TPSM84424
ZHCSHN0A –FEBRUARY 2018–REVISED APRIL 2018
www.ti.com.cn
6.4 Thermal Information
TPSM84424
MOL (QFN)
24 PINS
22
THERMAL METRIC(1)
UNIT
RθJA
ψJT
Junction-to-ambient thermal resistance(2)
Junction-to-top characterization parameter(3)
Junction-to-board characterization parameter(4)
°C/W
°C/W
°C/W
2.1
ψJB
13.6
(1) For more information about thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.
(2) The junction-to-ambient thermal resistance, RθJA, applies to devices soldered directly to a 100 mm × 100 mm, 4-layer PCB with 2 oz.
copper and natural convection cooling. Additional airflow reduces RθJA
.
(3) The junction-to-top board characterization parameter, ψJT, estimates the junction temperature, TJ, of a device in a real system, using a
procedure described in JESD51-2A (section 6 and 7). TJ = ψJT × Pdis + TT; where Pdis is the power dissipated in the device and TT is
the temperature of the top of the device.
(4) The junction-to-board characterization parameter, ψJB, estimates the junction temperature, TJ, of a device in a real system, using a
procedure described in JESD51-2A (sections 6 and 7). TJ = ψJB × Pdis + TB; where Pdis is the power dissipated in the device and TB is
the temperature of the board 1mm from the device.
6.5 Electrical Characteristics
Over –40°C to +105°C ambient temperature, VIN = 12 V, VOUT = 1.2 V, IOUT = IOUTmax, fsw = 450 kHz (unless otherwise
noted); CIN1 = 2× 10-µF, 25-V, 1210 ceramic; CIN2 = 100-µF, 50-V, electrolytic; COUT = 4× 47-µF, 10-V, 1210 ceramic.
Minimum and maximum limits are specified through production test or by design. Typical values represent the most likely
parametric norm and are provided for reference only.
PARAMETER
TEST CONDITIONS
MIN
4.5(1)
3.7
TYP
MAX UNIT
INPUT VOLTAGE (VIN
)
VIN
Input voltage
Over IOUT range
VIN increasing
VIN decreasing
VEN = 0 V
17
V
V
4.1
3.9
3
4.3
UVLO
ISHDN
VIN undervoltage lockout
Shutdown supply current
V
11
10
µA
OUTPUT VOLTAGE (VOUT
)
VOUT(ADJ) Output voltage adjust
Over IOUT range
0.6
V
VOUT(Ripple) Output voltage ripple
20-MHz bandwidth
16
mV
FEEDBACK
TA = 25°C, IOUT = 0 A
0.596
0.595
0.6
0.6
0.1
0.8
0.604
0.605
V
V
Feedback voltage(2)
–40°C ≤ TJ ≤ 125°C, IOUT = 0 A
Over VIN range, TA = 25°C, IOUT = 0 A
Over IOUT range, TA = 25°C
VFB
Line regulation
mV
mV
Load regulation
CURRENT
Output current
IOUT
Natural convection, TA = 25°C
0
4
A
A
Overcurrent threshold
11
PERFORMANCE
VOUT = 5 V, fSW = 1.2 MHz
VOUT = 3.3 V, fSW = 1.0 MHz
94%
93%
91%
87%
86%
VIN = 12 V,
IOUT = 4 A
ƞ
Efficiency
VOUT = 1.8 V, fSW = 600 kHz
VOUT = 1.2 V, fSW = 450 kHz
VOUT = 1 V, fSW = 400 kHz
25% to 75% load step, 2A/µs slew rate,
RTT = 4.02 kΩ,
COUT = 200-µF ceramic + 220-µF polymer
27
35
mV
mV
Transient response
voltage deviation
25% to 75% load step, 2A/µs slew rate,
RTT = 3.40 kΩ, COUT = 200-µF ceramic
(1) For output voltages 0.6 V to < 5.5 V, the recommended minimum VIN is 4.5 V or (VOUT + 1 V), whichever is greater. For output
voltages 5.5 V to < 9 V, the recommended minimum VIN is (VOUT + 2 V). For output voltages 9 V to 10 V, the recommended minimum
VIN is (VOUT + 3 V).
(2) The overall output voltage tolerance will be affected by the tolerance of the external RFBT and RFBB resistors.
6
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