PT7748C [TI]

SWITCHING REGULATOR, SMA27;


型号：	PT7748C
厂家：	TEXAS INSTRUMENTS
描述：	SWITCHING REGULATOR, SMA27 开关
文件：	总8页 (文件大小：155K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

— Not Recommended for New Designs —

PT7720 Series

17A, 12-V Input “Big-Hammer II”

Programmable ISR

SLTS048B

(Revised 5/21/2002)

Features

• +12V Bus Input

• 5-bit Programmable:

1.3V to 3.5V or

4.5V to 7.6V

• High Efficiency

• Differential Remote Sense

• 27-pin SIP Package

• Parallelable with PT7748

17A current booster

Pin-Out Information

Pin Function

Ordering Information

Description

The PT7720 series is a +12-V input,

17-A output, high-performance Integrated

Switching Regulator (ISR), housed in a

27-pin SIP package. The 17A capability

allows easy integration of the latest high-

speed, low-voltage microprocessors and

bus drivers into +12V power systems.

The output voltage is programmable

using a 5-bit code. The output voltage

range and code for the PT7721 is com-

patible with Intel’s Pentium II processor.

The PT7720 series has been designed

to work in parallel with one or more of

the PT7748 current boosters, allowing

the output load current capacity to be

increased in increments of 17A.

Pin Function

15 GND

16 GND

17 GND

18 GND

19 GND

20 Vout

21 Vout

22 Vout

23 Vout

24 Vout

PT 7721r = 1.3 to 3.5 Volts

PT 7722r = 4.5 to 7.6 Volts

PT 7748r = 17-A Booster

VID0

VID1

VID2

VID3

STBY #

VID4

Vin

PT Series Suffix

(PT1234x)

Vin

Case/Pin

O rder

Package

Configuration Suffix

Code *

10 Vin

11 Vin

12 Sense Gnd

13 GND

14 GND

Vertical

Horizontal

SMD

(EJE)

(EJF)

(EJG)

25 Vout

26 Sense Vout

27 Sync Out

* Previously known as package styles 1000/

1010. (Reference the applicable package code

drawing for the dimensions and PC board

layout)

For further information, see application

notes.

A differential remote sense is provided

to compensate for voltage drop between

the ISR to the load. A 1200µF of output

capacitance is required for proper operation.

Standard Application

PROGRAMMING PINS

VID0

VID1

VID2

VID3

VID4

REMOTE SENSE (+)

V_IN

V_OUT

7 - 11

20 - 25

PT7720

1µH

13 - 19

C_IN

C_OUT

LOAD

SYNC OUT

GND

STBY*

REMOTE SENSE (-)

= Required 560µF electrolytic

(See input filter note)

= Required 1200µF electrolytic

= Optional 1µH input choke

out

L₁

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

PT7720 Series

17 A, 12-V Input “Big-Hammer II”

Programmable ISR

Programming Information

PT7721

PT7722

VID4=1

Vout

VID4=0

VID4=1 VID4=0

VID3 VID2 VID1 VID0

Vout

2.0V

2.1V

2.2V

2.3V

2.4V

2.5V

2.6V

2.7V

2.8V

2.9V

3.0V

3.1V

3.2V

3.3V

3.4V

3.5V

1.30V

4.5V

6.1V

1.35V

1.40V

1.45V

1.50V

1.55V

1.60V

1.65V

1.70V

1.75V

1.80V

1.85V

1.90V

1.95V

2.00V

2.05V

4.6V

4.7V

4.8V

4.9V

5.0V

5.1V

5.2V

5.3V

5.4V

5.5V

5.6V

5.7V

5.8V

5.9V

6.0V

6.2V

6.3V

6.4V

6.5V

6.6V

6.7V

6.8V

6.9V

7.0V

7.1V

7.2V

7.3V

7.4V

7.5V

7.6V

Logic 0 = Pin 12 potential (remote sense gnd)

Logic 1 = Open circuit (no pull-up resistors)

VID3 and VID4 may not be changed while the unit is operating.

