PT3402C [TI]

1-OUTPUT 30W DC-DC REG PWR SUPPLY MODULE, SMD-14;


型号：	PT3402C
厂家：	TEXAS INSTRUMENTS
描述：	1-OUTPUT 30W DC-DC REG PWR SUPPLY MODULE, SMD-14 输出元件
文件：	总14页 (文件大小：320K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

PT3400 Series

35-W 48-V Input Isolated

DC/DC Converter

SLTS164B - JULY 2002 - REVISED OCTOBER 2002

Features

• Input Voltage Range:

36V to 75V

• Differential Remote Sense

• Over-Current Protection

• Space Saving Package

• Solderable Copper Case

• Safety Approvals Pending

• 35W Output Power

• 90% Efficiency

• 1500 VDC Isolation

• Low Profile (8 mm)

• Adjustable Output Voltage

• Dual-Logic On/Off Enable

• Power-Up Sequence Control

Description

Ordering Information

Pin-Out Information

Pin Function

PT3401r = 3.3V/10A (33W)

PT3402r = 2.5V/12A (30W)

The PT3400 Excalibur™ power modules

are a series of 35-W rated DC/DC converters

housed in a low-profile space-saving copper

case. Fully isolated for telecom applications,

the series includes a number of standard volt-

ages, including 1.0 VDC. Other applications

include industrial, high-end computing, and

other distributed power applications that

require input-to-output isolation.

PT3400 modules incorporate a feature

that simplifies the design of multiple voltage

power supplies in DSP and ASIC applications.

Using the SEQ control pin, the output voltage

of two PT3400 modules in a power supply

system can be made to self sequence at power-

up. Other features include output voltage

adjust, over-current protection, input under-

voltage lockout, and a differential remote

sense to compensate for any voltage drop

between the converter and load.

EN 1

EN 2*

–V_in

PT3403r = 1.8V/12A (21.6W)

PT3404r = 1.5V/16A (24W)

PT3405r = 1.4V/16A (22.4W)

PT3406r = 1.2V/16A (19.2W)

PT3407r = 1V/16A (16W)

+V_in

SEQ

PT3408r = 5V/7A

(35W)

V_outAdj

–V_sense

–V_out

PT Series Suffix

(PT1234x)

Case/Pin

Order

Package

10 –V_out

11 +V_out

12 +V_out

13 +V_out

14 +V_sense

Configuration

Suffix

Code

Vertical

Horizontal

SMD

(EPL)

(EPM)

(EPN)

(Reference the applicable package code draw-

ing for the dimensions and PC board layout)

* Negative logic

Shaded functions indicate those

pins that are referenced to –V_in

Standard Application

Remote Sense (+)

+V_OUT

+V_IN

+V_SENSE

+V_IN

11–13

+V_OUT

EN 1

† C_OUT

330µF

PT3400

EN 2

–V_IN

–V_OUT

8–10

–V_OUT

–V_IN

* Remote Sense (–)

–V_SENSE

V_oAdj

SEQ

†

An output capacitor is required on models

with an output voltage less than 2.5V.

V_OAdj

SEQ

–V_sense(pin 7) must be connected to -V_out

either at the load or directly to pin 8 of the

converter.

For technical support and more information, see inside back cover or visit www.ti.com

PT3400 Series

35-W 48-V Input Isolated

DC/DC Converter

SLTS164B - JULY 2002 - REVISED OCTOBER 2002

Specifications (Unless otherwise stated, T_a=25°C, V_in=48V, C_in=0µF, I_o=I_omax, and C_outas required)

PT3400 Series

Characteristic

Symbol

Conditions

Min

Typ

Max

Units

Output Current

I_o

Over V_inrange

V_o≤1.5V

V_o= 1.8V/2.5V

V_o=3.3V

—

V_o= 5V

Input Voltage Range

Set Point Voltage Tolerance

Temperature Variation

Line Regulation

V_in

Over I_oRange

—

0.8

VDC

%V_o

V_otol

Reg_temp

Reg_line

–40° ≤T_a≤ +85°C, I_o=I_omin

Over V_inrange

—

V_o=5.0V

V_o≤3.3V

V_o=5.0V

V_o≤3.3V

(1)

