PTH08T255W
www.ti.com ........................................................................................................................................................................................... SLTS290 – NOVEMBER 2008
40-A, 8-V to 14-V INPUT, 3-V to 5.25-V OUTPUT,
NON-ISOLATED, ADJUSTABLE POWER MODULE
FEATURES
1
•
•
•
•
•
•
2
•
•
•
•
•
•
•
•
•
Up to 40-A Output Current
8-V to 14-V Input Voltage
Wide-Output Voltage Adjust (3.0 V to 5.25 V)
±1.5% Total Output Voltage Variation
Efficiencies up to 96%
Output Overcurrent Protection
(Nonlatching, Auto-Reset)
Operating Temperature: –40°C to 85°C
Safety Agency Approvals: (Pending)
– UL/IEC/CSA-C22.2 60950-1
Prebias Startup
On/Off Inhibit
Differential Output Voltage Remote Sense
Adjustable Undervoltage Lockout
Auto-Track™ Sequencing
Multi-Phase, Switch-Mode Topology
TurboTrans™ Technology
•
•
•
Designed to meet Ultra-Fast Transient
Requirements up to 300 A/µs
SmartSync Technology
Parallel Operation
APPLICATIONS
•
•
•
Complex Multi-Voltage Systems
Servers
Workstations
DESCRIPTION
The PTH08T255W is a high-performance 40-A rated, non-isolated power module. This module represents the
2nd generation of the popular PTH series power modules with a reduced footprint and improved features.
Operating from an input voltage range of 8 V to 14 V, the PTH08T255W requires a single resistor to set the
output voltage to any value over the range, 3.0 V to 5.25 V. The wide input voltage range makes the
PTH08T255W particularly suitable for advanced computing and server applications that utilize a loosely
regulated 9.6-V to 12-V intermediate distribution bus.
The module incorporates a comprehensive list of features. Output overcurrent and over-temperature shutdown
protects against most load faults. A differential remote sense ensures tight load regulation. An adjustable
under-voltage lockout allows the turn-on voltage threshold to be customized. Auto-Track™ sequencing is a
popular feature that greatly simplifies the simultaneous power-up and power-down of multiple modules in a
power system. Additionally, the capability to current share between multiple PTH08T255W modules allows for
load currents greater than 40A on a single rail.
The PTH08T255W includes new patented technologies, TurboTrans™ and SmartSync. The TurboTrans feature
optimizes the transient response of the regulator while simultaneously reducing the quantity of external output
capacitors required to meet a target voltage deviation specification. Additionally, for a target output capacitor
bank, TurboTrans can be used to significantly improve the regulators transient response by reducing the peak
voltage deviation. SmartSync allows for switching frequency synchronization of multiple modules, thus simplifying
EMI noise suppression tasks and reducing input capacitor RMS current requirements.
The module uses double-sided surface mount construction to provide a low profile and compact footprint.
Package options include both through-hole and surface mount configurations that are lead (Pb) - free and RoHS
compatible.
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Auto-Track, TMS320, TurboTrans are trademarks of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008, Texas Instruments Incorporated
PTH08T255W
SLTS290 – NOVEMBER 2008 ........................................................................................................................................................................................... www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
STANDARD APPLICATION
[A]
20
VI
2
Track
6
VI
7
VI
3
5
RTT
1%
0.05 W
(Optional)
+Sense
19
Share Comp CLKIO
TT
+Sense 17
14 VI
VO 10
15 VI
VO 11
PTH08T255W
Inhibit
21 Inhibit/UVLO
-Sense 16
22 SmartSync
+
Config
1
CI
1000 mF
(Required)
GND
GND
8
9
12
13
VO
AGND
VOAdj
4
18
RSET
1%, 0.05 W
(Required)
+ C
O
1000 mF
(Required)
L
O
A
D
-Sense
GND
UDG-08144
A.
When using the AutoTrack feature with the PTH08T225W, a 100-kΩ pull-up resistor to VI is required. If the AutoTrack
feature is not used, this pin must be directly connected to VI.