Specifications (Unless otherwise stated, T_a=25°C, V_in=12V, C_in=560µF, C_out=1200µF, and I_o=I_omax)

PT7720 SERIES

Typ

Characteristics

Symbols

Conditions

Min

Max

Units

(1)

(2)

Output Current

I^o

Ta = +60°C, 200 LFM, pkg N,

Ta = +25°C, natural convection,

Vo ≤5V

0.1

—

0.1

Output Power

Ta = +60°C, 200 LFM, pkg N,

Ta = +25°C, natural convection,

Vo ≥5V

—

Input Voltage Range

Vin

0.1A ≤ Io ≤ 17A

11.0

—

14.0

Output Voltage Tolerance

∆V^o

0°C ≤ Ta ≤ +60°C

(PT7721)

(PT7722)

Vo–0.03

—

Vo+0.03

%Vo

Line Regulation

Load Regulation

V^oRipple/Noise

Regline

Regload

11V ≤ Vin ≤ 14V (with remote sense)

0.1 ≤ Io ≤ 17A (with remote sense)

—

(PT7721)

(PT7722)

—

mVpp

100

Transient Response

with Cout = 1200µF

t^tr

Io step between 7.5A and 15A

Vo over/undershoot

—

100

200

—

µSec

Vos

Efficiency

I^o= 10A

Vo =5.0V

V^o= 3.3V

V^o= 2.5V

Vo = 1.5V

—

Switching Frequency

ƒ_s

11V ≤ Vin ≤ 14V

0.1A ≤ Io ≤ 17A

300

350

400

kHz

(3)

Operating Temperature Range

Storage Temperature

Mechanical Shock

—

+85

°C

-40

+125

Per Mil-STD-883D, Method 2002.3 , 1 msec,

Half Sine, mounted to a fixture

—

TBD

—

G’s

Mechanical Vibration

Weight

Per Mil-STD-883D, Method 2007.2,

20-2000 Hz, Soldered in a PC board

—

TBD

—

G’s

—

Vertical

—

grams

Horizontal

Notes: (1) The ISR will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.

(2) The PT7720 series can be easily paralleled with one or more of the PT7748 Current Boosters to provide increased output current in increments of 17A.

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

Output Capacitors: The PT7720 series requires a minimum output capacitance of 1200µF for proper operation. Do not use Oscon type capacitors. The maximum allow-

able output capacitance is (57,000 ÷ Vout)µF, or 15,000µF, whichever is less.

Input Filter: An input inductor is optional for most applications. The input inductor must be sized to handle 7ADC with a typical value of 1µH. The input capacitance

must be rated for a minimum of 4 Arms of ripple current when operated at maximum output current and maximum output voltage. Contact an applications specialist

for input capacitor selection for applications at other output voltages and output currents.

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

Typical Characteristics

PT7720 Series

17 A, 12-V Input “Big-Hammer II”

Programmable ISR

PT7721/PT7722 @V_in=12V (See Note A)

Safe Operating Area, Vin=+12V (See Note B)

PT7721, Vout=+3.3V, Pkg N)

Efficiency vs Output Current

100

V_out

Airflow

200LFM

5.0V

3.3V

2.5V

1.5V

120LFM

60LFM

Nat conv

10 12 14 16 18 20

Output Current (A)

Output Ripple vs Output Current

PT7722, Vout=+5.0V, Pkg N)

V_out

Airflow

200LFM

120LFM

60LFM

5.0V

3.3V

2.5V

1.5V

Nat conv

10 12 14 16 18 20

Output Current (A)

Power Dissipation vs Output Current

V_out

5.0V

3.3V

2.5V

1.5V

10 12 14 16 18 20

Output Current (Amps)

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

PT7721/22, PT7748

Using the PT7748 17-A Current Booster

with the PT7720 Series Programmable ISRs

the respective input/output filter notes in the PT7720

product data sheet.

The PT7748 is a 17-A “Current Booster” module

for the PT7720 series of regulators. The booster is

controlled directly by the regulator, and effectively

adds a parallel output stage. This allows the system

to run sychronously, providing a low noise solution.

Up to four booster modules can be connected to a

single regulator. Each booster increases the available

output current by 17A. Combinations of a regulator

and booster modules can supply power for virtually

any multi-processor application.

