RT7234

RT7231 RICHTEK | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 18

Technical content

Features

zzzzz ACOTTM Mode Enables Fast Transient Response zzzzz 4.5V to 18V Input Voltage Range zzzzz 4A Output Current zzzzz 50mΩΩΩΩΩ Internal Low Site N-MOSFET zzzzz Advanced Constant On-Time Control zzzzz Support All Ceramic Capacitors zzzzz Up to 95% Efficiency zzzzz 650kHz Switching Frequency at all Load Current (RT7231, RT7233) zzzzz Discontinuous Operating Mode at Light Load (RT7232, RT7234) zzzzz Adjustable Output Voltage from 0.765V to 8V zzzzz Adjustable Soft-Start zzzzz Cycle-by-Cycle Current Limit zzzzz Input Under Voltage Lockout zzzzz Thermal Shutdown zzzzz RoHS Compliant and Halogen Free

Applications

z Industrial and Commercial Low Power Systems z Computer Peripherals z LCD Monitors and TVs z Green Electronics/Appliances z Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs Simplified Application Circuit 4A, 18V, 650kHz, ACOTTM Synchronous Step-Down Converter * : VCC pin for TSSOP-14 (Exposed Pad) only. VS pin for TSSOP-14 (Exposed Pad) only. GND pin for TSSOP-14 (Exposed Pad) only. PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. PGOOD* RT7231/32/33/34 VREG5 FB VCC* VIN BOOT SW SS VOUTVIN GND* PGND ENEnable Power GOOD VS*

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. RT7234 Package Type SP : SOP-8 (Exposed Pad-Option 2) Lead Plating System G : Green (Halogen Free and Pb Free) RT7232 Package Type CP : TSSOP-14 (Exposed Pad) QW : WDFN-10L 3x3 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) RT7233 Package Type SP : SOP-8 (Exposed Pad-Option 2) Lead Plating System G : Green (Halogen Free and Pb Free) RT7231 Package Type CP : TSSOP-14 (Exposed Pad) QW : WDFN-10L 3x3 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free)

Ordering Information

Discontinuous Operating Mode Note : Richtek products are : \ RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. \ Suitable for use in SnPb or Pb-free soldering processes. Marking Information Pin Configurations (TOP VIEW) TSSOP-14 (Exposed Pad) 1Q= : Product Code YMDNN : Date Code RT7231GQW RT7233GSP : Product Number YMDNN : Date Code RT7233GSP RT7231GCP : Product Number YMDNN : Date Code RT7231GCP SOP-8 (Exposed Pad)WDFN-10L 3x3 EN FB PGOOD SS VIN VIN BOOT SW SW VREG5 PGND EN FB VREG5 SS VIN BOOT PGND SW PGND 4 5 RT7234GSP : Product Number YMDNN : Date Code RT7234GSP 1P= : Product Code YMDNN : Date Code RT7232GQW RT7232GCP : Product Number YMDNN : Date Code RT7232GCP Continuous Switching Mode FB VIN PGND GND SS VREG5 PGOOD EN PGND SW SW BOOT VS VCC PGND RT7231GCP YMDNN 1Q=YM DNN 1P=YM DNN RT7232GCP YMDNN RT7234 GSPYMDNN RT7233 GSPYMDNN

DS7231/32/33/34-00 March 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Functional Pin Description Pin No. TSSOP-14 (Exposed Pad) WDFN-10L 3x3 SOP-8 (Exposed Pad) Pin Name Pin Function 1 -- -- VS Output Voltage Sense Input. 2 2 2 FB Feedback Voltage Input. It is used to regulate the output of the converter to a set value via an external resistive voltage divider. The feedback threshold voltage is 0.765V typically. 3 3 3 VREG5 Internal Regulator Output. Connect a 1 μF capacitor to GND to stabilize output voltage. 4 4 4 SS Soft-Start Time Setting. Connect an external capacitor between this pin and GND to set the soft- start time. 5 -- -- GND Analog Ground. 6 5 -- PGOOD Open Drain Power Good Indicator Output. 7 1 1 EN Enable Control Input. A logic-high enables the converter; a logic-low forces the IC into shutdown mode reducing the supply current to less than 10μA. 8, 9, 15 (Exposed pad) (Exposed pad) 5, 9 (Exposed Pad) PGND Power Ground. The exposed pad must be soldered to a large PCB and connected to PGND for maximum power dissipation. 10, 11 6, 7 6 SW Switch Node. Connect this pin to an external L-C filter. 12 8 7 BOOT Bootstrap Supply for High Side Gate Driver. Connect a 0.1μF capacitor between the BOOT and SW pin. 13 9, 10 8 VIN Power Input. The input voltage range is from 4.5V to 18V. Must bypass with a suitably large ( ≥10μF x 2) ceramic capacitor. 14 -- -- VCC Supply Voltage Input for Internal Linear Regulator to the Control Circuitry.

