MIC5205-3.3BM5

Part: MIC5205 from Micrel, Inc.

Type: Low-Noise LDO Regulator

Description: The MIC5205 is an efficient linear voltage regulator with ultra low-noise output, very low dropout voltage (typically 165mV at 150mA), and very low ground current (600 μA at 100mA output), offering guaranteed 150mA output and better than 1% initial accuracy.

Operating Conditions:

• Supply voltage: +2.5V to +16V
• Operating temperature: -40°C to +125°C (Junction Temperature)
• Max output current: 150mA

Absolute Maximum Ratings:

• Max supply voltage: -20V to +20V
• Max continuous current: 500 mA (Current Limit)
• Max junction/storage temperature: +125°C (Junction), +150°C (Storage)

Key Specs:

• Output Voltage Accuracy: ±1% (at 25°C), ±2% (over -40°C to +125°C)
• Line Regulation: 0.004 %/V (Typ), 0.05 %/V (Max) for VIN = VOUT + 1V to 16V
• Load Regulation: 0.02 % (Typ), 0.5 % (Max) for IL = 0.1mA to 150mA
• Dropout Voltage: 165 mV (Typ), 350 mV (Max) at IL = 150mA
• Quiescent Current (shutdown): 0.01 μA (Typ), 5 μA (Max) at VEN ≤ 0.18V
• Ground Pin Current: 1300 μA (Typ), 2500 μA (Max) at IL = 150mA
• Current Limit: 320 mA (Typ), 500 mA (Max) at VOUT = 0V
• Output Noise: 260 nV/√Hz (Typ) at IL = 50mA, CL = 2.2μF, 470pF from BYP to GND

Features:

• Ultra-low-noise output
• High output voltage accuracy
• Guaranteed 150mA output
• Low quiescent current
• Low dropout voltage
• Extremely tight load and line regulation
• Very low temperature coefficient
• Current and thermal limiting
• Reverse-battery protection
• 'Zero' off-mode current
• Logic-controlled electronic enable

Applications:

• Cellular telephones
• Laptop, notebook, and palmtop computers
• Battery-powered equipment
• PCMCIA VCC and VPP regulation/switching
• Consumer/personal electronics
• SMPS post-regulator/dc-to-dc modules
• High-efficiency linear power supplies

Package:

• SOT-23-5

• Ultra-low-noise output
• High output voltage accuracy
• Guaranteed 150mA output
• Low quiescent current
• Low dropout voltage
• Extremely tight load and line regulation
• Very low temperature coefficient
• Current and thermal limiting
• Reverse-battery protection
• 'Zero' off-mode current
• Logic-controlled electronic enable

• Cellular telephones
• Laptop, notebook, and palmtop computers
• Battery-powered equipment
• PCMCIA VCC and VPP regulation/switching
• Consumer/personal electronics
• SMPS post-regulator/dc-to-dc modules
• High-efficiency linear power supplies

___________________________________________________________________________________________________________

VIN = VOUT + 1V; IL = 100μA; CL = 1.0μF; VEN ≥ 2.0V; TJ = 25 ° C, bold values indicate -40 ° C ≤ TJ ≤ +125 ° C; unless noted.

C

C

C

• Enable Input Voltage (V EN ).............................-20V to +20V
• Power Dissipation (P D ) .................Internally Limited, Note 3
• Lead Temperature (soldering, 5 sec.)........................260 ° C
• Junction Temperature (T J ) ........................-40 ° C to +125 ° C
• Storage Temperature (T S ).........................-65 ° C to +150 ° C

The MIC5205 is designed to provide 150mA of continuous current in a very small package. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. To determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation:

$text {of the device and the following base} P _ { D ( max ) } = frac { ≤ft ( T _ { J ( max ) } - T _ { A } right ) } { θ _ { J A } }$

TJ(max) is the maximum junction temperature of the die, 125 ° C, and TA is the ambient operating temperature. θ JA is layout dependent; Table 1 shows examples of junction-toambient thermal resistance for the MIC5205.

Table 1. SOT-23-5 Thermal Resistance

The actual power dissipation of the regulator circuit can be determined using the equation:

$P _ { D } = ( V _ { I N } - V _ { O U T } ) I _ { O U T } + V _ { I N } I _ { G N D }$

Substituting PD(max) for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC5205-3.3BM5 at room temperature with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows:

$detemmed { text {as follows} } colon P _ { D ( max ) } = frac { ( 1 2 5 ^ { ° } C - 2 5 ^ { ° } C ) } { 2 2 0 ^ { ° } C / W } P _ { D ( max ) } = 4 5 5 m W$

The junction-to-ambient thermal resistance for the minimum footprint is 220 ° C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of 3.3V and an output current of 150mA, the maximum input voltage can be determined. From the Electrical Characteristics table, the maximum ground current for 150mA output current is 2500μA or 2.5mA.

$4 5 5 m W & = ( V _ { text {IN} } - 3 . 3 V ) 1 5 0 m A + V _ { text {IN} } 2 . 5 m A 4 5 5 m W & = V _ { text {IN} } × 1 5 0 m A - 4 9 5 m W + V _ { text {IN} } 2 . 5 m A 9 5 0 m W & = V _ { text {IN} } × 1 5 2 . 5 m A$

$V _ { I N ( max ) } = 6 . 2 3 VTherefore, a 3.3V application at 150mA of output current can accept a maximum input voltage of 6.2V in a SOT23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the Regulator Thermals section of Micrel's Designing with Low-Dropout Voltage Regulators handbook.

Ultra-Low-Noise Regulator Application

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