Load Regulation

Reg_load

Over I_orange

Total Output Voltage Variation

Efficiency

∆V_otot

Includes set-point, line, load,

—

%V_o

–40° ≤T_a≤ +85°C

I_o=70% of I_omax

V_o= 5V

V_o=3.3V

V_o=2.5V

V_o=1.8V

V_o=1.5V

V_o=1.4V

V_o=1.2V

V_o= 1V

—

V_oRipple (pk-pk)

V_r

20MHz bandwidth

V_o≥3.3V

V_o≤2.5V

—

mV_pp

Transient Response

t_tr

∆V_tr

V_adj

0.1A/µs load step, 50% to 75% I_omax

V_oover/undershoot

—

–5

–0

100

—

µs

%V_o

Output Adjust

V_o≥2.5V

V_o≤1.8V

%V_o

+10

Over-Current Threshold

I_TRIP

V_in=36V

V_o=5.0V

V_o=3.3V

—

12.5

V_o= 2.5V/1.8V

V_o≤1.5V

Switching

Under-Voltage Lockout

Frequencyƒ_s

Over V_inrange

250

—

300

350

—

kHz

UVLO

Rising

Falling

Enable On/Off (Pins 1, 2)

Input High Voltage

Referenced to –V_in(pin 3)

(2)

V_IH

V_IL

—

Open

+0.4

Input Low Voltage

–0.3

Input Low Current

I_IL

I_in

C_in

C_out

—

0.5

—

TBD

µF

Standby Input Current

Internal Input Capacitance

External Output Capacitance

standbypins

connected

—

1.0

(3)

V_o=1.0V

V_o≤1.8V

V_o≥2.5V

470

330

—

µF

Isolation Voltage

Capacitance

Resistance

Input–output/input–case

Input to output

1500

—

1500

—

MΩ

Input to output

(4)

(5)

Operating Temperature Range

Solder Reflow Temperature

Storage Temperature

T_reflow

Over V_inrange

Surface temperature of module pins or case

—

–40

—

–40

—

°C

(6)

215

125

ReliabilityMTBF

Mechanical Shock

Mechanical Vibration

Per

Bellcore

TR-332

2.8

—

10 Hrs

50% stress, T_a=40°C, ground benign

—

Per Mil-Std-883D, method 2002.3,

1mS, half-sine, mounted to a fixture

Mil-Std-883D, Method 2007.2,

20-2000Hz, PCB mounted

—

TBD

—

G’s

(7)

Vertical

Horizontal

—

TBD

—

G’s

Weight

—

grams

Flammability—

Materials

meet

94V-0

Notes: (1) If the remote sense feature is not being used, –V_sense(pin 7) must be connected to –V_out(pin 8).

(2) The On/Off Enable inputs (pins 1 & 2) have internal pull-ups. They may either be connected to –V_inor left open circuit. Leaving pin 1 open-circuit and

connecting pin 2 to –V_inallows the the converter to operate when input power is applied. The maximum open-circuit voltage of the Enable pins is 10V.

(3) An output capacitor is required for proper operation for all models in which the output voltage is 1.8VDC or less. For models with an output voltage of

2.5V or higher an output capacitor is optional.

(4) For operation below 0°C, Cout must have stable characteristics. Use low ESR tantalum capacitors, or capacitors with a polymer type dielectric.

(5) See Safe Operating Area curves or contact the factory for the appropriate derating.

(6) During reflow of SMD package version do not elevate the module case, pins, or internal component temperatures above a peak of 215°C. For further

guidance refer to the application note, “Reflow Soldering Requirements for Plug-in Surface Mount Products,” (SLTA051).

(7) The case pins on through-hole pin configurations (N & A) must be soldered. For more information see the applicable package outline drawing.

