rt9903 Richtek Technology Corporation, rt9903 Datasheet
rt9903
Available stocks
Related parts for rt9903
rt9903 Summary of contents
Page 1
... Channel DC/DC Converters IC with High-Efficiency Step-Up General Description The RT9903 is a complete power-supply solution for digital still cameras and other hand-held devices. It integrates a high-efficiency fours step-up DC-DC charge pump. The two Step-up DC-DC converters (CH1,CH2) accept inputs from 1.5V to 5.5V and regulate a resistor- adjustable output up to 17V. ...
Page 2
... R5 R6 1.2k 2.2k 1.2k C12 C13 C10 4.7nF 6.8nF 56nF www.richtek.com 2 Preliminary C15 4.7uF L1 17 4.7uH VDD 11 LX3 LX1 AGND FB1 16 PGND 9 FB3 RT9903 VBATT L2 4.7uH LX2 R4 10k 6 CS4 FB2 Q1 5 EXT4 Si2302 7 FB4 INCD 13 EN1 14 EN2 12 EN3 15 EN4 FB-CP 19 COMP1 23 COMP2 10 COMP3 8 ...
Page 3
... R11 5.1M 1nF 22 C28 R12 360k 2 C24 D5 68nF SS0520 R13 C25 to C26 SS0520 750k 10uFx2 3 R14 330k VCC 3.3V C27 1uF FB2 INCD CX - Charge Pump + Oscillator Thermal + Protection - Soft Start 10uA CS4 FB4 PGND (Exposed Pad) RT9903 +15V (+CCD) -7.5V (-CCD) FBCP + - RT www.richtek.com 3 ...
Page 4
... RT9903 Functional Pin Description Pin No. Pin Name 1 CX Charge Pump External Driver Pin. 2 INCD Charge Pump Input Pin. 3 FB_CP Charge Pump Feedback Pin Frequency Setting Resistor Connection Pin. 5 EXT4 CH4 External Power Switch. 6 CS4 CH4 Current Sense Input Pin. 7 FB4 CH4 Feedback Input ...
Page 5
... V = 0V, EN1 EN2 V = 3.3V EN3 EN4 V = 3.6V, VDD 0.15V FB4 REF I VDD4 0V, EN1 EN2 3.3V EN3 EN4 RT9903 − 0 − 0.3V to 20V − 0. 1.923W − 40°C to 85°C − 65°C to 150°C Min Typ Max 2.4 -- 5 ...
Page 6
... RT9903 Parameter Oscillator Free Running Frequency CH1, CH2, CH3 Maximum Duty Cycle CH4 Maximum Duty Cycle Reference Voltage (CH1, CH2, CH3, CH4, CH5) Feedback Reference Voltage Feedback Reference Voltage Feedback Voltage (Charge Pump) Error Amplifier GM Compensation Source Current Compensation Sink Current ...
Page 7
... Output Ripple LX1 V = 2.5V 3.3V, @I BAT DD OUT Time (1us/Div) V & Output Ripple LX1 V = 3.8V 3.3V, @I BAT DD OUT Time (1us/Div) CH2 Efficiency vs. Output Current 100 V = 15V OUT 4. 2. Output Current (mA) RT9903 = 30mA = 30mA www.richtek.com 7 ...
Page 8
... RT9903 V & Output Ripple LX2 V = 2.5V 3.3V, @I BAT DD Time (1us/Div) V & Output Ripple LX2 V = 3.8V 3.3V, @I BAT DD Time (1us/Div) CH3 Efficiency vs. Input Voltage 100 4 series WLED 20mA LED 2.4 2.8 Input Voltage (V) www.richtek.com 8 Preliminary = 30mA OUT = 30mA OUT 3.2 3.6 4 4.4 V & Output Ripple ...
Page 9
... BAT DD Time (1us/Div) V & Output Ripple LX4 3.3V, @I BAT DD Time (1us/Div) DS9903-07 August 2007 Preliminary = 20mA OUT = 20mA OUT = 100mA OUT RT9903 V & Output Ripple LX3 V = 3.8V 3.3V, @I BAT DD OUT Time (1us/Div) CH4 Efficiency vs. Output Current 100 V = 3.3V OUT ...
Page 10
... RT9903 V & Output Ripple LX4 V = 2.5V 3.3V, @I BAT DD Time (1us/Div) V & Output Ripple LX4 3.3V, @I BAT DD Time (1us/Div) CH4 Load Transient Response 3.3V, @I BAT DD Time (1ms/Div) www.richtek.com 10 Preliminary = 100mA OUT = 100mA OUT = 100mA to 350mA OUT V & Output Ripple LX4 V = 2.5V 3.3V, @I ...
Page 11
... Time (2.5us/Div) DS9903-07 August 2007 Preliminary = 100mA to 350mA OUT V & Output Ripple 2.5V 3.3V BAT DD Time (2.5us/Div) V & Output Ripple 3.8V 3.3V BAT DD Time (2.5us/Div) Frequency vs 2500 2000 1500 1000 500 100 150 R (kΩ) RT RT9903 Resistor 200 250 300 www.richtek.com 11 ...
Page 12
... RT9903 Application Information The RT9903 is a five-Channel DC/DC converter for digital still cameras and other hand-held device. The five channels DC/DC converters are as follows: CH1: Step-up, asynchronous voltage mode DC/DC converter with an internal power MOSFET, current limit protection, and over voltage protection. This channel is designed to supply output voltage from 3 ...
Page 13
... I is the maximum output current. Typical LOAD target crossover frequency is 1/6 of RHPZ. For example assume 0.5A, the R OUT LOAD then : f = 66KHz RHPZ RT9903 + Inductor DC(ON) External_MOS ) much less than that C ) are OUT ) and capacitor the inductor ...
Page 14
... RT9903 Step-2 Calculate C C Choose f = 10KHz, and then C C simplified loop-gain formula. Loop gain = (1- Where Gm is the transconductance of error amplifier, and R is the current sense amplifier transresistance our design, Gm=200us and then ...
Page 15
... Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com DETAIL A Pin #1 ID and Tie Bar Mark Options Dimensions In Inches Min Max 0.031 0.039 0.000 0.002 0.007 0.010 0.007 0.012 0.156 0.159 0.091 0.108 0.156 0.159 0.091 0.108 0.020 0.014 0.018 RT9903 1 2 www.richtek.com 15 ...