AAT2120

AAT2120 ANALOGICTECH | Alldatasheet

Document overview

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• PDF pages: 20

Technical content

Features

• V IN Range: 2.7V to 5.5V
• V OUT Range: 0.6V to VIN
• Up to 500mA Output Current
• Up to 96% Efficiency
• Low Noise Light Load Mode
• 45µA Typical Quiescent Current
• 1.8MHz Switching Frequency
• Soft-Start Control
• Over-Temperature and Current Limit Protection
• 100% Duty Cycle Low-Dropout Operation
• <1µA Shutdown Current
• Small External Components
• Ultra-Small STDFN22-8 Package
• Temperature Range: -40°C to +85°C

Applications

• Bluetooth ® Headsets
• Cellular Phones
• Digital Cameras
• Handheld Instruments
• Micro Hard Disk Drive
• Portable Music Players
• USB Devices

(Top View) GND FB VP VIN EN N/C PGND LX Pin # Symbol Function 1 VP Input power pin; connected to the source of the P-channel MOSFET. Connect to the input capacitor. 2 VIN Input bias voltage for the converter. 3 GND Non-power signal ground pin. 4 FB Feedback input pin. Connect this pin to an external resistive divider for adjustable output. 5 N/C No connect. 6 EN Enable pin. A logic high enables normal operation. A logic low shuts down the converter. 7 LX Switching node. Connect the inductor to this pin. It is connected internally to the drain of both high- and low-side MOSFETs. 8 PGND Input power return pin; connected to the source of the N-channel MOSFET. Connect to the output and input capacitor return. EP Exposed paddle (bottom): connect to ground directly beneath the package. 2 2120.2007.10.1.1 AAT2120 500mA Low Noise Step-Down Converter

Symbol Description Value Units PD Maximum Power Dissipation (STDFN22-8) 2 W θJA Thermal Resistance2 (STDFN22-8) 50 °C/W Symbol Description Value Units VIN Input Voltage and Bias Power to GND 6.0 V VLX LX to GND -0.3 to V IN + 0.3 V VOUT FB to GND -0.3 to V IN + 0.3 V VEN EN to GND -0.3 to 6.0 V TJ Operating Junction Temperature Range -40 to 150 °C TLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi- tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. 2120.2007.10.1.1 3 AAT2120 500mA Low Noise Step-Down Converter

Electrical Characteristics1 VIN = 3.6V, TA = -40°C to +85°C, unless otherwise noted; typical values are T A = 25°C. Symbol Description Conditions Min Typ Max Units VIN Input Voltage 2.7 5.5 V VIN Rising 2.3 V VUVLO UVLO Threshold Hysteresis 70 mV VIN Falling 1.4 V VOUT Output Voltage Tolerance2 IOUT = 0 to 500mA, -3.0 3.0 %VIN = 2.7V to 5.5V VOUT Output Voltage Range 0.6 V IN V IQ Quiescent Current No Load 45 85 µA ISHDN Shutdown Current EN = GND 1.0 µA ILIM P-Channel Current Limit 700 mA RDS(ON)H High-Side Switch On Resistance 0.59 Ω RDS(ON)L Low-Side Switch On Resistance 0.42 Ω ΔVLinereg/ΔVIN Line Regulation V IN = 2.7V to 5.5V 0.2 %/V VFB Feedback Threshold Voltage Accuracy V IN = 3.6V 0.591 0.600 0.609 V IFB FB Leakage Current V OUT = 1.0V 0.2 µA FOSC Oscillator Frequency 1.8 MHz TS Startup Time From Enable to Output 100 µsRegulation TSD Over-Temperature Shutdown Threshold 105 °C THYS Over-Temperature Shutdown Hysteresis 15 °C VEN(L) Enable Threshold Low 0.6 V VEN(H) Enable Threshold High 1.4 V IEN Input Low Current V IN = VEN = 5.5V -1.0 1.0 µA 1. The AAT2120 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assu red by design, characterization, and correlation with statistical process controls. 2. Output voltage tolerance is independent of feedback resistor network accuracy. 4 2120.2007.10.1.1 AAT2120 500mA Low Noise Step-Down Converter

