Preliminary
Absolute Maximum Ratings
Output Voltage
LX Pin Voltage
CE Pin Voltage
(1)
RT9261B
8V
8V
-0.3 to V
OUT
+0.3V
400mA
0.5W
0.25W
100°C/W
300°C/W
250°C/W
-20 to +85°C
-65°C to 150°C
260°C
LX Pin Output Current
Power Dissipation, P
D
@ T
A
= 25°C
SOT-89
SOT-25
Package Thermal Resistance
SOT-89,
θ
JC
SOT-89,
θ
JA
SOT-25,
θ
JA
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
Notes: (1) Applicable to RT9261B-xxCB
Electrical Characteristics
(Refer to Fig. 1)
Parameter
Output Voltage Accuracy
Input Voltage
Start-up Voltage
Hold-on Voltage
Input Current 1
(1) (2)
(1)
(2)
(1)
(2)
Symbol
∆V
OUT
V
IN
V
ST
V
HO
Test Conditions
Min
-2
--
--
0.7
--
--
--
--
--
120
160
--
140
65
--
0.65
Typ
--
--
0.8
--
24
36
6.5
18
20
--
--
--
190
75
80
0.8
Max Units
+2
7
1
--
36
45
10
36
45
--
--
0.5
240
85
--
1.0
µA
%
V
V
V
µA
µA
I
OUT
= 1mA, V
IN
: 0
→
2V
I
OUT
= 1mA, V
IN
: 2
→
0V
To be measured at V
IN
in
continuous switching
To be measured at V
OUT
in
switch off condition
V
OUT
≤
3.5V
3.5V
<
V
OUT
≤
5V
Input Current 2
Input Current 3
V
OUT
≤
3.5V
3.5V
<
V
OUT
≤
5V
LX Switching Current
LX Leakage Current
Maximum Oscillator Frequency
Oscillator Duty Cycle
Efficiency
V
LX
Voltage Limit
Notes:
V
OUT
≤
3.5V
(1)
To be measured at V
IN
in
no load (guaranteed by I
1
and I
2
)
I
SWITCHING
V
LX
= 0.4V
I
LEAKAGE
F
MAX
D
OSC
On (V
LX
“L”) side
LX switch on
V
LX
= 6V
3.5V
<
V
OUT
≤
5V
(2)
mA
µA
KHz
%
%
V
(1) V
IN
= 1.8V, V
SS
= 0V, I
OUT
= 1mA, Topt = 25°C, and External Circuit of Typical Application
(2) V
IN
= 3V, V
SS
= 0V, I
OUT
= 1mA, Topt = 25°C, and External Circuit of Typical Application
DS9261B-03 September 2001
www.richtek-ic.com.tw
3
ETC [ ETC ]
