Datasheet

1
P2 = type 1
2 Ro (C2 + Co)´ ´p
1
P2 = type 2b
2 R3 | | Ro Co´ ´p
1
P2 = type 2a
2 R3 | | Ro (C2 + Co)´ ´p
1
Z1
2 R3 C1
=
p ´ ´
1
P1
2 Ro C1
=
p ´ ´
ea
R2
A1 = gm Ro| | R3
R1 + R2
´ ´
ea
R2
A0 = gm Ro
R1 + R2
´ ´
Z1
P1 P2
s
1
2
EA A0
s s
1 1
2 2
f
f f
æ ö
+
ç ÷
p ´
è ø
= ´
æ ö æ ö
+ ´ +
ç ÷ ç ÷
p ´ p ´
è ø è ø
ea
OUT
gm
C =
2 BW (Hz)´p
ea
Aol(V/V)
Ro =
gm
TPS54160 , TPS54160A
SLVSB56C –MAY 2012–REVISED FEBRUARY 2014 www.ti.com
Feature Description (continued)
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8.4 Device Functional Modes
8.4.1 Operation with V
IN
< 3.5 V (Minimum V
IN
)
The device is recommended to operate with input voltages above 3.5 V. The typical VIN UVLO threshold is 2.5 V
and the device may operate at input voltages down to the UVLO voltage. At input voltages below the actual
UVLO voltage, the device will not switch. The PWRGD output will be controlled once V
IN
is above 1.5 V
maximum. If EN is externally pulled up to V
IN
or left floating, when VIN passes the UVLO threshold the device will
become active. Switching is enabled the soft start sequence is initiated. The TPS54160 will start at the soft start
time determined by the external soft start capacitor at the SS/TR pin.
8.4.2 Operation with EN Control
The enable threshold voltage is 1.25 V typical. With EN held below that voltage the device is disabled and
switching is inhibited even if V
IN
is above its UVLO threshold. The IC quiescent current is reduced in this state. If
the EN voltage is increased above the threshold while V
IN
is above its UVLO threshold, the device becomes
active. Switching is enabled, and the soft start sequence is initiated. The TPS54160 will start at the soft start time
determined by the external slow start capacitor at the SS/TR pin.
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