For technical support and more information, see inside back cover or visit www.ti.com

Typical Characteristics

PT3400 Series

35-W 48-V Input Isolated

DC/DC Converter

SLTS164B - JULY 2002 - REVISED OCTOBER 2002

PT3408, 5VDC (See Note A)

PT3401, 3.3 VDC (See Note A)

PT3402, 2.5 VDC (See Note A)

Efficiency vs Output Current

100

V_IN

36.0V

48.0V

60.0V

75.0V

36.0V

48.0V

60.0V

75.0V

36.0V

48.0V

60.0V

75.0V

Iout (A)

Ripple vs Output Current

V_IN

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

Iout (A)

Power Dissipation vs Output Current

V_IN

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

Iout (A)

Safe Operating Area (See Note B)

PT3408; V_IN=60V

Safe Operating Area (See Note B)

PT3401; V_IN=60V

Safe Operating Area (See Note B)

PT3402; V_IN=60V

Airflow

200LFM

120LFM

60LFM

200LFM

120LFM

60LFM

200LFM

120LFM

60LFM

Nat conv

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

For technical support and more information, see inside back cover or visit www.ti.com

Typical Characteristics

PT3400 Series

35-W 48-V Input Isolated

DC/DC Converter

SLTS164B - JULY 2002 - REVISED OCTOBER 2002

PT3403, 1.8 VDC (See Note A)

PT3404/5, 1.5/1.4 VDC (See Note A)

PT3406, 1.2 VDC (See Note A)

Efficiency vs Output Current

100

V_IN

36.0V

48.0V

60.0V

75.0V

36.0V

48.0V

60.0V

75.0V

36.0V

48.0V

60.0V

75.0V

Iout (A)

Ripple vs Output Current

V_IN

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

Iout (A)

Power Dissipation vs Output Current

V_IN

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

75.0V

60.0V

48.0V

36.0V

Iout (A)

Safe Operating Area (See Note B)

PT3403; V_IN=60V

Safe Operating Area (See Note B)

PT3404; V_IN=60V

Safe Operating Area (See Note B)

PT3406; V_IN=60V

Airflow

200LFM

120LFM

60LFM

200LFM

120LFM

60LFM

200LFM

120LFM

60LFM

Nat conv

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

For technical support and more information, see inside back cover or visit www.ti.com

Typical Characteristics

PT3400 Series

35-W 48-V Input Isolated

DC/DC Converter

SLTS164B - JULY 2002 - REVISED OCTOBER 2002

PT3407, 1.0 VDC (See Note A)

Efficiency vs Output Current

100

V_IN

36V

48V

60V

75V

Iout (A)

Ripple vs Output Current

V_IN

75V

60V

48V

36V

Iout (A)

Power Dissipation vs Output Current

V_IN

75V

60V

48V

36V

Iout (A)

Safe Operating Area (See Note B)

PT3406; V_IN=60V

Airflow

200LFM

120LFM

60LFM

Nat conv

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

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Operating Features of the PT3400 Series

of Isolated DC/DC Converters

Under-Voltage Lockout

An Under-Voltage Lock-Out (UVLO) inhibits the opera-

tion of the converter until the input voltage is above the

UVLO threshold (see the data sheet specification). Below

this voltage, the module’s output is held off, irrespective

of the state of either the EN1 & EN2 enable controls.

The UVLO allows the module to produce a clean transi-

tion during both power-up and power-down, even when

the input voltage is rising or falling slowly. It also reduces

the 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 threshold includes about 1V of hysteresis.

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 5A, is

recommended. Active current limiting can be imple-

mented 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 converter specifica-

tions). The recommended direction for airflow is into the

longest side of the module’s metal case. See Figure 1-1.

If EN2 (pin 2) is connected to -V_in(pin 3) and EN1 (pin 1)

is left open, the module will automatically power up when

the input voltage rises above the UVLO threshold (see

data sheet ‘Standard Application’ schematic). Once

operational, the converter will conform to its operating

specifications when the minimum specified input voltage

is reached.

Figure 1-1

Over-Current Protection

To protect against load faults, the PT3400 series incor-

porates output over-current protection. Applying a load

that exceeds the converter’s over-current threshold (see

applicable specification) will cause the regulated output

to shut down. Following shutdown the module will peri-

odically 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 succesive shutdown and power up until the load

fault is removed. Once the fault is removed, the converter

then automatically recovers and returns to normal op-

eration.

