D52LC

MAX1556_10 MAXIM | Alldatasheet

Document overview

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Technical content

Features

o Up to 97% Efficiency o 95% Efficiency at 1mA Load Current o Low 16µA Quiescent Current o 1MHz PWM Switching o Tiny 3.3µH Inductor and Adjustable Output o 1.2A Guaranteed Output Current (MAX1556/MAX1556A) o Voltage Positioning Optimizes Load-Transient Response o Low 27µA Quiescent Current in Dropout o Low 0.1µA Shutdown Current o No External Schottky Diode Required o Analog Soft-Start with Zero Overshoot Current o Small, 10-Pin, 3mm x 3mm TDFN Package MAX1556/MAX1556A/MAX1557 16µA IQ, 1.2A PWM Step-Down DC-DC Converters TOP VIEW LX OUT SHDN 6 INP SS GND IN PGND TDFN MAX1556 MAX1556A MAX1557 Pin Configuration

Ordering Information

2.6V TO 5.5V VOLTAGE SELECT OUTPUT 0.75V TO VIN PGND OUT INP IN MAX1556 MAX1556A MAX1557 Typical Operating Circuit 19-3336; Rev 2; 6/10 EVALUATION KIT AVAILABLE PART TEMP RANGE PIN-PACKAGE TOP MARK MAX1556ETB+ -40 °C to +85°C 10 TDFN-EP* ACQ MAX1556AETB+ -40 °C to +85°C 10 TDFN-EP* AUJ MAX1557ETB+ -40 °C to +85°C 10 TDFN-EP* ACR *EP = Exposed paddle. +Denotes a lead(Pb)-free/RoHS-compliant package. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

16µA IQ, 1.2A PWM DC-DC Step-Down Converters ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN = VINP = VSHDN = 3.6V, TA = - 40°C to +85°C. Typical values are at T A = +25°C, unless otherwise noted.) (Note 1) Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Continuous Power Dissipation (T A = +70°C) PARAMETER CONDITIONS MIN TYP MAX UNITS Input Voltage 2.6 5.5 V Undervoltage-Lockout Threshold V IN rising and falling, 35mV hysteresis (typ) 2.20 2.35 2.55 V No switching, D1 = D2 = GND 16 25Quiescent Supply Current Dropout 27 42 µA TA = +25°C 0.1 1Shutdown Supply Current SHDN = GND TA = +85°C 0.1 µA Output Voltage Range 0.75 V IN V No load -0.25 +0.75 +1.75 300mA load -0.75 0 +0.75 600mA load -1.5 -0.75 0 1200mA load, MAX1556 -2.75 -2.25 -1.25 TA = 0°C to +85°C (Note 2) 1200mA load, MAX1556A -2.25 No load -0.75 +2.25 300mA load -1.5 +1.5 600mA load -2.25 +0.50 Output Accuracy TA = -40°C to +85°C (Note 2) 1200mA load, MAX1556 -4.0 -1.0 MAX1556/MAX1556A 1200Maximum Output Current MAX1557 600 mA TA = +25°C 0.01 0.1D1 = D2 = GND MAX1556/MAX1557 TA = +85°C 0.01OUT Bias Current For preset output voltages 3 4.5 µA No load -0.50 +0.75 +1.75 300mA load -1.2 0 +1.2 600mA load -1.75 -0.75 +0.25 D1 = D2 = GND, VOUT = 0.75V at 300mA (typ), TA = 0°C to +85°C MAX1556/MAX1557 1200mA load, MAX1556 only -3.25 -2.25 -1.25 No load -1.25 +2.25 300mA load -1.75 +1.50 600mA load -2.75 +0.25 FB Threshold Accuracy D1 = D2 = GND, VOUT = 0.75V at 300mA (typ), TA = -40°C to +85°C MAX1556/MAX1557 1200mA load, MAX1556 only -4.25 -1.00 Note 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should take care not to exceed the IC’s package power-dissipation limits.

