Datasheet

-50 -25 0 25 50 75 100 125 150
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
±3 Sigma
Typical
+3 Sigma
Junction Temperature (°C)
COMP Voltage (V)
RDSON-StaticDrain-SourecOnStateResistance- W
0
20
40
60
80
100
120
140
160
180
200
-50 -25 0 25 50 75 100 125 150
T -JunctionTemperature-°C
J
V =3.3V
IN
PWRGD-Threshold-%V
ref
88
90
92
94
96
98
100
102
104
106
108
110
VsenseRising,V =3.3V
IN
VsenseRising
VsenseFalling
VsenseFalling
-50 -25 0 25 50 75 100 125 150
T -JunctionTemperature-°C
J
I -SupplyCurrent- A
CC
m
300
310
320
330
340
350
360
370
380
390
400
3 3.5 4 4.5 5 5.5 6
V -InputVoltage-V
IN
T =25°C
J
TPS54218
SLVS974B –SEPTEMBER 2009–REVISED JULY 2013 www.ti.com
TYPICAL CHARACTERISTICS CURVES (continued)
SUPPLY CURRENT vs INPUT VOLTAGE PWRGD THRESHOLD vs TEMPERATURE
Figure 19. Figure 20.
MINIMUM COMP VOLTAGE CLAMP
vs
PWRGD ON RESISTANCE vs TEMPERATURE TEMPERATURE
Figure 21. Figure 22.
OVERVIEW
The TPS54218 is a 6-V, 2 A, synchronous step-down (buck) converter with two integrated n-channel MOSFETs.
To improve performance during line and load transients the device implements a constant frequency, peak
current mode control which reduces output capacitance and simplifies external frequency compensation design.
The wide switching frequency of 200 kHz to 2000 kHz allows for efficiency and size optimization when selecting
the output filter components. The switching frequency is adjusted using a resistor to ground on the RT/CLK pin.
The device has an internal phase lock loop (PLL) on the RT/CLK pin that is used to synchronize the power
switch turn on to a falling edge of an external system clock.
The TPS54218 has a typical default start up voltage of 2.6 V. The EN pin has an internal pull-up current source
that can be used to adjust the input voltage under voltage lockout (UVLO) with two external resistors. In addition,
the pull up current provides a default condition when the EN pin is floating for the device to operate. The total
operating current for the TPS54218 is 350 μA when not switching and under no load. When the device is
disabled, the supply current is less than 5 μA.
The integrated 30 mΩ MOSFETs allow for high efficiency power supply designs with continuous output currents
up to 2 amperes.
10 Submit Documentation Feedback Copyright © 2009–2013, Texas Instruments Incorporated
Product Folder Links :TPS54218