(VOUT = 1.2V; L = 1.5µH) Output Current (mA) Load Regulation (%) -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 0.1 1 10 100 VIN = 3.6V VIN = 4.2V VIN = 2.7V VIN = 5.0V Efficiency vs. Load (VOUT = 1.2V; L = 1.5µH) Output Current (mA) Efficiency (%) 100 0.1 1 10 100 100 VIN = 2.7V VIN = 3.6V VIN = 4.2V VIN = 5.0V Load Regulation (VOUT = 1.8V; L = 3.3µH) Output Current (mA) Load Regulation (%) -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 0.1 1 10 100 1000 VIN = 4.2V VIN = 2.7VVIN = 3.6V Efficiency vs. Load (VOUT = 1.8V; L = 3.3µH) Output Current (mA) Efficiency (%) 100 0.1 1 10 100 1000 VIN = 2.7V VIN = 3.6V VIN = 4.2V Load Regulation (VOUT = 3.0V; L = 4.7µH) Output Current (mA) Load Regulation (%) -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 0.1 1 10 100 1000 VIN = 3.6V VIN = 5.0V VIN = 4.2V Efficiency vs. Load (VOUT = 3.0V; L = 4.7µH) Output Current (mA) Efficiency (%) 100 0.1 1 10 100 1000 VIN = 3.6V VIN = 4.2V VIN = 5.0V 2120.2007.10.1.1 5 AAT2120 500mA Low Noise Step-Down Converter

No Load Quiescent Current vs. Input Voltage Input Voltage (V) Supply Current (µA) 85°C 25°C -40°C Switching Frequency Variation vs. Temperature (VIN = 3.6V; VOUT = 1.8V) Temperature (°C) Variation (%) -10 -40 -20 0 20 40 60 80 100 Frequency Variation vs. Input Voltage Input Voltage (V) Frequency Variation (%) VOUT = 3.0V VOUT = 1.8V Output Voltage Error vs. Temperature (VIN = 3.6V; VOUT = 1.8V; IOUT = 500mA) Temperature (°C) Output Error (%) -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 -40 -20 0 20 40 60 80 100 Line Regulation (VOUT = 1.8V) Input Voltage (V) Accuracy (%) -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 IOUT = 10mA IOUT = 500mA IOUT = 250mA IOUT = 150mA IOUT = 50mA IOUT = 0mA Soft Start (VIN = 3.6V; VOUT = 1.8V; 500mA) Time (100µs/div) Enable and Output Voltage (top) (V) Inductor Current (bottom) (A) VO -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 VEN ILX 6 2120.2007.10.1.1 AAT2120 500mA Low Noise Step-Down Converter

(VOUT = 1.8V @ 500mA) Time (25µs/div) Output Voltage (top) (V) Input Voltage (bottom) (V) 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 VO VIN Load Transient Response (350mA to 500mA; VIN = 3.6V; VOUT = 1.8V; COUT = 4.7µF; CFF = 100pF) Time (25µs/div) Output Voltage (top) (V) Load and Inductor Current (bottom) (100mA/div) IO 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 VO ILX Load Transient Response (1mA to 500mA; VIN = 3.6V; VOUT = 1.8V; COUT = 4.7µF; CFF = 100pF) Time (20µs/div) Output Voltage (top) (V) Load and Inductor Current (bottom) (400mA/div) 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 VO IO ILX N-Channel RDS(ON) vs. Input Voltage Input Voltage (V) RDS(ON) (mΩΩ) 300 350 400 450 500 550 600 650 700 750 100°C 85°C 120°C 25°C P-Channel RDS(ON) vs. Input Voltage Input Voltage (V) RDS(ON) (mΩΩ) 300 400 500 600 700 800 900 1000 100°C 85°C 120°C 25°C 2120.2007.10.1.1 7 AAT2120 500mA Low Noise Step-Down Converter

(VIN = 3.6V; VOUT = 1.8V; IOUT = 500mA) Time (200ns/div) Output Voltage (AC Coupled) (top) (mV) Inductor Current (bottom) (A) -120 -100 -80 -60 -40 -20 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 VO ILX Output Ripple (VIN = 3.6V; VOUT = 1.8V; IOUT = 1mA) Time (2µs/div) Output Voltage (AC Coupled) (top) (mV) Inductor Current (bottom) (A) -120 -100 -80 -60 -40 -20 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 VO ILX 8 2120.2007.10.1.1 AAT2120 500mA Low Noise Step-Down Converter

