Datasheet

TPS54320
SLVS982A –AUGUST 2010–REVISED SEPTEMBER 2010 www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
T
J
= –40°C to 150°C, VIN = 4.5V to 17V, PVIN = 1.6V to 17V (unless otherwise noted)
DESCRIPTION CONDITIONS MIN TYP MAX UNIT
ERROR AMPLIFIER
Error amplifier Transconductance (gm) –2 mA < I
(COMP)
< 2 mA, V
(COMP)
= 1 V 1300 mMhos
Error amplifier dc gain VSENSE = 0.8 V 1000 3100 V/V
Error amplifier source/sink V
(COMP)
= 1 V, 100 mV input overdrive ±110 mA
Start switching threshold 0.25 V
COMP to Iswitch gm 12 A/V
CURRENT LIMIT
High-side switch current limit threshold 4.2 6.2 A
Low-side switch sourcing current limit 3.8 5.8 A
Low-side switch sinking current limit 1 2.6 A
Hiccup wait time before triggering hiccup 512 cycles
Hiccup time before restart 16384 cycles
THERMAL SHUTDOWN
Thermal shutdown 160 175 °C
Thermal shutdown hysteresis 10 °C
TIMING RESISTOR AND EXTERNAL CLOCK (RT/CLK PIN)
Minimum switching frequency Rrt = 240 kΩ (1%) 160 200 240 kHz
Switching frequency Rrt = 100 kΩ (1%) 400 480 560 kHz
Maximum switching frequency Rrt = 40.2 kΩ (1%) 1080 1200 1320 kHz
Minimum pulse width 20 ns
RT/CLK high threshold 2 V
RT/CLK low threshold 0.8 V
RT/CLK falling edge to PH rising edge delay Measure at 500 kHz with RT resistor in series 62 ns
Switching frequency range (RT mode set point 200 1200 kHz
and PLL mode)
PH (PH PIN)
Measured at 90% to 90% of PH,
Minimum on time 97 135 ns
T
A
= 25°C, I
PH
= 2A
Minimum off time BOOT-PH ≥ 3 V 0 ns
BOOT (BOOT PIN)
BOOT-PH UVLO 2.1 3 V
SLOW START AND TRACKING (SS/TR PIN)
SS charge current 2.3 mA
SS/TR to VSENSE matching V
(SS/TR)
= 0.4 V 29 60 mV
POWER GOOD (PWRGD PIN)
VSENSE falling (Fault) 91 % Vref
VSENSE rising (Good) 94 % Vref
VSENSE threshold
VSENSE rising (Fault) 109 % Vref
VSENSE falling (Good) 106 % Vref
Output high leakage VSENSE = Vref, V
(PWRGD)
= 5.5 V 30 100 nA
Output low I
(PWRGD)
= 2 mA 0.3 V
Minimum VIN for valid output V
(PWRGD)
< 0.5V at 100 mA 0.6 1 V
Minimum SS/TR voltage for PWRGD valid 1.2 1.4 V
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