
SLVSA24B
– OCTOBER 2009 – REVISED MARCH 2011
THERMAL INFORMATION
TPS54140-Q1
THERMAL METRIC(1)(2)
DGQ
DRC
UNITS
10 PINS
θJA
Junction-to-ambient thermal resistance (standard board)
62.5
56.5
θJA
Junction-to-ambient thermal resistance (custom board)(3)
57
61.5
θJCtop
Junction-to-case (top) thermal resistance
83
52.1
θJB
Junction-to-board thermal resistance
28
20.6
°C/W
ψJT
Junction-to-top characterization parameter
1.7
0.9
ψJB
Junction-to-board characterization parameter
20.1
20.8
θJCbot
Junction-to-case (bottom) thermal resistance
21
5.2
(1)
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report,
SPRA953.(2)
Power rating at a specific ambient temperature TA should be determined with a junction temperature of 150°C. This is the point where
distortion starts to substantially increase. See power dissipation estimate in application section of this data sheet for more information.
(3)
Test boards conditions:
(a) 3 inches x 3 inches, 2 layers, thickness: 0.062 inch
(b) 2 oz. copper traces located on the top of the PCB
(c) 2 oz. copper ground plane, bottom layer
(d) 6 thermal vias (13mil) located under the device package
ELECTRICAL CHARACTERISTICS
TJ = –40°C to 150°C, VIN = 3.5 V to 42 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY VOLTAGE (VIN PIN)
Operating input voltage
3.5
42
V
Internal undervoltage lockout
No voltage hysteresis, rising and falling
2.5
V
threshold
Shutdown supply current
EN = 0 V, 25
°C, 3.5 V ≤ VIN ≤ 42 V
1.3
4
μA
Operating : nonswitching supply
VSENSE = 0.83 V, VIN = 12 V, 25
°C
116
136
current
ENABLE AND UVLO (EN PIN)
Enable threshold voltage
No voltage hysteresis, rising and falling, 25
°C
0.9
1.25
1.55
V
Enable threshold +50 mV
±3.8
Input current
μA
Enable threshold
±50 mV
±0.9
Hysteresis current
±2.9
μA
VOLTAGE REFERENCE
TJ = 25°C
0.792
0.8
0.808
Voltage reference
V
0.784
0.8
0.816
HIGH-SIDE MOSFET
VIN = 3.5 V, BOOT-PH = 3 V
300
On-resistance
m
VIN = 12 V, BOOT-PH = 6 V
200
410
ERROR AMPLIFIER
Input current
50
nA
Error amplifier transconductance (gM) ±2 μA < ICOMP < 2 μA, VCOMP = 1 V
97
μMhos
±2 μA < ICOMP < 2 μA, VCOMP = 1 V,
Error amplifier transconductance (gM)
26
μMhos
during slow start
VVSENSE = 0.4 V
Error amplifier dc gain
VVSENSE = 0.8 V
10 000
V/V
Error amplifier bandwidth
2700
kHz
Error amplifier source/sink
V(COMP) = 1 V, 100 mV overdrive
±7
μA
COMP to switch current
6
A/V
transconductance
CURRENT LIMIT
Current limit threshold
VIN = 12 V, TJ = 25°C
1.8
2.7
A
Copyright
2009–2011, Texas Instruments Incorporated
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