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

PT Series Suffix

(PT1234

)

Case/Pin

Order

Package

Configuration Suffix

Code

Vertical

(ENE)

Horizontal

(ENF)

SMD

(ENG)

(Reference the applicable package code
drawing for the dimensions and PC
board layout)

PT7671--5 V

30-A Programmable
Integrated Switching Regulator

SLTS176A - NOVEMBER 2002 - REVISED JUNE 2003

Features

5 V Input Voltage

30 A Output Current

5-bit Programmable Output:
1.3 V to 3.5 V

93 % Efficiency

Differential Remote Sense

Over-Current Protection

Description

The PT7671 ExcaliburTM high perfor-

mance integrated switching regulator
(ISR) is rated for up to 30 A. Housed in
a 27-pin, space-saving, solderable cop-
per package, the PT7671 delivers a
higher output current than many mod-
ules of similar size. This makes it an
ideal choice where both a high output
current and minimum board space are
desirable. The PT7671 operates from a
+5-V input bus and produces a tightly
regulated output voltage that is pro-
grammable over the range, 1.3 V to
3.5 V. The output voltage is selected via
5-bit input code, which is compatible
with VRM specifications.

Over-Temperature Protection

27-Pin Solderable Copper Case

1.57 in² PCB Area (`N' Suffix)

IPC Lead-Free 2

Standard Application

= Required 1500 µF electrolytic

out

= Required 330 µF electrolytic

= Optional 1 µH input choke

PT7671

2025

1319

711

O
A
D

OUT

PROGRAMMING PINS

OUT

GND

SENSE(+)

SENSE()

STBY

VID0

VID1
VID2
VID3

1 µH

GND

VID4

Ordering Information

PT7671

o = 1.3 to 3.5 Volts

The PT7671 is most suitable for

powering high-end DSP, ASIC, and
microprocessor circuits that require
core or I/O logic supply voltages as low
as 1.3 V.

Other features include output short-

circuit and over-temperature protection,
a standby control, and a differential
remote sense to compensate for voltage
drop between the regulator and load.

The PT7671 is also pin compatible

with the 20-A rated PT7711.

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

* For STBY pin:

open =output enabled
ground =output disabled.

Pin-Out Information

Pin Function

VID0

VID1

VID2

VID3

STBY *

VID4

Vin

Sense()

GND

Pin Function

GND

Vout

Sense(+)

Do not connect

PT7671--5 V

30-A Programmable
Integrated Switching Regulator

Programming Information

VID4=1

VID4=0

VID3 VID2 VID1 VID0

Vout

2.00 V

1.30 V

2.10 V

1.35 V

2.20 V

1.40 V

2.30 V

1.45 V

2.40 V

1.50 V

2.50 V

1.55 V

2.60 V

1.60 V

2.70 V

1.65 V

2.80 V

1.70 V

2.90 V

1.75 V

3.00 V

1.80 V

3.10 V

1.85 V

3.20 V

1.90 V

3.30 V

1.95 V

3.40 V

2.00 V

3.50 V

2.05 V

Logic 0 = Pin 12 potential (Rem Sense Gnd)
Logic 1 = Open circuit (no pull-up resistors)
VID 3 & VID4 must not be changed while the unit is operating.

Pin Descriptions

Vin:

The positive input voltage power node to the mod-

ule, which is referenced to common GND.

GND:

This is the common ground connection for the

' and `V

out

' power connections. It is also the 0 VDC

reference for the `STBY' control input.

STBY:

The STBY pin is an open-collector/drain nega-

tive logic input that is referenced to GND. Applying a
low-level ground signal to this input disables the module's
output and places the regulator in "standby" mode. When
in standby, the input current drawn by the regulator is
significantly reduced. If the STBY input is left open-
circuit, the module will produce an output whenever a
valid input source is applied.

VID0VID4:

Selects the set-point output voltage of the

regulator according to the applicable program code (See
programming information). Each input, VID0 through
VID4, is either connected to `Sense()' or left open circuit.

Vout:

The regulated positive power output with respect

to the GND node. The set point voltage at this node is
defined by the status of the pins VID0 through VID4.

