TI PT4403N

PT4400 Series
75-W 48-V Input Isolated
DC/DC Converter
SLTS160B
(Revised 7/19/2002)
Features
• Up to 75W Output:
20A @3.3V, 15A @5V
• Input Voltage Range:
36V to 75V
• Programmable Output Voltage
• 91% Efficiency (PT4403)
• 1500 VDC Isolation
• On/Off Control
• Over-Current Protection
•
•
•
•
•
•
Differential Remote Sense
Output Over-Voltage Protection
Over-Temperature Shutdown
Undervoltage Lockout
Low Profile Package (12mm)
Compact PCB Layout:
(Horizontal Config. 1.45in × 2.6in,
Vertical Config. < 1 in2)
• Solderable Copper Case
• Agency Approvals Pending
Description
Ordering Information
The PT4400 series of power modules are singleoutput isolated DC/DC converters, housed in a
compact 21-pin low-profile (12mm) package.
These modules are rated up to 75W with load
currents as high as 20A. The output voltage is set
within a pre-defined range via a 5-bit input code.
The PT4400 series operates from a standard
48-V telecom CO supply and occupies only 3.9in²
of PCB area. These modules offer OEMs a compact
and flexible high-output power source for use with
high-end microprocessors, DSPs, general purpose
logic and analog. They are suitable for distributed
power applications in both telecom and computing
environments.
Features include output over-current protection,
on/off control, output over-voltage protection
(OVP), over-temperature shutdown, under-voltage lockout (UVLO), and an output differential
remote sense. The modules are fully integrated
for stand-alone operation, and require no additional
components.
PT4401H = 1.3 to 3.5 Volts
PT4402H = 1.05 to 1.75Volts
PT4403H = 3.4 to 5.7 Volts
Pin-Out Information
Pin Function
PT Series Suffix (PT1234 x )
Case/Pin
Configuration
Order
Suffix
Package
Code
N
A
C
(ENM)
(ENN)
(ENP)
Vertical
Horizontal
SMD
(Reference the applicable package code drawing for
the dimensions and PC layout)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Remote On/Off *
-Vin
-Vin
+Vin
+Vin
Pin Not Present
VID 0
VID 1
VID 2
VID 3
VID 4 †
(–)Remote Sense
-Vo
-Vo
-Vo
-Vo
+Vo
+Vo
+Vo
+Vo
(+)Remote Sense
* For more information consult
the applicable application note.
† VID 4 does not function on the
PT4402 & PT4403
Standard Application
+ REMOTE SENSE
+ V OUT
21
– V IN
4, 5
+ V in
+ V out
17–20
PT4401
2, 3
Co
– V in
-V out
Remote
On/Off
1
VID0 - VID4
7
8
9
10 11
L
O
A
D
+
+ V IN
+ V sns
13–16
– V OUT
-V sns
12
– REMOTE SENSE
PROGRAMMING PINS #
C o = Optional 330µF Electrolytic Capacitor
# VID programming pins set fo 3.3V output
For technical support and more information, see inside back cover or visit www.ti.com
PT4400 Series
75-W 48-V Input Isolated
DC/DC Converter
Environmental Specifications
Characteristics
Symbols
Conditions
Min
Typ
Max
Units
Operating Temperature Range
Storage Temperature
Mechanical Shock
Ta
Ts
Over Vin Range
—
Per Mil-STD-883D, Method 2002.3
1 msec, ½ Sine, mounted
Mil-STD-883D, Method 2007.2
Vertical
20-2000 Hz, PCB mounted
Horizontal
Vertical/Horizontal
Case temperature - auto reset
Meets UL 94V-O
–40
–40
—
—
+85 (i)
+125
°C
°C
—
—
—
—
—
TBD
TBD (ii)
TBD (ii)
50
115
—
—
—
—
—
G’s
Mechanical Vibration
Weight
ShutdownTemperature
Flammability
—
OTP
—
G’s
grams
°C
Notes (i) See SOA curves or consult factory for appropriate derating
(ii) The case pins on the through-hole package types (suffixes N &A) must be soldered. For more information see the applicable package outline drawing.
