Step-Down Converter. RT2859A Datasheet


RT2859A Converter. Datasheet pdf. Equivalent


Part Number

RT2859A

Description

Synchronous Step-Down Converter

Manufacture

Richtek

Total Page 17 Pages
Datasheet
Download RT2859A Datasheet


RT2859A
Reference
Design
Sample &
Design
Tools
Buy
®
RT2859A/B
3A, 18V, 650kHz, ACOTTM Synchronous Step-Down Converter
General Description
The RT2859A/B are high-performance 650kHz 3A step-
down regulators with internal power switches and
synchronous rectifiers. They feature quick transient
response using their Advanced Constant On-Time
(ACOTTM) control architecture that provides stable
operation with small ceramic output capacitors and without
complicated external compensation, among other benefits.
The input voltage range is from 4.5V to 18V and the output
is adjustable from 0.765V to 7V.
The proprietary ACOTTM control improves upon other fast-
response constant on-time architectures, achieving nearly
constant switching frequency over line, load, and output
voltage ranges. Since there is no internal clock, response
to transients is nearly instantaneous and inductor current
can ramp quickly to maintain output regulation without
large bulk output capacitance. The RT2859A/B are stable
with and optimized for ceramic output capacitors.
With internal 70mΩ switches and 70mΩ synchronous
rectifiers, the RT2859A/B display excellent efficiency and
good behavior across a range of applications, especially
for low output voltages and low duty cycles. Cycle-by-
cycle current limit, input under-voltage lockout, externally-
adjustable soft-start, output under- and over-voltage
protection, and thermal shutdown provide safe and smooth
operation in all operating conditions.
The RT2859A and RT2859B are each available in
the WQFN-16L 3x3 package, with exposed thermal pads.
The RT2859B switches continuously even at light loads
to avoid low-frequency interference while the RT2859A
features a power-saving discontinuous operating mode at
light loads.
Features
Fast Transient Response
Steady 650kHz Switching Frequency at all Load
Current (RT2859B)
Discontinuous Operating Mode at Light Load
(RT2859A)
3A Output Current
Advanced Constant On-Time (ACOTTM) Control
Optimized for Ceramic Output Capacitors
4.5V to 18V Input Voltage Range
Internal 70mΩ Switch and 70mΩ Synchronous
Rectifier
0.765V to 7V Adjustable Output Voltage
Externally-Adjustable, Pre-Biased Compatible Soft-
Start
Cycle-by-Cycle Current Limit
Optional Output Discharge Function
Output Over- and Under-voltage Shut Down
Latched (RT2859ALGQW/RT2859BLGQW Only)
With Hiccup Mode (RT2859AHGQW/RT2859BHGQW
Only)
Input Under-Voltage Lockout
Thermal Shutdown
RoHS Compliant and Halogen Free
Simplified Application Circuit
VIN
Power Good
VREG5
Input Signal
RT2859A/B
VIN SW
VCC
BOOT
PGOOD
VS
EN FB
SS VREG5
GND PGND
VOUT
Copyright ©2019 Richtek Technology Corporation. All rights reserved.
DS2859A/B-05 May 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1

RT2859A
RT2859A/B
Applications
Industrial and Commercial Low Power Systems
Computer Peripherals
LCD Monitors and TVs
Green Electronics/Appliances
Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Marking Information
RT2859AHGQW
48= : Product Code
48=YM
DNN
YMDNN : Date Code
RT2859ALGQW
45=YM
DNN
45= : Product Code
YMDNN : Date Code
Ordering Information
RT2859A/B
Package Type
QW : WQFN-16L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
H : Hiccup Mode OVP & UVP
L : Latched OVP & UVP
Note :
A : PSM
B : PWM
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Pin Configuration
(TOP VIEW)
RT2859BHGQW
3Z=YM
DNN
3Z= : Product Code
YMDNN : Date Code
16 15 14 13
FB
VREG5
SS
GND
1
2
3
4
GND
17
12 BOOT
11 SW
10 SW
9 SW
5 678
RT2859BLGQW
3Y=YM
DNN
3Y= : Product Code
YMDNN : Date Code
WQFN-16L 3x3
Copyright ©2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS2859A/B-05 May 2019


Features Reference Design Sample & Design Too ls Buy ® RT2859A/B 3A, 18V, 650kHz , ACOTTM Synchronous Step-Down Converte r General Description The RT2859A/B ar e high-performance 650kHz 3A stepdown r egulators with internal power switches and synchronous rectifiers. They featur e quick transient response using their Advanced Constant On-Time (ACOTTM) cont rol architecture that provides stable o peration with small ceramic output capa citors and without complicated external compensation, among other benefits. Th e input voltage range is from 4.5V to 1 8V and the output is adjustable from 0. 765V to 7V. The proprietary ACOTTM cont rol improves upon other fastresponse co nstant on-time architectures, achieving nearly constant switching frequency ov er line, load, and output voltage range s. Since there is no internal clock, re sponse to transients is nearly instanta neous and inductor current can ramp qui ckly to maintain output regulation with out large bulk output capacitance. The RT2859A/B are stable with.
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