RT8059GJ5

Part: RT8059 — Richtek Technology Corporation

Type: Synchronous Buck Converter

Description: 1.5MHz, 1A, high efficiency PWM step-down DC/DC converter capable of delivering 1A output current over a wide input voltage range from 2.8V to 5.5V.

Operating Conditions:

• Supply voltage: 2.8V to 5.5V
• Operating temperature: -40°C to 85°C
• Junction temperature: -40°C to 125°C

Absolute Maximum Ratings:

• Max supply voltage: 6.5V
• Max junction temperature: 150°C
• Max storage temperature: -65°C to 150°C

Key Specs:

• Quiescent Current (I_Q): 78 μA (I_OUT = 0mA, V_FB = V_REF + 5%)
• Shutdown Current (I_SHDN): 0.1 μA (EN = GND)
• Reference Voltage (V_REF): 0.588V to 0.612V (Typ 0.6V)
• Adjustable Output Range (V_OUT): V_REF to V_IN - 0.2V
• P-Channel Current Limit (I_LM_P): 1.5A (Typ)
• Oscillator Frequency (f_OSC): 1.2MHz to 1.8MHz (Typ 1.5MHz, I_OUT = 100mA)
• P-MOSFET R_ON: 0.28 Ω (Typ, I_OUT = 200mA)
• N-MOSFET R_ON: 0.25 Ω (Typ, I_OUT = 200mA)

Features:

• Wide Input Voltage from 2.8V to 5.5V
• Adjustable Output from 0.6V to VIN
• 1A Output Current
• 95% Efficiency
• No Schottky Diode Required
• 1.5MHz Fixed Frequency PWM Operation
• Small TSOT-23-5 Package
• RoHS Compliant and Halogen Free

Applications:

• NIC Card
• Cellular Telephones
• Personal Information Appliances
• Wireless and DSL Modems
• MP3 Players
• Portable Instruments

Package:

• TSOT-23-5

• Wide Input Voltage from 2.8V to 5.5V
• Adjustable Output from 0.6V to VIN
• 1A Output Current
• 95% Efficiency
• No Schottky Diode Required
• 1.5MHz Fixed Frequency PWM Operation
• Small TSOT-23-5 Package
• RoHS Compliant and Halogen Free

• NIC Card
• Cellular Telephones
• Personal Information Appliances
• Wireless and DSL Modems
• MP3 Players
• Portable Instruments

For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula :

where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θ JA is the junction to ambient thermal resistance.

For recommended operating condition specifications of the RT8059, the maximum junction temperature is 125 ° C and TA is the ambient temperature. The junction to ambient thermal resistance, θ JA, is layout dependent. For TSOT23-5 packages, the thermal resistance, θ JA, is 255 ° C/W on a standard JEDEC 51-3 single-layer thermal test board. The maximum power dissipation at TA = 25 ° C can be calculated by the following formula :

PD(MAX) = (125 ° C -25 ° C) / (255 ° C/W) = 0.392W for TSOT-23-5 package

Table 1. Suggested Component Values

Table 1. Suggested Component Values

• V OUT (V) R1 (k ) R2 (k ) C FF (pF) L ( H) C OUT ( F) X5R 16V 0805
• 1 38.3 56.2 22 to 39 1.5 10
• 1.2 56 56 15 to 39 1.5 10
• 1.8 113 56.2 0 to 8.2 2.2 10
• 2.5 178 56 0 to 12 2.2 10
• 3.3 249 54.9 0 to 8.2 2.2 10

Note : All the input and output capacitors are the suggusted values, refering to the effective capacitances, subject to any de-rating effect, like a DC Bias.