1-1-2 Switching Mode Regulator ICs STA810M Series Separate Excitation Switching Mode Regulator ICs with Flywheel Diode ■Features • • • • • • • • ■Lineup Output current: 1.5A High efficiency: TYP83% (STA811M) Built-in flywheel diode (schottky-barrier diode) Requires only 3 discrete components: output coil, input and output capacitors Phase correction and output voltage adjustment performed internally Built-in reference oscillator (125kHz) Built-in foldback-overcurrent and thermal protection circuits Built-in ON/OFF circuit (soft start available) Part Number Output Voltage (V) STA811M 6.5 Output voltage: 2.5V, 3.3V, 5V, 9V, 12V and adjustable types are projected. ■Absolute Maximum Ratings*1 Symbol Ratings Unit DC Input Voltage Parameter VIN 43 V Output Current IO 1.5 A PD1 18.2 (With infinite heatsink) W Power ■Applications • Power supplies for telecommunication equipment • Onboard local power supplies • OA equipment • For stabilization of the secondary-side output voltage of switching power supplies Dissipation*2 PD2 2.7 (Without heatsink, stand-alone operation) W Junction Temperature Tj +125 °C Storage Temperature Tstg –40 to +125 °C Thermal Resistance (junction to case) θ j-c 5.5 °C/W Thermal Resistance (junction to ambient air) θ j-a 37 °C/W *1: Absolute maximum ratings show the destructive limit. No parameter should exceed the ratings in transient or normal operations. *2: Limited by thermal protection. ■Recommended Operating Conditions*1 Ratings Parameter Symbol DC Input Voltage Range Output Current Range*2 STA811M Unit Conditions min. max. VIN1 8.5 9.5 V IO=0 to 1A VIN2 9.5 40 V IO=0 to 1.5A VIN ≥ 9.5V IO 0 1.5 A Operating Junction Temperature Range Tjop –30 +125 °C Operating Temperature Range*2 Top –30 +80 °C *1: Recommended operating conditions show operating conditions required for normal circuit function described in the electrical characteristics. These conditions must be followed in actual use. *2: Limited by Ta-PD characteristics. ■Electrical Characteristics (Ta=25°C) Ratings Parameter Symbol STA811M min. VO Output Voltage Line Regulation Load Regulation Temperature Coefficient of Output Voltage Overcurrent Protection Starting Current 6.63 % 125 Conditions kHz VIN=28V, IO=1A VLine 40 Conditions 100 VLoad 10 Conditions 40 mV VIN=28V, IO=0.2 to 1A ∆VO/∆T ±0.5 mV/ °C 1.6 Conditions A VIN=28V VSSL 0.5 Outflow Current at Low Voltage ISSL 100 Quiescent Circuit Current 2 mV VIN=10 to 30V, IO=1A Low Level Voltage Quiescent Circuit Current 1 V VIN=28V, IO=1A fO IS 6.5 83 Conditions Oscillation Frequency max. VIN=28V, IO=1A η Efficiency*1 ON/OFF Terminal*2 6.37 Conditions Unit typ. Conditions Iq Conditions µA VSSL=0V 7 mA VIN=28V, IO=0A Iq(OFF) Conditions V 200 µA VIN=28V, VON/OFF=0.3A *1: Efficiency is calculated from the following formula. η (%) = VO·IO × 100 VIN·IIN *2: Pin 7 is the ON/OFF pin. Soft start at power on can be performed by connecting a capacitor to this pin. The output can also be turned ON/OFF with this pin. The output is stopped by setting the voltage of this pin to VSSL or lower. ON/OFF-pin voltage can be changed with an open-collector drive circuit of a transistor. When using both the soft-start and ON/OFF functions together, the discharge current from C3 flows into the ON/OFF control transistor. Therefore, limit the current securely to protect the transistor if C3 capacitance is large. The ON/OFF pin is pulled up to the power supply in the IC, so applying the external voltage is prohibited. If this pin is not used, leave it open. 86 ICs STA811M STA811M STA811M 7 ON/OFF 7 ON/OFF 7 ON/OFF C3 VO. ON/OFF Soft start C3 Soft start +VO. ON/OFF STA810M Series ■External Dimensions (SIP8 [STA 8Pin]) (Unit : mm) STA811M a Pin Assignment q SWOUT w GND e VIN r N.C t GND y VOS u ON/OFF i GND 1.2±0.1 (Measured at the root of pin) (1) 3.15±0.5 1.7MAX 2.3±0.2 b SK 9±0.2 4±0.2 2–(R1) 2–(R 0.65 ) R-END (3.1) 1.15+0.2 –0.1 7×P2.54±0.1=17.78 (Measured at the root) C1.5±0.5 0.55+0.2 –0.1 4.3±0.7 (Measured at the tip) 20.15±0.3 Plastic Mold Package Type Flammability: UL 94V-0 Product Mass: Approx. 2.0 g 0.7 1 2 3 4 5 6 7 0.7 Plan View 8 ■Block Diagram STA811M VIN C1 3 SW OUT VIN 1 L VOUT + + Overcurrent Protection PReg. ON/OFF 7 ON/OFF Soft Start + C3 Latch & Driver Reset C2 GND Di 2 Oscillator + – Comparator Error Amp VOS Thermal Protection 6 + – Reference Voltage GND 5,8 ■Typical Connection Diagram ■Thermal Derating 20 L1 1.SW 3.VIN STA811M + 7.ON/OFF C1 6.VOS 2.GND 5,8.GND 18 VOUT + C2 C3 GND GND C1: 220 µF/50V C2: 470 µF/25V C3: 0.47 µF/10V (Only when using soft start function) L1: 100 µH Power Dissipation PD (W) VIN Without Insulating Sheet With Silicone Grease Heatsink: Alminum With Infinite Heatsink 16 14 12 10 100×100×2mm (11.5°C/W) PD = VO·IO 8 100 –1 ηχ 6 50×50×2mm (17.9°C/W) 4 25×50×2mm (25°C/W) 2 Without Heatsink (37°C/W) 0 –25 0 25 50 75 100 Ambient Temperature Ta (°C) 125 VO : VIN : IO : ηχ : Output voltage Input voltage Otuput current Efficiency (%) ICs 87 ●STA810M Series ■Typical Characteristics Efficiency Output Voltage Rise Output Voltage Fluctuation 8 100 6.70 Efficiency η (%) 80 70 VIN=8.5V 20V 28V 40V 60 50 40 6 Output Voltage VO (V) Output Voltage VO (V) 90 4 lO=0A 1A 1.5A 2 6.60 VIN=40V 28V 6.50 20V 8.5V 6.40 30 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 1.6 0 5 Output Current IO (A) Overcurrent Protection Characterisitcs 20 25 6.30 30 Thermal Protection VIN=8.5V 28V 40V 4 2 0.5 1 1.5 2 Output Current IO (A) 0.2 2.5 3 6 4 TSD OFF TSD ON 2 0 50 75 100 125 0.4 0.6 0.8 1.0 1.2 1.4 1.6 Temperature Characteristics 150 175 Ambient Temperature Ta (°C) 200 Efficiency η (%) Frequency Freq (kHz) 6 0 0 Output Current IO (A) 8 Output Voltage VO (V) Output Voltage VO (V) 15 Intput Voltage VIN (V) 8 0 10 160 6.65 140 6.6 Freq 120 VO 100 6.5 η 80 60 –50 6.55 0 50 Output Current VO (A) 0 6.45 100 6.4 150 Ambient Temperature Ta (°C) 5