The AAT2120 is a high performance 500mA, 1.8MHz monolithic step-down converter designed to operate with an input voltage range of 2.7V to 5.5V. The converter operates at 1.8MHz, which minimizes the size of external components. Typical values are 3.3µH for the output inductor and 4.7µF for the ceramic output capacitor. The device is designed to operate with an output voltage as low as 0.6V. Power devices are sized for 500mA current capability while maintaining over 90% efficiency at full load. Low current efficiency is maintained at greater than 80% down to 1mA of load current. At dropout, the converter duty cycle increases to 100% and the output voltage tracks the input volt- age minus the R DS(ON) drop of the P-channel high- side MOSFET. A high-DC gain error amplifier with internal com- pensation controls the output. It provides excellent transient response and load/line regulation. Soft start eliminates any output voltage overshoot when the enable or the input voltage is applied. Functional Block Diagram EN LX Err Amp Logic DH DL PGND VPFB GND Voltage Reference INPUT VIN 2120.2007.10.1.1 9 AAT2120 500mA Low Noise Step-Down Converter

500mA Low Noise Step-Down Converter 10 2120.2007.10.1.1 Control Loop The AAT2120 is a 500mA current mode step-down converter. The current through the P-channel MOSFET (high side) is sensed for current loop control, as well as short-circuit and overload pro- tection. A fixed slope compensation signal is added to the sensed current to maintain stability for duty cycles greater than 50%. The peak current mode loop appears as a voltage-programmed current source in parallel with the output capacitor. The output of the voltage error amplifier programs the current mode loop for the necessary peak switch current to force a constant output voltage for all load and line conditions. Internal loop compensation ter- minates the transconductance voltage error amplifier output. The error amplifier reference is fixed at 0.6V. Soft Start / Enable Soft start increases the inductor current limit point in discrete steps when the input voltage or enable input is applied. It limits the current surge seen at the input and eliminates output voltage overshoot. When pulled low, the enable input forces the AAT2120 into a low-power, non-switching state. The total input current during shutdown is less than 1µA. Current Limit and Over-Temperature Protection For overload conditions, the peak input current is lim- ited. As load impedance decreases and the output voltage falls closer to zero, more power is dissipated internally, raising the device temperature. Thermal protection completely disables switching when inter- nal dissipation becomes excessive, protecting the device from damage. The junction over-temperature threshold is 105°C with 15°C of hysteresis. Under-Voltage Lockout Internal bias of all circuits is controlled via the V IN power. Under-voltage lockout (UVLO) guarantees sufficient V IN bias and proper operation of all inter- nal circuits prior to activation. Applications Information Inductor Selection The step-down converter uses peak current mode control with slope compensation to maintain stability for duty cycles greater than 50%. The output induc- tor value must be selected so the inductor current down slope meets the internal slope compensation requirements. The internal slope compensation for the adjustable and low-voltage fixed versions of the AAT2120 is 0.45A/µsec. This equates to a slope compensation that is 75% of the inductor current down slope for a 1.8V output and 3.0µH inductor. This is the internal slope compensation for the AAT2120. When externally programming to 3.0V, the calculated inductance is 5.0µH. In this case, a standard 4.7µH value is selected. For most designs, the AAT2120 operates with an inductor value of 1µH to 4.7µH. Table 1 displays inductor values for the AAT2120 with different output voltage options. Manufacturer's specifications list both the inductor DC current rating, which is a thermal limitation, and the peak current rating, which is determined by the saturation characteristics. The inductor should not show any appreciable saturation under normal load conditions. Some inductors may meet the peak and average current ratings yet result in excessive loss- es due to a high DCR. Always consider the losses associated with the DCR and its effect on the total converter efficiency when selecting an inductor. m 0.75 ⋅ VO 0.45A µsec A µsec A A µsec 0.75 ⋅ VO m = = = 0.45 L 0.75 ⋅ 1.8V 3.0µH A µsec

