TI PT7681N

PT7681—5V
30-A Programmable ISR
With Margin Up/Down Controls
SLTS177B - DECEMBER 2002 - REVISED JULY 2006
Features
• 5V Input Voltage
• 30A Output Current
• 4-bit Programmable Output:
2V to 3.5V
• 95% Efficiency
• Margin Up/Down Controls
• Differential Remote Sense
•
•
•
•
•
Description
Over-Current Protection
Over-Temperature Protection
27-Pin Solderable Copper Case
1.57in² PCB Area (‘N’ Suffix)
IPC Lead-Free 2
Ordering Information
The PT7681 Excalibur™ is a high
performance integrated switching regulator (ISR), which is housed in a 27-pin
space-saving solderable copper package. Operating from a +5V input source,
the PT7681 delivers up to 30A of output current over the adjustable output
voltage range of 2V to 3.5V. The high
output current and relatively small size
makes the PT7681 suitable for powering high-end DSP, microprocessor,
and ASIC circuits requiring core or I/O
logic supply voltages as low as 2V. The
output voltage is programmable via a
4-bit input code.
PT7681o = 2 to 3.5 Volts
A special feature of the PT7681 is
the Margin Up and Margin Down
controls. These controls provide a
convenient method for testing the
load circuit over its supply voltage
margins during production and qualification test programs.
Other features include output shortcircuit and over-temperature protection,
a standby on/off control, and a differential remote sense to compensate for
voltage drop between the regulator and
load.
PT Series Suffix (PT1234 x )
Case/Pin
Order
Configuration Suffix
N
A
C
Vertical
Horizontal
SMD
Package
Code
(ENE)
(ENF)
(ENG)
(Reference the applicable package code
drawing for the dimensions and PC
board layout)
Standard Application
VID0
VID1
VID2
VID3
PROGRAMMING PINS
SENSE(+)
4
3
2
1
26
L1
VIN
7-11
1µH
CIN
+
5
13-19
6
VOUT
20-25
PT7681
27
12
L
O
A
D
+
COUT
GND
GND
STBY
SENSE(–)
MARG
DN
MARGUP
MARG
UP
MARGDN
For technical support and more information, see inside back cover or visit www.ti.com
Cin = Required 1500µF electrolytic
Cout = Required 330µF electrolytic
L 1 = Optional 1µH input choke
PT7681—5V
30-A Programmable ISR
With Margin Up/Down Controls
SLTS177B - DECEMBER 2002 - REVISED JULY 2006
Pin-Out Information
Programming Information
Pin Function
Pin Function
1
VID0
15
GND
2
VID1
16
GND
3
VID2
17
GND
4
5
VID3
STBY *
18
19
GND
GND
6
MARGDN
20
7
Vin
Vin
Vin
21
Vout
Vout
22
23
Vout
Vout
Vin
Vin
24
11
25
Vout
Vout
12
13
Sense(–)
GND
26
27
Sense(+)
MARGUP
14
GND
8
9
10
* For STBY pin:
VID3 VID2 VID1 VID0
1
1
1
1
1
1
1
0
1
1
0
1
1
1
0
0
1
0
1
1
1
0
1
0
1
0
0
1
1
0
0
0
0
1
1
1
0
1
1
0
0
1
0
1
0
1
0
0
0
0
1
1
0
0
1
0
0
0
0
1
0
0
0
0
Vout
2.00V
2.10V
2.20V
2.30V
2.40V
2.50V
2.60V
2.70V
2.80V
2.90V
3.00V
3.10V
3.20V
3.30V
3.40V
3.50V
Logic 0 = Pin 12 potential (Rem Sense Gnd)
Logic 1 = Open circuit (no pull-up resistors)
VID 3 must not be changed while the unit is operating.
open =output enabled
ground =output disabled.
Pin Descriptions
Vin: The positive input voltage power node to the module, which is referenced to common GND.
GND: This is the common ground connection for the
‘Vin’ and ‘Vout’ power connections. It is also the 0VDC
reference for the ‘STBY’ control input.
STBY: The STBY pin is an open-collector/drain negative logic input that is referenced to GND. Applying a
ground signal to this input will disable the module’s
output and place 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.
VID0–VID3: Selects the set-point output voltage of the
regulator according to the applicable program code (See
programming information). Each input, VID0 through
VID3, must either be 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 VID3.
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 VID3. 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.
