MAX5026

MAX5028EUT MAXIM | Alldatasheet

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Technical content

Features

♦ Input Voltage Range: 3V to 11V (MAX5026/MAX5028) 4.5V to 11V (MAX5025/MAX5027) ♦ Wide Output Voltage Range: VCC to 36V ♦ Output Power: 120mW (max) ♦ User-Adjustable Output Voltage with MAX5025/MAX5026 Using External Feedback Resistors ♦ Fixed 30V Output Voltage: MAX5027/MAX5028 ♦ Internal 1.3Ω (typ), 40V Switch ♦ Constant PWM Frequency Provides Easy Filtering in Low-Noise Applications ♦ 500kHz (typ) Switching Frequency ♦ 1μA (max) Shutdown Current ♦ Small, 6-Pin SOT23 Package MAX5025–MAX5028 500kHz, 36V Output, SOT23, PWM Step-Up DC-DC Converters GND FB

16 L X

MAX5025– MAX5028 SOT23-6 TOP VIEW

34 SHDN

L1VCC = 4.5V TO 11V (MAX5027) VCC = 3V TO 11V (MAX5028) D1 VCC GND FB PGND LX MAX5027 MAX5028 SHDN Typical Operating Circuit 19-2239; Rev 2; 3/09 EVALUATION KIT AVAILABLE

Ordering Information

PA RT TEMP RANGE PIN- PACK AGE MAX5025EUT-T -40°C to +85°C 6 SOT23-6 MAX5026EUT-T -40°C to +85°C 6 SOT23-6 MAX5027EUT-T -40°C to +85°C 6 SOT23-6 MAX5028EUT-T -40°C to +85°C 6 SOT23-6 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. Selector Guide appears at end of data sheet.

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC = 5V, SHDN = VCC, TA = -40°C to +85°C, unless otherwise noted. Typical values are at T A = +25°C.) (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. CC + 0.3V) CC + 0.3V) Continuous Power Dissipation (T A = +70°C) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUPPLY VOLTAGE MAX5026/MAX5028 3.0 11Input Voltage Range V CC MAX5025/MAX5027 4.5 11 V Undervoltage Lockout VUVLO Rise/fall, hysteresis = 3mV 2.25 2.65 2.95 V Supply Current I CC MAX5025/MAX5026, FB = 1.4V MAX5027/MAX5028, FB = 35V 350 1000 µA Shutdown Current I SHDN SHDN = GND 0.01 1µ A BOOST CONVERTER MAX5025/MAX5027 345 500 1000Switching Frequency f SW MAX5026/MAX5028, VCC = 3.3V 410 500 670 kHz MAX5025/MAX5027, ILOAD = 2mA, VCC = 4.5V to 11V, VOUT = 30V 0.25 Line Regulation MAX5026/MAX5028, ILOAD = 0.5mA, VCC = 3V to 11V, VOUT = 30V 0.25 %/V MAX5025/MAX5027, VCC = 5V, ILOAD = 0 to 4mA, VOUT = 30V 2.0 Load Regulation MAX5026/MAX5028, VCC = 3.3V, ILOAD = 0 to 1mA, VOUT = 30V 1.0 Thermal Shutdown 140 °C Thermal Shutdown Hysteresis 2° C

