Datasheet
TPS54120
www.ti.com
SBVS180C –JANUARY 2012–REVISED JUNE 2012
ELECTRICAL CHARACTERISTICS
At T
J
= –40°C to +125°C, V
(PVIN)
= V
(VIN)
= 12 V, V
(LDOIN)
= DC-DC_OUT
(1)
= 4.1 V, V
(OUT)
= 3.3 V, I
(OUT)
= 10 mA,
V
(EN)
= floating, C
(OUT)
= 100 μF, unless otherwise noted.
TPS54120
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
POWER SUPPLY (VIN AND PVIN PINS)
V
(PVIN)
PVIN pin input voltage range 1.6 17 V
VIN pin input voltage range 4.5 17 V
V
(VIN)
UVLO threshold VIN rising 4.0 4.5 V
UVLO hysteresis 150 mV
I
SD(VIN)
VIN pin shutdown current V
(EN)
= 0 V 2 5 µA
I
OP
VIN pin operating current (no switching) V
(VSENSE)
= 810 mV 600 800 µA
DC-DC BOOT (BOOT PIN)
(V
BOOT
– V
PH
) UVLO 2.1 3 V
DC-DC CONVERTER ENABLE (EN PIN)
V
IL(EN)
EN pin low-level input voltage Falling 1.10 1.17 V
V
IH(EN)
EN pin threshold Rising 1.21 1.26 V
I
(EN)
EN pin input current V
(EN)
= 1.1 V 1.15 µA
EN pin hysteresis current V
(EN)
= 1.3 V 3.4 µA
DC-DC CONVERTER VOLTAGE REFERENCE
V
ref
Reference voltage 0 A ≤ I
(OUT)
≤ 1 A 0.792 0.800 0.808 V
DC-DC MOSFET
V
(BOOT)
– V
(PH)
= 3 V 77 mΩ
R
HS
High-side switch resistance
V
(BOOT)
– V
(PH)
= 6 V 57 103 mΩ
R
LS
Low-side switch resistance V
(VIN)
= 12 V 50 87 mΩ
DC-DC ERROR AMPLIFIER
g
M
Error amplifier transconductance –2 µA ≤ I
(COMP)
≤ 2 µA, V
(COMP)
= 1 V 1300 µMho
Error amplifier dc gain V
(SENSE)
= 0.8 V 1000 3100 V/V
I
(COMP)
Error amplifier output current V
(COMP)
= 1 V, 100-mV input overdrive ±110 µA
Switching start threshold 0.25 V
COMP pin to I
SWITCH
g
M
12 A/V
DC-DC CURRENT LIMIT
I
LIM(HS)
High-side switch current limit 4.2 6.2 A
Sourcing 3.8 5.8 A
I
LIM(LS)
Low-side switch current limit
Sinking 1 2.6 A
Wait time before triggering protection 512 cycles
Wait time before start 16384 cycles
DC-DC SOFT-START (SS PIN)
SS pin charge current 2.3 µA
SS pin to VSENSE pin matching V
(SS)
= 0.4 V 29 60 mV
DC-DC POWER GOOD (PWRGD PIN )
VSENSE falling (fault, undervoltage) 0.91V
ref
V
VSENSE rising (good, undervoltage) 0.94V
ref
V
VSENSE pin threshold
VSENSE rising (fault, overvoltage) 1.09V
ref
V
VSENSE falling (good, overvoltage) 1.06V
ref
V
High-level output leakage current V
(VSENSE)
= V
ref
, V
(PWRGD)
= 5.5 V 30 100 nA
Low-level output voltage I
(PWRGD)
= 2 mA 0.3 V
Minimum VIN voltage for valid output V
(PWRGD)
< 0.5 V at 100 µA 0.6 1 V
Minimum SS voltage for PWRGD valid 1.2 1.4 V
(1) DC-DC_OUT refers to the regulated output voltage of the switching regulator (see Figure 28).
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