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Function Block Diagram * : VCC pin for TSSOP-14 (Exposed Pad) only. VS pin for TSSOP-14 (Exposed Pad) only. GND pin for TSSOP-14 (Exposed Pad) only. PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Operation The RT7231/32/33/34 is a synchronous step-down converter with advanced constant on-time control mode. Using the ACOT TM control mode can reduce the output capacitance and provide fast transient response. It can minimize the component size without additional external compensation network. Power Good (for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only) After soft-start is finished, the power good function will be activated. When the FB is activated, the PGOOD will become an open-drain output. If the FB is below, the PGOOD pin will be pulled low. Internal Regulator The regulator provides 5V power to supply the internal control circuit. Connecting a 1 μF ceramic capacitor for decoupling and stability is required. Soft-Start In order to prevent the converter output voltage from overshooting during the startup period, the soft-start function is necessary. The soft-start time is adjustable and can be set by an external capacitor. Current Protection The inductor current is monitored via the internal switches in cycle-by-cycle. Once the output voltage drops under UV threshold, the device will enter latch mode for TSSOP- 14 (Exposed Pad), and hiccup mode for WDFN-10L 3x3. UVLO Protection To protect the chip from operating at insufficient supply voltage, the UVLO is needed. When the input voltage of VCC is lower than the UVLO falling threshold voltage, the device will be latch-off. Output Discharge Control (for TSSOP-14 (Exposed Pad) only) When EN pin is low, the RT7231/32 will discharge the output with an internal 50Ω MOSFET connected between V OUT to GND pin. Thermal Shutdown When the junction temperature exceeds the OTP threshold value, the IC will shut down the switching operation. Once the junction temperature cools down and is lower than the OTP lower threshold, the converter will automatically resume switching VCC* POR & Reg Driver BOOT VREG5 Control VBIAS On-Time VIN FB Min. Off-Time Ripple Gen. VREF ZC Comparator SS SW PGND EN VREG5 OC 2µA VREG5 UV & OV SW FB VS* VIN Comparator -FB 0.9 x VREF PGOOD* GND*

DS7231/32/33/34-00 March 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Recommended Operating Conditions (Note 3) Absolute Maximum Ratings (Note 1) z Power Dissipation, PD @ TA = 25°C z Package Thermal Resistance (Note 2) (VIN = 12V, TA = 25°C, unless otherwise specified)

Electrical Characteristics

Parameter Symbol Test Conditions Min Typ Max Unit Supply Current Shutdown Current I SHDN V EN = 0V -- 1 10 μA Quiescent Current I Q V EN = 5V, VFB = 0.8V -- 1 1.3 mA Logic Threshold Logic-High 2 -- 18 EN Input Voltage Logic-Low -- -- 0.4 V VFB Voltage and Discharge Resistance TA = 25°C 0.757 0.765 0.773 Feedback Threshold Voltage V FB TA = −40°C to 85°C 0.755 -- 0.775 V Feedback Input Current I FB V FB = 0.8V -- 0.01 0.1 μA VOUT Discharge Resistance R DIS V EN = 0V, VS = 0.5V -- 50 100 Ω VREG5 Output VREG5 Output Voltage V REG5 6V ≤ VIN ≤ 18V, 0 < IVREG5 < 5mA 4.8 5.1 5.4 V

