RT4723 Dual Output AMOLED Bias General Description Features The RT4723 is a highly integrated Boost, LDO and inverting charge pump to generate positive and negative output voltage. The negative output voltages can be adjusted from 0.6V to 2.4V with 100mV steps by SWIRE interface protocol. The part maintains the highest efficiency by utilizing a 0.33x/0.5x mode fractional charge pump with automatic mode transition. With its input voltage range of 2.5V to 4.6V, RT4723 is optimized for products powered by single-cell battery and the output current up to 30mA. The RT4723 is available in WL-CSP-15B 1.39x2.07 (BSC) package to achieve optimized solution for PCB space. Ordering Information RT4723 2.5V to 4.6V Supply Voltage Range Single Wire Protocol Fixed 4.6V Positive Voltage Output Negative Voltage Output from 0.6V to 2.4V per 0.1V by SWIRE Pin Auto-Mode Transition of 0.33x/0.5x Charge Pump Built-in Soft-Start 30mA Maximum Output Current Programmable Output Fast Discharge Function High Impedance Output when IC Shutdown UVLO, OCP, SCP, OTP Protection Shutdown Current < 1A Available in 15-Ball WL-CSP Package Applications Package Type WSC : WL-CSP-15B 1.39x2.07 (BSC) AMOLED Bias in Portable Device Marking Information Note : Richtek products are : 36W RoHS compliant and compatible with the current 36 : Product Code W : Date Code requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L1 VIN VIN LXP CBOOST BOOST CIN VOP VOP COP RT4723 C2P VON VON CF2 CON C2N C1P SWIRE CF1 C1N GND Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 PGND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT4723 Pin Configurations (TOP VIEW) GND A1 A2 A3 C2N B3 C2P C3 C1N D3 C1P E3 VOP VON SWIRE B1 B2 PGND VIN C1 C2 GND LXP D1 D2 GND PGND E1 E2 BOOST WL-CSP-15B 1.39x2.07 (BSC) Functional Pin Description Pin No. Pin Name Pin Function A1, C2, D2 GND Ground. A2 VON Negative Terminal Output. A3 C2N Flying Capacitor 2 Negative Connection. B1 SWIRE Enable and VON Voltage Setting. B2, E1 PGND Power Ground. B3 C2P Flying Capacitor 2 Positive Connection. C1 VIN Power Input. C3 C1N Flying Capacitor 1 Negative Connection. D1 LXP Switching Node of Boost Converter. D3 C1P Flying Capacitor 1 Positive Connection. E2 BOOST Output Voltage of Boost Converter. E3 VOP Positive Terminal Output. Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Function Block Diagram BOOST LXP VIN UVLO SCP1 Bandgap Reference VREF LDO VOP -0.33x/-0.5x Charge Pump C1P C1N C2P C2N P1 PWM Logic N1 GM + DAC RP2 OCP1 VREF RP1 Oscillator Fast Discharge VOP VON Soft-Start SWIRE Pulse Counter VON RN2 PGND SCP2 + DAC RN1 GND VREF Operation The RT4723 is a highly integrated Boost, LDO and inverting charge pump to generate positive and negative output voltage. It can support input voltage range from 2.5V to 4.6V and the output current up to 30mA. The VOP positive output voltage is set at a typical value of 4.6V. The VON negative output voltage is set at a typical value of -2.4V and can be programmed through single wire protocol (SWIRE pin). Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 The available voltage range is from -0.6V to -2.4V with 100mV per step. The RT4723 provides OverTemperature Protection (OTP) and Short Circuit Protection (SCP) mechanisms to prevent the device from damage with abnormal operations. When the SWIRE voltage is logic low for more than 350us, the IC will be shut down with low input supply current less than 1A. is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT4723 Absolute Maximum Ratings (Note 1) Supply Input Voltage VIN Pin ------------------------------------------------------------------------------------- 0.3V to 6V Output voltage VOP Pin ------------------------------------------------------------------------------------------- 0.3V to 6V Output voltage VON Pin ------------------------------------------------------------------------------------------- 6V to 0.3V Others pin to GND -------------------------------------------------------------------------------------------------- 