Datasheet

TPS65251
SLVSAA4D –JUNE 2010–REVISED DECEMBER 2012 www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
T
J
= -40°C to 125°C, VIN = 12 V, f
SW
= 1 MHz (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
FEEDBACK, REGULATION, OUTPUT STAGE
V
IN
= 12V T
J
= 25°C -1% 0.8 1%
V
FB
Feedback voltage V
V
IN
= 4.5 to 18V -2% 0.8 2%
I
FB
Feedback leakage current 50 nA
Minimum on time
t
ON_MIN
80 120 ns
(current sense blanking)
Line regulation - DC V
INB
= 4.5 V to 18 V,
V
LINEREG
0.5 % V
OUT
∆V
OUT
/∆V
INB
I
OUT
= 1000 mA
Load regulation - DC I
OUT
= 10 % - 90%
V
LOADREG
0.5 % V
OUT
/A
∆V
OUT
/∆I
OUT
I
OUT,MAX
MOSFET (BUCK 1)
H.S. Switch Turn-On resistance high side FET on CH1 V
IN
= 12 V, T
J
= 25°C 95 mΩ
L.S. Switch Turn-On resistance low side FET on CH1 V
IN
= 12 V, T
J
= 25°C 50 mΩ
MOSFET (BUCK 2)
H.S. Switch Turn-On resistance high side FET on CH2 V
IN
= 12 V, T
J
= 25°C 120 mΩ
L.S. Switch Turn-On resistance low side FET on CH2 V
IN
= 12 V, T
J
= 25°C 80 mΩ
MOSFET (BUCK 3)
H.S. Switch Turn-On resistance high side FET on CH3 V
IN
= 12 V, T
J
= 25°C 120 mΩ
L.S. Switch Turn-On resistance low side FET on CH3 V
IN
= 12 V, T
J
= 25°C 80 mΩ
ERROR AMPLIFIER
g
M
Error amplifier transconductance –2 µA < I
COMP
< 2 µA 130 µmhos
gm
PS
COMP to ILX g
M
ILX = 0.5 A 10 A/V
POWER GOOD RESET GENERATOR
Output falling (device will be
85
disabled after t
ON_HICCUP
)
VUV
BUCKX
Threshold voltage for buck under voltage %
Output rising (PG will be asserted) 90
t
UV_deglitch
Deglitch time (both edges) Each buck 11 ms
t
ON_HICCUP
Hiccup mode ON time VUV
BUCKX
asserted 12 ms
All converters disabled. Once
Hiccup mode OFF time before re-start is
t
OFF_HICCUP
t
OFF_HICCUP
elapses, all converters 15 ms
attempted
will go through sequencing again.
Output rising (high side fet will be
109
forced off)
VOV
BUCKX
Threshold voltage for buck over voltage %
Output falling (high side fet will be
107
allowed to switch )
Measured after minimum reset
t
RP
minimum reset period period of all bucks power-up 1 s
successfully
THERMAL SHUTDOWN
T
TRIP
Thermal shut down trip point Rising temperature 160 °C
T
HYST
Thermal shut down hysteresis Device re-starts 20 °C
T
TRIP_DEGLITCH
Thermal shut down deglitch 110 µs
CURRENT LIMIT PROTECTION
RLIM
1
Limit resistance range Buck 1 75 300 kΩ
RLIM
2&3
Limit resistance range Bucks 2 and 3 100 300 kΩ
V
IN
= 12 V, f
SW
= 500 kHz,
ILIM
1
Buck 1 adjustable current limit range 1.2 5.5 A
see Figure 24
V
IN
= 12 V, f
SW
= 500 kHz,
ILIM
2
Buck 2 adjustable current limit range 1 4.1 A
see Figure 25
V
IN
= 12 V, f
SW
= 500 kHz,
ILIM
3
Buck 3 adjustable current limit range 1.3 4.4 A
see Figure 26
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