2
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
www.ti.com ........................................................................................................................................................................................... SLTS290 – NOVEMBER 2008
ORDERING INFORMATION
For the most current package and ordering information, see the Package Option Addendum at the end of this datasheet, or see
the TI website at www.ti.com.
DATASHEET TABLE OF CONTENTS
DATASHEET SECTION
PAGE NUMBER
ENVIRONMENTAL AND ABSOLUTE MAXIMUM RATINGS
3
ELECTRICAL CHARACTERISTICS TABLE (PTH08T255W)
4
TERMINAL FUNCTIONS
6
TYPICAL CHARACTERISTICS (VI = 12V)
7
ADJUSTING THE OUTPUT VOLTAGE
8
INPUT & OUTPUT CAPACITOR RECOMMENDATIONS
9
TURBOTRANS™ INFORMATION
13
SOFT-START POWER-UP
17
REMOTE SENSE
17
OUTPUT INHIBIT
18
OVERCURRENT PROTECTION
18
OVER-TEMPERATURE PROTECTION
18
SYCHRONIZATION (SMARTSYNC)
19
AUTO-TRACK SEQUENCING
20
UNDERVOLTAGE LOCKOUT (UVLO)
23
CURRENT SHARING
24
CURRENT SHARING SOA GRAPHS
26
CURRENT SHARING LAYOUT
27
PREBIAS START-UP
27
TAPE & REEL AND SHIPPING TRAY DRAWING
29
ENVIRONMENTAL AND ABSOLUTE MAXIMUM RATINGS
(Voltages are with respect to GND)
UNIT
Vtrack
Track pin voltage
–0.3 to VI + 0.3
TA
Operating temperature range Over VI range
Twave
Wave soldering temperature
Surface temperature of module body or pins
(5 seconds maximum)
Treflow
Solder reflow temperature
Surface temperature of module body or pins
Tstg
Storage temperature
Storage temperature of module removed from shipping package
Tpkg
Packaging temperature
Shipping Tray or Tape and Reel storage or bake temperature
45
Mechanical shock
Per Mil-STD-883D, Method 2002.3 1 msec, 1/2
sine, mounted
AD suffix
500
AS and AZ suffix
125
Mechanical vibration
Mil-STD-883D, Method 2007.2 20-2000 Hz
Weight
Flammability
(1)
V
–40 to 85
AD suffix
260
AS suffix
235 (1)
AZ suffix
260 (1)
°C
–55 to 125
G
20
16.7
grams
Meets UL94V-O
During reflow of surface mount package version do not elevate peak temperature of the module, pins or internal components above the
stated maximum.
3
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
SLTS290 – NOVEMBER 2008 ........................................................................................................................................................................................... www.ti.com
ELECTRICAL CHARACTERISTICS
PTH08T255W
TA = 25°C, VI = 12 V, VO = 3.3 V, CI = 1000 µF, CO = 1000 µF, and IO = IO max (unless otherwise stated)
PARAMETER
TEST CONDITIONS
PTH08T255W
MIN
TYP
UNIT
MAX
25°C, natural convection
0
40
60°C, 200 LFM
0
40
IO
Output current
Over VO range
VI
Input voltage range
Over IO and VO range
8.0
14
VOADJ
Output voltage adjust range
Over IO range
3.0
5.25
Set-point voltage tolerance
VO
η
ILIM
±0.5
–40°C < TA < 85°C
±0.3
%Vo
Over VI range
±5
mV
Load regulation
Over IO range
±5
Total output variation
Includes set-point, line, load, –40°C ≤ TA ≤ 85°C
Efficiency
IO = 30 A
VO Ripple (peak-to-peak)
20-MHz bandwidth
20
Overcurrent threshold
Reset, followed by auto-recovery
80
A
Recovery time
200
µs
VO over/undershoot
135
mV
Recovery time
400
µs
35
mV
Transient response
2.5 A/µs load step
50 to 100% IOmax
ΔVtrTT
95%
RSET = 34.5 kΩ, VO = 3.3 V
94%
w/o TurboTrans
CO= 1000 µF, TypeC
w/ TurboTrans
CO= 5000 µF, TypeC
RTT = short
VO over/undershoot
Pin to GND
dVtrack/dt
Track slew rate capability
CO ≤ CO (max)
UVLOADJ
VI increasing, RUVLO = OPEN
Adjustable Under-voltage lockout
VI decreasing, RUVLO = OPEN
(pin 21)
Hysteresis
7.2
