features. They are an ideal choice for applications
where board space is a premium and performance
cannot be compromised. These modules provide
18A of output current, yet are housed in a low-
profile, 18-pin package that is almost half the
size of the previous product generation. The
integral copper case construction requires no
heatsink, and offers the advantages of solderabil-
ity and a small footprint (0.736 in² for suffix ‘N’).
Both through-hole and surface mount pin con-
figurations are available.
The PT5800 series operates from a 5-V input
bus and provides a convenient point-of-load power
source for the industry’s latest high-performance
DSPs and microprocessors. The series includes
output voltage options as low as 1.0VDC.
Other features include external output voltage
adjustment, a ±5% margin control, on/off inhibit,
short circuit protection, thermal shutdown, and a
differential remote sense.
Ordering Information
PT5801H
PT5802H
PT5803H
PT5804H
PT5805H
PT5806H
= 3.3 Volts
= 2.5 Volts
= 1.8 Volts
= 1.5 Volts
= 1.2 Volts
= 1.0 Volts
Pin-Out Information
Pin Function
1
2
3
4
5
6
7
V
o
Adjust
Inhibit*
Margin Dn*
Margin Up*
V
in
V
in
V
in
Sense(–)
GND
GND
GND
GND
GND
V
out
V
out
V
out
V
out
Sense(+)
PT Series Suffix
(PT1234
x
)
Case/Pin
Configuration
Vertical
Horizontal
SMD
Order
Suffix
Package
Code
(EPP)
(EPQ)
(EPS)
8
9
10
11
12
13
14
15
16
17
18
N
A
C
(Reference the applicable package code draw-
ing for the dimensions and PC board layout)
* Denotes negative logic:
Open = Normal operation
Ground = Function active
Standard Application
Margin Dn
Margin Up
V
o
Adjust
1
5, 6, 7
4
3
18
14–17
Sense(+)
V
OUT
V
IN
C
IN
820µF
(Required)
Inhibit
GND
PT5800
2
9–13
8
Sense(–)
For technical support and more information, see inside back cover or visit www.ti.com
+
L
O
A
D
C
OUT
330µF
(Required)
+
GND
C
in
= Required 820µF
C
out
= Required 330µF
PT5800 Series
18-A 5-V Input Adjustable
Integrated Switching Regulator
SLTS171A JANUARY 2003 - REVISED - MARCH 2003
Specifications
Characteristics
(Unless otherwise stated, T
a
=25°C, V
in
=5V, C
in
=820µF, C
out
=330µF, and I
o
=I
o
max)
Symbols
I
o
V
in
V
o
tol
∆Reg
temp
∆Reg
line
∆Reg
load
∆Reg
tot
η
Conditions
V
in
=5V
Over I
o
range
–40°C <T
a
< +85°C
Over V
in
range
Over I
o
range
Includes set-point, line, load,
–40°C
≤
T
a
≤
+85°C
PT5801 (3.3V)
I
o
=12A
PT5802 (2.5V)
PT5803 (1.8V)
PT5804 (1.5V)
PT5805 (1.2V)
PT5806 (1.0V)
20MHz bandwidth
1A/µs load step, 50 to 100% I
o
max,
Recovery Time
V
o
over/undershoot
Reset, followed by auto-recovery
With V
o
Adjust
With Margin Up/Dn
Over V
in
and I
o
ranges
Referenced to GND (pins 9–13)
Pin 2 to GND
Pin 2 to GND
Min
0
4.5
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
250
V
in
–0.5
–0.2
—
—
820
(3)
330
(4)
–40
(4)
—
—
–40
5.8
—
—
—
—
PT5800 SERIES
Typ
Max
—
—
—
±0.5
±8
±5
—
94
92
90
88
86
84
20
50
100
30
±15
(1)
±5
300
—
—
–10
5
—
—
—
110
—
—
—
500
20
20
20
(7)
(7)
Units
A
V
%V
o
%V
o
mV
mV
%V
o
Output Current
Input Voltage Range
Set-Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Variation
Efficiency
18
5.5
±2
—
—
—
±3
—
—
—
—
—
—
—
—
—
—
—
—
350
Open
(2)
0.8
—
—
—
5,000
85
(5)
—
215
(6)
125
—
—
—
—
—
%
V
o
Ripple (pk-pk)
Transient Response
V
r
t
tr
∆V
tr
I
TRIP
V
o
adj
ƒ
s
V
IH
V
IL
I
IL
I
in
standby
C
in
C
out
T
a
OTP
T
reflow
T
s
MTBF
mVpp
µSec
mV
A
%
kHz
V
µA
mA
µF
µF
°C
°C
°C
°C
10
6
Hrs
G
G
grams
Over-Current Threshold
Output Voltage Adjust
Switching Frequency
Inhibit Control (pin 2)
Input High Voltage
Input Low Voltage
Input Low Current
Standby Input Current
External Input Capacitance
External Output Capacitance
Operating T
emperature Range
Over-T
emperature Protection
Solder Reflow T
emperature
Storage T
emperature
Reliability
Mechanical Shock
Mechanical Vibration
Weight
Flammability
—
—
Over V
in
range
Measured at center of case, auto-reset
Surface temprature of module pins or case
—
Per Bellcore TR-332
50% stress, T
a
=40°C, ground benign
Mil-STD-883D, Method 2002.3
Half Sine, mounted to a fixture
Mil-STD-883D, Method 2007.2,
Suffix N
20-2000 Hz, PCB mounted
Suffixes A, C
—
Materials meet UL 94V-0
Notes:
(1) This is a typical value. For the adjustment limits of a specific model consult the related application note on output voltage adjustment.
