LT3080EDD#PBF Linear Technology, LT3080EDD#PBF Datasheet - Page 15

• Manufacturer Part Number: LT3080EDD#PBF
• Description: IC REG LDO ADJ 1.1A 8-DFN
• Manufacturer: Linear Technology

Specifications of LT3080EDD#PBF

• Regulator Topology: Positive Adjustable
• Voltage - Output: 0 ~ 36 V
• Voltage - Input: 1.2 ~ 36 V
• Voltage - Dropout (typical): 1.35V @ 1.1A
• Number Of Regulators: 1
• Current - Output: 1.1A
• Current - Limit (min): 1.1A
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Voltage Regulator Type: Linear
• Topology: LDO
• Regulator Output Type: Adjustable
• Polarity Type: Positive
• Number Of Outputs: Single
• Input Voltage (min): 1.2V
• Input Voltage (max): 36V
• Output Voltage: 0 to 30V
• Package Type: DFN EP
• Output Current: 1.1A
• Load Regulation: 1.3mV
• Line Regulation: 0.003mV/V
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Dropout Voltage@current (max): 0.2@100mA/0.5@1100mA
• Pin Count: 8
• Mounting: Surface Mount
• Quiescent Current (max): 1mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The second technique for reducing power dissipation,
shown in Figure 9, uses a resistor in parallel with the
LT3080. This resistor provides a parallel path for current
fl ow, reducing the current fl owing through the LT3080.
This technique works well if input voltage is reasonably
constant and output load current changes are small. This
technique also increases the maximum available output
current at the expense of minimum load requirements.
As an example, assume: V
5.5V, V
I
than 90% of I
Calculating R
APPLICATIONS INFORMATION
OUT(MIN)
(5% Standard value = 3.6Ω)
R
P
=
OUT
5.5V – 3.2V
= 0.7A. Also, assuming that R
0.63A
= 3.3V, V
P
OUT(MIN)
yields:
OUT(MIN)
= 3.65Ω
= 630mA.
IN
= V
= 3.2V, I
Figure 9. Reducing Power Dissipation Using a Parallel Resistor
CONTROL
OUT(MAX)
P
= 5V, V
carries no more
C1
= 1A and
IN(MAX)
V
SET
R
CONTROL
SET
LT3080
+
–
=
The maximum total power dissipation is (5.5V – 3.2V) •
1A = 2.3W. However the LT3080 supplies only:
Therefore, the LT3080’s power dissipation is only:
R
choose appropriate wattage resistors to handle and dis-
sipate the power properly. With this confi guration, the
LT3080 supplies only 0.36A. Therefore, load current can
increase by 0.64A to 1.64A while keeping the LT3080 in
its normal operating range.
P
P
1A –
dissipates 1.47W of power. As with the fi rst technique,
DIS
OUT
IN
= (5.5V – 3.2V) • 0.36A = 0.83W
5.5V – 3.2V
R
P
C2
3.6Ω
3080 F09
V
V
IN
OUT
= 0.36A
LT3080
15
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