MARGDN: This is an open-collector/drain negative logic
input. Applying a ground signal to this input increases
the output voltage of the module by up to 5%. The control provides a convenient method for testing the operation
of the load circuit over its supply voltage tolerance margins.
MARGUP: An open-collector/drain negative logic input
that operates similar to the MARGDN control. Applying
a ground signal to this input automatically decreases the
output by up to 5%.
For technical support and more information, see inside back cover or visit www.ti.com
Typical Characteristics
PT7681—5V
30-A Programmable ISR
With Margin Up/Down Controls
SLTS177B - DECEMBER 2002 - REVISED JULY 2006
Specifications (Unless otherwise stated, Ta =25°C, Vin =5V, Cin =1,500µF, Cout =330µF, Vo =3.3V, and Io =Iomax)
PT7681
Characteristics
Symbols
Conditions
Min
Output Current
Io
Ta = 60°C, 200LFM, pkg N
Ta = 25°C, Natural convection
Input Voltage Range
Vin
Over Io range
4.5
—
5.5
Set-Point Voltage Tolerance
Vo tol
All output voltages
—
±10
±25
Temperature Variation
Regtemp
–40°C =Ta =+85°C, I o =Iomin
—
±1
—
Line Regulation
Regline
Over Vin range
—
±5
—
mV
Load Regulation
Regload
Over Io range
—
±5
—
mV
Total Output Voltage Variation
. Vo tol
Includes set-point, line, load,
–40°C =T a =+85°C
—
±1.5
±3
%Vo
Efficiency
.
Io =15A
Vo =3.3V
Vo =2.5V
Vo =1.8V
—
—
—
93
92
89
—
—
—
%
Io =30A
Vo =3.3V
Vo =2.5V
Vo =1.8V
—
—
—
90
87
83
—
—
—
%
mVpp
0
0
Typ
—
—
Max
Units
30
29
A
V
(1)
mV
%Vo
Vo Ripple (pk-pk)
Vr
20MHz bandwidth
—
40
—
Transient Response
ttr
1A/µs load step, 50% and 100% Io max
—
25
—
µSec
Vos
Vo over/undershoot
—
±200 (2)
—
mV
Over-Current Threshold
I TRIP
Reset followed by auto-recovery
—
38
—
A
Output Margin Adjust
Switching Frequency
Vo adj
ƒs
Pin 6 or 26 connected to pin 12
Over Vin range
—
250
±5
300
—
350
%
kHz
STBY* Input Requirements
Input High Voltage
Input Low Voltage
Input Low Current
VIH
VIL
I IL
Referenced to GND
—
—
0.3
Open (3)
0.8
—
V
Pin 5 to GND
2.0
-0.2
—
Standby Input Current
Iin standby
Pin 5 to GND
—
6
—
mA
330
mA
External Capacitance
Cout
—
15,000
µF
Operating Temperature Range
Ta
Over Vin Range
–40
—
85
(5)
°C
Solder Reflow Temperature
Treflow
Surface temperature of module pins or case
—
—
215
(6)
Storage Temperature
Ts
—
–40
—
125
°C
Mechanical Shock
—
Per Mil-STD-883D, Method 2002.3
1 msec, Half Sine, mounted to a fixture
—
500
—
G’s
Mechanical Vibration
—
Mil-STD-883D, Method 2007.2
20-2000 Hz
—
—
20 (7)
TBD (7)
—
—
G’s
Weight
—
Vertical/Horizontal
—
36
—
grams
Flammability
—
Materials meet UL 94V-0
Suffix A
Suffixes N,C
(4)
°C
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 (<1µA)
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 330µF for proper operation. An input capacitance of 1500µF is also required. This
must be rated for a minimum of 1.1Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For further information 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 30ADC with a typical value of 1µH.