Output Voltage Programming Information
PT4401
VID3 VID2 VID1 VID0
PT4402
PT4403
VID4=1
Vout
VID4=0
Vout
VID4= ×
Vout
VID4= ×
Vout
†
1
1
1
1
1
1
1
0
N/D *
2.10V
1.30V
1.35V
N/D *
1.05V
N/D *
3.40V
1
1
1
1
0
0
1
0
2.20V
2.30V
1.40V
1.45V
1.10V
1.15V
3.56V
3.72V
1
1
0
0
1
1
1
0
2.40V
2.50V
1.50V
1.55V
1.20V
1.25V
3.88V
4.05V
1
1
0
0
0
0
1
0
2.60V
2.70V
1.60V
1.65V
1.30V
1.35V
4.21V
4.37V
0
0
1
1
1
1
1
0
2.80V
2.90V
1.70V
1.75V
1.40V
1.45V
4.53V
4.69V
0
0
1
1
0
0
1
0
3.00V
3.10V
1.80V
1.85V
1.50V
1.55V
4.86V
5.02V
0
0
0
0
1
1
1
0
3.20V
3.30V
1.90V
1.95V
1.60V
1.65V
5.18V
5.34V
0
0
0
0
0
0
1
0
3.40V
3.50V
2.00V
2.05V
1.70V
1.75V
5.50V
5.67V
Logic 0 =Pin 12 potential; (–)Remote Sense
Logic 1 =Open circuit (no pull-up resistors)
†
* N/D = Output voltage is not defined
† VID 4 (pin 11) of PT4402 & PT4403 is don’t care (×).
Note: During operation, changes to the program code should be limited to 15% of Vo so as to avoid activating the output OV protection.
Pin Descriptions
+Vin: The positive input for the module with respect to
–Vin. When powering the module from a –48V telecom
central office supply, this input is connected to the primary
system ground.
+Vo: The positive power output with respect to -Vo, which
is DC isolated from the input supply pins. If a negative
output voltage is desired, +Vo should be connected to the
secondary circuit common and the output taken from –Vo.
–Vin: The negative input supply for the module, and the
0VDC reference for the Remote On/Off input. When
powering the module from a +48V supply, this input is
connected to the 48V(Return).
–Vo: The negative power output with respect to +Vo,
which is DC isolated from the input supply pins. This
output is normally connected to the secondary circuit
common when a positive output voltage is desired.
Remote On/Off: A positive logic input that is referenced to
–Vin. Pulling this input down to –Vin potential disables
the module’s output. If this input is left open-circuit, the
module will produce an output whenever a valid input
source is applied.
+Remote Sense: Provides the converter with remote sense
capability to regulate the set-point voltage directly at the
load. When used with –Remote Sense, the regulation
circuitry will compensate for voltage drop between the
converter and the load. The pin may be left open circuit,
but connecting it to +Vo will improve load regulation.
VID0 – VID4: Selects the set-point output voltage of the
converter according to the applicable program code.
VID0 – VID4 must either be connected to (–)Remote
Sense or left open circuit. Note: For the PT4402 & PT4403,
VID 4 is internally disabled and may be left open circuit.
–Remote Sense: This is the logic ‘0’ reference for the
inputs VID0 – VID4, and provides the converter with
remote sense capability when used in conjunction with
+Remote Sense. For optimum output voltage accuracy
this pin should always be connected to –Vo.