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Note 1. Stresses beyond those listed “Absolute Maximum Ratings ” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θ JA is measured at T A = 25 °C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Parameter Symbol Test Conditions Min Typ Max Unit Line Regulation 6V ≤ VIN ≤ 18V, IVREG5 = 5mA -- -- 20 mV Load Regulation 0 < IVREG5 < 5mA -- -- 100 mV Output Current I VREG5 V IN = 6V, VREG5 = 4V -- 70 -- mA RDS(ON) High-Side RDS(ON)_H (VBOOT − VSW) = 5.5V -- 120 -- Switch On Resistance Low-Side RDS(ON)_L -- 50 -- mΩ Current Limit Current Limit ILIM 4.7 5.4 7.5 A Thermal Shutdown Thermal Shutdown Threshold T SD Shutdown Temperature -- 150 -- Thermal Shutdown Hysteresis ΔTSD -- 20 -- On-Time Timer Control On-Time t ON V IN = 12V, VOUT = 1.05V -- 135 -- ns Minimum Off-Time t OFF(MIN) VFB = 0.7V -- 260 310 ns Soft-Start SS Charge Current V SS = 0V -- 6 -- μA SS Discharge Current V SS = 0.5V 0.1 0.2 -- mA UVLO UVLO Threshold Wake Up V REG5 3.6 3.85 4.1 Hysteresis 0.16 0.35 0.47 V Power Good VFB Rising 85 90 95 PGOOD Threshold VFB Falling -- 85 -- PGOOD Sink Current PGOOD = 0.5V 2.5 5 -- mA Output Under Voltage and Over Voltage Protection OVP Trip Threshold OVP Detect 115 120 125 % OVP Prop Delay -- 5 -- μs UVP Trip Threshold 65 70 75 UVP Hysteresis -- 10 -- UVP Prop Delay -- 250 -- μs UVP Enable Delay t UVPEN Relative to Soft-Start Time -- tSS x 1.7 -- ms

Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation.

• : VCC pin for TSSOP-14 (Exposed Pad) only.

VS pin for TSSOP-14 (Exposed Pad) only. GND pin for TSSOP-14 (Exposed Pad) only. PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Table 1. Suggested Component Values (VIN = 12V)

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Typical Operating Characteristics Output Voltage vs. Output Current 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 0 0.5 1 1.5 2 2.5 3 3.5 4 Output Current (A) Output Voltage (V) VIN = 18V VIN = 12V VIN = 5V VOUT = 1.05V RT7232/34 Output Voltage vs. Output Current 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 0 0.5 1 1.5 2 2.5 3 3.5 4 Output Current (A) Output Voltage (V) VIN = 18V VIN = 12V VIN = 5V VOUT = 1.05V RT7231/33 Feedback Threshold Voltage vs. Temperature 0.750 0.755 0.760 0.765 0.770 0.775 0.780 -50 -25 0 25 50 75 100 125 Temperature (°C) Feedback Threshold Voltage (V ) VIN = 12V, VOUT = 1.05V, IOUT = 0A Output Voltage vs. Input Voltage 1.040 1.042 1.044 1.046 1.048 1.050 1.052 1.054 1.056 1.058 1.060 4 6 8 1 01 21 41 61 8 Input Voltage (V) Output Voltage (V) VIN = 4.5V to 18V, V OUT = 1.05V Efficiency vs. Output Current 100 0.001 0.01 0.1 1 10 Output Current (A) Efficiency (%) VIN = 5V VIN = 12V VIN = 18V VOUT = 1.05V RT7231/33 Efficiency vs. Output Current 100 0.001 0.01 0.1 1 10 Output Current (A) Efficiency (%) VIN = 5V VIN = 12V VIN = 18V VOUT = 1.05V RT7232/34

DS7231/32/33/34-00 March 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Switching Frequency vs. Temperature 600 610 620 630 640 650 660 670 680 690 700 -50 -25 0 25 50 75 100 125 Temperature (°C) Switching Frequency (kHz) 1 Switching Frequency vs. Input Voltage 600 610 620 630 640 650 660 670 680 690 700 4 6 8 1 01 21 41 61 8 Input Voltage (V) Switching Frequency (kHz) 1 Current Limit vs. Input Voltage 4.0 4.5 5.0 5.5 6.0 6.5 7.0 4 6 8 1 01 21 41 61 82 0 Input Voltage (V) Current Limit (A) Current Limit vs. Temperature 4.0 4.5 5.0 5.5 6.0 6.5 7.0 -50 -25 0 25 50 75 100 125 Temperature (°C) Current Limit (A) VIN = 12V, VOUT = 1.05V Load Transient Response Time (100 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 1A to 4A RT7231/32/33/34 VOUT (5mV/Div) IOUT (2A/Div) Load Transient Response Time (100 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 0A to 4A VOUT (20mV/Div) RT7231/33 IOUT (2A/Div)