MAX5025–MAX5028ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V, SHDN = VCC, TA = -40°C to +85°C, unless otherwise noted. Typical values are at T A = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS MAX5025, VCC = 4.5V to 11V 1.19 1.25 1.31 MAX5027, VCC = 4.5V to 11V 28.5 30.0 31.5 MAX5026, VCC = 3.3V to 11V 1.212 1.25 1.288FB Set Point V FB MAX5028, VCC = 3.3V to 11V 29.0 30 31 V MAX5025/MAX5026, FB = 1V 110 310 nAFB Input Bias Current I FB MAX5027/MAX5028, FB = 30V 100 170 µA Output Voltage Adjustment Range MAX5025/MAX5026 V CC + 1 36 V LX OUTPUT MAX5026/MAX5028, VCC = 3V 2.0 4.0 VCC = 5V 1.3 3.0LX On-Resistance R ON ILX = 40mA VCC = 11V 1.0 2.5 Ω Switch Current Limit I LIM Note 2 260 mA MAX5025/MAX5026, VFB = 1.4V LX Leakage Current V LX = 40V MAX5027/MAX5028, VFB = 35V 0.01 10 µA LOGIC INPUT: SHDN Input Low Level V IL 0.8 V Input High Level V IH 2.4 V Input Bias Current -1 1 µA Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design. Note 2: Switch current-limit accuracy is typically ±20% and is a function of the input voltage. ILIM = (VIN/5) (260mA). 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters 02468 1 0 MAX5025-28 toc01 LOAD CURRENT (mA) EFFICIENCY (%) EFFICIENCY vs. LOAD CURRENT (VOUT = 12V) MAX5026 VCC = 5V, VOUT = 12V CIRCUIT OF FIGURE 2. R1 = 147kΩ, R2 = 16.2kΩ 04 26 8 MAX5025-28 toc02 LOAD CURRENT (mA) EFFICIENCY (%) EFFICIENCY vs. LOAD CURRENT (VOUT = 15V) MAX5026 VCC = 5V, VOUT = 12V CIRCUIT OF FIGURE 2. R1 = 147kΩ, R2 = 13kΩ 012345 MAX5025-28 toc03 LOAD CURRENT (mA) EFFICIENCY (%) EFFICIENCY vs. LOAD CURRENT (VOUT = 24V) MAX5026 VCC = 5V, VOUT = 24V CIRCUIT OF FIGURE 2. R1 = 147kΩ, R2 = 8.07kΩ 01234 MAX5025-28 toc04 LOAD CURRENT (mA) EFFICIENCY (%) EFFICIENCY vs. LOAD CURRENT (VOUT = 30V) MAX5026 VCC = 5V, VOUT = 30V CIRCUIT OF FIGURE 2. R1 = 147kΩ, R2 = 6.34kΩ 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 01234 MAX5025-28 toc05 LOAD CURRENT (mA) STARTUP VOLTAGE (V) MAX5026 MINIMUM STARTUP VOLTAGE vs. LOAD CURRENT 150 100 200 250 300 350 400 450 500 0369 1 2 MAX5025-28 toc06 SUPPLY VOLTAGE (V) SUPPLY CURRENT (μA) MAX5026/MAX5028 SUPPLY CURRENT vs. SUPPLY VOLTAGE CURRENT INTO VCC PIN DEVICE NOT SWITCHING 3579 1 1 MAX5025-28 toc07 SUPPLY VOLTAGE (V) NO LOAD SUPPLY CURRENT (mA) MAX5026 NO LOAD SUPPLY CURRENT vs. SUPPLY VOLTAGE CIRCUIT OF FIGURE 2 VOUT = 30V 150 350 250 550 450 750 650 850 -40 0 20-20 40 60 80 SUPPLY CURRENT vs. TEMPERATURE MAX5025-28 toc08 TEMPERATURE (°C) SUPPLY CURRENT (μA) CURRENT INTO VCC PIN VCC = 11V VCC = 9V VCC = 7V VCC = 5V VCC = 3V 200 300 250 450 400 350 600 550 500 650 -40 0 20-20 40 60 80 MAX5025-28 toc09 TEMPERATURE (°C) SWITCHING FREQUENCY (kHz) MAX5026 SWITCHING FREQUENCY vs. TEMPERATURE VCC = 5V VOUT = 30V CIRCUIT OF FIGURE 2. Typical Operating Characteristics (VCC = 5V, VOUT = 30V, TA = +25°C, unless otherwise noted.)

MAX5025–MAX5028 Typical Operating Characteristics (continued) (VCC = 5V, VOUT = 30V, TA = +25°C, unless otherwise noted.) 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters EXITING SHUTDOWN MAX5025-28 toc10 OUTPUT VOLTAGE 20V/div INDUCTOR CURRENT 50mA/div SHUTDOWN VOLTAGE 5V/div 30V 2ms/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 1mA. CIRCUIT OF FIGURE 3 ENTERING SHUTDOWN MAX5025-28 toc11 30V OUTPUT VOLTAGE 20V/div SHUTDOWN VOLTAGE 5V/div 100ms/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 1mA. CIRCUIT OF FIGURE 3 MAX5025-28 toc12 LX PIN 20V/div VOUT 2mV/div AC-COUPLED IL 100mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 0.1mA. CIRCUIT OF FIGURE 2 LIGHT-LOAD SWITCHING WAVEFORM WITHOUT RC FILTER MAX5025-28 toc13 LX PIN 20V/div VOUT 1mV/div AC-COUPLED IL 100mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 0.1mA. CIRCUIT OF FIGURE 3 LIGHT-LOAD SWITCHING WAVEFORM WITH RC FILTER MAX5025-28 toc14 LX PIN 20V/div VOUT 5mV/div AC-COUPLED IL 200mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 2mA. CIRCUIT OF FIGURE 2 MEDIUM-LOAD SWITCHING WAVEFORM WITHOUT RC FILTER MAX5025-28 toc15 LX PIN 20V/div VOUT 1mV/div AC-COUPLED IL 200mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 2mA. CIRCUIT OF FIGURE 3 MEDIUM-LOAD SWITCHING WAVEFORM WITH RC FILTER

