rt9218 Richtek Technology Corporation, rt9218 Datasheet
rt9218
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rt9218 Summary of contents
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... Synchronous Buck PWM DC-DC and Linear Power Controller General Description The RT9218 is a dual output with one synchronous buck PWM and one linear controller. The part is proposed to generate logic-supply voltages for PC based systems. The high-performance device includes internal soft-start, frequency-compensation networks, power good signaling ...
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... D1 1N4148 C7 1uF Q1 2.2 MU PHASE OUT 4k C9 470uF voltage C8 0.1uF 2.2 RT9218 10R BOOT PHASE 13 2 UGATE OPS GND 4 11 LGATE VCC C10 1uF 5 10 PGOOD DRV 9 6 FBL C11 ...
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... PGOOD (Pin 10) PGOOD is an open-drain output used to indicate that the regulator is within normal operating voltage ranges and in power on stage and IN it's implemented with a specific sequence as following chart. NC (Pin 6,7,8) No internal connection. RT9218 www.richtek.com 3 ...
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... RT9218 Function Block Diagram Bias & Regulators (3V_Logic & 3VDD_Analog) VCC + DRV - FBL PGOOD FB Timing Diagram FSB_VTT (1.2V @ 5Amp) VTT_GD www.richtek.com 4 VCC Power On Reference Reset 0.8V REF 0.64V UV_S + Soft-Start - & Fault Logic 0.64V + UV_L - + Oscillator (300k/600kHz) GND Specific Power Sequence for LDO ...
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... UGATE and LGATE Open Rising V CC CCRTH V CCHYS 12V REF 12V OSC CC ΔV OSC RT9218 +15V CC − 0. 0.3V PHASE BOOT + 0.3V VCC − 40°C to 150°C − 40°C to 125°C − 40°C to 85°C Min Typ Max Units -- 6 15 ...
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... RT9218 Parameter Error Amplifier (GM) E/A Transconductance Open Loop DC Gain Linear Regulator DRV Driver Source Reference Voltage PWM Controller Gate Drivers (V Upper Gate Source Upper Gate Sink Lower Gate Source Lower Gate Sink Dead Time Protection FB Under-Voltage Trip FBL Under-Voltage Trip OC Current Source ...
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... 0 Output Current (A) Frequency vs. Temperature 350 330 310 290 270 250 -40 - Temperature (°C) OCP UGATE V = 12V 20A OCSET 15kΩ OCSET Time (5us/Div) RT9218 110 140 (10V/Div) (10A/Div) www.richtek.com 7 ...
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... RT9218 V Switching CC SV OUT I OUT UGATE 12Vto 10A OUT Time (10ms/Div) Power On SV OUT I OUT UGATE Time (500us/Div) Dead Time (Rising 25A OUT Time (25ns/Div) www.richtek.com 8 (100mV/Div) SV OUT I OUT (10A/Div) UGATE (20V/Div (10V/Div) (500mV/Div) ...
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... Time (5us/Div) Soft Start & PGOOD (1V/Div) PGOOD (500mV/Div) SV OUT (2A/Div Time (10ms/Div) DS9218-08 March 2007 UGATE (10V/Div) SV OUT (100mV/Div OUT 1/20ms L = 2.2uH (10A/Div 2.5A/ 2000uF RT9218 Transient Response (Falling 2.2uH C = 2000uF = V = 12V IN = 15A to 0A Time (25us/Div) www.richtek.com 9 ...
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... RT9218 Application Information Inductor Selection The selection of output inductor is based on the considerations of efficiency, output power and operating frequency. Low inductance value has smaller size, but results in low efficiency, large ripple current and high output ripple voltage. Generally, an inductor that limits the ripple current (Δ ...
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... The input capacitor must be cable of handling this ripple current. Sometime, for higher efficiency the low ESR capacitor is necessarily. PWM Loop Stability RT9218 is a voltage mode buck converter using the high gain error amplifier with transconductance (OTA, Operational Transconductance Amplifier). The transconductance : ...
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... RT9218 OPS (Over Current Setting, VIN_POR and Shutdown) 1.OCP Sense the low-side MOSFET's R Connecting a resistor (R ) from this pin to the source of the upper MOSFET and the drain of the lower MOSFET OCSET sets the over-current trip point. R set the converter over-current trip point (I OPS pin function is similar to RC charging or discharging circuit, so the over-current trip point is very sensitive to parasitic capacitance (ex ...
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... V Figure 6. OCP and VIN_POR actions 3. Shutdown Pulling low the OPS pin by a small single transistor can shutdown the RT9218 PWM controller as shown in typical application circuit. Soft Start A built-in soft-start is used to prevent surge current from power supply input during power on. The soft-start voltage is controlled by an internal digital counter ...
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... LDO Power Sequence In VGA field, the MOSFET of LV OUT voltage not OUT This connection may trigger UV protection to shutdown RT9218, but using the typical application circuit won't have this issue. See figure 9 using OPS pin to control the power sequence. www.richtek.com 14 hiccup restart power ...
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... MOSFETs should be sized to carry 2A peak currents. 5V/12V GND Figure 10. The connections of the critical components in the converter Below PCB gerber files are our test board for your reference : DS9218-08 March 2007 IQ1 IL V OUT Q1 IQ2 Q2 VCC GND LGATE RT9218 UGATE FB RT9218 and C each IN OUT LOAD www.richtek.com 15 ...
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... RT9218 www.richtek.com 16 DS9218-08 March 2007 ...
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... According to our test experience, you must still notice two items to avoid noise coupling : 1.The ground plane should not be separated. 2.V rail adding the LC filter is recommended. CC DS9218-08 March 2007 RT9218 www.richtek.com 17 ...
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... RT9218 Outline Dimension J I Symbol Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 www.richtek.com Dimensions In Millimeters Min Max 8.534 8.738 3.810 3.988 1.346 1.753 0.330 0.508 1.194 1 ...