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PDF A8591 Data sheet ( Hoja de datos )
| Número de pieza | A8591 | |
| Descripción | 2A Buck Regulator Family | |
| Fabricantes | Allegro | |
| Logotipo |  |
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A8591
Wide Input Voltage, 2 A Buck
Regulator Family with Low-IQ Mode
FEATURES AND BENEFITS
• Automotive AEC-Q100 qualified
• Withstands surge input to 40 VIN for load dump
• Operates down to 3.4 VIN (typ), 3.6 VIN (max) for idle stop
• Utilizes pulse-frequency modulation (PFM) for low-IQ mode
• 10 μA Sleep mode (automatic PWM / Low-IQ PFM
mode selection)
• Fixed output voltage options: 3.3 or 5 V with ±1%
accuracy
• Delivers up to 2 A of output current
• Integrated 110 mΩ high-side MOSFET
• Adjustable switching frequency from 300 kHz to 2.4 MHz
• EMI reduction features:
□□Frequency dithering
□□Controlled switching node
• External synchronization capability
• Maximum duty cycle for low dropout
• Active low NPOR output with 7.5 ms delay
• Pre-bias startup capable: VOUT increases monotonically,
will not cause a reset
Continued on the next page…
PACKAGE:
10-Pin, 3 × 3 mm Wettable Flank DFN
with Exposed Thermal Pad (suffix EJ)
Not to scale
DESCRIPTION
TheA8591 is designed to provide the power supply requirements
of next generation car audio and infotainment systems.
The A8591 provides all the control and protection circuitry
to produce a high-current regulator with ±1% output voltage
accuracy.
The A8591 employs current-mode control to provide simple
compensation, excellent stability, and fast transient response.
The A8591 employs pulse-frequency modulation (PFM) to
draw less than 33 µA from 12 VIN while supplying 5 V/40 µA
(A8591, 5 VOUT), or less than 24 μA from 12 VIN while
supplying 3.3 V/40 μA(A8591-1, 3.3 VOUT).When operational,
the A8591 operates down to at least 3.6 VIN (VIN falling). The
Sleep feature allows for very low standby current.
Features of the A8591 include a programmable PWM
switching frequency. The regulator switching frequency can
be synchronized to an external clock. The A8591 has external
compensation to optimize stability and transient response for
a wide range of external components and applications. The
A8591 has a fixed soft-start time of 5 ms.
Continued on the next page…
APPLICATIONS:
• Automotive:
□□Instrument clusters
□□Audio systems
□□Navigation
□□HVAC
• Home audio
• Network and telecom
• Industrial
A8591-DS
V
IN
SYNC
R
FSET
1
VIN
C
IN
2
VIN
8
GND
9
SW
A8591
10
BOOT
5
VOUT
C
BOOT
47 nF
L
O
D1
2 A/40 V
V
OUT
C
O
3
EN/SLEEP
4
FSET /SYNCPWM
7
COMP
R
PU
6
NPOR
NPOR
C
P
R
Z
See Table 2 for recommended component values
C
Z
Typical Application Diagram
1 page  
A8591
Wide Input Voltage, 2 A Buck
Regulator Family with Low-IQ Mode
PINOUT DIAGRAM AND TERMINAL LIST TABLE
VIN 1
VIN 2
EN/SLEEP 3
FSET/SYNCPWM
VOUT
4
5
PAD
10 BOOT
9 SW
8 GND
7 COMP
6 NPOR
EJ Package, 10-Pin 3 × 3 mm DFN Pinouts
Terminal List Table
Number
Name
1, 2 VIN
3 EN/SLEEP
4 FSET/SYNCPWM
5 VOUT
6 NPOR
7 COMP
8 GND
9 SW
10 BOOT
– PAD
Function
Power input for the control circuits and the drain of the internal high-side N-channel MOSFET. Connect this pin to
a power supply of 4 to 35 V. A high-quality, high-frequency ceramic capacitor should be placed and grounded very
close to this pin.
This pin must be set high to enable the device. If this pin is set low, the device will enter a very low current
shutdown or sleep state (VOUT = 0 V). If the application does not require a sleep mode, then this pin can be tied
directly to VIN. Do not float this pin.
Frequency setting and PWM synchronization pin. A resistor, RFSET , from this pin to GND sets the PWM switching
frequency. See Figure 11 and/or Equation 1 to determine the value of RFSET. Applying a clock signal to this pin
forces PWM mode and synchronizes the PWM switching frequency.
Connect this pin to the output of the regulator. This pin supplies internal circuitry when its voltage level is high
enough. Also, through an on-chip voltage divider, this pin connects to the negative feedback input of the error
amplifier. Keep the VOUT pin quiet and Kelvin connect.
Active-low, power-on reset output signal. This pin is an open-drain output that transitions from low to high
impedance after the output has maintained regulation for tdPOR .
Output of the error amplifier, and compensation node for the current-mode control loop. Connect a series RC
network from this pin to GND for loop compensation. See the Design and Component Selection section of this
datasheet for further details.
Ground pin.
The source for the internal high-side N-channel MOSFET. The external freewheeling diode (D1) and output inductor
(LO) should be connected to this pin. Both D1 and LO should be placed close to this pin and connected with
relatively wide traces.
High-side gate drive boost input. This pin supplies the drive for the high-side N-channel MOSFET. Connect a 47 nF
ceramic capacitor from BOOT to SW.
Exposed pad of the package providing enhanced thermal dissipation. This pad must be connected to the ground
plane(s) of the PCB with at least 6 vias, directly in the pad.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
5 Page 
1.80
VIH
1.26
1.24
VIH
1.75
A85911.70
1.65
VIL
1.22
1.20 Wide Input Voltage, 2 A Buck
Regu1.l18ator Family wViILth Low-IQ Mode
1.16
1.60
-50 -25 0 25 50 75 100 125 150 175
Temperature (°C)
1.14
-50 -25 0 25 50 75 100 125 150 175
Temperature (°C)
NPOR Overvoltage and Undervoltage Thresholds
versus Temperature
5.8
5.6
V5.4 NPOROV(5.0V)
5.2
5.0
V4.8
NPORUV(5.0V)
4.6
4.4
4.2 VOUT = 5 V
4.0
-50 -25 0 25 50 75 100 125 150 175
Temperature (°C)
NPOR Overvoltage and Undervoltage Thresholds
versus Temperature
3.8
V3.6
NPOROV(3.3V)
3.4
3.2
3.0
V2.8 NPORUV(3.3V)
2.6
2.4
2.2 VOUT = 3.3 V
2.0
-50 -25 0 25 50 75 100 125 150 175
Temperature (°C)
NPOR Low Output Voltage versus Temperature
300
250 IOUT = 2 mA
200
150
100
50
0
-50 -25
0 25 50 75 100 125 150 175
Temperature (°C)
8.20
8.15
8.10
8.05
8.00
7.95
7.90
7.85
7.80
7.75
-50
NPOR Time Delay versus Temperature
-25 0 25 50 75 100 125 150
Temperature (°C)
175
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet A8591.PDF ] | |
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