MIC5504/MT

Part: MIC5501/2/3/4

Type: Low Dropout Regulator (LDO)

Key Specs:

• Input Voltage Range: 2.5V to 5.5V
• Fixed Output Voltages: 1.0V to 3.3V
• Output Current: 300 mA
• Output Accuracy: ±2%
• Low Quiescent Current: 38 μA (Typ.)
• Low Dropout Voltage: 160 mV @ 300 mA (Typ.)
• Operating Junction Temperature: -40°C to +125°C

Features:

• Stable with 1 μF Ceramic Output Capacitors
• Output Discharge Circuit (MIC5502, MIC5504)
• Internal Enable Pull-Down (MIC5503, MIC5504)
• Thermal-Shutdown and Current-Limit Protection
• Zero-off-mode current state

Applications:

• Smartphones
• DSC, GPS, PMP, and PDAs
• Medical Devices
• Portable Electronics
• 5V Systems

Package:

• 4-Lead 1.0 mm x 1.0 mm Ultra Thin DFN Package
• 5-Lead SOT23 Package (MIC5501/4)

• Input Voltage Range: 2.5V to 5.5V
• Fixed Output Voltages from 1.0V to 3.3V
• 300 mA Ensured Output Current
• High Output Accuracy (±2%)
• Low Quiescent Current: 38 μA
• Stable with 1 μF Ceramic Output Capacitors
• Low Dropout Voltage: 160 mV @ 300 mA
• Output Discharge Circuit: MIC5502, MIC5504
• Internal Enable Pull-Down: MIC5503, MIC5504
• Thermal-Shutdown and Current-Limit Protection
• 4-Lead 1.0 mm x 1.0 mm Ultra Thin DFN Package
• MIC5501/4 5-Lead SOT23 Package

• Smartphones
• DSC, GPS, PMP, and PDAs
• Medical Devices
• Portable Electronics
• 5V Systems

The descriptions of the pins are listed in Table 3-1.

TABLE 3-1: PIN FUNCTION TABLE

Electrical Characteristics: VIN = VEN = VOUT + 1V; CIN = COUT = 1 μF; IOUT = 100 μA; TJ = +25°C, bold values indicate -40°C to +125°C, unless noted.

• Enable Voltage (VEN) -0.3V to VIN
• Power Dissipation (PD) Internally Limited, Note 1
• ESD Rating (Note 2) 3 kV

The MIC5501/2/3/4 are designed to provide 300 mA of continuous current in a very small package. Maximum ambient operating temperature can be calculated based on the output current and the voltage drop across the part. For example if the input voltage is 3.6V, the output voltage is 2.8V, and the output current is 300 mA. The actual power dissipation of the regulator circuit can be determined using Equation 4-1:

EQUATION 4-1:

$P_D = (V_IN - V_OUT1) × I_OUT + V_IN × I_GND$

Because this device is CMOS and the ground current is typically <100 μA over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation:

EQUATION 4-2:

$P_D = (3.6V - 2.8V) × 300mA = 0.240W$

To determine the maximum ambient operating temperature of the package, use the junction-to-ambient thermal resistance of the device and Equation 4-3:

EQUATION 4-3:

$P_D(MAX) = frac{T_J(MAX) - T_A}{θ_JA}$

Where:

TJ(MAX) = 125°C, the max. junction temp. of the die. θJA = Thermal resistance of 250°C/W for the UDFN package.

Substituting PD for PD(MAX) and solving for the ambient operating temperature will give the maximum operating conditions for the regulator circuit. The junction-to-ambient thermal resistance for the minimum footprint is 250°C/W.

The maximum power dissipation must not be exceeded for proper operation.

For example, when operating the MIC5501-YMT at an input voltage of 3.6V and 300 mA load with a minimum footprint layout, the maximum ambient operating temperature TA can be determined as follows:

EQUATION 4-4:

0.240W 125C TA = – 250C/W TA = 65C

Therefore, the maximum ambient operating temperature allowed in a 1 mm × 1 mm UDFN package is 65°C. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the "Regulator Thermals" section of Microchip's Designing with Low-Dropout Voltage Regulators handbook.