For technical support and more information, see inside back cover or visit www.ti.com
PT4401—48V
75-W 48-V Input Isolated
DC/DC Converter
PT4401 Specifications
(Unless otherwise stated, T a =25°C, Vin =48V, Vo =3.3V, C o =0µF, and Io =Iomax)
Characteristic
Symbol
Conditions
Min
PT4401
Typ
Max
Units
Output Current
Input Voltage Range
Set Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Voltage Variation
Io
Vin
Vo tol
Regtemp
Regline
Regload
∆Votot
Over Vin range
Over Io Range
0
36
—
—
—
—
—
48
±0.6 (1)
±0.8
±1
±1
20
75
—
—
—
—
A
V
%Vo
%Vo
mV
mV
—
±1.6
±3
%Vo
Efficiency
Vo Ripple (pk-pk)
Transient Response
η
Vr
ttr
∆Vtr
ITRIP
OVP
ƒo
UVLO
—
—
—
—
—
—
—
—
89
50
75
±5
26
125
300
32
—
—
—
—
—
—
—
—
%
mVpp
µs
%Vo
A
%Vo
kHz
V
4.5
–0.2
—
—
—
0
1500
—
10
—
—
–0.3
2
1.4
Open (2)
+0.8
—
—
—
5,000
—
—
—
V
Over-Current Threshold
Output Over-Voltage Protection
Switching Frequency
Under-Voltage Lockout
Remote On/Off Input
Input High Voltage
Input Low Voltage
Input Low Current
–40° >Ta > +85°C
Over Vin range
Over Io range
Includes set-point, line, load,
–40° >Ta > +85°C
20MHz bandwidth
1A/µs load step, 50% to 100% Iomax
Vo over/undershoot
Shutdown, followed by auto-recovery
Output shutdown and latch off
Over Vin range
Referenced to –Vin
VIH
VIL
IIL
Iin standby
Cin
Cout
Standby Input Current
Internal Input Capacitance
External Output Capacitance
Isolation Voltage
Capacitance
Resistance
pins 1 & 2 connected
Between +Vo and –Vo
Input-output & input-case
Input-output
Input-output
—
1200
—
mA
mA
µF
µF
Vdc
pF
MΩ
Notes: (1) If (–)Remote Sense is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy.
(2) The Remote On/Off input has an internal pull-up. If it is left open-circuit the module will operate when input power is applied. A discrete MOSFET or
bipoloar transistor is recommended to control this input. The open-circuit voltage is typically 5V. See application notes for interface considerations.
PT4401 Characterstic Data
Efficiency vs Load Current; Vin =48V (See Note A)
Power Dissipation vs Load Current; Vo =3.3V (See Note A)
100
12
10
90
VIN
8
3.3V
2.5V
1.8V
1.5V
80
70
Pd - Watts
Efficiency - %
VOUT
75.0V
60.0V
48.0V
36.0V
6
4
60
2
50
0
0
4
8
12
16
20
0
4
8
Iout (A)
12
16
20
Iout (A)
Output Ripple vs Load Current; Vin =48V (See Note A)
Safe Operating Area; Vin =48V (See Note B)
100
90
Ripple - mV
VOUT
3.3V
2.5V
1.8V
1.5V
60
40
20
Ambient Temperature (°C)
80
80
Airflow
70
300LFM
200LFM
100LFM
Nat conv
60
50
40
30
0
20
0
4
8
12
16
20
0
Iout (A)
4
8
12
16
20
Iout (A)
Note A: All data listed in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the DC-DC Converter.
Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperature.