For technical support and more information, see inside back cover or visit www.ti.com
Typical Characteristics
PT7681—5V
30-A Programmable ISR
With Margin Up/Down Controls
SLTS177B - DECEMBER 2002 - REVISED JULY 2006
Performance Characteristics; VOUT =3.3V
Safe Operating Area Curves
(See Note A)
Efficiency vs Output Current; VIN =5V
(See Note B)
PT7681, VIN =5VDC, VOUT =3.3V
100
90
80
Ambient Temperature (°C)
Efficiency - %
90
80
70
60
Airflow
70
400LFM
200LFM
60LFM
Nat conv
60
50
40
30
50
20
0
5
10
15
20
25
30
0
5
10
Iout (A)
Ripple vs Output Current
20
25
30
PT7681, VIN =5VDC, VOUT =2.5V
90
60
VIN
40
5.5V
5.0V
4.5V
30
20
10
Ambient Temperature (°C)
80
50
Ripple - mV
15
Iout (A)
Airflow
70
400LFM
200LFM
60LFM
Nat conv
60
50
40
30
20
0
0
5
10
15
20
25
0
30
5
10
15
20
25
30
Iout (A)
Iout (A)
Power Dissipation vs Output Current; V IN =5V
12.00
10.00
Pd - Watts
8.00
6.00
4.00
2.00
0.00
0
5
10
15
20
25
30
Iout (A)
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.
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT7680 Series
Operating Features and System Considerations
for the PT7680 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 PT7681 with a 15-A load,
and with the output voltage programmed to 3.3V.
Figure 1-1
Vo (2V/Div)
Iin (10A/Div)
Vin (2V/Div)
HORIZ SCALE: 10ms/Div
Over-Current Protection
To protect against load faults, the PT7680 series of regulators 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 a cycle of
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 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
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 Vout 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 0.6V. (0.3V 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.
Margin Up/Margin Down
The MARGUP/MARGDN controls allow up to a 5%
momentary adjustment of the regulator’s output voltage
set point. This adjustment is independent of the VID
control inputs and provides a convenient method for
testing the load circuit’s supply voltage margins. A 5%
adjustment is made by simply connecting either control
input directly to the remote sense ground. Adjustments
of less than 5% can be accommodated by grounding the
input through a suitably sized padding resistor.
Note: These inputs must be controlled with a low-leakage
(<1µA) open-collector/open-drain transistor. Do not add pullup resistors or use a push-pull logic gate to drive these pins.
Over-Temperature Protection
The PT7680 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 softstart 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 mechanism to prevent thermal stress to the regulator. Operation at
or close to the thermal shutdown temperature is not recommended 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.
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT7680 Series
Capacitor Recommendations for the PT7680
Series of 30-A Switching Regulators
Input Capacitor:
The recommended input capacitance is determined by
1.1A minimum ripple current rating and 1500µF minimum capacitance.
Ripple current and <100m. equivalent series resistance
(ESR) values are the major considerations, along with
temperature, when designing with different types of
capacitors. Tantalum capacitors have a recommended
minimum voltage rating of twice the maximum DC
voltage + AC ripple. This is necessary to insure reliability for input voltage bus applications.
Output Capacitors:
The ESR of the required capacitors is less than 100m. .
Electrolytic capacitors have marginal ripple performance
at frequencies greater than 400kHz but excellent low
frequency transient response. Above the ripple frequency,
ceramic capacitors are necessary to improve the transient
response and reduce any high frequency noise components
apparent during higher current excursions. Preferred
low ESR type capacitor part numbers are identified in
Table 2-1.
Tantalum Capacitors( Optional Output Capacitors)
Tantalum type capacitors can be used for the output but
only the AVX TPS series, Sprague 593D/594/595 series
or Kemet T495/T510 series. These capacitors are recommended over many other tantalum types due to their
higher rated surge, power dissipation, and ripple current
capability. As a caution the TAJ series by AVX is not
recommended. This series has considerably higher ESR,
reduced power dissipation, and lower ripple current capability. The TAJ series is also less reliable than the AVX
TPS series when determining power dissipation capability. Tantalum or Oscon® types are recommended for
applications where ambient temperatures fall below 0°C.
Capacitor Table
Table 2-1 identifies the characteristics of capacitors from a
number of vendors with acceptable ESR and ripple current (rms) ratings. The 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
(Equivalent Series Resistance at 100kHz) are critical parameters
necessary to insure both optimum regulator performance and
long capacitor life.
Table 2-1: Input/Output Capacitors
Capacitor
Vendor/
Series
Capacitor Characteristics
Quantity
Working
Voltage
Value(µF)
(ESR) Equivalent
Series Resistance
105°C Maximum
Ripple
Current(Irms)
Physical
Size(mm)
Input
Bus
Output
Bus
Panasonic
FK (SMT)
25V
35V
2200
330
0.038.
0.080.
1800mA
850mA
16x16.5
10x10.2
1
1
1
EEVFK1E222M
EEVFK1V331P
FC (Radial)
16V
16V
470
1500
0.090.
0.043.
