Datasheet

PTN78020W
PTN78020H
SLTS228C – DECEMBER 2004– REVISED AUGUST 2011 www.ti.com
ELECTRICAL CHARACTERISTICS
operating at 25°C free-air temperature, V
I
= 24 V, V
O
= 12 V, I
O
= I
O
(max), C
I
= 4× 4.7 µF, C
O
= 330 µF (unless otherwise
noted)
PTN78020H
PARAMETER TEST CONDITIONS
MIN TYP MAX UNIT
V
o
=12 V 0.1 6
(1)
I
O
Output current T
A
= 25°C, natural convection airflow V
o
=15 V 0.1 6
(1) (2)
A
V
o
= 22 V 0.1 4.09
(2)
V
I
Input voltage range Over I
O
range 15
(3)
36 V
Set-point voltage tolerance T
A
= 25°C ±2%
(4)
Temperature variation –40°C to +85°C ±0.5%
Line regulation Over V
I
range ±10 mV
V
O
Load regulation Over I
O
range ±10 mV
Includes set point, line, load
Total output voltage variation ±3%
(4)
–40 < T
A
< 85°C
V
I
< 19 V 11.85 V
I
– 3
19 V ≤ V
I
≤ 25 V 11.85 V
I
– 4
V
O
(adj) Output voltage adjust range V
V
I
> 25 V 11.85 22
V
I
= 24 V, R
SET
= 383 k Ω, V
O
= 12 V 94%
η Efficiency V
I
= 24 V, R
SET
= 15 kΩ, V
O
= 15 V 95%
V
I
= 32 V, R
SET
= 95.3 Ω, V
O
= 22 V 96%
Output voltage ripple 20-MHz bandwith 1% V
O
V
(PP)
I
O (LIM)
Current limit threshold ΔV
O
= –50 mV 8.0 A
1 A/µs load step from 50% to 100% I
O
max
Transient response Recovery time 200 µs
V
O
over/undershoot 200 mV
Input high voltage (V
IH
) 1 Open
(5)
V
Inhibit control (pin 3) Input low voltage (V
IL
) –0.1 0.3
Input low current (I
IL
) 0.25 mA
I
I(stby)
Input standby current Pin 3 connected to GND 17 mA
V
I
increasing 12.2
UVLO Undervoltage lockout V
V
I
decreasing 12
F
S
Switching frequency Over V
I
and I
O
ranges 440 550 660 kHz
C
I
External input capacitance Ceramic and nonceramic 18.8
(6)
µF
Ceramic 0 300
µF
C
O
External output capacitance Nonceramic 330
(7)
2,000
Equiv. series resistance (nonceramic) 10
(8)
mΩ
Per Telcordia SR-332, 50% stress,
MTBF Calculated reliability 5.6
10
6
Hr
T
A
= 40°C, ground benign
(1) The maximum output current is 6 A or a maximum output power of 90 W, whichever is less. Above an input voltage of 24 V, the
maximum output current must be derated by 125 mA per volt above 24 V. See the Typica lCharacteristics section for further guidance.
(2) Above an output voltage of 15 V, the maximum output current must be derated by 285 mA per volt. The maximum output power is 90 W.
See the application information for further guidance.
(3) For output voltages less than 19 V, the minimum input voltage is 15 V or (V
O
+ 3) V, whichever is greater. For output voltages of 19 V
and higher, the minimum input voltage is (V
O
+ 4 V). See the Application Information section for further guidance.
(4) 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 with 100 ppm/°C or better temperature stability.
(5) This control pin has an internal pullup, and if left open-circuit, the module operates when input power is applied. The open-circuit voltage
is typically 1.5 V. A small, low-leakage (< 100 nA) MOSFET is recommended for control. See the Application Information section for
further guidance.
(6) Four external 4.7-µF ceramic capacitors are required across the input (V
I
and GND) for proper operation. Locate the capacitors close to
the module.
(7) 330 µF of output capacitance is required for proper operation. See the Application Information section for further guidance.
(8) This is the typical ESR for all the electrolytic (nonceramic) capacitance. Use 17 mΩ as the minimum when using max-ESR values to
calculate.
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