Sense(+):

Provides the regulator with the capability to

regulate the set-point voltage at the load. When used
with `Sense()', the regulation circuitry will compensate
for voltage drop between the converter and the load.
This pin may be left open circuit, but connecting it to
`Vout' will improve load regulation.

Sense():

This is the logic `0' reference for the inputs

VID0 through VID4. It also provides the regulator with a
differential remote sense capability when used with the
`Sense(+)' input. For optimum output voltage accuracy
this pin should always be connected to GND.

SLTS176A - NOVEMBER 2002 - REVISED JUNE 2003

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

PT7671--5 V

30-A Programmable
Integrated Switching Regulator

Specifications

(Unless otherwise stated, T

=25 °C, V

=5 V, C

=1,500 µF, C

out

=330 µF, V

=3.3 V, and I

max)

PT7671

Characteristics

Symbols

Conditions

Min

Typ

Max

Units

Output Current

= 60 °C, 200LFM, pkg N

= 25 °C, Natural convection

Input Voltage Range

Over I

range

4.5

5.5

Set-Point Voltage Tolerance

tol

All output voltages

±10

±25

(1)

Temperature Variation

Reg

temp

40 °C

+85 °C, I

min

±1

Line Regulation

Reg

line

Over V

range

±5

Load Regulation

Reg

load

Over I

range

±5

Total Output Voltage Variation

tol

Includes set-point, line, load,

±1.5

±2.5

40 °C

+85 °C

Efficiency

=15 A

=3.3 V

=2.5 V

=1.8 V

=30 A

=3.3 V

=2.5 V

=1.8 V

Ripple (pk-pk)

20 MHz bandwidth

Transient Response

1 A/µs load step, 50 % and 100 % I

max

µSec

over/undershoot

±200

(2)

Over-Current Threshold

TRIP

Reset followed by auto-recovery

Switching Frequency

Over V

range

250

300

350

kHz

STBY* Input Requirements

Input High Voltage

Referenced to GND

2.0

Open

(3)

Input Low Voltage

-0.2

0.8

Input Low Current

Pin 5 to GND

0.3

Standby Input Current

standby

Pin 5 to GND

External Capacitance

out

330

(4)

15,000

µF

Operating Temperature Range

Over V

Range

(5)

°C

Solder Reflow Temperature

reflow

Surface temperature of module pins or case

215

(6)

°C

Storage Temperature

125

°C

Reliability

MTBF

Per Bellcore TR-332

3.4

Hrs

50 % stress, T

=40 °C, ground benign

Mechanical Shock

Per Mil-STD-883D, Method 2002.3

500

G's

1 msec, Half Sine, mounted to a fixture

Mechanical Vibration

Mil-STD-883D, Method 2007.2

Suffixes A, N

(7)

G's

20-2000 Hz

Suffix C

(7)

Weight

Vertical/Horizontal

grams

Flammability

Materials meet UL 94V-0

Notes: (1) If the remote sense ground is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy.

(2) The transient response may be improved by placing additional capacitors with low equivalent series resistance (ESR) on the output.
(3) The STBY* control (pin 5) has an internal pull-up. If it is left open-circuit, the module will operate when input power is applied. A low-leakage (<1 µA)

MOSFET must be used to control this pin. The open-circuit voltage may be as high as Vin.

(4) For operation below 0 °C, Cin and Cout must have stable characteristics. Use either low ESR tantalum or Oscon® capacitors.
(5) See safe Operating Area curves or consult 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 Power Surface Products," (SLTA051).

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

External Capacitors: The regulator require a minimum output capacitance of 330 µF for proper operation. An input capacitance of 1500 µF is also required. This
must be rated for a minimum of 1.1 Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For further informa-
tion refer to the application note regarding capacitor selection for this product.
Input Filter:

An input filter inductor is optional for most applications. The inductor must be sized to handle 30 ADC with a typical value of 1 µH.