2. The 1-µH filter choke located at the input of each

regulator and booster module (L_in) is optional for most

applications. If specified, each inductor must be sized

to handle 7ADC at full output load.

3. The pin-out of the current booster modules include a

number pins identified, “No Connect” (see Table 1).

These pins are not connected internally to the module

but must be soldered to a pad to preserve the unit’s

mechanical integrity.

A current booster is not a stand-alone product, and

can only operate with a regulator. It is housed in

the same package as its compatible regulator, and

shares the same mechanical outline. Except for an

increase in output current, the overall performance

of a PT7720 regulator/booster combination is identi-

cal to that of a stand-alone regulator. Refer to the

appropriate data sheet for the performance speci-

fications.

4. A similar PCB footprint and trace layout between the

regulator and each booster will facilitate current sharing

between all modules.

Table 1-1; PT7748 Pin-Out Information

Pin Function

10 V_in

11 V_in

12 No Connect

13 GND

14 GND

15 GND

16 GND

17 GND

18 GND

Pin Function

19 GND

20 V_out

No Connect

V_in

21 V_out

Notes:

22 V_out

23 V_out

1. Each booster requires the same amount of input and

output capacitance as recommended for a stand-alone

regulator. See the Standard Application schematic and

24 V_out

25 V_out

V_in

26 No Connect

27 Sync In

Figure 1-1; Current Booster Application Schematic

PROGRAMMING PINS

VID0

VID1

VID2

VID3

VID4

REMOTE SENSE (+)

Lin

V_IN

V_OUT

7 - 11

20 - 25

PT7720

1µH

13 - 19

C_IN

C_OUT

LOAD

STBY*

GND

REMOTE SENSE (-)

Lin

7 - 11

20 - 25

PT7748

1µH

13 - 19

C_OUT

C_IN

To Additional

Boosters

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

Application Notes

PT7720 Series

Pin-Coded Output Voltage Adjustment on the

“Big Hammer II” Series ISRs

ground (pins 13-19) can also be used for programming,

doing so will degrade the load reglation of the product.

4. If active devices are used to ground the voltage control

pins, low-level open drain MOSFET devices should be

used over bipolar transistors. The inherent V_ce(sat) in

bipolar devices introduces errors in the device’s internal

divider network. Discrete transistors such as the BSS138,

2N7002, or the IRLML2402 are examples of appropriate

devices.

Power Trends PT7720 series ISRs incorporate pin-coded

voltage control to adjust the ouput voltage. The control

pins are identified VID0 - VID4 (pins 1, 2, 3, 4, & 6)

respectively. When the control pins are left open-circuit,

the ISR will regulate at its factory trimmed output voltage.

Each pin is internally connected to a precision resistor,

which when grounded changes the output voltage by a

set amount. By selectively grounding VID0-VID4, the

output voltage of each ISR in the PT7720 series ISRs

can be programmed in incremental steps over its speci-

fied output voltage range. The output voltage ranges

offered by these regulators provide a convenient method

of voltage selection for many applications. In addition,

the program code and output voltage range of the PT7721

model is compatible with the voltage ID specification

defined by Intel Corporation for voltage regulator modules

(VRMs) used to power Pentium® II microprocessors.

Refer to Figure 2-1 below for the connection schematic,

and the PT7720 Data Sheet for the appropriate pro-

gramming code information.

Active Voltage Programming:

Special precautions should be taken when making changes

to the voltage control progam code while the unit is

powered. It is highly recommended that the ISR be either

powered down or held in standby. Changes made to the

program code while V_outis enabled induces high current

transients through the device. This is the result of the

electrolytic output capacitors being either charged or dis-

charged to the new output voltage set-point. The transient

current can be minimized by making only incremental

changes to the binary code, i.e. one LSB at a time. A

minimum of 100µs settling time between each program

state is also recommended. Making non-incremental

changes to VID3 and VID4 with the output enabled is

discouraged. If they are changed, the transients induced

can overstress the device resulting in a permanent drop

in efficiency. If the use of active devices prevents the

program code being asserted prior to power-up, pull pin

5 (STBY) to the device GND during the period that the

input voltage is applied to V_in. Releasing pin 5 will then

allow the device output to execute a soft-start power-up

to the programmed voltage.