For technical support and more information, see inside back cover or visit www.ti.com
PT4402—48V
75-W 48-V Input Isolated
DC/DC Converter
PT4402 Specifications
(Unless otherwise stated, T a =25°C, Vin =48V, Vo =1.5V, C o =0µF, and Io =Iomax)
Characteristic
Symbol
Conditions
Min
PT4402
Typ
Max
Units
Output Current
Input Voltage Range
Set Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Voltage Variation
Io
Vin
Vo tol
Regtemp
Regline
Regload
∆Votot
Over Vin range
Over Io Range
0
36
—
—
—
—
—
48
±0.6 (1)
±0.8
±1
±1
20
75
—
—
—
—
A
V
%Vo
%Vo
mV
mV
—
±1.6
±3
%Vo
Efficiency
Vo Ripple (pk-pk)
Transient Response
η
Vr
ttr
∆Vtr
ITRIP
OVP
ƒo
UVLO
—
—
—
—
—
—
—
—
84
40
75
±3
28
125
300
32
—
—
—
—
—
—
—
—
%
mVpp
µs
%Vo
A
%Vo
kHz
V
4.5
–0.2
—
—
—
0
1500
—
10
—
—
–0.3
2
1.4
Open (2)
+0.8
—
—
—
5,000
—
—
—
V
Over-Current Threshold
Output Over-Voltage Protection
Switching Frequency
Under-Voltage Lockout
Remote On/Off Input
Input High Voltage
Input Low Voltage
Input Low Current
–40° >Ta > +85°C
Over Vin range
Over Io range
Includes set-point, line, load,
–40° >Ta > +85°C
Io =10A
20MHz bandwidth
1A/µs load step, 50% to 100% Iomax
Vo over/undershoot
Shutdown, followed by auto-recovery
Output shutdown and latch off
Over Vin range
Referenced to –Vin
VIH
VIL
IIL
Iin standby
Cin
Cout
Standby Input Current
Internal Input Capacitance
External Output Capacitance
Isolation Voltage
Capacitance
Resistance
pins 1 & 2 connected
Between +Vo and –Vo
Input-output & input-case
Input-output
Input-output
—
1200
—
mA
mA
µF
µF
Vdc
pF
MΩ
Notes: (1) If (–)Remote Sense is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy.
(2) The Remote On/Off input has an internal pull-up. If it is left open-circuit the module will operate when input power is applied. A discrete MOSFET or
bipoloar transistor is recommended to control this input. The open-circuit voltage is typically 5V. See application notes for interface considerations.
PT4402 Characterstic Data
Power Dissipation vs Load Current; Vo =1.5V (See Note A)
Efficiency vs Load Current; Vin =48V (See Note A)
10
90
8
VIN
VOUT
Pd - Watts
Efficiency - %
80
1.75V
1.5V
1.2V
1.05V
70
60
75.0V
60.0V
48.0V
36.0V
6
4
2
0
50
0
4
8
12
16
0
20
4
8
12
16
20
Iout (A)
Iout (A)
Output Ripple vs Load Current; Vin =48V (See Note A)
Safe Operating Area; Vin =48V (See Note B)
90
100
Ripple - mV
VOUT
1.75V
1.5V
1.2V
1.05V
60
40
20
Ambient Temperature (°C)
80
80
70
60
200LFM
100LFM
Nat conv
50
40
30
0
0
4
8
12
Iout (A)
16
20
20
0
4
8
12
16
20
Iout (A)
Note A: All data listed in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the DC-DC Converter.
Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperature.
For technical support and more information, see inside back cover or visit www.ti.com
PT4403—48V
75-W 48-V Input Isolated
DC/DC Converter
PT4403 Specifications
(Unless otherwise stated, T a =25°C, Vin =48V, Vo =5.02V, C o =0µF, and I o =Iomax)
Characteristic
Symbol
Conditions
Min
PT4403
Typ
Max
Units
Output Current
Input Voltage Range
Set Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Voltage Variation
Io
Vin
Vo tol
Regtemp
Regline
Regload
∆Votot
Over Vin range
Over Io Range
0
36
—
—
—
—
—
48
±0.6 (1)
±0.8
±2
±1
15
75
—
—
—
—
A
V
%Vo
%Vo
mV
mV
—
±1.6
±3
%Vo
Efficiency
Vo Ripple (pk-pk)
Transient Response
η
Vr
ttr
∆Vtr
ITRIP
OVP
ƒo
UVLO
—
—
—
—
—
—
—
—
91
70
75
±2
23
125
300
32
—
—
—
—
—
—
—
—
%
mVpp
µs
%Vo
A
%Vo
kHz
V
4.5
–0.2
—
—
—
0
1500
—
10
—
—
–0.3
2
1.4
Open (2)
+0.8
—
—
—
5,000
—
—
—
V
Over-Current Threshold
Output Over-Voltage Protection
Switching Frequency
Under-Voltage Lockout
Remote On/Off Input
Input High Voltage
Input Low Voltage
Input Low Current
–40° >Ta > +85°C
Over Vin range
Over Io range
Includes set-point, line, load,
–40° >Ta > +85°C
20MHz bandwidth
1A/µs load step, 50% to 100% Iomax
Vo over/undershoot
Shutdown, followed by auto-recovery
Output shutdown and latch off
Over Vin range
Referenced to –Vin
VIH
VIL
IIL
Iin standby
Cin
Cout
Standby Input Current
Internal Input Capacitance
External Output Capacitance
Isolation Voltage
Capacitance
Resistance
pins 1 & 2 connected
Between +Vo and –Vo
Input-output & input-case
Input-output
Input-output
—
1200
—
mA
mA
µF
µF
Vdc
pF
MΩ
Notes: (1) If (–)Remote Sense is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy.
