A8499 Regulator Datasheet

A8499 Datasheet, PDF, Equivalent


Part Number

A8499

Description

High Voltage Step-Down Regulator

Manufacture

Allegro MicroSystems

Total Page 7 Pages
Datasheet
Download A8499 Datasheet


A8499
www.DataSheet4U.com
Features and Benefits
8 to 50 V input range
Integrated DMOS switch
Adjustable fixed off-time
Highly efficient
Adjustable 1.2 to 24 V output
A8499
High Voltage Step-Down Regulator
Description
The A8499 is a step down regulator that will handle a wide
input operating voltage range.
The A8499 is supplied in a low-profile 8-lead SOIC with
exposed pad (package LJ).
Applications include:
Printer power supplies
Consumer equipment power supplies
Package: 8-Lead SOIC with exposed
thermal pad (suffix LJ)
Approximate Scale 1:1
Typical Application
CBOOT
0.01 μF
BOOT
VIN
ENB
RTSET
121 kΩ
TSET
GND
A8499
LX
VBIAS
FB
D1
+42 V
C3
100 μF
50 V
C3
0.22 μF
L1
47 μH
R1
17.8 kΩ
R2
10.2 kΩ
VOUT
3.3 V / 1.2 A
ESR
COUT
220 μF
10 V
90.0
88.0
86.0
84.0
82.0
80.0
78.0
76.0
74.0
72.0
70.0
0
Efficiency vs. Output Current
VOUT (V)
3.3
5
200 400 600 800 1000 1200 1400
IOUT (mA)
Circuit for 42 V step down to 3.3 V at 1.2 A. Efficiency data from circuit shown in left panel.Data is for reference only.
A8499-DS, Rev. 3

A8499
A8499
Functional Block Diagram
High Voltage Step-Down Regulator
BOOT
VIN
µC ENB
TSET
GND
UVLO
TSD
Boot Charge
Switch
Disable
Switch PWM
+
I_Peak
Clamp
I_Demand
COMP
Soft Start
Ramp Generation
VIN
LX
L1
D1
VOUT
ESR
COUT
FB
Bias Supply
VBIAS
VBIAS is connected to VOUT
when VOUT target is between
3.3 and 5 V
1.2 V
Absolute Maximum Ratings
Supply Voltage, VIN ......................................................................... 50 V
VBIAS Input Voltage, VBIAS .................................................–0.3 to 7 V
Switch Voltage, VLX......................................................................... –1 V
ENB Input Voltage, VENB ......................................................–0.3 to 7 V
Junction Temperature, TJ(max) ....................................................... 150°C
Storage Temperature, TS ............................................... –55°C to 150°C
Operating Ambient Temperature, TA............................... –20°C to 85°C
Ordering Information
Use the following complete part numbers when ordering:
Part Numbera
Packingb
A8499SLJTR-T
13 in. reel, 3000 pieces/reel
A8499SLJ-T
98 pieces/tube
aLeadframe plating 100% matte tin.
bContact Allegro for additional packing options.
Package Thermal Characteristics*
Package
RθJA
(°C/W)
PCB
LJ 35
4-layer
* Additional information is available on the Allegro Web site
Description
LJ package, SOIC surface mount with
exposed thermal pad
Allegro MicroSystems, Inc.
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com


Features www.DataSheet4U.com A8499 High Voltage Step-Down Regulator Features and Benefi ts ▪ ▪ ▪ ▪ ▪ 8 to 50 V input range Integrated DMOS switch Adjustable fixed off-time Highly efficient Adjust able 1.2 to 24 V output Description Th e A8499 is a step down regulator that w ill handle a wide input operating volta ge range. The A8499 is supplied in a lo w-profile 8-lead SOIC with exposed pad (package LJ). Applications include: ▪ Printer power supplies ▪ Consumer eq uipment power supplies Package: 8-Lead SOIC with exposed thermal pad (suffix LJ) Approximate Scale 1:1 Typical App lication +42 V Efficiency vs. Output Current CBOOT 0.01 μF C3 100 μF 50 V BOOT VIN C3 0.22 μF ENB LX A8499 TS ET RTSET L1 47 μH VOUT 3.3 V / 1.2 A VBIAS R1 17.8 kΩ 121 kΩ GND FB D1 ESR COUT 220 μF 10 V 90.0 88.0 86.0 84.0 82.0 80.0 78.0 76.0 74.0 72.0 70.0 0 200 400 600 800 1000 Efficiency % VOUT (V) 3.3 5 1200 1400 R2 10.2 kΩ IOUT (mA) Circuit for 42 V step down to 3.3 V at 1.2 A. Efficiency data from circuit.
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