(2) The Inhibit control (pin 2) has an internal pull-up to V
in
, and if left open-circuit the module will operate when input power is applied. A small low-
leakage (<100nA) MOSFET is recommended to control this input. See application notes for more information.
(3) An 820µF electrolytic input capacitor is required for proper operation. This capacitor must be rated for a minimumm of 0.7 Arms of ripple current.
(4) For operation below 0°C, C
OUT
must have stable characteristics. Use either low-ESR tantalum or Oscon® type capacitors.
(5) See SOA curves or consult factory for the appropriate derating.
(6) During solder 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 Mount 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.
For technical support and more information, see inside back cover or visit www.ti.com
PT5800 Series
18-A 5-V Input Adjustable
Integrated Switching Regulator
SLTS171A JANUARY 2003 - REVISED - MARCH 2003
Pin Descriptions
Vin:
The positive supply voltage input for the module
with respect to the common ground (GND).
Vout:
This is the regulated output voltage from the mod-
ule with respect to the common ground (GND).
GND:
The common ground node to which the input,
output, and external control signals are referenced.
Sense(–):
Provides the regulator with the ability to sense
the set-point voltage directly across the load. For opti-
mum output voltage accuracy this pin should always be
connected to
GND,
even for applications that demand a
relatively light load.
Sense(+):
When used with
Sense(–),
the regulation circuitry
will compensate for voltage drop between the converter
and the load. The pin may be left open circuit, but con-
necting it to
V
out
will optimize load regulation.
Inhibit*:
This is an open-collector (open-drain) negative
logic input, referenced to
GND.
Pulling this pin to
GND
disables the module’s output voltage. If
Inhibit*
is
left open circuit, the output will be active whenever a
valid input source is applied.
V
o
Adjust:
This pin is used to trim the output voltage
over a typical range of ±15% of nominal. The adjust-
ment method uses an external resistor. The resistor is
connected from
V
o
Adjust
to either the
(-)Sense
or
(+)Sense,
in order to adjust the output either up or down, respec-
tively. Consult the related application note for the adjust
limits of a specific part.
Margin Dn*:
When this open-collector (open-drain) input
is asserted to
GND,
the output voltage is automatically
decreased by 5% from the nominal. This feature is used in
applications where the load circuit must be tested for
operation at the extreme values of its supply voltage
tolerance.
Margin Up*:
This is an open-collector (open-drain) input.
When this is asserted to
GND,
the output voltage is
automatically increased by 5% from the nominal.
Typical Characteristics
Performance Data; V
in
=5V
(See Note A)
Efficiency vs Output Current
100
6
5
Power Dissipation vs Output Current
90
80
70
PT5801
PT5802
PT5803
PT5804
PT5805
PT5806
Efficiency - %
4
Pd - Watts
3
2
60
1
50
0
3
6
9
12
15
18
0
0
3
6
9
12
15
18
Iout (A)
Iout (A)
Output Ripple vs Output Current
50
90
80
Safe Operating Curves; V
in
=5V
(See Note B)
Ambient Temperature (°C)
40
70
60
50
40
30
Airflow
200LFM
120LFM
60LFM
Nat conv
30
20
PT5802
PT5801
PT5803
PT5804
PT5805
PT5806
Ripple - mV
10
0
0
3
6
9
12
15
18
20
0
3
6
9
12
15
18
Iout (A)
Iout (A)
Note A:
Characteristic data has been developed from actual products tested at 25°C. This data is considered typical data 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
PT5800 & PT5810 Series
Operating Features and System Considerations
for the PT5800 & PT5810 Regulator Series
The PT5800 (5-V input) and the PT5810 (3.3-V input)
series of integrated switching regulators (ISRs) provide
step-down voltage conversion for output loads of up to
18A.
