RT7251A/B
Absolute Maximum Ratings
(Note 1)
Supply Voltage, VIN -----------------------------------------------------------------------------------------------
−0.3V
to 19V
SW ---------------------------------------------------------------------------------------------------------------------
−0.3V
to (V
IN
+ 0.3V)
BOOT to SW --------------------------------------------------------------------------------------------------------
−0.3V
to 6V
All Other Pins -------------------------------------------------------------------------------------------------------
−0.3V
to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-8L 2x2 ------------------------------------------------------------------------------------------------------- 0.833W
Package Thermal Resistance (Note 2)
WDFN-8L 2x2,
θ
JA
-------------------------------------------------------------------------------------------------- 120°C/W
WDFN-8L 2x2,
θ
JC
-------------------------------------------------------------------------------------------------- 8.2°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------ 260°C
Junction Temperature ---------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range -------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) --------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ----------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 4)
Supply Input Voltage, VIN ---------------------------------------------------------------------------------------- 4V to 17V
Junction Temperature Range -------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
IN
= 12V, T
A
= 25°C, unless otherwise specified)
Parameter
Shutdown Supply Current
Supply Current
Feedback Current
High Side Switch On
Resistance
Low Side Switch On
Resistance
Upper Switch Current Limit
Lower Switch Current Limit
Oscillation Frequency
Short-Circuit Oscillation
Frequency
Maximum Duty Cycle
Symbol
I
SHDN
I
OUT
I
FB
R
DS(ON)1
R
DS(ON)2
V
EN
= 0V
Test Conditions
V
EN
= 3V, V
FB
= 0.9V
4V
≤
V
IN
≤
17V
V
FB
= 0.8V
Min
--
--
0.788
--
--
--
Typ
1
0.6
0.8
10
145
140
3
1
340
800
95
170
93
84
Max
5
1
0.812
--
--
--
--
--
380
900
--
--
--
--
Unit
μA
mA
V
nA
mΩ
mΩ
A
A
kHz
kHz
%
Feedback Reference Voltage V
FB
Min. Duty Cycle, V
BOOT
−
V
SW
= 4.8V
Maximum Loading = 1.5A
From Drain to Source
f
OSC1
f
OSC2
D
MAX
For RT7251A
For RT7251B
V
FB
= 0V, For RT7251A
V
FB
= 0V, For RT7251B
V
FB
= 0.7V, For RT7251A
V
FB
= 0.7V, For RT7251B
--
--
300
700
--
--
--
--
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS7251A/B-01 April 2012
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
