ADP3000AR-3.3-REEL

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Micropower Step-Up/Step-Down Fixed 3.3 V, 5 V, 12 V, Adjustable High Frequency Switching Regulator ADP3000 Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent ri ghts of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Tel: 781.329.4700 www.analog.com Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.

FEATURES

Operates at supply voltages from 2 V to 30 V Works in step-up or step-down mode Very few external components required High frequency operation up to 400 kHz Low battery detector on-chip User-adjustable current limit Fixed and adjustable output voltage 8-lead PDIP, 8-lead SOIC, and 14-lead TSSOP packages Small inductors and capacitors

APPLICATIONS

Notebook, palmtop computers Cellular telephones Hard disk drives Portable instruments Pagers GENERAL DESCRIPTION The ADP3000 is a versatile step-up/step-down switching regulator. It operates from an input supply voltage of 2 V to 12 V in step-up mode, and from 2 V to 30 V in step-down mode. Operating in pulse frequency mode (PFM), the device consumes only 500 µA, making it ideal for applications requiring low quiescent current. It delivers an output current of 180 mA at

3.3 V from a 2 V input in step-up mode, and an output current

of 100 mA at 3 V from a 5 V input in step-down mode. The ADP3000 operates at 400 kHz switching frequency. This allows the use of small external components (inductors and capacitors), making it convenient for space-constrained designs. The auxiliary gain amplifier can be used as a low battery detector, linear regulator, undervoltage lockout, or error amplifier. FUNCTIONAL BLOCK DIAGRAMS COMPARATOR GAIN BLOCK/ ERROR AMP 400kHz OSCILLATOR DRIVER 1.245V REFERENCE R1 R2 ADP3000 SET VIN GND SENSE ILIM SW1 SW2 00122-001 Figure 1. ADP3000-3.3V ILIM VIN SW1 FB (SENSE) SW2GND 100µF 10V 120V 6.8µH IN5817 100µF 10V VIN 2V TO 3.2V 3.3V 180mA C1, C2 = AVX TPS D107 M010R0100 L1 = SUMIDA CR43-6R8 00122-002 Figure 2. Typical Application Figure 3. Step-Down Mode Operation

Rev. A | Page 2 of 16 TABLE OF CONTENTS Power Transistor Protection Diode in Step-Down

REVISION HISTORY

9/04—Data Sheet Changed from Rev. 0 to Rev. A 1/97—Revision 0: Initial Version OBSOLETE

Rev. A | Page 3 of 16 SPECIFICATIONS 0°C ≤ TA ≤ +70°C, VIN = 3 V , unless otherwise noted.1 Table 1. ADP3000 Parameter Conditions Symbol Min Typ Max Unit INPUT VOLTAGE Step-up mode VIN 2.0 12.6 V Step-down mode 30.0 V SHUT-DOWN QUIESCENT CURRENT VFB > 1.43 V; VSENSE > 1.1 × VOUT IQ 500 µA COMPARATOR TRIP POINT VOLTAGE ADP30002 1.20 1.245 1.30 V OUTPUT SENSE VOLTAGE ADP3000-3.33 VOUT 3.135 3.3 3.465 V ADP3000-5 3 4.75 5.00 5.25 V ADP3000-12 3 11.40 12.00 12.60 V COMPARATOR HYSTERESIS ADP3000 8 12.5 mV OUTPUT HYSTERESIS ADP3000-3.3 32 50 mV ADP3000-5 32 50 mV ADP3000-12 75 120 mV OSCILLATOR FREQUENCY fOSC 350 400 450 kHz DUTY CYCLE VFB < VREF D 65 80 % SWITCH-ON TIME ILIM tied to VIN, VFB= 0 tON 1.5 2 2.55 µs SWITCH SATURATION VOLTAGE TA = +25°C VSAT Step-Up Mode VIN = 3.0 V, ISW = 650 mA 0.5 0.75 V V IN = 5.0 V, ISW = 1 A 0.8 1.1 V Step-Down Mode VIN = 12 V, ISW = 650 mA 1.1 1.5 V FEEDBACK PIN BIAS CURRENT ADP3000 VFB = 0 V IFB 160 330 nA SET PIN BIAS CURRENT VSET = VREF ISET 200 400 nA GAIN BLOCK OUTPUT LOW ISINK = 300 µA, VSET = 1.00 V VOL 0.15 0.4 V REFERENCE LINE REGULATION 5 V ≤ VIN ≤ 30 V 0.02 0.15 %/V 2 V ≤ VIN ≤ 5 V 0.2 0.6 %/V GAIN BLOCK GAIN RL = 100 kΩ4 AV 1000 6000 V/V GAIN BLOCK CURRENT SINK VSET ≤ 1 V ISINK 300 µA CURRENT LIMIT 220 Ω from ILIM to VIN ILIM 400 mA CURRENT LIMIT TEMPERATURE COEFFICIENT −0.3 %/°C SWITCH-OFF LEAKAGE CURRENT Measured at SW1 pin 1 10 µA V SW1= 12 V, TA = +25°C MAXIMUM EXCURSION BELOW GND TA = +25°C ISW1 ≤ 10 µA, switch off −400 −350 mV 1 All limits at temperature extremes are guaranteed via correlation using standard statistical methods. 2This specification guarantees that both the high and low trip points of the comparator fall within the 1.20 V to 1.30 V range. 3The output voltage waveform will exhibit a saw-tooth shape due to the comparator hysteresis. The output voltage on the fixed output versions will always be within the specified range. 4100 kΩ resistor connected between a 5 V source and the AO pin. OBSOLETE

