rt9278 Richtek Technology Corporation, rt9278 Datasheet
rt9278
Available stocks
Related parts for rt9278
rt9278 Summary of contents
Page 1
... Alkaline/ NiMH or one-cell Li-Ion/Li-polymer battery. The RT9278 is boost converter with PWM control loop, provide up to 95% efficiency by using a synchronous rectifier. The maximum peak current in the internal switch is limited 2A. ...
Page 2
... VDD EN C3 RT9278 1uF VOUT 8 PGND 2.2uF 2 9 COMP LDRI 3 10 GND LFB 18.2k GPIO Chip Enable 4 7 VDD EN RT9278 2.5k VOUT 2 COMP 8 PGND 9 10 LDRI LFB GND C3 1uF Q1 AO7401 C4 2.2uF R2 300k I 700mA strobe Q1 I Movie 100ms AO3403 2 ...
Page 3
... GND PGND C COMP Figure 6. Synchronous Boost Converter Q1 AO3403 C5 R5 20uF R4 620k 510k R6 40.2k V OUT1 3.3V/300mA Q1 AO3403 C5 R5 40uF R4 887k 510k R6 110k 7 C3 1uF C C OUT R2 FF 40uF RT9278 V OUT 3. 22pF 1uF V OUT2 1.8V/150mA C6 C7 22pF 30uF V OUT www.richtek.com 3 ...
Page 4
... RT9278 Table 1. Component Selection for Figure 6 (L=2.2 H) Input Voltage Output Voltage (V) (V) 1.5~3.0 3.3 1.5~3.3 5.0 3.0~4.5 5.0 Table 2. Component Selection for Figure 6 (L=4.7 H) Input Voltage Output Voltage (V) (V) 1.5~3.0 3.3 1.5~3.3 5.0 3.0~4.5 5.0 Table 3. Component Selection for Figure 6 (L=6.8 H) Input Voltage Output Voltage (V) (V) 1.5~3.0 3.3 1.5~3.3 5.0 3.0~4.5 5.0 Table 4. Component Selection for Figure 6 (L=10 H) Input Voltage ...
Page 5
... Linear Controller Feedback Input. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Error Error AMPLIFIER Comparator - - + + Oscillator Slope and Compen- Shutdown sation Control - + Pin Function Control and Driver Logic Current Sense RT9278 VOUT LX PGND LDRI www.richtek.com 5 ...
Page 6
... RT9278 Operation RT9278 integrates a high-efficiency step-up DC-DC converter and a linear regulator controller. The boost converter is based on a fixed frequency, pulse-width-modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. Current mode control with external compensation network makes it easy to stabilize the system and keep maximum flexibility ...
Page 7
... Test Conditions 1mA ST L BAT V OUT_ADJ 3.3V 0.9V SW OFF OUT FB EN Pin = 0V, Open Loop I OFF V Close Loop 3.3V FB OUT (MAX 3.3V OUT V = 3.3V OUT 3.3V SW OUT RT9278 Min Typ Max Units -- 1 1.1 -- 5.5 V 2 200 350 0.784 0.8 0.816 V -- 650 -- kHz -- 85 -- ...
Page 8
... RT9278 Parameter Linear Controller Feedback Voltage for Linear Controller EN Input High Level Threshold EN Input Low Level Threshold Thermal Shutdown Thermal Shutdown Hysterises Note 1.Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied ...
Page 9
... Temperature ( C) Efficiency vs. Output Current 100 V = 5.0V OUT Output Current (mA) Input Voltage vs. Output Voltage V = 5.0V OUT 1.6 1.925 2.25 2.575 1.93 2.58 2.9 3.225 3.55 3.875 3.23 Input Voltage (V) RT9278 1.5V IN 100 1000 3.88 4.2 www.richtek.com 9 ...
Page 10
... RT9278 Output Voltage vs. Output Current 3.310 3.305 3.300 3.295 3.290 3.285 3.280 3.275 3.270 3.265 3.260 3.255 V = 3.3V OUT 3.250 1 10 Output Current (mA) Power LED Efficiency vs. Input Voltage 100 3.5V 200mA 4.7 H LED 0 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 Input Voltage (V) Normal Operation ...
Page 11
... OUT LOAD 400 200 -50 Time (1ms/Div) Flash LED V = 3.0V, Power LED = 200mA to 700mA (100mV/Div) (2V/Div) (500mA /Div) I LED I (500mA/Div Time (10ms/Div) Flash LED V = 4.3V, Power LED = 200mA to 700mA (100mV/Div) (2V/Div) (500mA/Div) I LED (500mA/Div Time (10ms/Div) RT9278 www.richtek.com 11 ...
Page 12
... Linear Regulator Linear Regular MOSFETs Selection I IN(MAX) The linear controller of RT9278 was designed to drive an external P-Channel MOSFET. The main consideration of pass MOSFETs of linear regulator is package selection for efficient removal of heat. The power dissipation of a linear regulator is Plinear = (V ...
Page 13
... V-Type 10L DFN 3x3 Package Richtek Technology Corporation Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com RT9278 2 1 DETAIL A Pin #1 ID and Tie Bar Mark Options Dimensions In Inches Min Max 0 ...