STOD1812PUR

STOD1812 Power supply for PMOLED display panel Features ■ Synchronous step-up converter ■ Input voltage range from 2.5 V to 5.5 V ■ Maximum output current 120 mA ■ Efficiency: 75 % at IO = 10 mA - 30 mA; 85 % at IO = 30 mA - 120 mA ■ Switching at 1.2 MHz in typical application conditions ■ Enable pin for shutdown mode ■ True load disconnect ■ Soft-start to limit inrush current ■ UVLO protection ■ Adjustable output voltage up to 20 V ■ Low quiescent current: < 1 µA in shutdown mode ■ Over-temperature protection ■ Package: DFN10L 3x3 mm, 0.8 mm ■ Operating junction temperature range: -40 °C to 125 °C Applications ■ Passive matrix OLED power supplies ■ Mobile phones ■ PDAs ■ Camcorders ■ Digital still cameras Table 1. DFN10L (3x3 mm) Description STOD1812 is a step-up converter designed to power passive matrix OLED (PMOLED) displays, providing the pre-charge and biasing voltage of the column matrix driver. STOD1812 uses a pulsed frequency modulation (PFM) control mode technique. The high switching frequency makes it possible to reduce the value and size of the external components. This device is particularly suitable for battery-operated applications, where overall system efficiency is the major concern. Synchronous rectification has been integrated in the device in order to eliminate the external Schottky diode. An internal compensation net is also integrated, enabling the STOD1812 to provide excellent load transient performance in addition to good load regulation. The output voltage is set using two external resistors. Over-temperature protection and undervoltage lockout (UVLO) functions are integrated in the device. An additional switch implements a true load disconnection feature which stops the currrent flowing from the input when the device is in shutdown mode. The EN pin turns off the device, reducing the quiescent current to 0.1 µA. Device summary Order code Package Packaging STOD1812PUR DFN10L (3x3 mm) 3000 parts per reel March 2008 Rev 1 1/19 www.st.com 19 Contents STOD1812 Contents 1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Boost controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.2 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.3 Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.4 Under voltage lockout (UVLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6 Typical application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8 Typical application performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 STOD1812 Diagram 1 Diagram Figure 1. Internal block diagram Figure 2. Schematic diagram 3/19 Pin configuration STOD1812 2 Pin configuration Figure 3. Pin connections (top view) Table 2. Pin description Pin n° Symbol 1 OUT Output voltage 2 OUT Output voltage 3 GND Ground 4 FB Feedback 5 EN DC supply voltage enable control pin. ON =VI. When pulled low put the device in shutdown mode. 6 VI Input supply voltage. 7 LX Switching node 8 LX Switching node 9 PGND Power ground 10 PGND Power ground Exp Pad 4/19 Description Exposed Pad. It must be connected to power ground STOD1812 Maximum ratings 3 Maximum ratings Table 3. Absolute maximum ratings Symbol Parameter Value Unit VI DC supply voltage -0.3 to 6 V EN Enable pin -0.3 to 6 V FB Feedback pin -0.3 to 6 V LX Switching node -0.3 to 20 V ILX Switching current Internally limited A -0.3 to 20 V Internally limited mW Storage temperature range -65 to 150 °C Operating temperature range -40 to 125 °C Value Unit 30.9 °C/W Value Unit 2 kV VOUT PD TSTG TJ Table 4. Converter output voltage Power dissipation Thermal data Symbol RthJA Table 5. Parameter Thermal resistance junction-ambient (tested on 2 layers board) ESD data Symbol ESD Parameter Human Body Model 5/19 Electrical characteristics STOD1812 4 Electrical characteristics Table 6. Electrical characteristics (TJ = -40 °C to 125 °C, VI = 3.6 V, CI = CO = 4.7 µF, L = 2.2 µH, IO = 80 mA, VEN = VI, VO = 18 V, R1=270 kΩ, R2 = 20 kΩ unless otherwise specified). Symbol Parameter Test conditions Min. Typ. Max. Unit 5.5 V Supply section VI Supply input voltage IO=0 to 120mA 2.5 IO Load current VI=2.5V to 5.5V 120 UVLO_H Under voltage lockout HIGH UVLO_L Under voltage lockout LOW IQ mA 2.3 2.1 2.4 V 2.2 V IO=120mA 1.3 mA No Load, Switching 0.3 mA VFB=VI - No Load, No Switching 35 50 µA VEN =GND 100 300 nA Quiescent current VEN H Enable high threshold VI=2.5V to 5.5V VEN L Enable low threshold VI=2.5V to 5.5V 0.4 V IEN Enable input current VEN=Vi 500 nA 1.2 V Dynamic performance TON MAX TON max time TSS Soft-start time DMAX ν 0.5 µs 0.6 ms 95 % IO=5 to 30mA 75 % IO=30 to 120mA 85 % From enable to output regulation Maximum duty cycle Efficiency Step-up converter section VFB1 Feedback voltage VI=2.5V to 5.5V IFB Feedback leakage current VI=2.5V to 5.5V VO_MAX Output voltage range VI=2.5V to 5.5V; IO=0 to 120mA ΔVO_SLI Static line regulation VI=2.5V to 5.5V, IO1=120mA, ΔVO_SLO Static load regulation IO=0 to 120mA, VI=3.6V; ΔVO_LIT Line transient regulation ΔVO_LOT Load transient regulation 6/19 1.18 1.21 1.24 V 30 100 nA 18 V 0.6 %/V 0.0016 %/mA VI=2.5V to 3.0V, IO1=120mA, TR=TF=50µs TA=25°C 80 mV IO=5 to 120mA and IO=120 to 5mA, TR=TF=10µs TA=25°C, peak to peak 250 mV STOD1812 Table 6. Symbol SVR IPK Electrical characteristics Electrical characteristics (continued) (TJ = -40 °C to 125 °C, VI = 3.6 V, CI = CO = 4.7 µF, L = 2.2 µH, IO = 80 mA, VEN = VI, VO = 18 V, R1=270 kΩ, R2 = 20 kΩ unless otherwise specified). Parameter Test conditions Min. Typ. Max. Unit Supply voltage rejection IO=5 to 120mA at 200Hz-Pulse 0.5VPP TDMA noise standard, TA=25°C see Figure 14 40 mV Inductor peak current TA=25°C 2.4 A RDSONP Resistance on P-channel 0.60 0.80 Ω RDSONN Resistance on N-channel 0.25 0.65 Ω Thermal shutdown OTP OTPHYST Over temperature protection 150 °C Over temperature protection hysteresis 20 °C 7/19 Functional description STOD1812 5 Functional description 5.1 Boost controller STOD1812 is a boost converter operating in PFM (pulsed frequency modulation) mode. The converter monitors the output voltage through the bridge resistor divider R1 and R2, and when the feedback voltage falls below the feedback voltage, the boost switch tSW turns on and the inductor current ramps up. The inductor current is measured by detecting the temperature compensated drain voltage of the boost MOSFET. The boost turns off when its drain voltage reaches the internal reference, the main switch remains off until the minimum off time has passed and the feedback voltage is below the reference again. A maximum ON time prevents the switch tSW from staying ON for an excessively long period. In order to calculate the values of the bridge resistors with a fixed VO, the following formula can be used: VO 1,21 5.2 -1= R1 R2 Enable The ENABLE pin is a logic input signal that turns on the controller when the voltage on this pin is equal to or higher than 1.2 V. When the voltage is at or below 0.4 V the STOD1812 goes into shutdown mode. In this case, the true-shutdown switch is turned off and the overall power consumption is reduced to 0.1 µA. No pull-up or pull-down is present on this pin. 5.3 Efficiency The total consumption of some PMOLED displays can be as low as 1 mA. In order to increase the battery life of the device, the STOD1812 offers high efficiency over a wide range of output load current and input voltages. See typical application efficiency performance in Section 8 on page 11. 