A8586 Datasheet, PDF (1/19 Pages) Allegro MicroSystems – Output voltage adjustable from 0.8 to 30 V

A8586, A8586-1, A8586-2
Wide Input Voltage, Adjustable Frequency,
3.5 Amp Buck Regulator
FEATURES AND BENEFITS
• Automotive AEC-Q100 qualified
• Supply voltage from 3.8 to 36 V
• Output voltage adjustable from 0.8 to 30 V
• Maximized duty cycle for low dropout operation
• Low 30 μA operational quiescent current
• 150 mΩ integrated MOSFET switch
• Programmable switching frequency up to 4 MHz
• Improved EMC with frequency dithering (A8586 and
A8586-2) and controlled switch node rise and fall times
• Ceramic capacitor stable
• Internal soft-start
• Overcurrent protection
APPLICATIONS
• High-Voltage Power
Conversion
• Automotive Systems
• Industrial Power System
• Distributed Power
Systems
• Battery-Powered Systems
PACKAGES:
10-Pin DFN with Exposed
Thermal Pad (suffix EJ)
8-Pin SOIC with Exposed
Thermal Pad (suffix LJ)
Not to scale
DESCRIPTION
The A8586 is a high frequency step-down switching regulator
with an integrated high-side power MOSFET. It provides up 3.5
Aoutput current. TheA8586 can achieve fast transient response
using current-mode control and simple external compensation.
The wide input range of 3.8 to 36 V makes the A8586 suitable
for a wide range of step-down applications, including those in
an automotive input environment. Battery-driven applications
benefit from the low 30 μA operational quiescent current.
The A8586 maintains high efficiency across a wide load range
by the use of pulse-frequency modulation (PFM) as the load
reduces. This in turn reduces switching and gate driver losses
at light load. A8586-1 and A8586-2 are options that disable
the PFM function. A8586-1 also disables the dithering feature.
These can be useful when low output ripple and minimum
output capacitance is required.
Frequency foldback helps to prevent inductor current runaway
during startup and provides enhanced dropout performance.
Extensive protection features of the A8586 include pulse-by-
pulse current limit, hiccup mode short-circuit protection, open/
short freewheeling diode protection, BOOT open/short voltage
protection, VIN undervoltage lockout, and thermal shutdown.
The A8586 and A8586-2 are designed to aid in EMC/EMI
design by including frequency dithering, soft freewheel diode
turn-off, and well controlled switch node slew rates. A 4 MHz
oscillator allows the A8586 to switch outside EMI sensitive
frequencies bands such as the AM band or ADSL bands.
TheA8586 is available in industry-standard DFN-10 or SOIC-8
packages.
C_BST
Part
A8586
A8586-1
A8586-2
Dither
Feature
Yes
No
Yes
PFM
Operation
Yes
No
No
VIN
C_IN
BST
SW
VIN
EN
FB
COMP
C_Z
C_P
Optional
R_FREQ
L_O
VOUT
R_FB1
D
R_FB2
C_OUT
A8586-DS, Rev. 4
A8586 Simplified Schematic
January 17, 2017