500mA Low Noise Step-Down Converter 2120.2007.10.1.1 11 Table 1: Inductor Values. The 3.0µH CDRH2D09 series inductor selected from Sumida has a 150mΩ DCR and a 470mA DC current rating. At full load, the inductor DC loss is 9.375mW which gives a 2.08% loss in efficiency for a 250mA, 1.8V output. Input Capacitor Select a 4.7µF to 10µF X7R or X5R ceramic capac- itor for the input. To estimate the required input capacitor size, determine the acceptable input rip- ple level (V PP) and solve for C IN. The calculated value varies with input voltage and is a maximum when V IN is double the output voltage. Always examine the ceramic capacitor DC voltage coefficient characteristics when selecting the prop- er value. For example, the capacitance of a 10µF, 6.3V, X5R ceramic capacitor with 5.0V DC applied is actually about 6µF. The maximum input capacitor RMS current is: The input capacitor RMS ripple current varies with the input and output voltage and will always be less than or equal to half of the total DC load current. for V IN = 2 · VO The term appears in both the input voltage ripple and input capacitor RMS current equations and is a maximum when V O is twice VIN. This is why the input voltage ripple and the input capacitor RMS current ripple are a maximum at 50% duty cycle. The input capacitor provides a low impedance loop for the edges of pulsed current drawn by the AAT2120. Low ESR/ESL X7R and X5R ceramic capacitors are ideal for this function. To minimize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps the high frequency content of the input current localized, minimizing EMI and input voltage ripple. The proper placement of the input capacitor (C1) can be seen in the evaluation board layout in Figure 2. A laboratory test set-up typically consists of two long wires running from the bench power supply to the evaluation board input voltage pins. The induc- tance of these wires, along with the low-ESR ceramic input capacitor, can create a high Q net- work that may affect converter performance. This problem often becomes apparent in the form of excessive ringing in the output voltage during load transients. Errors in the loop phase and gain meas- urements can also result. Since the inductance of a short PCB trace feeding the input voltage is significantly lower than the power leads from the bench power supply, most applications do not exhibit this problem. VO VIN VO VIN IO RMS(MAX)I 2= VO VIN VO VIN VO VIN VO VIN CIN(MIN) = 1 VPP IO VO VIN VO VIN VO VIN CIN = VO VIN VPP IO Output Voltage (V) L1 (µH) 1.0 1.5 1.2 2.2 1.5 2.7 1.8 3.0 2.5 3.9 3.0 4.7 3.3 5.6

500mA Low Noise Step-Down Converter 12 2120.2007.10.1.1 In applications where the input power source lead inductance cannot be reduced to a level that does not affect the converter performance, a high ESR tantalum or aluminum electrolytic should be placed in parallel with the low ESR, ESL bypass ceramic. This dampens the high Q network and stabilizes the system. Output Capacitor The output capacitor limits the output ripple and provides holdup during large load transitions. A 4.7µF to 10µF X5R or X7R ceramic capacitor typi- cally provides sufficient bulk capacitance to stabi- lize the output during large load transitions and has the ESR and ESL characteristics necessary for low output ripple. For enhanced transient response and low temperature operation application, a 10µF (X5R, X7R) ceramic capacitor is recommended to stabilize extreme pulsed load conditions. The output voltage droop due to a load transient is dominated by the capacitance of the ceramic out- put capacitor. During a step increase in load cur- rent, the ceramic output capacitor alone supplies the load current until the loop responds. Within two or three switching cycles, the loop responds and the inductor current increases to match the load current demand. The relationship of the output volt- age droop during the three switching cycles to the output capacitance can be estimated by: Once the average inductor current increases to the DC load level, the output voltage recovers. The above equation establishes a limit on the minimum value for the output capacitor with respect to load transients. The internal voltage loop compensation also limits the minimum output capacitor value to 4.7µF. This is due to its effect on the loop crossover frequency (bandwidth), phase margin, and gain margin. Increased output capacitance will reduce the crossover frequency with greater phase margin. The maximum output capacitor RMS ripple current is given by: Dissipation due to the RMS current in the ceramic output capacitor ESR is typically minimal, resulting in less than a few degrees rise in hot-spot temperature. Adjustable Output Resistor Selection Resistors R1 and R2 of Figure 1 program the output to regulate at a voltage higher than 0.6V. To limit the bias current required for the external feedback resis- tor string while maintaining good noise immunity, the suggested value for R2 is 59kΩ. Decreased resistor values are necessary to maintain noise immunity on the FB pin, resulting in increased quiescent current. Table 2 summarizes the resistor values for various output voltages. With enhanced transient response for extreme pulsed load application, an external feed-forward capacitor, (C3 in Figure 1), can be added. Table 2: Adjustable Resistor Values For Step-Down Converter. R2 = 59kΩ R2 = 221kΩ VOUT (V) R1 (k Ω) R1 (k Ω) 0.8 19.6 75 0.9 29.4 113 1.0 39.2 150 1.1 49.9 187 1.2 59.0 221 1.3 68.1 261 1.4 78.7 301 1.5 88.7 332 1.8 118 442 1.85 124 464 2.0 137 523 2.5 187 715 3.3 267 1000 VOUT VREF 3.3V 0.6V VOUT · (VIN(MAX) - VOUT) RMS(MAX)I L · FS · VIN(MAX) COUT = 3 · ΔILOAD VDROOP · FS