Inhibit (pin 21) to GND, Track (pin 20) open
fs
Switching frequency
Over VI and IO ranges, SmartSync (pin 22) to GND
Open (3)
-0.2
tSYNC
CI
(1)
(2)
(3)
(4)
(5)
0.6
240
SYNC High-Level Input Voltage
µA
35
mA
(4)
(4)
(4)
5.5
SYNC Low-Level Input Voltage
0.8
200
Nonceramic
External input capacitance
kHz
400
2.0
SYNC Minimum Pulse Width
Ceramic
1000
V
-125
600
Synchronization frequency applied to pin 22
Synchronization (SYNC)
control (pin 22)
V
0.5
Input low current (IIL ), Pin 21 to GND
Input standby current
µA
V/ms
8.0
6.7
Input low voltage (VIL)
Iin
%Vo
mVPP
1
Input high voltage (VIH)
fSYNC
(1)
–130 (2)
Track input current (pin 20)
Inhibit control (pin 21)
mV
±1.5
RSET = 1.36 kΩ, VO = 5.0 V
IIL
VSYNCL
V
%Vo
Line regulaltion
ΔVtr
VSYNCH
(1)
V
Temperature variation
ttr
ttrTT
±1
A
kHz
V
V
nSec
(5)
22
µF
The set-point voltage tolerance is affected by the tolerance and stability of RSET. The stated limit is unconditionally met if RSET has a
tolerance of 1% with 100 ppm/C or better temperature stability.
A low-leakage ( 4700 µF).
To ensure stability, a minimum amount of output capacitance is required for a given RTT resistor value. The value
of RTT must be calculated using the minimum required output capacitance determined from Figure 8.
15
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
SLTS290 – NOVEMBER 2008 ........................................................................................................................................................................................... www.ti.com
TurboTrans
AutoTrack
RTT
20 kW
TurboTrans
+Sense
VI
+Sense
VI
VO
VO
PTH08T255W
Inhibit/UVLO
+
-Sense
CO
2000 mF
Type B
+
SmartSync Config
CI
1000 mF
(Required)
CI2
22 mF
GND
AGND
VOAdj
RSET
L
O
A
D
-Sense
GND
GND
UDG-08146
Figure 9. Typical TurboTrans™ Application
16
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
www.ti.com ........................................................................................................................................................................................... SLTS290 – NOVEMBER 2008
Soft-Start Power Up
The Auto-Track feature allows the power-up of multiple PTH/PTV modules to be directly controlled from the
Track pin. However in a stand-alone configuration, or when the Auto-Track feature is not being used, the Track
pin should be directly connected to the input voltage, VI (see Figure 10).
VI
(5 V/div)
20
Track
VI
6
VI
7
VI
PTH08T255W
14 VI
+
15 VI
CI
GND GND GND GND
8
9
12
13
VO
(2 V/div)
GND
II
(5 A/div)
UDG-08147
t – Time – 10 ms/div
Figure 10. Defeating the Auto-Track Function
Figure 11. Power-Up Waveform
When the Track pin is connected to the input voltage the Auto-Track function is permanently disengaged. This
allows the module to power up entirely under the control of its internal soft-start circuitry. When power up is
under soft-start control, the output voltage rises to the set-point at a quicker and more linear rate.
From the moment a valid input voltage is applied, the soft-start control introduces a short time delay (typically
10 ms–15 ms) before allowing the output voltage to rise.
The output then progressively rises to the module’s setpoint voltage. Figure 11 shows the soft-start power-up
characteristic of the PTH08T255W operating from a 12-V input bus and configured for a 5.0-V output. The
waveforms were measured with a 25-A constant current load and the Auto-Track feature disabled. The initial rise
in input current when the input voltage first starts to rise is the charge current drawn by the input capacitors.
