rt9218b Richtek Technology Corporation, rt9218b Datasheet
rt9218b
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rt9218b Summary of contents
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... Synchronous Buck PWM DC-DC and Linear Power Controller General Description The RT9218B 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 2.2 0.1uF RT9218B 10R BOOT PHASE 13 2 UGATE OPS GND 4 11 VCC C10 LGATE 1uF 5 10 DRV PGOOD 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 it's implemented with a specific sequence as following in power on stage and IN chart. NC (Pin 6,7,8) No internal connection. RT9218B www.richtek.com 3 ...
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... RT9218B 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 0.6V UV_S + Soft-Start - & Fault Logic 0.6V + UV_L - + Oscillator (300k/600kHz) GND Specific Power Sequence for LDO 90% ...
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... UGATE and LGATE Open Rising CCRTH CC V CCHYS 12V REF 12V OSC CC ΔV OSC RT9218B +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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... RT9218B 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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... Soft Start & PGOOD (1V/Div) (500mV/Div) SV OUT (2A/Div Time (10ms/Div) Frequency vs. Temperature 350 330 310 290 270 250 -40 - Temperature (°C) OCP UGATE V = 12V 20A OCSET 15kΩ OCSET Time (5us/Div) RT9218B 80 110 140 (10V/Div) (10A/Div) www.richtek.com 7 ...
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... RT9218B Transient Response (Rising) UGATE (10V/Div) SV OUT (100mV/Div 12V 15A OUT I L (10A/Div 1/20ms 2.5A/us Time (5us/Div) Power On SV OUT I OUT UGATE Time (500us/Div) Dead Time (Rising 12V 25A OUT Time (25ns/Div) www.richtek.com 8 UGATE (10V/Div) SV OUT (100mV/Div) ...
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... Equivalent series resistor of output capacitor OUT = 1/2 Δ Figure 2. The related waveforms of output capacitor RT9218B V = OUT V IN (1) . Figure 2 shows the C V OUT = L I OUT L ΔI L Δ Δ www.richtek.com 9 ...
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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 RT9218B is a voltage mode buck converter using the high gain error amplifier with transconductance (OTA, Operational Transconductance Amplifier). The transconductance : ...
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... MOSFET on resistance according to the following equation : OCSET × 40uA R OCSET = I OCSET R of the lower DS(ON) UGATE (10V/Div) I (10A/Div) L UGATE (10V/Div) I (10A/Div) L RT9218B − 0.4V MOSFET OCP OPS (200mV/Div 5V 12V 1.5V OUT Time (5μs/Div) OCP V = 12V 12V 1.5V OUT Time (2.5μ ...
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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 RT9218B 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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... In VGA field, the MOSFET of LV OUT voltage not OUT This connection may trigger UV protection to shutdown RT9218B, but using the typical application circuit won't have this issue. See figure 9 using OPS pin to control the power sequence. DS9218B-09 March 2007 hiccup restart sequence power sensing ...
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... GND Figure 10. The connections of the critical components in the converter Below PCB gerber files are our test board for your reference : www.richtek.com 14 IQ1 IL V OUT Q1 IQ2 Q2 VCC GND LGATE RT9218B UGATE FB and C each IN OUT LOAD DS9218B-09 March 2007 ...
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... DS9218B-09 March 2007 RT9218B www.richtek.com 15 ...
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... RT9218B 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 www.richtek.com 16 DS9218B-09 March 2007 ...
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... Lead SOP Plastic 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 RT9218B H M Dimensions In Inches Min Max 0.336 0.344 0.150 0.157 ...