755mA
1690mA
10x12.5
16x15
1
1
1
EEUFC1C471
EEUFC1C152S
United LXZ
Chemi -Con
FX
25V
16V
10V
330
1500
680
0.090.
0.038.
0.015.
760mA
1660mA
4735mA
10x12.5
12.5x20
10x10.5
1
2
1
1
1
LXZ25VB331M10X12LL
LXZ16VB152M12X20LL
10FX680M
Nichicon
PL Series
NX (SM)
25V
10V
10V
390
1500
330
0.080.
0.050.
0.024.
720mA
1330mA
3770mA
12.5x15
16x15
10x8
1
5
1
1
1
UPL1E391MHH6
UPL1A152MHH6
PNX1A331MCR1GS
Oscon
SP (Radial)
SVP (SMT)
10V
10V
470
330
0.015.
0.017.
>4510mA
>3950mA
10x10.5
9x12x8.3
3
4
1
1
10SP470M
10SVP330M
AVX
Tanatalum
TPS- Series
10V
10V
330
330
0.10.
0.060.
1414mA
1826mA
7.3Lx
4.3Wx
4.1H
5
5
1
1
TPSV337M010R0100
TPSV337M010R0060
Sprague
Tantalum
595D/594D
10V
10V
330
680
0.045.  4 =0.011.
0.09.
>4500mA
>1510mA
7.3L x
5.7W x
4.0H
5
2
1
1
594D337X0010R2T
595D687X0010R2T
(Surface Mount)
Kemet
Tantalum
T510/T495
Series
10V
330
0.035.
2000mA
5
1
510X337M010AS
10V
220
0.07.  2 =0.035.
4.3Wx7.3L
x4.0H
>2000mA
6
2
T495X227M010AS
(Surface Mount)
10V
220
0.04.
3000mA
6
2
10TPB220M
(Surface Mount)
Sanyo Poscap
TPB
7.2L x
4.3W x
3.1H
Vendor Number
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT7680 Series
Using the Standby Function on the PT7680
Series of 30-A Switching Regulators
For applications requiring On/Off control of the output
voltage, the 30-A rated PT7680 series of Excalibur ISRs
incorporate an on/off “Standby” function. This feature
may be used for power-up/shutdown sequencing, or to
change the output voltage while input power is applied.
See related notes: “Pin-Coded Output Voltage Adjustment
of the PT7680 Series of 30-A ISRs.”
Figure 3-2
Vo (2V/Div)
Iin (5A/Div)
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 Vin (pins 7-11) with respect to
GND (pins 13-19). Connecting pin 5 to ground 1 will
disable the regulator output 2. This places the regulator
in standby mode, and reduces the input current to typically
6mA. If a ground signal is applied to pin 5 prior to powerup, the regulator output will remain inactive during the
period that input power is applied.
The standby input must be controlled with an opencollector (or open-drain) discrete transistor (See Figure
3-1). Table 3-1 gives the input requirements.
2V
–0.2V
Open Cct.
0.8V
0.5mA
HORIZ SCALE: 5ms/Div
Notes:
1. The Standby input of the PT7680 series of regulators
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 equal to Vin. To
set the regulator output to zero, the control pin must be
“pulled” to less than 0.8Vdc with a 0.5mA sink to ground.
Table 3-1 Standby Control Input Requirements
Parameter
Min
Typ
Max
Enable
Disable
Istby (low)
Vstby (o/c)
Vstby (5V/Div)
1
2. In the standby mode the output of the regulator is tristate, and the output voltage falls at the rate that the
load circuit discharges the output filter capacitors.
Vin
Turn-On Time: Turning Q1 in Fig. 3-1 off, removes the
low-voltage signal at pin 5 and enables the output 3. After a delay of less than 5ms, the output voltage rises to
full regulation within 30ms 4. Fig. 3-2 shows the typical
output voltage waveform of a PT7681 following the
turn-off of Q1 at time t =0 secs. In the circuit of Fig. 3-1,
the output voltage is set to 3.3V. The waveform was
measured with a +5V input source voltage, and 15-A
output load.
3. When the ground signal to the Standby pin is removed,
the regulator output initiates a soft-start cycle by first
asserting a low impedance to ground. If an external
voltage is applied to the output bus, it will sink current and
possibly over-stress the part.
4. The turn-off time of Q1, or rise time of the standby input
is not critical. Turning Q1 off slowly will not affect regulator
operation. However, a slow turn-off time will increase
both the initial delay and rise-time of the output voltage.
