RT9161A-33GX Richtek USA Inc, RT9161A-33GX Datasheet - Page 6

• Manufacturer Part Number: RT9161A-33GX
• Description: IC REG LDO 3.3V 500MA SOT89
• Manufacturer: Richtek USA Inc

Specifications of RT9161A-33GX

• Regulator Topology: Positive Fixed
• Voltage - Output: 3.3V
• Voltage - Input: Up to 12V
• Voltage - Dropout (typical): 0.75V @ 500mA
• Number Of Regulators: 1
• Current - Output: 500mA (Max)
• Current - Limit (min): 500mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TO-243AA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

RT9161/A
Application Information
A 10uF capacitor with 200mΩ or higher ESR, connecting
between VOUT and GND pins, is recommended for
stability. A capacitor with ESR smaller than 200 mΩ may
cause VOUT oscillation as shown in Figure 1. Operating
temperature should be well considered to ensure that the
capacitance is no less than 10uF over the operating
temperature range. Please take the notice that Aluminum
electrolytic capacitors may cause VOUT oscillation when
operating below −25°C. The capacitance can be increased
without limit for better transient response.
A 1uF or higher capacitor should be placed between VIN
and GND to filter out input noise and ensure stable output
voltage.
Thermal protection limits power dissipation in RT9161/A.
When the operation junction temperature exceeds 165°C,
the OTP circuit starts the thermal shutdown function and
turns the pass element off. The pass element turn on again
after the junction temperature cools by 30°C.
For continuous operation, do not exceed absolute
maximum operation junction temperature 125°C. The
power dissipation definition in device is :
P
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
www.richtek.com
6
D
0.01
= (V
100
0.1
10
Region of Stable C
1
0
IN
V
C
C
− V
IN
IN
OUT
= 1uF
= 3.3V
OUT
= 10uF
100
) x I
OUT
Load Current (mA)
Figure 1
200
+ V
OUT
IN
x I
ESR vs. Load Current
Q
300
Instable
Stable
400
500
P
Where T
temperature 125°C, T
θ
For recommended operating conditions specification of
RT9161/A, where T
temperature of the die (125°C) and T
ambient temperature. The junction to ambient thermal
resistance θ
the thermal resistance θ
JEDEC 51-3 single-layer 1S thermal test board. The
maximum power dissipation at T
by following formula :
P
SOT-23-3 packages
P
SOT-89 packages
P
SOT-223 packages
P
TO-92 packages
The maximum power dissipation depends on operating
ambient temperature for fixed T
resistance θ
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
JA
D(MAX)
D(MAX)
D(MAX)
D(MAX)
D(MAX)
is the junction to ambient thermal resistance.
800
700
600
500
400
300
200
100
0
= ( T
= ( 125°C
= ( 125°C
= ( 125°C
= ( 125°C
0
J(MAX)
SOT-23-3 package
JA
J(MAX)
JA
is layout dependent. For SOT-223 packages,
15
. For RT9161/A packages, the Figure 2 of
Figure 2. Derating Curves
is the maximum operation junction
−
−
−
−
−
30
T
25°C ) / 250 = 0.400 W for
25°C ) / 175 = 0.571 W for
25°C ) / 135 = 0.741 W for
25°C ) / 160 = 0.625 W for
Ambient Temperature (°C)
SOT-223 package
A
A
J(MAX)
) / θ
is the ambient temperature and the
45
JA
JA
is 135°C/W on the standard
is the maximum junction
TO-29 package
60
A
= 25°C can be calculated
SOT-89 package
DS9161/A-34 April 2010
75
J(MAX)
A
is the maximum
90
and thermal
105
120