16µA IQ, 1.2A PWM DC-DC Step-Down Converters Note 1: All units are 100% production tested at TA = +25°C. Limits over the operating range are guaranteed by design. Note 2: For the MAX1556, 3.3V output accuracy is specified with a 4.2V input. ELECTRICAL CHARACTERISTICS (continued) (VIN = VINP = VSHDN = 3.6V, TA = - 40°C to +85°C. Typical values are at T A = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS VIN = 2.6V to 3.6V -0.37MAX1556, D1 = IN, D2 = GND; MAX1556A D1 = D2 = IN VIN = 3.6V to 5.5V 0.33 VIN = 2.6V to 3.6V -0.1 Line Regulation MAX1557, D1 = IN, D2 = GND VIN = 3.6V to 5.5V 0.09 VIN = 3.6V 0.35 0.7p-Channel On-Resistance MAX1557 VIN = 2.6V 0.42 Ω VIN = 3.6V 0.27 0.48n-Channel On-Resistance VIN = 2.6V 0.33 Ω MAX1556/MAX1556A 1.5 1.8 2.1p-Channel Current-Limit Threshold MAX1557 0.8 1.0 1.2 A n-Channel Zero Crossing Threshold 20 35 45 mA MAX1556/MAX1556A 1.8RMS LX Output Current MAX1557 1.0 ARMS TA = +25°C 0.1 10LX Leakage Current VIN = 5.5V, LX = GND or IN TA = +85°C 0.1 µA Maximum Duty Cycle 100 % Minimum Duty Cycle 0% Internal Oscillator Frequency 0.9 1 1.1 MHz SS Output Impedance ∆VSS / ISS for ISS = 2µA 130 200 300 k Ω SS Discharge Resistance SHDN = GND, 1mA sink current 90 200 Ω Thermal-Shutdown Threshold +160 °C Thermal-Shutdown Hysteresis 15 °C LOGIC INPUTS (D1, D2, SHDN) Input-Voltage High 2.6V ≤ VIN ≤ 5.5V 1.4 V Input-Voltage Low 0.4 V TA = +25°C 0.1 1Input Leakage TA = +85°C 0.1 µA

16µA IQ, 1.2A PWM DC-DC Step-Down Converters Typical Operating Characteristics (VIN = VINP = 3.6V, D1 = D2 = SHDN = IN, Circuits of Figures 2 and 3, TA = +25°C, unless otherwise noted.) EFFICIENCY vs. LOAD CURRENT WITH 3.3V OUTPUT MAX1556/7 toc01 LOAD CURRENT (mA) EFFICIENCY (%) 100101 100 0.1 1000 10,000 VIN = 5V VIN = 3.6V VIN = 4.2V EFFICIENCY vs. LOAD CURRENT WITH 2.5V OUTPUT MAX1556/7 toc02 LOAD CURRENT (mA) EFFICIENCY (%) 100101 100 0.1 1000 10,000 VIN = 3.6V VIN = 3V VIN = 2.6V VIN = 5V EFFICIENCY vs. LOAD CURRENT WITH 1.8V OUTPUT MAX1556/7 toc03 LOAD CURRENT (mA) EFFICIENCY (%) 100101 100 0.1 1000 10,000 VIN = 5V VIN = 3.6V VIN = 3V VIN = 2.6V EFFICIENCY vs. LOAD CURRENT WITH 1.0V OUTPUT (MAX1557) MAX1556/7 toc04 LOAD CURRENT (mA) EFFICIENCY (%) 100101 100 0.1 1000 VIN = 5VVIN = 3.6V VIN = 3V VIN = 2.6V OUTPUT VOLTAGE vs. LOAD CURRENT MAX1556/7 toc05 LOAD CURRENT (mA) OUTPUT VOLTAGE (V) 1000800600400200 1.75 1.76 1.77 1.78 1.79 1.80 1.81 1.82 1.83 1.84 1.74 0 1200 TA = -45°C TA = +25°C TA = +85°C OUTPUT VOLTAGE vs. INPUT VOLTAGE WITH 600mA LOAD MAX1556/7 toc06 INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.780 1.781 1.782 1.783 1.784 1.785 1.786 1.787 1.788 1.789 1.779 2.5 5.5 TA = -40°C TA = +25°C TA = +85°C OUTPUT VOLTAGE vs. INPUT VOLTAGE WITH NO LOAD MAX1556/7 toc07 INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.804 1.805 1.806 1.807 1.808 1.809 1.810 1.811 1.812 1.803 2.5 5.5 TA = -40°C TA = +25°C TA = +85°C SUPPLY CURRENT vs. INPUT VOLTAGE MAX1556/7 toc08 INPUT VOLTAGE (V) SUPPLY CURRENT (µA) 5432 HEAVY-LOAD SWITCHING WAVEFORMS MAX1556/7 toc09 VOUT AC-COUPLED 10mV/div VLX ILX 2V/div 400ns 500mA/div ILOAD = 750mA