Figure 3-1
26
Senes(+)
4 3 2 1
VID3 - VID0
7–11
5V
PT7681
Vin
STBY
5
GND
13–19
Vo
20–25
Senes(–)
12
+
+
C in
Inhibit
V o =3.3V
C out
L
O
A
D
Q1
BSS138
COM
For technical support and more information, see inside back cover or visit www.ti.com
COM
Application Notes
PT7680 Series
Pin-Coded Output Voltage Adjustment of the
PT7680 Series of 30-A Switching Regulators
The PT7680 Excalibur™ family of converters use a pin
code to adjust the output voltage. This feature uses the
control inputs, VID0–VID3 (pins 1–4). When these pins
are left open-circuit, the ISR regulates at its default output
voltage. Each of the programming pins are internally
connected to a precision resistor, and when pulled low 1
applies a weighted change to the output voltage. By
selectively connecting VID0–VID3 to Sense(–) 2, the
output voltage of these ISRs can be programmed in
incremental steps over their specified output voltage
range. The program codes and output voltages offered
by these ISRs are compatible with the Voltage ID
specifications used by popular microprocessors. See
Figure 4-1 for the connection schematic, and the
respective device data sheet for the programming code
information.
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 Vce(sat) in
bipolar devices introduces errors in the device’s internal
divider network. Discrete transistors such as the BSS138,
2N7002, or IRLML2402 are examples of appropriate
devices.
Active Voltage Programming:
Special precautions should be taken when making changes
to the output voltage progam code while the unit is
powered. This activity can induce current transients
through the device as a result of the electrolytic output
capacitors being either charged or discharged 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 is
discouraged.
Notes:
1. The programming convention is as follows:Logic 0:
Connect to pin 12; Sense(–).
Logic 1:
Open circuit/open drain (See Note 2)
When active devices are used to program the output
voltage, their state should be asserted prior to the input
power being applied. One approach is to pull STBY (pin 5)
control to GND prior to power up. After the host board
has then asserted the program code, the ground signal
to pin 5 can be removed. This will allow the regulator to
intiate a clean soft-start power-up to the desired program
voltage. For more information on the use of the Standby
function, consult the related application note, “Using
the Standby Function on the PT7680 Series of 30-A
Switching Regulators.”
2. For optimal output voltage accuracy Sense(–) (pin 12)
should always be used as the logic ‘0’ reference. The
input/output ground (pins 13-19) can also be used if
pin 12 is connected to pin 13 external to the module.
3. Do not connect pull-up resistors to the voltage
programming pins.
Figure 4-1
4 3 2 1
+5V
26
VID3 - VID0
L1
7–11
1µH
(Optional)
SNS(+)
PT7681
V IN
STBY
GND
5
13–19
SNS(–)
12
+
+
Cin
STBY
VOUT
20–25
V OUT
Cout
Q1
L
O
A
D
Sense(–)
COM
Power GND
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT7680 Series
Using the Up/Down Margin Adjust Controls on the
PT7680 Series of 30-A Regulators
The PT7680 series of integrated switching regulator
modules incorporate MARGUP (pin 27) and MARGDN
(pin 6) control inputs. These controls allow the output
voltage set point to be momentarily adjusted 1, either
up or down, by a nominal 5%. The adjustment is independent of the VID control inputs and provides a
convenient method for dynamically testing the load
circuit’s power supply voltage over its operating margin
or range. The 5% adjustment is made by driving the
appropriate margin control input to the ground reference
at Sense(-) (pin 12) 2. An open drain, low-leakage (<1µA),
logic-level MOSFET or p-channel JFET is recommended
for this purpose. Adjustments of less than 5% are also
possible using a series resistor (See Figure 5.1). The value
of the resistor can be selected from Table 5.1, or calculated using the following formulas.
Notes:
1. The MARGUP and MARGDN controls were not
intended to be activated simultaneously. If they are
their affects on the output voltage may not completely
cancel, resulting in a slight shift in the output voltage
set point.
2. When possible use the Sense(-) (pin 12) as the ground
reference. This will produce a more accurate adjustment
of the output voltage at the load circuit terminals. GND
(pins 13-19) can be used if the Sense(-) pin is connected to
GND near the regulator.
