ATI2202 ANALOGTECHNOLOGIES | Alldatasheet

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Table 1. Pin Function Descriptions 1 BS High-side gate drive boost input. BS supplies the drive for the high-side N-Channel MOSFET switch. Connect a 0.01μF or greater capacitor from SW to BS to power the high side switch. divider from the output voltage. The feedback threshold is 0.923.

6 COMP

capacitor from COMP to GND is required. regulator, drive it low to turn it off. Pull up with 100kΩ resistor for automatic startup. operational sections of this specification is not implied.

Figure 6. Block Diagram Table 2. Characteristics (TA = +25°C, VIN = +12V, unless otherwise noted.)

Copyrights 2000-2021, Analog Technologies, Inc. All Rights Reserved. Updated on 11/5/2021 Email: staff@analogti.com/sales@analogti.com 5 Analog Technologies ATI2202 ATI2202 Step-Down DC/DC Converter Upper Switch Current Limit Minimum duty cycle 2.4 3.4 A Lower Switch Current Limit From drain to source 1.1 A COMP to Current Sense Transconductance G CS 3.5 A/V Oscillation Frequency F OSC1 340 kHz Short Circuit Oscillation Frequency F OSC2 V FB = 0V 100 kHz Maximum Duty Cycle D MAX V FB = 1.0V 90 % Minimum On Time* 220 ns EN Shutdown Threshold Voltage V EN rising 1.1 1.5 2.0 V EN Shutdown Threshold Voltage Hysteresis 210 mV EN Lockout Threshold Voltage 2.2 2.5 2.7 V EN Lockout Hysteresis 210 mV Input Under Voltage Lockout Threshold V IN rising 3.80 4.10 4.40 V Input Under Voltage Lockout Threshold Hysteresis 2.10 mV Soft-start Current V SS = 0V 6 μA Soft-start Period C SS = 0.1μF 15 ms Thermal Shutdown* 160 °C * Guaranteed by design, not tested. SETTING THE OUTPUT VOLTAGE The output voltage is set using a resistive voltage divider from the output voltage to FB pin. The voltage divider divides the output voltage down to the feedback voltage by the ratio: V FB = VOUT ×R3/ (W1+R3) Where V FB is the feedback voltage and V OUT is the output voltage. Thus the output voltage is: VOUT = 0.923 ×(W1+R3)/R3 R2 can be as high as 100k Ω, but a typical value is 10k Ω. Using the typical value for R2, R1 is determined by: Note: W1 is a potentiometer. INDUCTOR The inductor is required to supply constant current to the output load while being driven by the switched input voltage. A larger value inductor will result in less ripple current that will result in lower output ripple voltage. However, the larger value inductor will have a larger physical size, higher series resistance, and/or lowe r saturation current. A good rule for determining the inductance to use is to allow the peak-to-peak ripple current in the inductor to be approximately 30% of the ma ximum switch current limit. Also, make sure that the peak inductor current is below the maximum switch current limit. The inductance value can be calculated by: L = [V OUT / (fS×ΔIL)] × (1− VOUT / VIN) Where VOUT is the output voltage, V IN is the input voltage, f s is the switching frequency, and ΔlL is the peak-to-peak inductor ripple current. Choose an inductor that will not saturate under the maximum inductor peak current. The pe ak inductor current can be calculated by: ILP = ILOAD + [VOUT / (2× fS×L)] × (1− VOUT / VIN) Where ILOAD is the load current. The choice of which style inductor to use mainly depends on the price vs. size requirements and any EMI requirements. OPTIONAL SCHOTTKY DIODE During the transition between high-side switch and low-side switch, the body diode of the low-side power MOSFET

Table 3. Diode Selection Guide X5R or X7R dielectrics when using ceramic capacitors. The input capacitor can be elect rolytic, tantalum or ceramic. sufficient charge to prevent excessive voltage ripple at input. Where C1 is the input capacitance value. output voltage ripple is mainly caused by the capacitance. optimized for a wide range of capacitance and ESR values. Where GEA is the error amplifier transconductance.

Copyrights 2000-2021, Analog Technologies, Inc. All Rights Reserved. Updated on 11/5/2021 Email: staff@analogti.com/sales@analogti.com 9 Analog Technologies ATI2202 ATI2202 Step-Down DC/DC Converter Table 4. Symbols Dimension (mm) Dimension (inch) MIN MAX MIN MAX A 1.30 1.70 0.051 0.067 A1 0.00 0.15 0.000 0.006 A2 1.25 1.52 0.049 0.060 b 0.33 0.51 0.013 0.020 c 5.80 6.20 0.228 0.244 D 4.80 5.11 0.189 0.201 D1 3.15 3.45 0.124 0.136 E 3.80 4.00 0.150 0.157 E1 2.26 2.56 0.089 0.101 e 1.27BSC 0.050BSC H 0.19 0.25 0.0075 0.0098 L 0.41 1.27 0.016 0.050 θ 0° 8° 0° 8°

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