(2) The Remote On/Off input has an internal pull-up. If it is left open-circuit the module will operate when input power is applied. A discrete MOSFET or
bipoloar transistor is recommended to control this input. The open-circuit voltage is typically 5V. See application notes for interface considerations.
PT4403 Characterstic Data
Efficiency vs Load Current; Vo =5V (See Note A)
Power Dissipation vs Load Current; Vo =5V (See Note A)
10
100
8
90
VIN
36.0V
48.0V
60.0V
75.0V
80
70
Pd - Watts
Efficiency - %
VIN
75.0V
60.0V
48.0V
36.0V
6
4
2
60
0
50
0
3
6
9
12
0
15
3
6
12
15
Safe Operating Area; Vin =48V (See Note B)
Output Ripple vs Load Current; Vo =5V (See Note A)
90
150
VIN
100
75.0V
60.0V
48.0V
36.0V
75
50
25
Ambient Temperature (°C)
80
125
Ripple - mV
9
Iout (A)
Iout (A)
70
Airflow
60
200LFM
100LFM
Nat conv
50
40
30
0
20
0
3
6
9
12
15
0
Iout (A)
3
6
9
12
15
Iout (A)
Note A: All data listed in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the DC-DC Converter.
Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperature.
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT4400 Series
Operating Features and System Considerations for
the PT4400 Series of Isolated DC/DC Converters
Over-Current Protection
To protect against load faults, the PT4400 series incorporates output over-current protection. Applying a load
that exceeds the converter’s over-current threshold (see
applicable specification) will cause the regulated output
to momentarily fold back and shut down. Following
shutdown the module will periodically 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 operation.
Output Over-Voltage Protection
The PT4400 DC/DC converter series incorporates protection circuitry that continually senses for an output
overvoltage (OV) condition. The OV threshold automatically tracks the VID output voltage program setting
to a level that is 25% higher than that programmed at
the control pins, VID0 through VID4. If the converter
output voltage exceeds this OV threshold, the converter
is immediately shut down and remains in a latched-off
state. In order to resume normal operation the converter
must be actively reset. This can only be done by momentarily removing the input power to the converter. For
failsafe operation and redundancy, the OV protection
uses circuitry that is independent of the converter’s
internal feedback loop.
Over-Temperature Protection
Over-temperature protection is provided by an internal
temperature sensor, which closely monitors the temperature of the converter’s metal case. If the case temperature
exceeds a nominal 115°C, the converter will shut down.
The converter will then automatically restart when the
sensed temperature drops back to approximately 105°C.
When operated outside its recommended thermal derating
envelope (see data sheet SOA curves), the converter will
typcially cycle on and off at intervals from a few seconds
to one or two minutes. This is to ensure that the internal
components are not permanently damaged from excessive thermal stress.
Under-Voltage Lockout
The Under-Voltage Lock-Out (UVLO) is designed to
prevent the operation of the converter until the input
voltage is close to the minimum input voltage. The
converter is held off when the input voltage is below the
UVLO threshold, and turns on when the input voltage
rises above the threshold. This prevents 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 converter will meet
full specifications when the minimum specified input
voltage is reached. The UVLO circuitry also overrides
the operation of the Remote On/Off control. Only when
the input voltage is above the UVLO threshold will
the Remote On/Off control be functional.