Rev. A | Page 4 of 16 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Rating Input Supply Voltage, Step-Up Mode 15 V Input Supply Voltage, Step-Down Mode 36 V SW1 Pin Voltage 50 V SW2 Pin Voltage −0.5 V to VIN Feedback Pin Voltage (ADP3000) 5.5 V Switch Current 1.5 A Maximum Power Dissipation 500 mW Operating Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C Lead Temperature (Soldering, 10 s) 300°C Thermal Impedance R-8 170°C/W RU-14 150°C/W N-8 120°C/W Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. OBSOLETE

Rev. A | Page 9 of 16 THEORY OF OPERATION The ADP3000 is a versatile, high frequency, switch mode power supply (SMPS) controller. The regulated output voltage can be greater than the input voltage (in boost or step-up mode) or less than the input voltage (in buck or step-down mode). This device uses a gated oscillator technique to provide high performance with low quiescent current. Figure 7 is a functional block diagram of the ADP3000. The internal 1.245 V reference is connected to one input of the comparator, and the other input is externally connected (via the FB pin) to a resistor divider, which is connected to the regulated output. When the voltage at the FB pin falls below 1.245 V , the 400 kHz oscillator turns on. The ADP3000 internal oscillator typically provides a 1.7 µs on time and a 0.8 µs off time. A driver amplifier provides base drive to the internal power switch, and the switching action raises the output voltage. When the voltage at the FB pin exceeds 1.245 V , the oscillator shuts off. While the oscillator is off, the ADP3000 quiescent current is only 500 µA. The comparator’s hysteresis ensures loop stability without requiring external components for frequency compensation. The maximum current in the internal power switch is set by connecting a resistor between V IN and the ILIM pin. When the maximum current is exceeded, the switch is turned off. The current limit circuitry has a time delay of about 0.3 µs. If an external resistor is not used, connect I LIM to VIN. This yields the maximum feasible current limit. Further information on ILIM is included in the Applications Information section. An uncommitted gain block on the ADP3000 can be connected as a low battery detector. The inverting input of the gain block is internally connected to the 1.245 V reference. The noninverting input is available at the SET pin. A resistor divider, connected between V IN and GND with the junction connected to the SET pin, causes the AO output to go low when the low battery set point is exceeded. The AO output is an open collector NPN transistor that can sink in excess of 300 µA. The ADP3000 provides external connections for both the collector and the emitter of its internal power switch, permitting both step-up and step-down modes of operation. For the step-up mode, the emitter (Pin SW2) is connected to GND, and the collector (Pin SW1) drives the inductor. For step- down mode, the emitter drives the inductor, while the collector is connected to V IN. The output voltage of the ADP3000 is set with two external resistors. Three fixed voltage models are also available: ADP3000-3.3 (3.3 V), ADP3000-5 (5 V), and ADP3000-12 (12 V). The fixed voltage models include laser-trimmed, voltage-setting resistors on the chip. On the fixed voltage models of the ADP3000, simply connect the feedback pin (Pin 8) directly to the output voltage. OBSOLETE

recommended inductors and their vendors. the ADP3000’s current limit, without becoming saturated. drum core geometry inductors should be used. resistance lower than 0.2 Ω. Table 4. Recommended Inductors recommended capacitors and their vendors. Panasonic HFQ series, and the Sanyo OS-CON series. ADP3000’s rms switching current. current charging surges by derating the capacitor voltage by 2:1. Table 5. Recommended Capacitors 1N5818, the 1N5819, the MBRS120LT3, and the MBR0520LT1. signal diodes should be avoided as well. current limit to be programmed with a single external resistor. ripple as low as 40 mV to 80 mV , as well as a low input ripple. the full load current in buck applications. LIM circuit is shown in Figure 24. and Figure 15 give values for lower current limit levels. Figure 24. ADP3000 Current Limit Operation

Rev. A | Page 12 of 16 Step-Down [] [] −⎟⎟ ⎛ += INQ SW O SAT CEIN O CESATSWD V II I V V V βV I P 211 ) ( where: ISW is ILIMIT when the current limit is programmed externally; otherwise, ISW is the maximum inductor current. VCE(SAT) is 1.2 V (typical value). Check this value by applying ISW to Figure 10. VO is the output voltage. IO is the output current. VIN is the input voltage. D is 0.75 (typical duty ratio for a single switching cycle). IQ is 500 µA (typical shutdown quiescent current). β is 30 (typical forced beta). The temperature rise can be calculated using the following equation: JADP T θ × = ∆ where: ∆T is temperature rise. PD is device power dissipation. θJA is thermal resistance (junction-to-ambient). For example, consider a boost converter with the following specifications: VIN is 2 V . VO is 3.3 V . IO is 180 mA. ISW is 0.8 A (externally programmed). Using the step-up power dissipation equation: 18 . 0 ) 4 ( 3 . 3 21 75 . 030 ⎡ −⎥⎦ ⎡ + × = EPD ∆T is 185 mW (170°C/W) = 31.5°C, using the R-8 package. ∆T is 185 mW (120°C/W) = 22.2°C, using the N-8 package. At a 70°C ambient, the die temperature would be 101.45°C for the R-8 package and 92.2°C for the N-8 package. These junction temperatures are well below the maximum recommended junction temperature of 125°C. Finally, the die temperature can be decreased up to 20% by using a large metal ground plate as ground pickup for the ADP3000. OBSOLETE

Figure 38. 14-Lead Thin Shrink Small Outline Package [TSSOP] registered trademarks are the prop erty of their respective owners.