With the sense leads connected, the difference between
the voltage measured at
V
out
and
GND
pins, and that
measured from
Sense(+)
to
Sense(–),
is the amount of IR
drop being compensated by the regulator. This should
be limited to 0.6V. (0.3V maximum between pins 17 &
18, and also between pins 8 & 9).
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.
Power up & Soft-Start Timing
Following either the application of a valid input source
voltage, or the removal of a ground signal to the
Inhihit*
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, t
d
(approx. 2ms). Figure 1-1 shows the
power-up characteristic of a PT5801 (3.3V) with a 10-A
load.
Figure 1-1
Over-Current Protection
To protect against load faults, the regulators incorporate
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 nor-
mal operation.
Vo (2V/Div)
Vin (2V/Div)
t
d
Over-Temperature Protection
An on-board temperature sensor protects the module’s
internal circuitry against excessively high temperatures.
A rise in the internal temperature may be the result of a
drop in airflow, or a high ambient temperature. If the
internal temperature exceeds the OTP threshold (see
data sheet specifications), the regulator’s
Inhibit*
control
is automatically pulled low. This disables the regulator,
allowing the output voltage to drop to zero as the exter-
nal output capacitors are discharged by the load circuit.
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.
HORIZ SCALE: 5ms/Div
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 connection resistance
between the regulator and the ‘point of regulation’ some
distance away. Leaving the sense pins disconnected will
not damage the regulator or load circuitry. An internal
15Ω resistor, connected between each sense pin and its
corresponding output node, keeps the output voltage in
regulation. However, it is important to connect
Sense(–)
to
GND
locally, as this provides a return path for the
regulator’s internal bias currents.
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT5800 & PT5810 Series
Startup of the PT5800 & PT5810 Series ISRs
with Back-Feeding Source (Pre-Bias Capability)
In complex digital systems an external voltage can
sometimes be present at the output of the regulator
during power up. For example, this voltage may be
backfed through a dual-supply logic component such as
an FPGA or ASIC. Another path might be via a clamp
diode (to a lower supply voltage) as part of a power-up
sequencing implementation.
Although the PT5800 (5-V input) and PT5810 (3.3-V
input) series of regulators will sink current under steady-
state operating conditions, they will not do so during
startup
1
as long as certain conditions are maintained
2
.
This feature allows these regulators to start up while an
external voltage is simultaneously applied to the output.
Figure 2-1 is an application schematic that demonstrates
this capability. The waveforms in Figure 2-2 show the
behavior of the circuit as input power is applied. Note
that the plot of the regulator output current (I
o
) is approxi-
mately zero up to the timestamp ‘A’, even though a voltage
is initially backfed to the output via the 3.3-V input supply
and diodes D
1
& D
2
. The regulator sources current
3
when
it begins raising the output above the back-fed voltage to
its nominal regulation value.
Notes
1. Startup includes both the application of a valid input
source voltage, or the removal of a ground signal from
the
Inhibit*
control (pin 2) with a valid input source
applied. The output of the regulator is effectively off
(tri-state), during the period that the
Inhibit*
control is
held low.
2. To ensure that the regulator does not sink current, the
input voltage must always be greater or equal to the
output voltage throughout the power-up and power-down
sequence.
3. If an external source backfeeding the regulator’s output
is greater than the nominal regulation voltage, the output
will begin sinking current at the end of its soft-start
power-up sequence. If this current exceeds the rated
output, the module could be overstressed.
Figure 2-2; Power-up Waveforms with Back-Feeding Source
Vin (1V/Div)
Vo (1V/Div)
Io (5A/Div)
HORIZ SCALE 5ms/Div
A
Figure 2-1; Schematic Demonstrating Startup into Pre-Bias Capability
V
IN
(3.3VDC)
D
1
D
2
18
Sense(+)
5–7
V
IN
PT5812
GND
V
OUT
14–17
V
O
(2.5V)
I
o
C
IN
C
out
COM
For technical support and more information, see inside back cover or visit www.ti.com
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