Primary-Secondary Isolation
The PT4400 DC/DC converter series incorporates electrical isolation between the input terminals (primary) and
the output terminals (secondary). All converters are
production tested to a withstand voltage of 1500VDC.
This specification complies with UL60950 and EN60950
and the requirements for operational isolation. This allows
the converter to be configured for either a positive or
negative input voltage source. The data sheet ‘Pin Descriptions’ section provides guidance as to the correct
reference that must be used for the external control signals.
Fuse Recommendations
If desired, an input fuse may be added to protect against
the application of a reverse input voltage.
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 specifications). The recommended direction for airflow is into,
or perpendicular to, the longest side of the module’s
metal case. See Figure 1.
Figure 1
Recommended direction for airflow is
into (perpendicular to) the longest side.
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT4400 Series
Using the Remote On/Off Function on the PT4400
Series of Isolated DC/DC Converters
For applications requiring output voltage On/Off control,
the PT4400 DC/DC converter series incorporates a “Remote On/Off” control (pin 1). This feature can be used to
switch the module off without removing the applied
input source voltage.
Table 2; UVLO Thresholds 4
Series
Vin Range
UVLO Threshold
PT4400
36 – 75V
32V ±2V
Figure 1
+ REMOTE SENSE
+V s n s
+V IN
4, 5
+V o u t
+V i n
–V IN
2, 3
-V o u t
Remote
On/Off
Table 1; Pin 1 Remote On/Off Control Requirements 1
Parameter
Min
Typ
Enable (VIH)
4.5V
—
—
Disable (VIL)
—
—
0.8V
Vo/c [Open-Circuit]
Iin [pin 1 at –Vin]
Max
5.0V
—
—
–0.5mA
Notes:
1. The Remote On/Off control uses –Vin (pins 2, 3) as its
ground reference. All voltages are with respect to –Vin.
2. Use an open-collector device (preferably a discrete
transistor) for the Remote On/Off input. A pull-up
resistor is not necessary. To disable the output voltage,
the control pin should be pulled low to less than +0.8V.
8
9
10 11
Note 1
13–16
0V
-V s n s
12
Q1
BSS138
1 =OFF
– REMOTE SENSE
PROGRAMMING PINS
Vdd
R1
10k
U1a
Note 1
Turn-On Time: In the circuit of Figure 1, turning Q1 on
applies a low-voltage to pin 1 and disables the converter
output. Correspondingly, turning Q1 off allows pin 1 to
be pulled high by an internal pull-up resistor. The converter produces a regulated output voltage within 50ms.
Figure 2 shows the output response of a PT4401 following
the turn-off of Q1. The turn off of Q1 corresponds to the
drop in Q1 Vgs. Although the rise-time of the output
voltage is short (<5ms), the indicated delay time will
vary depending upon the input voltage and the module’s
internal timing. The output voltage of the PT4401 was
set to 3.3V by connecting VID0 (pin 7), VID2 (pin 9),
and VID3 (pin 10) to the (–)Remote Sense (pin 12). The
waveforms were measured with 48VDC input voltage,
and a 10A resistive load.
Figure 2
3. The Remote On/Off pin may be controlled with devices that
have a totem-pole output. This is provided the output
high-level voltage (VOH) meets the module’s minimum
VIH specified in Table 1. Do not apply more than +20V.
If a TTL gate is used, a pull-up resistor may be required to
the logic supply voltage.
4. The PT4400 converters incorporate an “Under-Voltage
Lockout” (UVLO). The UVLO keeps the converter
off until the input voltage is close to the minimum
specified operating voltage. This is regardless of the
state of the Remote On/Off control. Table 2 gives the
UVLO input voltage thresholds.
VID0 - VID4
7
L
O
A
D
Co
–V i n
1
When placed in the “Off” state, the standby current drawn
from the input source is typically reduced to less than 1mA.
17–20
PT4401
Note 1
Figure 1 is an application schematic, which shows the
typical use of the Remote On/Off function. Note the discrete transistor (Q1). The Remote On/Off pin has its
own internal pull-up, allowing it to be controlled with an
open-collector or open-drain device (See notes 2 & 3).
