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A4450 Datasheet, PDF (5/34 Pages) Allegro MicroSystems – Buck-Boost Controller with Integrated Buck MOSFET
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A4450
Buck-Boost Controller
with Integrated Buck MOSFET
ELECTRICAL CHARACTERISTICS: Valid at 3 V ≤ VIN ≤ 36 V and VIN having first reached VINSTART,
‒40°C ≤ TJ ≤ 150°C, unless noted otherwise
Characteristics
Symbol
Test Conditions
Min. Typ.
GENERAL SPECIFICATIONS
Operating Input Voltage
VIN
VIN UVLO Start
VINSTART
VIN UVLO Stop
VINSTOP
Supply Quiescent Current 1
IQ
IQ(SLEEP)
PWM SWITCHING FREQUENCY AND DITHERING
After VIN > VINSTART, VEN ≥ 4 V
VIN rising
VIN falling, when in Buck-Boost mode
VIN = 13.5 V, VEN ≥ 4 V, no load
VIN = 13.5 V, VEN ≤ 1 V, no load
3.0
13.5
–
–
–
–
–
4.5
–
–
Switching Frequency
Frequency Dithering
VIN Dithering START Threshold
fOSC
ΔfOSC
VIN(DITHER,ON)
VIN Dithering STOP Threshold
VIN(DITHER,OFF)
VIN Dithering Hysteresis
VIN(DITHER,HYS)
THERMAL PROTECTION
Thermal Shutdown Threshold 2
Thermal Shutdown Hysteresis 2
TTSD
THYS
OUTPUT VOLTAGE SPECIFICATIONS
RFSET = 7.87 kΩ
RFSET = 41.2 kΩ
As a percent of fOSC
VIN rising, RNG = 15 kΩ, target VOUT = 5 V
VIN falling
VIN falling, RNG = 15 kΩ, target VOUT = 5 V
VIN rising
TJ rising
1.8
2.0
343
400
–
±12
7.0*
–
16.6
7.0*
–
18
–
1.5
160
170
–
20
Feedback Voltage Tolerance
VFB
PULSE-WIDTH MODULATION (PWM)
VIN = 13.5 V, EN = high
0.788 0.800
PWM Ramp Offset
LX Rising Slew Rate 2
LX Falling Slew Rate 2
Buck Minimum On-Time
Buck Minimum Off-Time
Boost Maximum Duty Cycle
COMP to LX Current Gain
Slope Compensation 2
INTERNAL MOSFET
VPWMOFFS
LXRISE
LXFALL
tON(MIN,BUCK)
tOFF(MIN,BUCK)
DMAX(BST)
gmPOWER
SE
VCOMP for 0% duty cycle
VIN = 13.5 V, 10% to 90%, ILX = 1 A
VIN = 13.5 V, 10% to 90%, ILX = 1 A
VIN = 3.5 V, VOUT = 8 V target, RNG = 25.5 kΩ, 2 MHz
VIN = 3.5 V, VOUT = 5 V target, RNG = 15 kΩ, 2 MHz
VIN = 3.5 V, VOUT = 3 V target, RNG = 9.31 kΩ, 2 MHz
fOSC = 2 MHz
fOSC = 400 kHz
–
–
–
–
–
–
–
–
3.5
1.76
0.35
400
1.5
1.8
85
85
0.75
0.57
0.31
4.7
2.2
0.44
MOSFET On Resistance
MOSFET Leakage
RDSon
IFET(LKG)
VIN = 13.5 V, TJ = –40°C (2), IDS = 0.1 A
VIN = 13.5 V, TJ = 25°C (2), IDS = 0.1 A
VIN = 13.5 V, TJ = 150°C, IDS = 0.1 A
VEN ≤ 1 V, VLX = 0 V, VIN = 13.5 V,
−40°C ≤ TJ ≤ 85°C (2)
–
60
–
80
–
140
–
–
Continued on the next page…
Max.
36
4.8
2.9
–
10
2.2
457
–
–
–
–
180
–
0.812
–
–
–
120
120
–
–
–
5.9
2.64
0.53
90
110
170
10
Unit
V
V
V
mA
µA
MHz
kHz
%
V
V
V
V
V
°C
°C
V
mV
V/ns
V/ns
ns
ns
–
–
–
A/V
A/µs
A/µs
mΩ
mΩ
mΩ
µA
Allegro MicroSystems, LLC
5
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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