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters Typical Operating Characteristics (continued) (VCC = 5V, VOUT = 30V, TA = +25°C, unless otherwise noted.) MAX5025-28 toc17 LX PIN 20V/div VOUT 1mV/div AC-COUPLED IL 200mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 4mA. CIRCUIT OF FIGURE 3 HEAVY-LOAD SWITCHING WAVEFORM WITH RC FILTER LOAD TRANSIENT RESPONSE MAX5025-28 toc18 OUTPUT VOLTAGE 200mV/div AC-COUPLED LOAD CURRENT 10mA/div 0mV 0mA 1ms/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 0 TO 4mA. CIRCUIT OF FIGURE 2 LINE TRANSIENT RESPONSE MAX5025-28 toc19 OUTPUT VOLTAGE 1mV/div AC-COUPLED INPUT VOLTAGE 100mV/div AC-COUPLED 0mV 0mV 2ms/div MAX5026, VCC = 5V TO 5.2V, VOUT = 30V, ILOAD = 1mA. CIRCUIT OF FIGURE 2 MAX5025-28 toc20 1.230 1.235 1.245 1.240 1.260 1.265 1.255 1.250 1.270FB PIN VOLTAGE (V) -40 0 20-20 40 60 80 TEMPERATURE (°C) MAX5026 FB PIN VOLTAGE vs. TEMPERATURE VCC = 11V VCC = 5V VCC = 3V 29.0 29.4 29.2 29.8 29.6 30.2 30.0 30.4 -40 0 20-20 40 60 80 MAX5025-28 toc21 TEMPERATURE (°C) FB PIN VOLTAGE (V) MAX5028 FB PIN VOLTAGE vs. TEMPERATURE VCC = 11V VCC = 5V VCC = 3V MAX5025-28 toc16 LX PIN 20V/div VOUT 5mV/div AC-COUPLED IL 200mA/div 0mA 1μs/div MAX5026, VCC = 5V, VOUT = 30V, ILOAD = 4mA. CIRCUIT OF FIGURE 2 HEAVY-LOAD SWITCHING WAVEFORM WITHOUT RC FILTER

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters 0.015 0.010 0.005 0.025 0.020 0.045 0.040 0.035 0.030 0.050 -40 -20 0 20 40 60 80 MAX5025-28 toc23 TEMPERATURE (°C) LX LEAKAGE CURRENT (μA) LX LEAKAGE CURRENT vs. TEMPERATURE CURRENT INTO LX PIN VLX = 40V 02 1 345 LOAD REGULATION MAX5025-28 toc24 LOAD CURRENT (mA) OUTPUT VOLTAGE (V) MAX5026 VCC = 5V WITH RC FILTER (CIRCUIT OF FIGURE 3) WITHOUT RC FILTER (CIRCUIT OF FIGURE 2) MAX5025-28 toc25 INPUT VOLTAGE (V) MAXIMUM LOAD CURRENT (mA) MAX5026 MAXIMUM LOAD CURRENT vs. INPUT VOLTAGE 975 100 0.1 31 1 A: VOUT = 12V B: VOUT = 24V C: VOUT = 30V D: VOUT = 32V E: VOUT = 36V A B E C D Typical Operating Characteristics (continued) (VCC = 5V, VOUT = 30V, TA = +25°C, unless otherwise noted.) 0.5 1.0 2.0 1.5 2.5 3.0 -40 0 -20 20 40 60 80 MAX5025-28 toc22 TEMPERATURE (°C) RON (Ω) SWITCH ON-RESISTANCE vs. TEMPERATURE VCC = 3V VCC = 5V VCC = 11V MAX5026

