®
RT6217A/B
24V, 3A, 500kHz, ACOT
TM
Step-Down Converter in 8 Pin TSOT-23
General Description
The RT6217A/B is a simple, easy-to-use, 3A synchronous
step-down DC-DC converter with an input supply voltage
range of 4.5V to 24V. The device build-in an accurate
0.791V reference voltage and integrates low R
DS(ON)
power
MOSFETs to achieve high efficiency in a TSOT-23-8 (FC)
package.
The RT6217A/B adopts Advanced Constant On-Time
(ACOT
TM
) control architecture to provide an ultrafast
transient response with few external components and to
operate in nearly constant switching frequency over the
line, load, and output voltage range. The RT6217A operates
in automatic PSM that maintains high efficiency during
light load operation. The RT6217B operates in Forced
PWM that helps meet tight voltage regulation accuracy
requirements.
The RT6217A/B senses both FETs current for a robust
over-current protection. It features cycle-by-cycle current
limit protection and prevent the device from the catastrophic
damage in output short circuit, over current or inductor
saturation. An externally adjustable soft-start function
prevents inrush current during start-up. The device also
includes input under-voltage lockout, output under-voltage
protection, and over-temperature protection (thermal
shutdown) to provide safe and smooth operation in all
operating conditions. The RT6217A/B is offered in a TSOT-
23-8(FC) package.
Features
Ω
Ω
3A Converter With Built-in 85mΩ/40mΩ Low R
DS(ON)
Power FETs
Input Supply Voltage Range : 4.5V to 24V
Output Voltage Range : 0.791V to 6V
Advanced Constant On-Time (ACOT
TM
) Control
Ultrafast Transient Response
No Needs For External Compensations
Optimized for Low-ESR Ceramic Output Capacitors
0.791V
±
1.5% High-Accuracy Feedback Reference
Voltage
Low Quiescent Current (150μA typ.)
μ
Both HS/LS FETs Protection for Robust Over-Current
Protection
Optional for Operation Modes :
�½
Power Saving Mode (PSM) at Light Load (RT6217A)
�½
Forced PWM Mode (RT6217B)
Light-load V
OUT
Ripple Reduction Technology in
PSM
Steady Switching Frequency (500kHz typ.)
Externally Adjustable Soft-Start
Monotonic Start-up for Pre-biased Output
Input Under-Voltage Lockout (UVLO)
Output Under-Voltage Protection (UVP) with Hiccup
Mode
Over-Temperature Protection (OTP) (Thermal
Shutdown)
Power Good Indication
Enable Control
RoHS Compliant and Halogen Free
Available In TSOT-23-8 (FC) Package
Simplified Application Circuit
RT6217A/B
V
IN
C
IN
Enable
V
PGOOD
R
PGOOD
PGOOD
SS
C
SS
FB
GND
R2
EN
SW
R1
C
FF
C
OUT
VIN
BOOT
R3
C
BOOT
L
V
OUT
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6217A/B-01 October 2018
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
