Datasheet
PTH08T250W
SLTS278G –NOVEMBER 2010–REVISED MARCH 2009
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ELECTRICAL CHARACTERISTICS
PTH08T250W
T
A
= 25°C, V
I
= 12 V, V
O
= 3.3 V, C
I
= 1000 µF, C
O
= 660 µF, and I
O
= I
O
max (unless otherwise stated)
PARAMETER TEST CONDITIONS PTH08T250W UNIT
MIN TYP MAX
25°C, natural convection 0 48
I
O
Output current Over V
O
range A
60°C, 200 LFM 0 50
0.7 ≤ V
O
< 1.2 4.5 14
(1)
V
I
Input voltage range Over I
O
range V
1.2 ≤ V
O
≤ 3.6 4.5 14
V
OADJ
Output voltage adjust range Over I
O
range 0.7 3.6 V
Set-point voltage tolerance ±0.5 ±1
(2)
%V
o
Temperature variation –40°C < T
A
< 85°C ±0.3 %V
o
V
O
Line regulaltion Over V
I
range ±5 mV
Load regulation Over I
O
range ±5 mV
Total output variation Includes set-point, line, load, –40°C ≤ T
A
≤ 85°C ±1.5
(2)
%V
o
R
SET
= 1.62 kΩ, V
O
= 3.3 V 94%
R
SET
= 5.23 kΩ, V
O
= 2.5 V 93%
R
SET
= 12.7 kΩ, V
O
= 1.8 V 91%
h Efficiency I
O
= 30 A R
SET
= 19.6 kΩ, V
O
= 1.5 V 90%
R
SET
= 35.7 kΩ, V
O
= 1.2 V 88%
R
SET
= 63.4 kΩ, V
O
= 1.0 V 86%
R
SET
= open, V
O
= 0.7 V 83%
V
O
Ripple (peak-to-peak) 20-MHz bandwidth 10
(1)
mV
PP
I
LIM
Overcurrent threshold Reset, followed by auto-recovery 100 A
t
tr
Recovery time 100 µs
w/o TurboTrans
C
O
= 660 mF, Type C
ΔV
tr
V
O
over/undershoot 160 mV
2.5 A/µs load step
Transient response
50 to 100% I
O
max
t
trTT
w/ TurboTrans Recovery time 100 µs
C
O
= 3300 mF, Type C
mV
ΔV
trTT
V
O
over/undershoot 45
R
TT
= short
I
IL
Track input current (pin 20) Pin to GND –130
(3)
µA
dV
track
/dt Track slew rate capability C
O
≤ C
O
(max) 1 V/ms
V
I
increasing, R
UVLO
= OPEN 4.3 4.45
Adjustable Under-voltage lockout
UVLO
ADJ
V
I
decreasing, R
UVLO
= OPEN 4.0 4.2 V
(pin 21)
Hysteresis, R
UVLO
≤ 127 kΩ 1.0
Input high voltage (V
IH
) Open
(4)
V
Inhibit control (pin 21) Input low voltage (V
IL
) -0.2 0.6
Input low current (I
IL
), Pin 21 to GND -125 µA
I
in
Input standby current Inhibit (pin 21) to GND, Track (pin 20) open 35 mA
f
s
Switching frequency Over V
I
and I
O
ranges, SmartSync (pin 22) to GND 600
(5)
kHz
f
SYNC
Synchronization frequency applied to pin 22 240
(5)
400
(5)
kHz
V
SYNCH
SYNC High-Level Input Voltage 2.0 5.5 V
Synchronization (SYNC)
control (pin 22)
V
SYNCL
SYNC Low-Level Input Voltage 0.8 V
t
SYNC
SYNC Minimum Pulse Width 200 nSec
(1) For output voltages less than 1.2 V, the output ripple may increase (up to 2×) when operating at input voltages greater than (V
O
× 12).
Adjusting the switching frequency using the SmartSync feature may increase or decrease this ratio. Please review the SmartSync
section of the Application Information for further guidance.
(2) The set-point voltage tolerance is affected by the tolerance and stability of R
SET
. The stated limit is unconditionally met if R
SET
has a
tolerance of 1% with 100 ppm/°C or better temperature stability.
(3) A low-leakage (<100 nA), open-drain device, such as MOSFET or voltage supervisor IC, is recommended to control pin 20. The
open-circuit voltage is less than 8 V
dc
.
(4) Do not place an external pull-up on this pin. If it is left open-circuit, the module operates when input power is applied. A small,
low-leakage (<100 nA) MOSFET is recommended for control. For additional information, see the related application section.
(5) The PTH08T250W is a two-phase power module. Each phase switches at 300 kHz typical, 180° out of phase from one another. The
over-all switching frequency is 600 kHz typical. SmartSync controls the frequency of an individual phase. When using SmartSync the
external synchronization frequency must be present before a valid input voltage is present, or before the release of inhibit control.
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