Power-up is complete within 30 ms.
Differential Output Voltage Remote Sense
Differential remote sense improves the load regulation performance of the module by allowing it to compensate
for any IR voltage drop between its output and the load in either the positive or return path. An IR drop is caused
by the output current flowing through the small amount of pin and trace resistance. With the sense pins
connected, the difference between the voltage measured directly between the VO and GND pins, and that
measured at the Sense pins, is the amount of IR drop being compensated by the regulator. This should be
limited to a maximum of 0.3V.
If the remote sense feature is not used at the load, connect +Sense (pin 17) to VO (pin11) and connect –Sense
(pin 16) to the module GND (pin 13).
The remote sense feature is not designed to compensate for the forward drop of nonlinear 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
connection they are effectively placed inside the regulation control loop, which can adversely affect the
stability of the regulator.
17
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
SLTS290 – NOVEMBER 2008 ........................................................................................................................................................................................... www.ti.com
On/Off Inhibit
For applications requiring output voltage on/off control, the PTH08T255W incorporates an Inhibit control pin. The
inhibit feature can be used wherever there is a requirement for the output voltage from the regulator to be turned
off. The power modules function normally when the Inhibit pin is left open-circuit, providing a regulated output
whenever a valid source voltage is connected to VI with respect to GND.
Figure 12 shows the typical application of the inhibit function. Note the discrete transistor (Q1). The Inhibit input
has its own internal pull-up. An external pull-up resistor should never be used with the inhibit pin. The input is not
compatible with TTL logic devices. An open-collector (or open-drain) discrete transistor is recommended for
control.
When Q1 it turned on, low voltage is applied to the Inhibit control pin and disables the output of the module. If Q1
is then turned off, the module executes a soft-start power-up sequence. A regulated output voltage is produced
within 20 ms. Figure 13 shows the typical rise in both the output voltage and input current, following the turn-off
of Q1. The turn off of Q1 corresponds to the rise in the waveform, VINH. The waveforms were measured with a
25-A constant current load.
VI
6
VI
7
VI
VO
(2 V/div)
PTH08T255W
14 VI
+
15 VI
CI
21 Inhibit/UVLO
GND GND GND GND
1=Inhibit
8
9
12
13
Q1
BSS 138
II
(5 A/div)
GND
VINH
(2 V/div)
UDG-08148
t – Time – 10 ms/div
Figure 12. On/Off Inhibit Control Circuit
Figure 13. Power-Up Response from Inhibit Control
Overcurrent Protection
For protection against load faults, all modules incorporate output overcurrent protection. Applying a load that
exceeds the regulator's overcurrent threshold causes the regulated output to shut down. Following shutdown, the
module periodically attempts to recover by initiating a soft-start power-up. This is described as a hiccup mode of
operation, whereby the module continues in a 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 module automatically recovers and returns to normal operation.
Overtemperature Protection (OTP)
A thermal shutdown mechanism 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, the module’s Inhibit control is internally pulled low. This turns
the output off. The output voltage drops as the external output capacitors are discharged by the load circuit. The
recovery is automatic, and begins with a soft-start power up. It occurs when the sensed temperature decreases
by about 10°C below the trip point.
18
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PTH08T255W
PTH08T255W
www.ti.com ........................................................................................................................................................................................... SLTS290 – NOVEMBER 2008
The overtemperature 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 reduces 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.
Smart Sync
Smart Sync is a feature that allows multiple power modules to be synchronized to a common frequency. When
not used, this pin must be connect to GND. Driving the Smart Sync pins with an external oscillator set to the
desired frequency, synchronizes all connected modules to the selected frequency. The synchronization
frequency can be higher or lower than the nominal switching frequency of the modules within the range of
240 kHz to 400 kHz.
Synchronizing modules powered from the same bus eliminates beat frequencies reflected back to the input
supply, and also reduces EMI filtering requirements. Eliminating the low beat frequencies (usually