SLTS176A - NOVEMBER 2002 - REVISED JUNE 2003

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

Performance Characteristics, V

=5 V

(See Note A)

Safe Operating Area Curves

(See Note B)

Efficiency vs Output Current

Ripple vs Output Current

Power Dissipation vs Output Current

PT7671, V

=5 VDC, V

OUT

=3.3 V

PT7671--5 V

30-A Programmable
Integrated Switching Regulator

Typical Characteristics

Iout (A)

Ambient Temperature (°C)

400LFM
200LFM
60LFM
Nat conv

Airflow

Iout (A)

Ambient Temperature (

°
C)

400LFM
200LFM
60LFM
Nat conv

Airflow

PT7671, V

=5 VDC, V

OUT

=2.5 V

100

Iout (A)

Efficiency - %

3.3V
2.5V
1.8V

OUT

100

Iout (A)

Ripple - mV

3.3V
2.5V
1.8V

OUT

Iout (A)

Pd - Watts

3.3V
2.5V
1.8V

OUT

Note A:

All characteristic data in the above graphs has been developed from actual products tested at 25 °C. This data is considered typical for the ISR.

Note B:

SOA curves represent operating conditions at which internal components are at or below manufacturer's maximum rated operating temperatures.

SLTS176A - NOVEMBER 2002 - REVISED JUNE 2003

Application Notes

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

PT7670 Series

sense pins disconnected will not damage the regulator.
An internal 15

resistor, connected between each sense

pin and its corresponding output node, keeps the output
voltage in regulation. If the remote sense feature is not
used it is important to at least connect the Sense() pin
to GND locally, as this provides a return path for the
regulator's internal bias currents.

With the sense leads connected, the difference between
the voltage measured between the V

out

and GND pins,

and that measured between the Sense(+) and Sense()
pins, is the amount of IR drop being compensated by the
regulator. This should be limited to 0.6 V. (0.3 V maximum
between pins 25 & 26, and also between pins 12 & 13).

Note: The remote sense feature is not designed to compensate
for the forward drop of non-linear or frequency dependent
components that may be placed in series with the converter
output. Examples include OR-ing diodes, filter inductors,
ferrite beads, and fuses. When these components are enclosed
by the remote sense connections they are effectively placed
inside the regulation control loop, which can adversely affect
the stability of the regulator.

Over-Temperature Protection
The PT7670 series of ISRs incorporates an on-board
temperature sensor, which protects the module's internal
circuitry against excessively high temperatures. A rise in
the temperature of the internal components may be the
result of a drop in airflow, or a high ambient temperature.
If the module's internal temperature exceeds its OTP
threshold (see data sheet specifications), the regulator
output is disabled and the output voltage is reduced to
zero. The recovery is automatic, and begins with a soft-
start power up. It occurs when the the sensed temperature
decreases by about 10 °C below the trip point.

Note: The over-temperature protection is a last resort mecha-
nism to prevent thermal stress to the regulator. Operation at
or close to the thermal shutdown temperature is not recom-
mended and will reduce the long-term reliability of the module.
Always operate the regulator within the specified Safe Operating
Area (SOA) limits for the worst-case conditions of ambient
temperature and airflow.

Over-Current Protection
To protect against load faults, the PT7670 series of regula-
tors incorporates output over-current protection. Applying
a load that exceeds the regulator's over-current threshold
(see data sheet specifications) will cause the regulated
output to shut down. Following shutdown the ISR will
periodically attempt to recover by initiating a soft-start
power-up. This is often described as a "hiccup" mode
of operation, whereby the module continues in the cycle
of successive shutdown and power up until the load fault
is removed. During this period, the average current flowing
into the fault is significantly reduced. Once the fault is
removed, the converter automatically recovers and returns
to normal operation.

Differential Remote Sense
Connecting the Sense(+) and Sense(-) pins to the load
circuit allows the regulator to compensate for limited
amounts of `IR' voltage drop. This voltage drop is caused
by current flowing through the trace resistance between
the power converter and the `point of regulation' some
distance away. Although not recommended, leaving the

Operating Features and System Considerations
for the PT7670 Series of ISRs

Power up & Soft-Start Timing
Following either the application of a valid input source
voltage, or the removal of a ground signal to the STBY
control pin (with input power applied), the regulator will
initiate a soft-start power up. The soft start slows the
rate at which the output voltage rises, and also introduces a
short time delay of approx. 10ms. Figure 1-1 shows the
power-up characteristic of a PT7671 with a 15-A load,
and with the output voltage programmed to 3.3 V.

Vo (2V/Div)

Iin (10A/Div)

Vin (2V/Div)

HORIZ SCALE: 10ms/Div

Figure 1-1

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