5.4 Under voltage lockout (UVLO) The minimum supply voltage is 2.5 V, under which the undervoltage lockout circuit operates with a typical threshold of 2.3 V. 8/19 STOD1812 Typical application information 6 Typical application information Figure 4. Typical application circuit connections Table 7. External components Symbol Parameter Min. Typ. Max. Unit L Inductor (ISAT = 2.5 A) 2.2 µH CI Ceramic capacitor SMD 4.7 µF CO Ceramic capacitor SMD 4.7 µF R1 Feedback resistor (for VO = 18 V) 270 kΩ R2 Feedback resistor (for VO = 18 V) 20 kΩ Note: The external components suggested in this document should be considered as a design reference guide. The performance data mentioned in the electrical characteristics table are not guaranteed for all the possible electrical parameters of the components included in this list. However, the operation of STOD1812 is not limited to the use of components included in this list. 9/19 Demonstration board 7 Demonstration board Figure 5. Demonstration board photo Figure 6. Suggested demonstration board schematic (top layer view) Figure 7. Suggested demonstration board schematic (bottom layer view) 10/19 STOD1812 STOD1812 Typical application performance 8 Typical application performance Figure 8. (VO = 18 V, L = 2.2 µH, CI = CO = 4.7 µF, R1 = 270 kΩ, R2 = 20 kΩ) Efficiency vs output current Figure 9. Efficiency vs input voltage 100 100 VI = VEN = from 2.5 V to 5.5 V, IO = 120 mA, T = 25 °C VI = VEN = 3.6 V, IO = from 5 mA to 120 mA, T = 25°C 90 Efficiency [%] Efficiency [%] 90 80 70 60 80 70 60 50 50 40 40 0 20 40 60 IO [mA] 80 100 120 Figure 10. Efficiency vs temperature 2.5 Frequency [MHz] Efficiency [%] VI = VEN = 3.6 V, IO = 120 mA 80 70 60 50 40 -75 -50 -25 0 25 50 75 100 125 3.5 4 VI [V] 4.5 5 5.5 Figure 11. Frequency vs temperature 100 90 3 150 2.5 2.3 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5 175 -75 T [°C] Figure 12. Line transient VIN = VEN = 3.6 V, IO = 80 mA -50 -25 0 25 50 75 T [°C] 100 125 150 175 Figure 13. Load transient response IO VO VI = from 2.5 V to 3 V, IO = 120 mA, VI (tRISE = tFALL) = 50µs, T = 25 °C VI = 3.6 V, IO from 5mA to 120mA, tRISE = tFALL = 10 µs, T = 25 °C 11/19 Typical application performance Figure 14. TDMA noise VI=VINH VO VI = VINH = from 2.9 V to 3.4 V, IO = 120 mA, VI (tRISE) = 50 µs, T = 25 °C 12/19 STOD1812 STOD1812 9 Package mechanical data Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. 13/19 Package mechanical data STOD1812 Figure 15. DFN10L package outline 8049731/A 14/19 STOD1812 Table 8. Package mechanical data DFN10L mechanical data mm. inch. Dim. Min. Typ. Max. Min. Typ. Max. A 0.70 0.75 0.80 0.028 0.030 0.031 A1 0 0.02 0.05 0 0.001 0.002 A3 0.20 0.008 b 0.18 0.25 0.30 0.007 0.010 0.012 D 2.90 3 3.10 0.114 0.118 0.122 D2 2.23 2.38 2.48 0.088 0.094 0.098 E 2.90 3 3.10 0.114 0.118 0.122 E2 1.49 1.64 1.74 0.059 0.065 0.069 e L 0.50 0.30 0.40 0.020 0.50 0.012 0.016 0.020 15/19 Package mechanical data STOD1812 Tape & reel QFNxx/DFNxx (3x3) mechanical data mm. inch. Dim. Min. Typ. A Min. Typ. 180 13.2 Max. 7.087 C 12.8 D 20.2 0.795 N 60 2.362 T 16/19 Max. 0.504 0.519 14.4 0.567 Ao 3.3 0.130 Bo 3.3 0.130 Ko 1.1 0.043 Po 4 0.157 P 8 0.315 STOD1812 Package mechanical data Figure 16. DFN10L footprint - recommended data 17/19 Revision history STOD1812 10 Revision history Table 9. Document revision history Date Revision 25-Mar-2008 1 18/19 Changes Initial release. STOD1812 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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