RT9361AGE Richtek USA Inc, RT9361AGE Datasheet - Page 9

• Manufacturer Part Number: RT9361AGE
• Description: IC DC-DC CONV CHRG PUMP SOT23-6
• Manufacturer: Richtek USA Inc

Specifications of RT9361AGE

• Internal Driver: Yes
• Type - Primary: Backlight, Flash/Torch
• Type - Secondary: White LED
• Mounting Type: Surface Mount
• Topology: PWM, Switched Capacitor (Charge Pump)
• Number Of Outputs: 1
• Frequency: 800kHz ~ 1.3MHz
• Voltage - Supply: 2.8 V ~ 5 V
• Voltage - Output: 5V
• Package / Case: SOT-23-6
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Efficiency
The efficiency of the charge pump regulator varies with
the output voltage version, the applied input voltage, the
load current, and the internal operation mode of the device.
The approximate efficiency is given by :
For a charge pump with an output of 5 volts and a nominal
input of 3 volts, the theoretical efficiency is 83.33%. Due
to internal switching losses and IC quiescent current
consumption, the actual efficiency can be measured as
82.72%.
Thermal Considerations
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 :
P
Where T
temperature 125°C, T
the θ
For recommended operating conditions specification of
RT9361, where T
temperature of the die (125°C) and T
ambient temperature. The junction to ambient thermal
resistance θ
2x2 is 165°C/W on the standard JEDEC 51-3 single layer
thermal test board. The maximum power dissipation at
T
P
T/SOT-23-6 packages
P
WDFN-6L 2x2 packages
The maximum power dissipation depends on operating
ambient temperature for fixed T
resistance θ
rating curves allows the designer to see the effect of rising
ambient temperature on the maximum power allowed.
DS9361A/B-12
Efficiency
=
A
D(MAX)
D(MAX)
D(MAX)
V
= 25°C can be calculated by following formula :
2V
OUT
JA
IN
= ( T
is the junction to ambient thermal resistance.
= (125°C − 25°C) / 165°C/W = 0.606W for
×
= (125°C − 25°C) / 250°C/W = 0.4W for
J(MAX)
100
(%)
JA
JA
J(MAX)
. For RT9361 packages, the Figure 5 of de-
−
for T/SOT-23-6 is 250°C/W and WDFN-6L
=
September 2009
−
P
is the maximum operation junction
−
P
OUT
- T
IN
(
×
J(MAX)
A
2
) / θ
A
×
Charge
100
is the ambient temperature and
JA
is the maximum junction
=
V
Pump
V
OU
IN
×
T
J(MAX)
2I
×
Operating
I
OUT
OUT
A
is the operated
and thermal
×
100
Mode)
PCB Board Layout
The RT9361A/B is a high-frequency switched-capacitor
converter, and therefore large transient currents will flow
in V
ripple, place all of the components as close to IC as
possible. Besides a solid ground plane is recommended
on the bottom layer of the PCB. The ground of C
C
as possible. Figure 6 and Figure 7 shows the typical PCB
layout of RT9361A/B EVB board.
OUT
IN
Figure 5. Derating Curves for RT9361 Packages
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
should be connected together and as close to the IC
and V
0
T/SOT-23-6
WDFN-6L 2x2
OUT
. For best performance and to minimize
25
Ambient Temperature (°C)
Figure 6
Figure 7
50
RT9361A/B
75
Single Layer PCB
www.richtek.com
100
IN
and
125
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