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters Pin Description PIN MAX5025/ MAX5026 MAX5027/ MAX5028 NAME FUNCTION 1 1 PGND Power Ground. Connect directly to local ground plane. Use a star ground configuration for low noise. 2 2 GND Ground. Connect directly to local ground plane. 3— F B Feedback Pin. Reference voltage is approximately 1.25V. Connect resistive-divider tap here. Minimize trace area at FB. See Setting the Output Voltage section. —3F B Feedback Pin. Connect VOUT to FB for +30V. Internal resistors divide down the output voltage. 44 SHDN Shutdown Pin. Connect to VCC to enable device. Connect to GND to shut down. 55 V CC Input Supply Voltage. Bypass with a 4.7µF ceramic capacitor. 66 L X Drain of Internal 40V N-Channel DMOS. Connect inductor/diode to LX. Minimize trace area at this pin to keep EMI down. Detailed Description The MAX5025–MAX5028 current-mode PWM con- trollers operate in a wide range of DC-DC conversion applications including boost, flyback, and isolated out- put configurations. These converters provide low- noise, high output voltages making them ideal for var- actor diode tuning applications as well as TFT LCD bias. Other features include shutdown, fixed 500kHz PWM oscillator, and a wide input range: 3V to 11V for MAX5026/MAX5028 and 4.5V to 11V for MAX5025/ MAX5027. The MAX5025–MAX5028 operate in discontinuous mode in order to reduce the switching noise at the out- put. Other continuous mode boost converters generate a large voltage spike at the output when the LX switch turns on because there is a conduction path between the output, diode, and switch to ground during the time needed for the diode to turn off. To reduce the output noise even further, the LX switch turns off by taking 40ns typically to transition from “ON” to “OFF.” As a consequence, the positive slew rate of the LX node is reduced and the current from the induc- tor does not “force” the output voltage as hard as would be the case if the LX switch were to turn off more quickly. PWM Controller The heart of the MAX5025–MAX5028 current-mode PWM controllers is a BiCMOS multi-input comparator that simultaneously processes the output-error signal and switch current signal. The main PWM comparator is direct summing, lacking a traditional error amplifier and its associated phase shift. The direct summing configuration approaches ideal cycle-by-cycle control over the output voltage since there is no conventional error amp in the feedback path. The device operates in PWM mode using a fixed-fre- quency, current-mode operation. The current-mode feedback loop regulates peak inductor current as a function of the output error signal. SHDN Input The SHDN pin provides shutdown control. Connect SHDN to V CC for normal operation. To disable the device, connect SHDN to GND. Design Procedure The MAX5025–MAX5028 can operate in a number of DC-DC converter configurations including step-up, sin- gle-ended primary inductance converter (SEPIC), and flyback. The following design discussions are limited to step-up, with a complete circuit shown in the Application Circuits section. Setting the Output Voltage The output voltage of the MAX5027/MAX5028 is fixed at 30V. The output voltage of the MAX5025/MAX5026 is set by two external resistors (R1 and R2, Figure 2 and Figure 3). First select the value of R2 in the 5k Ω to 50kΩ range. R1 is then given by:

the efficiency of the boost converter. (ESR) should be below 1 Ω for reasonable efficiency. for discontinuous mode operation. Table 1. Inductor Vendors Figure 1. Functional Diagram

fast recovery time and low forward-voltage drop. OUT. Table 2 lists diode vendors. ESL, and high capacitance value should be selected. over temperature than the Y5V ceramic capacitors. Table 2. Schottky Diode Vendors Table 3. Capacitor Table

MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters Selector Guide PART OUTPUT FREQUENCY TOLERANCE FB SET POINT TOLERANCE INPUT VOLTAGE MAX5025 Adjustable -31% to +100% ±5% 4.5V to 11V MAX5026 Adjustable -18% to +34% ±3% 3V to 11V MAX5027 Fixed 30V -31% to +100% ±5% 4.5V to 11V MAX5028 Fixed 30V -18% to +34% ±3% 3V to 11V

Package Information

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

6 SOT23 S8-2 21-0058

TRANSISTOR COUNT: 365 PROCESS: BiCMOS

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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 © 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX5025–MAX5028 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters

Revision History

0 10/01 Initial release — 1 12/01 Released the MAX5027 1 2 3/09 Revised the Absolute Maximum Ratings section. 2