RT8251
Electrical Characteristics
(V
IN
= 12V, T
A
= 25°C unless otherwise specified)
Parameter
Feedback Reference Voltage
High-Side Switch-On Resistance
Low-Side Switch-On Resistance
High-Side Switch Leakage
Current Limit
Current Sense Transconductance
Error Amplifier Tansconductance
Oscillator Frequency
Short Circuit Oscillation Frequency
Maximum Duty Cycle
Minimum On-Time
UVLO Threshold Rising
UVLO Threshold Hysteresis
EN Input Voltage
Logic Low
Logic High
Symbol
V
FB
R
DS(ON)1
R
DS(ON)2
Test Conditions
4.75V
≦
V
IN
≦
24V
Min
0.784
--
--
Typ
0.8
70
15
--
6.8
4.6
920
570
185
85
100
4.1
200
--
--
1
25
0.8
10
1
150
Max
0.816
--
--
10
--
--
--
720
--
--
--
--
--
0.4
5.5
--
--
1
--
--
--
Unit
V
mΩ
Ω
μA
A
A/V
μA/V
kHz
kHz
%
ns
V
mV
V
μA
μA
mA
μA
ms
°C
V
EN
= 0V, V
SW
= 0V
I
LIM
G
CS
gm
f
SW
V
FB
= 0V
D
MAX
t
ON
V
FB
= 0.7V
Duty = 85%; V
BOOT−SW
= 4.8V
Output Current to V
COMP
ΔI
C
= ±10μA
--
--
--
--
420
--
--
--
--
--
V
IL
V
IH
V
EN
= 0V
I
SHDN
I
Q
I
SS
T
SD
V
EN
= 0V
V
EN
= 2V, V
FB
= 1V
V
SS
= 0V
C
SS
= 10nF
--
1.4
--
--
--
--
--
--
Enable Pull Up Current
Shutdown Current
Quiescent Current
Soft-Start Current
Soft-Start Period
Thermal Shutdown
Note 1.
Stresses beyond those listed
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2.
θ
JA
is measured at T
A
= 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7.
θ
JC
is
measured at the exposed pad of the package.
Note 3.
Devices are ESD sensitive. Handling precaution is recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS8251-04 February 2013
www.richtek.com
5
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
