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1-1-2 Switching Mode Regulator ICs STA820M Series Separate Excitation Switching Mode Regulator ICs with Flywheel Diode Features * Output current: 3A * High efficiency: TYP 83% (STA821M) * 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 (110kHz) * Built-in foldback-overcurrent and thermal protection circuits * Built-in ON/OFF circuit (soft start available) Lineup Part Number STA821M Output Voltage (V) 5 Output voltage: 3.3V, 9V, 12V; adjustable types currently being planned Absolute Maximum Ratings*1 Parameter DC Input Voltage Output Current Power Dissipation*2 Symbol VIN IO PD1 PD2 Tj Tstg Ratings 31 3 18.2 (With infinite heatsink) 2.7 (Without heatsink, stand-alone operation) +125 -40 to +125 5.5 37 Unit V A W W C C C/W C/W Junction Temperature Storage Temperature Thermal Resistance (Junction to Case) Thermal Resistance (Junction to Ambient Air) Applications * Power supplies for telecommunication equipment * On-board local power supplies * OA equipment * For stabilization of the secondary-side output voltage of switching power supplies j-c j-a *1: The 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 DC Input Voltage Range Output Current Range*2 Operating Junction Temperature Range Ambient Temperature Range*2 Symbol min. VIN IO Tjop Top 7 0 -30 -30 STA821M max. 30 3 +125 +80 V A C C Unit *1: The recommended operating conditions show the operating conditions required for the normal circuit function described in the electrical characteristics. These conditions must be followed in actual use. *2: Limited by Ta-PD characteristics. Electrical Characteristics Ratings Parameter Symbol min. Output Voltage Efficiency*1 Oscillation Frequency Line Regulation Load Regulation Temperature Coefficient of Output Voltage Overcurrent Protection Starting Current ON/OFF Terminal*2 Low Level Voltage Outflow Current at Low Voltage VO Conditions 4.8 STA821M typ. 5.0 VIN=20V, IO=1A 83 VIN=20V, IO=1A 110 VIN=20V, IO=1A 40 VIN=10 to 30V, IO=1A 10 VIN=20V, IO=0.5 to 1.5A 0.5 3.1 VIN=20V 0.2 15 25 VSSL=0.2V 4 VIN=20V, IO=0A 35 40 100 max. 5.2 (Ta=25C) Unit V % kHz mV mV mV/ C A V Conditions fO Conditions VLine Conditions VLoad Conditions VO/T IS Conditions VSSL ISSL Conditions Iq Conditions A mA Quiescent Circuit Current *1: Efficiency is calculated from the following formula. (%) = VO*IO VIN*IIN x 100 *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. STA821M STA821M STA821M 7 ON/OFF 7 ON/OFF C3 7 ON/OFF C3 VO. ON/OFF Soft start Soft start +VO. ON/OFF 88 ICs STA820M Series External Dimensions (SIP8 [STA 8Pin]) 40.2 (Unit : mm) 2.30.2 1.7MAX 90.2 SK a b (1) STA821M 3.150.5 1.20.1 (Measured at the root) 2-(R1) R-END 2-(R 0.65 ) 1.15+0.2 -0.1 7xP2.540.1=(17.78) (Measured at the root) C1.50.5 20.150.3 (3.1) 0.55+0.2 -0.1 4.30.7 (Measured at the tip) Pin Assignment q SWOUT w GND e VIN r N.C t GND y VOS u ON/OFF i GND Plastic Mold Package Type Flammability: UL 94V-0 Product Mass: Approx. 2.0 g 0.7 0.7 1 2 3 4 5 6 7 8 Plan View Block Diagram STA821M VIN C1 + 3 VIN Internal Power Supply SW OUT Overcurrent Protection Di 1 L VOUT + C2 GND 2 Reset Oscillator 7 ON/OFF + - Latch & Driver Comparator + - Thermal Protection VOS 6 Error Amplifier Reference Voltage GND 5,8 Typical Connection Diagram L1 VIN 3.VIN 1.SW 6.VOS VOUT Ta-PD Characteristics 20 With Infinite Heatsink 18 Without Insulating Sheet With Silicone Grease Heatsink: Aluminum Power Dissipation PD (W) STA821M + C1 7.ON/OFF 16 14 12 10 8 6 50x50x2mm (17.9C/W) 4 2 Without Heatsink (37C/W) 25x50x2mm (25C/W) 2.GND 5,8.GND + C2 PD = VO*IO 100x100x2mm (11.5C/W) 100 -1 C3 GND GND VO : Output voltage VIN : Input voltage IO 75 100 125 : Output C1 C2 C3 L1 1000F/50V : 1000F/25V : 0.47F/10V(only when the soft start function is used) : 100H : current 0 -25 0 25 50 : Efficiency (%) Ambient Temperature Ta (C) ICs 89 |
Price & Availability of STA821M
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