500mA Low Noise Step-Down Converter 2120.2007.10.1.1 13 Thermal Calculations There are three types of losses associated with the AAT2120 step-down converter: switching loss- es, conduction losses, and quiescent current loss- es. Conduction losses are associated with the R DS(ON) characteristics of the power output switch- ing devices. Switching losses are dominated by the gate charge of the power output switching devices. At full load, assuming continuous conduc- tion mode (CCM), a simplified form of the losses is given by: I Q is the step-down converter quiescent current. The term tsw is used to estimate the full load step- down converter switching losses. For the condition where the step-down converter is in dropout at 100% duty cycle, the total device dis- sipation reduces to: Since R DS(ON), quiescent current, and switching losses all vary with input voltage, the total losses should be investigated over the complete input voltage range. Given the total losses, the maximum junction tem- perature can be derived from the θ JA for the STDFN22-8 package which is 50°C/W. TJ(MAX) = PTOTAL · ΘJA + TAMB PTOTAL = IO 2 · RDS(ON)H + IQ · VIN PTOTAL IO 2 · (RDS(ON)H · VO + RDS(ON)L · [VIN - VO]) VIN + (tsw · FS · IO + IQ) · VIN Figure 1: AAT2120 Schematic. Adj. 59kΩ 4.7μF 4.7μF C1 VP GND N/C 5 EN LX 7 PGND VIN2 FB4 AAT2120 VIN GND +VOUT GND (optional) 100pF LX

500mA Low Noise Step-Down Converter 2120.2007.10.1.1 15 Step-Down Converter Design Example Specifications VO = 1.8V @ 250mA, Pulsed Load ΔI LOAD = 200mA VIN = 2.7V to 4.2V (3.6V nominal) FS = 1.8MHz TAMB = 85°C 1.8V Output Inductor (use 3.0µH; see Table 1) For Sumida inductor CDRH2D09-3R0, 3.0µH, DCR = 150m Ω. 1.8V Output Capacitor VDROOP = 0.1V 3.0µH · 1.8MHz · 4.2V 23 RMSI L1 · FS · VIN(MAX) = · 3 · ΔILOAD VDROOP · FS 3 · 0.2A 0.1V · 1.8MHz COUT = = = 3.3µF (use 3.3µF)

• = 66mArms (VO) · (VIN(MAX) - VO) = Pesr = esr · IRMS 2 = 5mΩ · (66mA)2 = 21.8µW IPKL1 = IO + ΔIL1 = 250mA + 95mA = 345mA2 PL1 = IO 2 ⋅ DCR = 250mA2 ⋅ 150mΩ = 9.375mW L1 = 1.67 ⋅ VO2 = 1.67 ⋅ 1.8V = 3µHµsec A µsec A

Input Ripple VPP = 25mV AAT2120 Losses TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + (50°C/W) · 26.14mW = 86°C PTOTAL + (tsw · FS · IO + IQ) · VIN IO 2 · (RDS(ON)H · VO + RDS(ON)L · [VIN -VO]) VIN 4.2V IO RMSI P = esr · IRMS 2= = 0.1Arms CIN = = = 1.16µF (use 4.7µF )1 VPP IO 25mV 0.2A AAT2120 500mA Low Noise Step-Down Converter 16 2120.2007.10.1.1

