure 3-3 shows the typical rise in the output voltage, following the turn-off of Q1. The turn off of
Q1 corresponds to the fall in the waveform, Q1 Vgs. The
waveforms were measured with a 5-A resistive load.
Vo (1 V/Div)
Figure 3-2
4
VO Adj
VIN =5 V
2
PTH05000W
Inhibit
+
HORIZ SCALE: 5 ms/Div
Current Limit Protection
The PTHxx000W modules protect against load faults
with a continuous current limit characteristic. Under a
load fault condition the output current cannot exceed
the current limit value. Attempting to draw current that
exceeds the current limit value causes the output voltage
to be progressively reduced. Current is continuously
supplied to the fault until it is removed. Upon removal of
the fault, the output voltage will promptly recover.
Thermal Shutdown
Thermal shutdown protects the module’s internal circuitry
against excessively high temperatures. A rise in temperature may be the result of a drop in airflow, a high ambient
temperature, or a sustained current limit condition. If
the junction temperature of the internal components
exceed 150 °C, the module will shutdown. This reduces
the output voltage to zero. The module will start up
automatically, by initiating a soft-start power up when
the sensed temperature decreases 10 °C below the thermal
shutdown trip point.
For technical support and further information visit http://power.ti.com
VO =2 V
5
VIN
CIN
330 µF
(Required)
Q1
BSS138
3
VO
GND
+
Iin (2 A/Div)
1
COUT
100 µF
(Optional)
4k87
0.1 W, 1 %
Inhibit
GND
GND
Figure 3-3
Vo (1 V/Div)
Q1 Vgs
(10 V/Div)
HORIZ SCALE: 5 ms/Div
L
O
A
D
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