Notes:

1. The programming convention is as follows:-

Logic 0:

Logic 1:

Connect to pin12 (Remote Sense Ground).

Open circuit/open drain (See notes 2, & 4)

2. Do not connect pull-up resistors to the voltage

programming pins.

3. To minimize output voltage error, always use pin 12 (Sense

Ground) as the logic “0” reference. While the regular

Figure 2-1

VID4

VID0

SNS(+)

20-25

7-11

Vin

+12V

PT7720

1µH

Synch

Out

(Optional)

STBY

GND

13-19

SNS(-)

Cin

Cout

STBY

COM

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

Application Notes continued

PT7720 Series

Figure 3-1

Using the Standby Function on the PT7720

“Big Hammer II” Programmable ISRs

For applications requiring output voltage On/Off control,

the PT7720 “Big Hammer” ISRs incorporate a standby

function. This feature may be used for power-up/shut-

down sequencing, and wherever there is a requirement

for the output status of the module to be controlled by

external circuitry.

VID4

VID0

Rem Sns (+)

20-25

7-11

Vin

+12V

V _o=3.3V

PT7721

Synch

Out

STBY

GND

13-19

Rem Sns (–)

C _in

C _out

The standby function is provided by the STBY* control,

pin 5. If pin 5 is left open-circuit the regulator operates

normally, providing a regulated output whenever a valid

supply voltage is applied to V_in(pins 7-11) with respect to

GND (pins 13-19). Connecting pin 5 to ground ¹will set

the regulator output to zero volts ². This places the regu-

lator in standby mode, and reduces the input current to

typcially 30mA (50mA max). If a ground signal is applied

to pin 5 prior to power-up, the regulator output will be

held at zero volts during the period that input power is

applied.

BSS138

Inhibit

C O M

Turn-On Time: Turning Q₁in Figure 3-1 off, removes the

low-voltage signal at pin 5 and enables the output. Fol-

lowing a brief delay of 5-15ms, the output voltage of the

PT7720 series regulators rise to full regulation within

The standby input must be controlled with an open-col-

lector (or open-drain) discrete transistor (See Figure 3-1).

Table 3-1 gives the threshold requirements.

20ms . Figure 3-2 shows the typical output voltage wave-

form of a PT7721, following the prompt turn-off of Q₁at

time t =0 secs. The output voltage in Figure 3-1 is set to

3.3V by connecting VID0 (pin 1), VID2 (pin 3), and

VID3 (pin 4) to the Sense Gnd (pin 12)^*. The wave-

form in Figure 3-2 was measured with a 12-V input

source voltage, and 15-A resistive load.

Table 3-1 Inhibit Control Threshold ¹

Parameter

Min

Max

Disable (V_IL

)

–0.1V

0.3V

Notes:

1. The Standby input on the PT7720 regulator series must be

controlled using an open-collector (or open-drain) discrete

transistor. Do Not use a pull-up resistor. The control input

has an open-circuit voltage of about 1.5Vdc. To set the

regulator output to zero, the control pin must be “pulled”

to less than 0.3Vdc with a low-level 0.1mA sink to ground.

Figure 3-2

V_o(2V/Div)

2. When placed in the standby mode, the regulator output

discharges the output capacitance with a low impedance to

ground. If an external voltage is applied to the output, it

will sink current and possibly over-stress the part.

3. The turn-off time of Q₁, or rise time of the standby input

is not critical on the PT7720 series. Turning Q₁off slowly,

over periods up to 100ms, will not affect regulator

operation. However, a slow turn-off time will increase

both the initial delay and rise-time of the output voltage.

t (milli - secs)

Consult the data sheet for details on other VID codes.

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

PACKAGE OPTION ADDENDUM

www.ti.com

6-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)

PT7722N

OBSOLETE SIP MODULE

EJE

TBD

Call TI

⁽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.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

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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PT7748C [TI]

相关型号：

PT7748N

PT7749

PT7749A

PT7749C

PT7749N

PT7750

PT7750A

PT7750C

PT7750N

PT7751

PT7751A

PT7751C