0.3V to 6V Power Dissipation, PD @ TA = 25°C WL-CSP-15B 1.39x2.07 (BSC) --------------------------------------------------------------------------------- 2W Package Thermal Resistance (Note 2) WL-CSP-15B 1.39x2.07 (BSC), JA --------------------------------------------------------------------------- 49.8°C/W Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------- 260C Junction Temperature --------------------------------------------------------------------------------------------- 150C Storage Temperature Range ------------------------------------------------------------------------------------ 65C to 150C ESD Susceptibility (Note 3) HBM (Human Body Model) -------------------------------------------------------------------------------------- 2kV MM (Machine Model) --------------------------------------------------------------------------------------------- 200V Recommended Operating Conditions (Note 4) Supply Input Voltage Range ---------------------------------------------------------------------------------------- 2.5V to 4.6V Positive Output Voltage ---------------------------------------------------------------------------------------------- 4.6V Negative Output Voltage Range ----------------------------------------------------------------------------------- 2.4V to 0.6V Ambient Temperature Range--------------------------------------------------------------------------------------- 40C to 85C Junction Temperature Range -------------------------------------------------------------------------------------- 40C to 125C Electrical Characteristics (VIN = 3.7V, VOP = 4.6V, VON = 2.4V, CIN = 4.7F, CBOOST = COP = 10F, CON = 20F, CF1 = 1F, L1 = 2.2H, TA = 25°C, unless otherwise specified.) Parameter Symbol Test Conditions Min Typ Max Unit 2.5 -- 4.6 V Power Supply Input Voltage Range VIN Under Voltage Lockout Threshold Voltage VUVLO_H VIN Rising -- 2.2 2.5 V VUVLO_L VIN Falling -- 2.1 2.3 V Over-temperature Protection TOTP (Note 5) -- 140 -- C Over-temperature Protection Hysteresis TOTP_HYST (Note 5) -- 15 -- C Shutdown Current ISHDN SWIRE = 0V -- -- 1 A Efficiency Peak 1 Eff_1 IOP = ION = 1mA -- 58 -- % Efficiency Peak 2 Eff_2 IOP = ION = 5mA -- 75 -- % Efficiency Peak 3 Eff_3 IOP = ION = 15mA -- 83 -- % -- 4.6 -- V LDO Output Positive Output Voltage Range VOP Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Parameter Symbol Test Conditions Min Typ Max Unit Positive Output Voltage Accuracy VOP_ACC 1 -- 1 % Positive Output Current Capability IOP_MAX -- -- 30 mA Positive Output Voltage Ripple VOP_RIPPLE IOP = 20mA -- 10 -- mV Line Regulation VOP_LINE VIN = 2.9 to 4.5V, IOP = 20mA -- 5 -- mV Load Regulation VOP_LOAD IOP = 0mA to 30mA -- 5 -- mV Fast Discharge Resistance RDISP -- 105 -- Short Circuit Protection VSCP1 -- < 80% VOP -- V 2.4 -- 0.6 V -- 100 -- mV (Note 5) (Note 5) Charge Pump Output Negative Output Voltage Range VON Negative Output Voltage Setting Range VON_SET Negative Output Voltage Accuracy VON_ACC 1 -- 1 % Negative Output Current Capability ION_MAX -- -- 30 mA Negative Charge Pump Switching Frequency fOSC_N 0.8 1 1.2 MHz Negative Output Voltage Ripple VON_RIPPLE ION = 20mA -- 20 -- mV Line Regulation VON_LINE VIN = 2.9 to 4.5V, ION = 20mA -- 10 -- mV Load Regulation VON_LOAD ION = 0mA to 30mA -- 30 -- mV Fast Discharge Resistance RDISN -- 60 -- Short Circuit Protection VSCP2 -- > 80% VON -- V SWIRE Turn-off Detection Time Toff_dly 350 -- -- s SWIRE Signal Stop Indicate Time Tstop 350 -- -- s Twait after Data Twait_int 10 -- -- ms Rising Input High Threshold Voltage Level VIH 1.2 -- VIN V Falling Input Low Threshold Voltage Level VIL 0 -- 0.4 V SWIRE Pull Low Resistor RSWIRE -- 300 -- k Wake up Delay Twkp -- -- 1 s SWIRE Rising Time TR -- -- 200 ns SWIRE Falling Time TF -- -- 200 ns Clocked SWIRE High TON 2 10 40 s Clocked SWIRE Low TOFF 2 10 40 s Per step (Note 5) (Note 5) Logic Input (SWIRE) Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT4723 Parameter Symbol Test Conditions Min Typ Max Unit SWIRE to VOP On Time TVOP_ON -- 1.6 -- ms Input Clocked SWIRE Frequency f SWIRE 25 -- 250 kHz 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. JA is measured at TA = 25C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Spec. is guaranteed by design. Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Typical Application Circuit L1 2.2µH VIN 2.5V to 4.6V CIN 4.7µF D1 LXP C1 VIN CBOOST 10µF E2 BOOST VOP E3 RT4723 B3 C2P CF2 1µF VON A2 CON1 10µF A3 C2N B1 C1P D3 SWIRE GND A1, C2, D2 VOP 4.6V COP 10µF C1N C3 CON2 10µF VON -0.6V to -2.4V CF1 1µF PGND B2, E1 Table 1. Component List of Evaluation Board Reference Qty. CIN 1 CBOOST, COP, CON1, CON2 Part Number Description Package Supplier GRM188R61C475KAAJ 4.7F/16V/X5R 0603 Murata 1 GRM188R61A106KE69 10F/10V/X5R 0603 Murata CF1, CF2 1 GRM155R61C105KE01 1F/16V/X5R 0402 Murata L1 1 GLCLK2R201A 2.2H 2.5mm x 2.0mm x 1.0mm ALPS Time Diagram SWIRE Interface TON TOFF 90% Twkp 10% TR TF Power Sequence Twait_int > 10ms VIN SWIRE 0 Tss2 ≤ 2ms Tss1 ≤ 3ms Toff_dly > 350μs Tstop > 350μs … 0 1 2 1.5ms ≤ Tdly ≤ 2.5ms 10 11 4.6V Hi-Z VOP 0 0 TVOP_ON -1.4V VON Hi-Z -2.4V Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT4723 Table 2. VON Output Voltage with SWIRE Pulse Pulse VON(V) 0 2.4 (default) 1 2.4 2 2.3 3 2.2 4 2.1 5 2.0 6 1.9 7 1.8 8 1.7 9 1.6 10 1.5 11 1.4 12 1.3 13 1.2 14 1.1 15 1.0 16 0.9 17 0.8 18 0.7 19 0.6 20 0 Table 3. VOP/VON Shutdown Discharge Selection with SWIRE Pulse Pulse Discharge 21 Enable Once pulse 21 received on SWIRE pin, the RT4723 will enable the discharge function to discharge the VOP/VON outputs for 20ms and then enter high impedance state when fault or power-off condition. The discharge function is default disabled and outputs keep high impedance state when fault or power-off condition . Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Typical Operating Characteristics Efficiency vs. Output Current VOP vs. Output Current 4.620 90 4.615 85 80 VOP (V) Efficiency (%) 4.610 VIN = 4.5V 75 VIN = 3.7V VIN = 2.7V 70 65 VOP = 4.6, VON = 2.4V 0.005 0.01 0.015 0.02 0.025 4.600 4.595 VIN = 2.7V 4.590 VIN = 3.7V 4.585 VIN = 4.5V VOP = 4.6, VON = 2.4V 4.580 60 0 4.605 0 0.03 0.005 0.01 Output Current (A) VON vs. Output Current 4.600 -2.365 4.599 -2.370 4.598 VIN = 3.7V VIN = 2.7V -2.390 4.596 -2.400 4.592 -2.405 0.02 0.025 2.5 0.03 3.5 4.0 Output Current (A) VON vs. Input Voltage Power On SWIRE (4V/Div) -2.36 VON (V) 3.0 Input Voltage (V) -2.35 IOP = 30mA -2.37 VOP = 4.6, V ON = 2.4V 4.590 -2.410 0.015 IOP = 30mA 4.591 VOP = 4.6, V ON = 2.4V 0.01 IOP = 10mA 4.594 4.593 0.005 0.03 IOP = 0mA 4.595 -2.395 0 0.025 4.597 VIN = 4.5V VOP (V) VON (V) -2.375 -2.385 0.02 VOP vs. Input Voltage -2.360 -2.380 0.015 Output Current (A) 4.5 5.0 VIN = 3.7V, VOP = 4.6V, VON = 2.4V VON (0.5V/Div) -2.38 IOP = 10mA -2.39 VOP (1V/Div) IOP = 0mA -2.40 VOP = 4.6, VON = 2.4V -2.41 2.5 3 3.5 4 Input Voltage (V) Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 4.5 IVIN (0.1A/Div) Time (1ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT4723 Power Off with Discharge VIN = 3.7V, VOP = 4.6V, VON = 2.4V SWIRE (4V/Div) Power OFF without Discharge SWIRE (4V/Div) VIN = 3.7V, VOP = 4.6V, VON = 2.4V VON (0.5V/Div) VON (0.5V/Div) VOP (1V/Div) IVIN (0.1A/Div) VOP (1V/Div) IVIN (0.1A/Div) Time (5ms/Div) Time (10ms/Div) Power On with SWIRE is Low Power On with SWIRE is High SWIRE (4V/Div) SWIRE (4V/Div) VIN (2V/Div) VIN (2V/Div) VBOOST (2V/Div) VBOOST (2V/Div) VIN = 3.7V, VOP = 0V, VON = 0V VIN = 3.7V, VOP = 4.6V, VON = -2.4V Time (10ms/Div) Time (10ms/Div) Power On with SWIRE from Low to High SWIRE (4V/Div) VIN (2V/Div) VBOOST (2V/Div) VIN = 3.7V Time (10ms/Div) Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Application Information The RT4723 is a highly integrated Boost, LDO and inverting charge pump to generate positive and negative output voltages for AMLOED bias. It can support input voltage range from 2.5V to 