Recommended direction for airflow is

into (perpendicular to) the longest side

Primary-Secondary Isolation

Electrical isolation is provided between the input termi-

nals (primary) and the output terminals (secondary). All

converters are production tested to a primary-secondary

withstand voltage of 1500VDC. This specification com-

plies with UL60950 and EN60950 and the requirements

for operational isolation. Operational isolation allows these

converters to be configured for either a positive or negative

input voltage source. The data sheet ‘Pin-Out Information’

uses shading to indicate which pins are associated with the

primary. They include pins 1 through 4, inclusive.

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Adjusting the Output Voltage of the 30W-Rated

PT3400 Series of Isolated DC/DC Converters

The output voltage of the PT3400 Excalibur™ series of

isolated DC/DC converters may be adjusted over a limited

range from the factory-trimmed nominal value. Adjust-

ment is accomplished with a single external resistor. The

placement the resistor determines the direction of adjust-

ment, either up or down, and the value of the resistor the

magnitude of adjustment. Table 3-1 gives the allowable

adjustment range for each model in the series as V_a(min)

and V_a(max) respectively. Note that converters with an

Notes:

1. The output voltage of the PT3401 (3.3V),

PT3402 (2.5V), and PT3408 (5V) may be adjusted either

higher or lower. All other models, which have an output

voltage of 1.8V or less, can only be adjusted higher.

2. Use only a single 1% resistor in either the R₁or (R₂)

location. Place the resistor as close to the converter as

possible.

output voltage of 1.8V or less can only be adjusted up .

3. Never connect capacitors to V_oAdj. Any capacitance added

Adjust Up: An increase in the output voltage is obtained

by adding a resistor, R₁between V_oAdj (pin 6), and –V_sense

(pin 7).

to this pin will affect the stability of the converter.

4. If the output voltage is increased, the maximum load

current must be derated according to the following

equation.

Adjust Down (PT3401, PT3402, & PT3408 Only): Add a

resistor (R₂), between V_oAdj (pin 6) and +V_sense(pin 14).

V_o× I_o(rated)

I_o(max)

V_a

Refer to Figure 3-1 and Table 3-2 for both the placement and

value of the required resistor, R₁or (R₂).

In any instance, the load current must not exceed the

converter’s rated output current I_o(rated) in Table 3-1.

The values of R₁[adjust up], and (R₂) [adjust down], can

also be calculated using the following formulas.

2 · R_o

V_a– V_o

R₁

– R_s

kΩ

(R₂)

R_o(V_a– 2)

V_o– V_a

– R_s

Where, V_a= Adjusted output voltage

V_o= Original output voltage

R_o= Resistor constant in Table 3-1

R_s= Internal series resistance in Table 3-1

Figure 3-1

Remote Sense (+)

+V_OUT

+V_SENSE

+V_IN

11–13

+V_OUT

(R₂)

Adj Down

EN 1

EN 2

–V_IN

† C_OUT

330µF

PT3400

R ₁

Adjust Up

–V_IN

–V_OUT

8–10

–V_OUT

* Remote Sense (–)

–V_SENSE

SEQ

V_oAdj

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes continued

PT3400 Series

Table 3-1

DC/DC CONVERTER ADJUSTMENT RANGE AND FORMULA PARAMETERS

Series Pt #

I_o(rated) ⁴

PT3408

PT3401

10A

PT3402

12A

PT3403

12A

PT3404

16A

PT3405

16A

PT3406

16A

PT3407

16A

V_o(nom)

V_a(min)

V_a(max)

R_o(kΩ)

R_s(kΩ)

3.3V

2.5V

1.8V

N/A

1.98V

6.49

66.5

1.5V

N/A

1.65V

7.5

100.0

1.4V

N/A

1.54V

7.5

100.0

1.2V

N/A

1.32V

7.5

100.0

1.0V

N/A

1.2V

7.5

66.5

4.75V

5.25V

8.87

66.5

3.135V

3.465V

9.76

2.375V

2.625V

10.0

66.5

29.4

Table 3-2

DC/DC CONVERTER ADJUSTMENT RESISTOR VALUES

Series Pt #

PT3408

PT3401

PT3402

PT3403

PT3404

PT3405

PT3406

PT3407

V_o(nom)

3.3V

2.5V

1.8V

1.5V

1.4V

1.2V

1.0V

V_a(req’d)