Table 5.1; Margin Up/Down Adjust Resistor Values
PADDING RESISTOR VALUES
Resistor Value Calculation
To reduce the margin adjustment to a value less than 5%,
series padding resistors are required (See RD and RU in
Figure 5.1). For the same amount of adjustment, the
resistor value calculated for RU and RD will be different.
RU
=
100 ( 6 – 1.2 . %)
.%
RD
=
4.99 (100 – . %)
.%
% Adjust
RU (Margin Up)
RD (Margin Dn)
0.0k.
30.0k.
80.0k.
180.0k.
480.0k.
0.0k.
24.9k.
66.5k.
150.0k.
399.0k.
5
4
3
2
1
k.
–94.81
k.
Where: . % = The required margin adjust in percent
Figure 5.1; Margin Up/Down Application Schematic
+V o
4 3 2 1
26
VID3 - VID0
+5V
7–11
PT7681
VIN
STBY
5
+
C in
0V
SNS(+)
GND
13–19
MARG
DN
6
+VOUT
20–25
VOUT
MARG
UP
27
RD
RU
SNS(–)
12
+
C out
L
O
A
D
Q1
Margin Dn
Q2
Margin Up
Sense(–)
PWR GND
For technical support and more information, see inside back cover or visit www.ti.com
Power GND
0V
(No resistor)
PACKAGE OPTION ADDENDUM
www.ti.com
28-Jul-2006
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
PT7681N
ACTIVE
SIP MOD
ULE
ENE
Pins Package Eco Plan (2)
Qty
27
10
TBD
Lead/Ball Finish
Call TI
MSL Peak Temp (3)
Level-1-215C-UNLIM
(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
MECHANICAL DATA
MMSI031 – SEPTEMBER 2001
ENE (R–MSIP–T27)
METAL SINGLE-IN-LINE MODULE
Suffix N
0.66 (16,76) MAX.
0.500 (12,70)
3.00 (76,20) MAX.
1
Note G
0.025 (0,63) TYP.
1.02 (25,90)
MAX.
0.017 (0,43) TYP.
0.100 (2,54) TYP.
0.050 (1,27) TYP.
0.050 (1,27) TYP.
0.160 (4,06) TYP.
0.140 (3,55) MIN.
See Note F
3.028 (76,91)
2.928 (74,37)
0.050 (1,27)
Note E
0.110 (2,79)
0.70 (17,78)
0.040 (1,01)
0.54 (13,71)
1
ø0.045 (1,14) MIN. 27 Places
Plated through
0.100 (2,54) 26 Places
0.164 (4,16)
0.350 (8,89)
0.090 (2,28)
2 Places
ø0.093 (2,36) MIN. 4 Places
Plated through holes.
See Note G.
PC Layout
4203526/A 08/01
NOTES: A.
B.
C.
D.
E.
F.
G.
All linear dimensions are in inches (mm).
This drawing is subject to change without notice.
2 place decimals are 0.030 (0,76mm).
3 place decimals are 0.010 (0,25mm).
Recommended mechanical keep out area.
Electrical pin length mounted on printed circuit board, from seating plane to pin end.
The case may be electrically connected to power ground plane.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,
enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
orders and should verify that such information is current and complete. All products are sold subject to TI’s terms
and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty. Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third-party products or services
does not constitute a license from TI to use such products or services or a warranty or endorsement thereof.
Use of such information may require a license from a third party under the patents or other intellectual property
of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction
of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for
such altered documentation.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that
product or service voids all express and any implied warranties for the associated TI product or service and
is an unfair and deceptive business practice. TI is not responsible or liable for any such statements.
Following are URLs where you can obtain information on other Texas Instruments products and application
solutions:
Products
Applications
Amplifiers
amplifier.ti.com
Audio
www.ti.com/audio
Data Converters
dataconverter.ti.com
Automotive
www.ti.com/automotive
DSP
dsp.ti.com
Broadband
www.ti.com/broadband
Interface
interface.ti.com
Digital Control
www.ti.com/digitalcontrol
Logic
logic.ti.com
Military
www.ti.com/military
Power Mgmt
power.ti.com
Optical Networking
www.ti.com/opticalnetwork
Microcontrollers
microcontroller.ti.com
Security
www.ti.com/security
Low Power Wireless www.ti.com/lpw
Mailing Address:
Telephony
www.ti.com/telephony
Video & Imaging
www.ti.com/video
Wireless
www.ti.com/wireless
Texas Instruments
Post Office Box 655303 Dallas, Texas 75265
Copyright  2006, Texas Instruments Incorporated