Table 1 gives the threshold requirements.
+3.3V
21
+
The converter functions normally with Pin 1 open-circuit,
providing a regulated output voltage when a valid source
voltage is applied to +Vin (pins 4, 5), with respect to
-Vin (pins 2, 3). When a low-level 1 ground signal is
applied to pin 1, the converter output will be turned off.
Vo (1V/Div)
Iin (1A/Div)
Delay Time
Q1 Vgs (10V/Div)
HORIZ SCALE: 5ms/Div
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT4400 Series
Pin-Coded Output Voltage Adjustment on the
PT4400 Programmable DC/DC Converters
5. On all models other than the PT4401, the contol input
VID4 (pin 11) is internally disabled and not functional.
6. 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
voltage control circuit. Discrete transistors such as the
BSS138 or IRLML2402 are examples of appropriate
devices.
The PT4400 series of isloated DC/DC converters have
a programmable output voltage. In each case the desired
output voltage must be selected from one of a number of
discrete voltages using the voltage programming control
pins. Depending on each model’s resolution and adjustment range, there are up to five control pins. They are
identified VID0–VID4 (pins 7–11) respectively. By
selectively strapping these control pins to (–)Remote
Sense (pin 12), the output voltage can be programmed
in incremental steps over the defined output voltage range.
The program code and output voltage range of the PT4401
is also compatible with the “Voltage ID” code defined in
the Intel® VRM 8.2 specification. Refer to Figure 1 for
the connection schematic, and the product specification
sheet for each model’s applicable program code.
Active Voltage Programming:
Special precautions should be taken when making changes
to the voltage progam code while the output is active.
This activity induces a transient, which may activate
the module’s output over-voltage (OV) protection. Once
triggered the OV protection circuit latches the output
off, and requires the momentary removal of input power
to reset the module. OV protection trips can be avoided
by limiting the output voltage adjustment to no more
than a 15% change from the initial voltage. Large transitions are best made with a series of incremental changes,
allowing 100µs settling time between each program state.
When using active devices to program the output voltage,
their state should be asserted prior to input power being
applied. An alternative is to pull pin 1 (Remote On/Off)
to -Vin (pins 2, 3) during the application of power, assert
the required program code, and then release pin 1. The
module will than initiate a soft-start power-up to the
desired program voltage.
Notes:
1. The programming convention is as follows:Logic 0:
Connect to pin 12 (–Remote Sense).
Logic 1:
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
(-Remote Sense) as the logic “0” reference. While -Vout
(pins 13-16) can also be used for programming, doing so
will degrade the voltage selection accuracy and load
regulation of the product.
4. When VID0–VID4 are all open circuit (logic 1), the
output voltage is undefined. In this state the output
voltage of the converter cannot be guaranteed, and can
vary with output load and input voltage.
Figure 1
+ REMOTE SENSE
+ VOUT
21
– V IN
4, 5
+ V in
+ V out
PT4400
2, 3
- V out
1
VID0 - VID4
7
8
9
L
O
A
D
Co
– V in
Remote
On/Off
INH
17–20
+
+ V IN
+ V sns
10 11
- V sns
13–16
– VOUT
12
Q1
BSS138
– REMOTE SENSE
PROGRAMMING PINS
For technical support and more information, see inside back cover or visit www.ti.com
PACKAGE OPTION ADDENDUM
www.ti.com
6-Dec-2006
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
PT4401A
ACTIVE
SIP MOD
ULE
ENN
21
8
TBD
Call TI
Level-1-215C-UNLIM
PT4401N
ACTIVE
SIP MOD
ULE
ENM
21
8
TBD
Call TI
Level-1-215C-UNLIM
PT4403A
NRND
SIP MOD
ULE
ENN
21
8
TBD
Call TI
Level-1-215C-UNLIM
PT4403N
ACTIVE
SIP MOD
ULE
ENM
21
8
TBD
Call TI
Level-1-215C-UNLIM
Lead/Ball Finish
MSL Peak Temp (3)
(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.
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Addendum-Page 1
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