1.975

1.950

1.925

1.900

1.875

1.850

1.825

1.800

7.7kΩ

20.0kΩ

37.3kΩ

5.25

5.20

5.15

5.10

5.05

5.00

4.95

4.90

4.85

4.80

4.75

4.5kΩ

22.2kΩ

51.8kΩ

111.0kΩ

288.0kΩ

63.3kΩ

107.0kΩ

193.0kΩ

453.0kΩ

(457.0)kΩ

(191.0)kΩ

(102.0)kΩ

(57.7)kΩ

(31.1)kΩ

1.650

1.625

1.600

1.575

1.550

1.525

1.500

1.475

1.450

1.425

1.400

0.0kΩ

20.0kΩ

50.0kΩ

100.0kΩ

200.0kΩ

500.0kΩ

3.465

3.432

3.399

3.366

3.333

3.330

3.267

3.234

3.201

3.168

3.135

51.8kΩ

81.4kΩ

131.0kΩ

229.0kΩ

525.0kΩ

20.0kΩ

50.0kΩ

100.0kΩ

200.0kΩ

500.0kΩ

(308.0)kΩ

(116.0)kΩ

(51.9)kΩ

(19.9)kΩ

(0.0)kΩ

1.32

1.30

1.28

1.26

1.24

1.22

1.20

1.15

1.10

1.08

1.06

1.04

1.02

1.00

25.0kΩ

50.0kΩ

87.5kΩ

150.0kΩ

275.0kΩ

650.0kΩ

2.625

2.600

2.575

2.550

2.525

2.500

2.475

2.450

2.425

2.400

2.375

131.0kΩ

171.0kΩ

237.0kΩ

371.0kΩ

771.0kΩ

8.5kΩ

33.5kΩ

83.5kΩ

121.0kΩ

184.0kΩ

309.0kΩ

683.0kΩ

(161.0)kΩ

(60.6)kΩ

(27.3)kΩ

(10.6)kΩ

(0.0)kΩ

R₁= Black

R₂= (Blue)

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Using the On/Off Enable Controls on the

PT3400 Series of DC/DC Converters

Negative Output Enable (Positive Inhibit)

To configure the converter for a negative enable function,

EN1 is left open circuit, and the system On/Off control

signal is applied to EN2. Applying less than 0.8V (with

respect to -V_in) to EN2, enables the converter outputs. An

example of this configuration is provided in Figure 2-2.

Note: The converter will only produce an output voltage if a

valid input voltage is applied to V_in.

The PT3400 series of DC/DC converters incorporate

two output enable controls. EN1 (pin 1) is the ‘positive

enable’ input, and EN2 (pin 2) is the ‘negative enable’

input. Both inputs are electrically referenced to -V_in

(pin 3), at the input or primary side of the converter.

The enable pins are ideally controlled with an open-

collector (or open-drain) discrete transistor. A pull-up

resistor is not required. If a pull-up resistor is added, the

pull-up voltage must be limited to 15V. The logic truth

table for EN1 and EN2 is given in Table 2-1, below.

Figure 2-2; Negative Enable Configuration

DC/DC

Module

Table 2-1; On/Off Enable Logic

EN 1

EN1 (pin 1)

EN2 (pin 2)

Output Status

EN 2

BSS138

Off

1 =Outputs On

–V_IN

–Vin

Logic ‘0’ = –Vin (pin 3) potential

Logic ‘1’ = Open Circuit

On/Off Enable Turn-On Time

Automatic (UVLO) Power-Up

The total turn-on time of the module is the combination

of a short delay period, followed by the time it takes the

output voltage to rise to full regulation. When the con-

verter is enabled from the EN1 or EN2 control inputs, the

turn-on delay time (measured from the transition of the

enable signal to the instance the outputs begin to rise)

is typically 50 milliseconds. By comparison, the rise time

of the output voltage is relatively short, and is between 1

and 2 milliseconds. The rise time varies with input voltage,

output load current, output capacitance, and the SEQ pin

function. Figure 2-3 shows the power-up response of a

PT3401 (3.3V), following the removal of the ground

signal at EN1 in Figure 2-1.