16µA IQ, 1.2A PWM DC-DC Step-Down Converters LIGHT-LOAD SWITCHING WAVEFORMS MAX1556/7 toc10 20mV/div AC-COUPLED VLX VOUT ILX 2V/div 4µs/div 200mA/div EXTERNAL FEEDBACK SWITCHING WAVEFORMS MAX1556/7 toc10b VLX ILX 2V/div 2µs/div 200mA/div VIN = 5V, VOUT = 3.3V, IOUT = 500mA SOFT-START/SHUTDOWN WAVEFORMS MAX1556/7 toc11 5V/div ILX VSHDN VOUT IIN 500mA/div 100µs/div 1V/div 500mA/div CSS = 470pF RLOAD = 4Ω SOFT-START RAMP TIME vs. CSS MAX1556/7 toc12 CSS (pF) SOFT-START RAMP TIME (ms) 500 1000 1500 2000 0.1 0 2500 LOAD TRANSIENT MAX1556/7 toc13 50mV/div AC-COUPLED 500mA/div VOUT IOUT 20µs/div IOUTMIN = 20mA LOAD TRANSIENT MAX1556/7 toc14 50mV/div AC-COUPLED 500mA/div VOUT IOUT 20µs/div IOUTMIN = 180mA LINE TRANSIENT MAX1556/7 toc15 10mV/div AC-COUPLED VIN VOUT ILX 3.5V 40µs/div 200mA/div BODE PLOT MAX1556/7 toc16 FREQUENCY (kHz) GAIN (dB) PHASE (DEGREES) 100101 -50 -40 -30 -20 -10 -60 -30 120 150 180 210 240 -60 0.1 1000 0dB PHASE MARGIN = 53° COUT = 22µF, RLOAD = 4Ω Typical Operating Characteristics (continued) (VIN = VINP = 3.6V, D1 = D2 = SHDN = IN, Circuits of Figures 2 and 3, TA = +25°C, unless otherwise noted.)

show the typical application circuits. off, the internal low-side n-channel MOSFET turns on. current ramps down, still providing current to the output. low-side MOSFET remains on until the next clock cycle. 1 IN Supply Voltage Input. Connect to a 2.6V to 5.5V source. 2 GND Ground. Connect to PGND. discharged through 200Ω to GND in shutdown.

4 OUT

6 D2 OUT Voltage-Select Input. See Table 1. 7 PGND Power Ground. Connect to GND. 10 D1 OUT Voltage-Select Input. See Table 1. ground plane to maximize thermal dissipation. Table 1. Output-Voltage-Select Truth Table A zero represents D_ being driven low or connected to GND. A 1 represents D_ being driven high or connected to IN.

for a few recommended inductors is listed in Table 2. MOSFETs turn off and LX becomes high impedance. Connect SHDN to IN or logic high for normal operation. as well as an adjustable output using external resistors. harmful effect on regulation or reliability. Table 2. Inductor Selection *Estimated based upon similar-valued prototype inductors.

Table 2 for recommended inductors and manufacturers. capacitor low at the switching frequency. 0.47µF capacitor from IN to GND. (MAX1556EVKIT) is available to speed design. should be placed as close as possible to the IC. be as close together as possible. Figure 6. Adjustable Output Voltage

PROCESS: BiCMOS MAX1556/MAX1556A/MAX1557 16µA IQ, 1.2A PWM DC-DC Step-Down Converters

Package Information

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package draw- ings may show a different suffix character, but the drawing per- tains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.

10 TDFN T1033-1 21-0137 90-0003

16µA IQ, 1.2A PWM DC-DC Step-Down Converters Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circu it patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

Revision History

0 7/04 Initial release — 1 3/08 Adding MAX1556A as a new version 1–12 2 6/10 Added soldering temperature, added TOC for external feedback switching waveforms, and added paragraph discussing noise coupling when using external feedback resistors 1, 2, 5, 6, 9, 10, 11