®
RT2805A
5A, 36V, 500kHz Current Mode Asynchronous Step-Down
Converter
General Description
The RT2805A is a current mode asynchronous step-down
converter that achieves excellent load and line regulation.
Over a wide input voltage range from 5.5V to 36V and
supports output current up to 5A. The Current mode
operation provides fast transient response and eases loop
stabilization.
An adjustable soft-start reduces the stress on the input
source at startup. In shutdown mode, the regulator draws
only 25μA of supply current. The RT2805A requires a
minimum number of readily available external
components, providing a compact solution. The RT2805A
provides protection functions inducing input under voltage
lockout, cycle-by-cycle current limit, short circuit
protection and thermal shutdown protection.
The RT2805A is available in the SOP-8 (Exposed Pad)
package.
Features
5A Output Current
Wide Operating Input Range 5.5V to 36V
Adjustable Output Voltage from 1.222V to 26V
High Efficiency up to 90%
Internal Compensation Minimizes External Parts
Count
Internal Soft-Start
110mΩ Internal Power MOSFET Switch
Ω
25μA Shutdown Mode
μ
Fixed 500kHz Frequency
Thermal Shutdown
Cycle-by-Cycle Current Limit
Available In an SOP8 (Exposed Pad) Package
RoHS Compliant and Halogen Free
Applications
Distributive Power Systems
Battery Charger
DSL Modems
Pre-regulator for Linear Regulators
Ordering Information
RT2805A
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
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.
Marking Information
RT2805AGSP : Product Number
RT2805A
GSPYMDNN
YMDNN : Date Code
Simplified Application Circuit
V
IN
C
IN
Chip Enable
EN
GND
FB
R2
VIN
BOOT
RT2805A
SW
D1
R1
C
OUT
C
BOOT
L1
V
OUT
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2805A-00 November 2012
www.richtek.com
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RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