Connecting EN2 to -V_inand leaving EN1 open-circuit

configures the converter for automatic power up (see data

sheet ‘Standard Application’). The converter control

circuitry incorporates an ‘under-voltage lockout’ (UVLO),

which disables the converter until a minimum input

voltage is present at

V_in(see data sheet specifications).

The UVLO ensures a clean transition during power up

and power down, allowing the converter to tolerate a

slowly rising input voltage. For most applications EN1

and EN2, can be configured for automatic power-up.

Positive Output Enable (Negative Inhibit)

To configure the converter for a positive enable function,

connect EN2 to -V_in, and apply the system On/Off control

signal to EN1. In this configuration, applying less than

0.8V (with respect to -V_in) to EN1 disables the converter

outputs. Figure 2-1 is an example of this implemention.

Figure 2-3; PT3401 Enable Turn-On

Vo (2V/Div)

Figure 2-1; Positive Enable Configuration

DC/DC

Module

(5V/Div)

EN1

EN 1

EN 2

BSS138

Delay Time

1 =Outputs Off

–V_IN

HORIZ SCALE: 5ms/DIV

–Vin

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Table 4-1; PT3400 Module Type Identification

Using the Power-Up Sequencing Feature of the

PT3400 Series of DC/DC Converters

PART No.

PT3401

PT3402

PT3403

PT3404

PT3405

PT3406

PT3407

VOUT

TYPE A

TYPE B

(3.3V)

(2.5V)

(1.8V)

(1.5V)

(1.4V)

(1.2V)

(1.0V)

Introduction

Power-up sequencing is a term used to describe the

order and timing that supply voltages power up in a

multi-voltage power supply system. Multi-voltage power

supply architectures are a common place requirement in

electronic circuits that employ high-performance mi-

croprocessors or digital signal processors (DSPs). These

circuits require a tightly regulated low-voltage supply

for the processor core, and a higher voltage to power

the processor’s system interface or I/O circuitry. Power-

up sequencing is often required between two such voltages

in order to manage the voltage differential during the brief

period of power-up. This reduces stress and improves the

long term reliability of the dual-voltage devices and their

associated circuitry. The most popular solution is termed

“Simultaneous Startup,” whereby the two affected voltages

both start at the same time and then rise at the same rate.

Table 4-2; Value of C₃in Sequencing Setup

MODULE #1 MODULE #2

C₃

COMMENTS

Wire link

Waveforms given in Figure 4-2

Waveforms given in Figure 4-3

Waveforms given in Figure 4-4

(5)

0.1µF

Notes

1. The two converters configured for sequenced power up

must be located close together on the same printed circuit

board.

Configuration for Power-up Sequencing

The PT3400 series converters have a feature that allows

individual modules to be easily configured for simulta-

neous startup. Using the SEQ control (pin 5), two PT3400

modules are simply interconnected with just a few passive

components. This eliminates much of the application

circuitry that would otherwise be required for this type of

setup. The schematic is given in Figure 4-1. The setup is

relatively simple but varies slightly with the combination

2. When configured for power-up sequencing, a minimum

of 1,000µF output capacitance is recommended at the

output of each converter.

3. The best results are obtained if a load of 1A or greater is

present at both converter outputs.

4. The capacitors, C₁and C₂, should each be placed close to

their associated converter, Module #1, and Module #2

respectively. Combining C₁and C₂to a single capacitor of

equivalent value is not recommended.

(5)

of output voltages being sequenced. Capacitor C₃is only

required when the modules selected are a mix between

a high-voltage module (3.3V through 1.8V), and a low-

voltage module (≤1.5V). For all other configurations

C₃is replaced by a wire link. For clarification Table 4-1

indicates which modules are a high voltage type (Type A),

and which are a low voltage type (Type B). Table 4-2

provides guidance as to the one combination that requires

the capacitor C₃. Examples of waveforms obtained from a

sequenced start-up between two PT3400 series modules

are provided in Figure 4-2, Figure 4-3, and Figure 4-4.

In each case the voltage difference during the synchronized

portion of the power up sequence is typically within 0.4V.

Both the timing and tracking of output voltages during

the power-up sequence will vary slightly with input voltage,

temperature, and with differences in the output capaci-

tance and load current between the two converter modules.