500mA Low Noise Step-Down Converter 2120.2007.10.1.1 17 Table 3: Evaluation Board Component Values. Table 4: Suggested Inductors and Suppliers. Inductance Max DC DCR Size (mm) Manufacturer Part Number (µH) Current (mA) (m Ω) LxWxH Type Sumida CDRH2D14-1R5 1.5 1800 50 3.0x3.0x1.55 Shielded Sumida CDRH2D14-2R2 2.2 1500 75 3.0x3.0x1.55 Shielded Sumida CDRH2D14-2R7 2.7 1350 85 3.0x3.0x1.55 Shielded Sumida CDRH2D14-3R3 3.3 1200 100 3.0x3.0x1.55 Shielded Sumida CDRH2D14-3R9 3.9 1100 110 3.0x3.0x1.55 Shielded Sumida CDRH2D14-4R7 4.7 1000 135 3.0x3.0x1.55 Shielded Sumida CDRH2D14-5R6 5.6 950 150 3.0x3.0x1.55 Shielded Sumida CDRH2D11-1R5 1.5 900 54 3.2x3.2x1.2 Shielded Sumida CDRH2D11-2R2 2.2 780 78 3.2x3.2x1.2 Shielded Sumida CDRH2D11-3R3 3.3 600 98 3.2x3.2x1.2 Shielded Sumida CDRH2D11-4R7 4.7 500 135 3.2x3.2x1.2 Shielded Taiyo Yuden NR3010 1.5 1200 80 3.0x3.0x1.0 Shielded Taiyo Yuden NR3010 2.2 1100 95 3.0x3.0x1.0 Shielded Taiyo Yuden NR3010 3.3 870 140 3.0x3.0x1.0 Shielded Taiyo Yuden NR3010 4.7 750 190 3.0x3.0x1.0 Shielded FDK MIPWT3226D-1R5 1.5 1200 90 3.2x2.6x0.8 Chip shielded FDK MIPWT3226D-2R2 2.2 1100 100 3.2x2.6x0.8 Chip shielded FDK MIPWT3226D-3R0 3 1000 120 3.2x2.6x0.8 Chip shielded FDK MIPWT3226D-4R2 4.2 900 140 3.2x2.6x0.8 Chip shielded Output Voltage R2 = 59k Ω R2 = 221kΩ1 VOUT (V) R1 (k Ω) R1 (k Ω) L1 (µH) 0.62 — — 1.5 0.8 19.6 75 1.5 0.9 29.4 113 1.5 1.0 39.2 150 1.5 1.1 49.9 187 1.5 1.2 59.0 221 1.5 1.3 68.1 261 1.5 1.4 78.7 301 2.2 1.5 88.7 332 2.7 1.8 118 442 3.0/3.3 1.85 124 464 3.0/3.3 2.0 137 523 3.0/3.3 2.5 187 715 3.9/4.2 3.3 267 1000 5.6 1. For reduced quiescent current, R2 = 221k Ω. 2. R2 is opened, R1 is shorted.

500mA Low Noise Step-Down Converter 18 2120.2007.10.1.1 Table 5: Surface Mount Capacitors. Value Voltage Temp. Case Manufacturer Part Number (µF) Rating Co. Size Murata GRM118R60J475KE19B 4.7 6.3 X5R 0603 Murata GRM188R60J106ME47D 10 6.3 X5R 0603

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All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Output Voltage Package Marking 1 Part Number (Tape and Reel)2 0.6V STDFN22-8 YDXYY AAT2120IES-0.6-T1 1. XYY = assembly and date code. 2. Sample stock is generally held on all part numbers listed in BOLD. 2120.2007.10.1.1 19 AAT2120 500mA Low Noise Step-Down Converter

500mA Low Noise Step-Down Converter 20 2120.2007.10.1.1 Advanced Analogic Technologies, Inc.

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Phone (408) 737-4600 Fax (408) 737-4611 © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech pr oduct. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service with- out notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, an d AnalogicTech disclaims any express or implied war- ranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a part icular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent An alogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holder s. Package Information1 STDFN22-8 All dimensions in millimeters. 2.00 ± 0.05Index Area 0.35 ± 0.05 2.00 ± 0.05 1.45 ± 0.05 0.45 ± 0.05 Top View Side View Bottom View Detail "A" 0.23 ± 0.05 Pin 1 Indicator (optional) 0.05 ± 0.05 0.55 ± 0.05 0.15 ± 0.025 Detail "A" 1. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not re quired to ensure a proper bottom solder connection.