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Power On from EN Time (500 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IOUT (2A/Div) VEN (5V/Div) VOUT (500mV/Div) Power Off from EN Time (500 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IOUT (2A/Div) VEN (5V/Div) VOUT (500mV/Div) Power Off from V IN Time (10ms/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IOUT (5A/Div) VIN (5V/Div) VOUT (1V/Div) Power On from V IN Time (2.5ms/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IOUT (5A/Div) VIN (5V/Div) VOUT (1V/Div) Switching Time (1 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 1A IL (1A/Div) VSW (10V/Div) VOUT (5mV/Div) Switching Time (1 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IL (2A/Div) VSW (10V/Div) VOUT (5mV/Div)

DS7231/32/33/34-00 March 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. UVLO Voltage vs. Temperature 3.4 3.5 3.6 3.7 3.8 3.9 4.0 -50 -25 0 25 50 75 100 125 Temperature (°C) UVLO Voltage (V) Falling Rising Power Good from EN Turn Off Time (2.5ms/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A RT7231/32 IOUT (5A/Div) VEN (5V/Div) VOUT (1V/Div) VPGOOD (5V/Div) Power Good from EN Turn On Time (250 μs/Div) VIN = 12V, VOUT = 1.05V, IOUT = 4A IOUT (5A/Div) VEN (5V/Div) VOUT (1V/Div) VPGOOD (5V/Div) RT7231/32 EN Threshold Voltage vs. Temperature 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 -50 -25 0 25 50 75 100 125 Temperature (°C) EN Threshold Voltage (V ) Rising VIN = 12V, VOUT = 1.05V Falling

Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. voltage as shown in Figure 4. Figure 4. Output Voltage Setting Protection (UVLO) that monitors the voltage of PVCC pin. voltage, the RT7231/32/33/34 will be turned off in this state. This is non-latch protection. temperature should be prevented from rising above 150°C. and decreases with higher inductance. use 1% tolerance or better divider resistors. trapezoidal current at the source of the high side MOSFET. deviations do not offer much relief. for COUT selection to ensure that the control loop is stable. and RMS current handling requirements.

Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Figure 5. External Bootstrap Diode stable temperature characteristics. on the maximum power dissipation. voltage is lower than 5.5V or duty ratio is higher than 65%.

DS7231/32/33/34-00 March 2013www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Outline Dimension Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 1.000 1.200 0.039 0.047 A1 0.000 0.150 0.000 0.006 A2 0.800 1.050 0.031 0.041 b 0.190 0.300 0.007 0.012 D 4.900 5.100 0.193 0.201 e 0.650 0.026 E 6.300 6.500 0.248 0.256 E1 4.300 4.500 0.169 0.177 L 0.450 0.750 0.018 0.030 U 1.900 2.900 0.075 0.114 V 1.600 2.600 0.063 0.102 14-Lead TSSOP (Exposed Pad) Plastic Package

DS7231/32/33/34-00 March 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.180 0.300 0.007 0.012 D 2.950 3.050 0.1 16 0.120 D2 2.300 2.650 0.091 0.104 E 2.950 3.050 0.1 16 0.120 E2 1.500 1.750 0.059 0.069 e 0.500 0.020 L 0.350 0.450 0.014 0.018 W-Type 10L DFN 3x3 Package 1 122 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. DETAIL A Pin #1 ID and Tie Bar Mark Options D E A L be SEE DETAIL A

DS7231/32/33/34-00 March 2013www.richtek.com Richtek Technology Corporation 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnish ed by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringeme nts of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of R ichtek or its subsidiaries. A BJ F H M C D I Y X EXPOSED THERMAL PAD (Bottom of Package) 8-Lead SOP (Exposed Pad) Plastic Package Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 4.801 5.004 0.189 0.197 B 3.810 4.000 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.510 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.000 0.152 0.000 0.006 J 5.791 6.200 0.228 0.244 M 0.406 1.270 0.016 0.050 X 2.000 2.300 0.079 0.091 Option 1 Y 2.000 2.300 0.079 0.091 X 2.100 2.500 0.083 0.098 Option 2 Y 3.000 3.500 0.118 0.138