5. The capacitor C₃is only required whenever a Type A and

Type B converter are connected together for sequenced

power-up. In this event C₃should always be connected to

the SEQ control (pin 5) of the Type B module, or the

converter with the lowest output voltage. For all other

converter configurations C₃is not required, and is

replaced by a copper trace or wire link.

6. The capacitors selected for C₁, C₂, & C₃should be of

good quality and have stable characteristics. Capacitors

with an X7R dielectric, and 5% tolerance are

recommended.

7. The enable controls, EN1 & EN2, are optional for a

sequenced pair of converters. If an enable signal is desired,

EN1 or EN2 of both converters units must be controlled

from a single transistor.

This power-up sequencing solution may not be suitable

for every application. To ensure compatibility the appli-

cation should be tested against all variances. For additional

support please contact a Plug-in Power applications

specialist.

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Figure 4-1; Configuration for Power-Up Sequencing

Module #1

(Highest V_o)

+V_IN

Remote Sense (+)

+V_IN

+Sense

Vo₁

11–13

+V_OUT

EN 1

EN 2

† C_OUT

1,000µF

LOAD

8–10

–V_IN

–V_OUT

–V_IN

Remote Sense (–)

–Sense

SEQ

V_oAdj

C₁

0.1µF

(Note 4)

Module #2

(Lowest V _o)

Remote Sense (+)

+V_IN

+Sense

Vo₂

11–13

+V_OUT

Q₁

BSS138

(Note 8)

EN 1

EN 2

† C_OUT

1,000µF

LOAD

1 =Inhibit

8–10

–V_OUT

–V_IN

Remote Sense (–)

–Sense

SEQ

V_oAdj

C₃

†

For sequencing configurations, a 1,000µF

electrolytic capacitor is recommended at

the output of each converter. See Note 2.

(Note 5 &

Table 4-2)

C₂

0.1µF

(Note 4)

For technical support and more information, see inside back cover or visit www.ti.com

Application Notes

PT3400 Series

Figure 4-3; Power-Up Sequence Example with Two Type ‘A’ Modules

The adjacent plot shows an example of power-

up sequencing between two Type ‘A’ modules.

In this example the PT3401 (3.3V) and PT3402

(2.5V) are featured. Each converter had a con-

stant current load of 5A applied to its respective

output.

Vo1 (1V/Div)

Vo2 (1V/Div)

HORIZ SCALE: 5ms/Div

Figure 4-2; Power-Up Sequence Example with Two Type ‘B’ Modules

The adjacent plot shows an example of power-

up sequencing between two Type ‘B’ modules.

In this example the PT3405 (1.4V) and PT3406

(1.2V) are featured. Each converter had a con-

stant current load of 5A applied to its respective

output.

Vo1 (0.5V/Div)

Vo2 (0.5V/Div)

HORIZ SCALE: 5ms/Div

Figure 4-4; Power-Up Sequence Example Using Type ‘A’ & ‘B’ Modules

The adjacent plot shows an example of power-

up sequencing between a Type ‘A’ and a Type

‘B’ module. In this example the PT3401 (3.3V)

and PT3405 (1.4V) are featured. Each converter

had a constant current load of 5A applied to its

respective output.

Vo1 (1V/Div)

Vo2 (1V/Div)

HORIZ SCALE: 5ms/Div

For technical support and more information, see inside back cover or visit www.ti.com

PACKAGE OPTION ADDENDUM

www.ti.com

10-Jan-2013

PACKAGING INFORMATION

Orderable Device

Status Package Type Package Pins Package Qty

Eco Plan Lead/Ball Finish

MSL Peak Temp

Samples

Drawing

(1)

(2)

(3)

(Requires Login)

PT3401A

PT3404A

PT3405A

PT3408C

LIFEBUY SIP MODULE

OBSOLETE SIP MODULE

LIFEBUY SIP MODULE

EPM

EPN

TBD

Call TI

Level-1-215C-UNLIM

Call TI

Level-3-215C-168HRS

⁽¹⁾The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

⁽²⁾Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

⁽³⁾MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

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In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 1

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PT3402C [TI]

相关型号：

PT3402N

PT3403

PT3403C

PT3403N

PT3404

PT3404A

PT3404C

PT3404N

PT3405

PT3406

PT3406C

PT3407