4.6V and the output current up to 30mA. The VOP positive output voltage is generated from the LDO supplied from a synchronous Boost converter, and VOP is set at a The inductance can eventually according to the following equation : typical value of 4.6V. The Boost converter output also drives an inverting charge pump controller to generate VON negative output voltage which is set at a typical value of 2.4V. The negative output voltage can be programmed through the dedicated pin which implements single wire protocol and the available voltage range is from 0.6V to 2.4V with 100mV per step. system performance, a shielded inductor is preferred to Input Capacitor Selection Input ceramic capacitor with 4.7F capacitance is suggested for applications. For better voltage filtering, select ceramic capacitors with low ESR, X5R and X7R types are suitable because of their wider voltage and temperature ranges. Boost Inductor Selection The inductance depends on the maximum input current. As a general rule, the inductor ripple current range is 20% to 40% of the maximum input current. If 40% is selected as an example, the inductor ripple current can be calculated according to the following equations : VOUT IOUT(MAX) IIN(MAX) = VIN IL = 0.4 IIN(MAX) where η is the efficiency of the VOP Boost converter, IIN(MAX) is the maximum input current, and IL is the inductor ripple current. The input peak current can then be obtained by adding the maximum input current with half of the inductor ripple current as shown in the following equation : be determined η VIN VOUT VIN 2 L 0.4 VOUT I OUT(MAX)fOSC 2 where f OSC is the switching frequency. For better avoid EMI problems. Boost Output Capacitor Selection The output ripple voltage is an important index for estimating IC performance. This portion consists of two parts. One is the product of ripple current with the ESR of the output capacitor, while the other part is formed by the charging and discharging process of the output capacitor. As shown in Figure 1, VOUT1 can be evaluated based on the ideal energy equalization. According to the definition of Q, the VOUT1 value can be calculated as the following equation : 1 =C OUT VOUT1 fSOC IOUT D = fSOC COUT Q = IOUT D VOUT1 where f OSC is the switching frequency and D is the duty cycle. Finally, taking ESR into consideration, the overall output ripple voltage can be determined by the following equation : VOUT = VESR + VOUT1 = VESR + IOUT D fOSC COUT where VESR = ICrms x RCESR The output capacitor, COUT, should be selected accordingly. IPEAK = 1.2 x IIN(MAX) Note that the saturated current of the inductor must be greater than IPEAK. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT4723 Over Current Protection The RT4723 includes a cycle-by-cycle current limit IL Input Current function which monitors the inductor current during each ON period. The power switch will be forced off to avoid large current damage once the current is over the limit level. Inductor Current Short Circuit Protection Output Current Time DTs Output Ripple (ac) Time VOUT1 The RT4723 has an advanced output short-circuit protection mechanism which prevents the IC from damage by unexpected applications. When the output becomes shorted to ground, and the output voltage is under the limit level with 1ms (typ.) duration, the bias function enters shutdown mode and can only re-start normal operation after triggering the SWIRE pin. Figure 1. Output Ripple Voltage Without Contribution of ESR Under Voltage Lockout To prevent abnormal operation of the IC in low voltage condition, an under voltage lockout is included which shuts down IC operation when input voltage is lower than the specified threshold voltage. Soft-Start The RT4723 employs an internal soft-start feature to avoid high inrush current during start-up. The soft-start function is achieved by clamping the output voltage of the internal error amplifier with another voltage source that is increased slowly from zero to near VIN during the soft-start period. Negative Output Voltage Setting The Negative output voltage can be programmed by a MCU through the dedicated pin according to Table 2 “VON Output Voltage with SWIRE Pulse”. Shutdown Delay and Discharge When the SWIRE signal is logic low for more than 350s, the IC function will be shut down. The output VOP/VON can be actively discharged to GND with discharge function enabled referring to Table 3 “VOP/VON Shutdown Discharge Selection with SWIRE Pulse”. In shutdown mode, the input supply current for the IC is less than 1A. Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 Over Temperature Protection The RT4723 equips an over temperature protection circuitry to prevent overheating due to excessive power dissipation. The OTP will shut down the bias operation when ambient temperature exceeds 140C. Once the ambient temperature cools down by approximately 15C, IC will automatically resume normal operation. To maintain continuous operation, the maximum junction temperature should be prevented from rising above 125C. Thermal Considerations For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : PD(MAX) = (TJ(MAX) TA) / JA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and JA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125C. The junction to ambient thermal resistance, JA, is layout dependent. For WL-CSP-15B 1.39x2.07 (BSC) package, the thermal resistance, JA, is 49.8C/W on a standard JEDEC 51-7 four-layer thermal test board. is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 The maximum power dissipation at TA = 25C can be calculated by the following formula : PD(MAX) = (125C 25C) / (49.8C/W) = 2W for WL-CSP-15B 1.39x2.07 (BSC) package Layout Considerations For the best performance of RT4723, the following PCB layout guidelines should be strictly followed. The maximum power dissipation depends on the operating ambient temperature for fixed TJ(MAX) and thermal resistance, JA. The derating curve in Figure 2 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. close to the IC as possible. The traces should be wide and short especially for the high current output loop. The input and output bypass capacitor should be placed as close to the IC as possible and connected 2.5 Maximum Power Dissipation (W)1 For good regulation, place the power components as Four-Layer PCB to the ground plane of the PCB. 2.0 The flying capacitor should be placed as close to the C1P/C1N/C2P/C2N pin as possible to avoid noise 1.5 injection. 1.0 Minimize the size of the LXP node and keep the traces wide and short. Care should be taken to avoid 0.5 running traces that carry any noise-sensitive signals near LXP or high-current traces. 0.0 0 25 50 75 100 Ambient Temperature (°C) 125 Separate power ground (PGND) and analog ground (GND). Connect the GND and the PGND islands at Figure 2. Derating Curve of Maximum Power a single end. Make sure that there are no other Dissipation connections between these separate ground planes. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 CON2 RT4723 CON1 VON GND SWIRE CIN VIN GND VON C2N SWIRE PGND C2P VIN GND C1N LXP GND C1P PGND BOOST VOP CF2 CF1 CBST VOP L1 COP GND Figure 3. PCB Layout Guide Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS4723-00 April 2016 RT4723 Outline Dimension Symbol Dimensions In Millimeters Dimensions In Inches Min. Max. Min. Max. A 0.500 0.600 0.020 0.024 A1 0.170 0.230 0.007 0.009 b 0.240 0.300 0.009 0.012 D 2.020 2.120 0.080 0.083 D1 E 1.600 1.340 0.063 1.440 0.053 0.057 E1 0.800 0.031 e 0.400 0.016 WL-CSP-15B 1.39x2.07 (BSC) Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st 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 furnished 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 infringements 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 Richtek or its subsidiaries. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS4723-00 April 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 15