19-1455; Rev 1; 6/99 SOT23 Vibrator Motor Driver ____________________________Features ♦ Fixed 1.25V or Adjustable (1.25V to 6.5V) Output ♦ Low Cost ♦ Thermal Overload Protection ♦ Output Current Limit ♦ Reverse Battery Protection ♦ Low 0.1nA Off Supply Current ♦ Low 80µA Full-Load Supply Current ________________________Applications Ordering Information Wireless Handset Vibrator Motor Drivers Pager Vibrator Motor Drivers PART TEMP. RANGE MAX1749EUK-T -40°C to +85°C Typical Operating Circuit PINPACKAGE 5 SOT23 TOP MARK ADIX Pin Configuration TOP VIEW 1.25V UP TO 120mA 2.5V TO 6.5V OUT IN ON 1 5 SET 4 OUT COUT 1µF CIN 1µF ON MAX1749 ON BATTERY SET GND 2 MAX1749 OFF GND IN 3 SOT23-5 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX1749 General Description The MAX1749 allows for a constant vibration force while operating from a +2.5V to +6.5V input range and delivering up to 120mA. A PMOS pass transistor allows the 80µA supply current to remain independent of the load. The output voltage can be adjusted from +1.25V to VIN with an external resistor-divider. When turned off (ON = low), the MAX1749 supply current drops to 1µA (max) to minimize battery drain. Other features include short-circuit protection, thermal shutdown protection, and reverse battery protection. The MAX1749 is available in a 5-pin SOT23 package. MAX1749 SOT23 Vibrator Motor Driver ABSOLUTE MAXIMUM RATINGS IN to GND ....................................................................-7V to +7V Output Short-Circuit Duration ............................................Infinite SET to GND ..............................................................-0.3V to +7V ON to GND ..................................................................-7V to +7V ON to IN....................................................................-7V to +0.3V OUT to GND ................................................-0.3V to (VIN + 0.3V) Continuous Power Dissipation (TA = +70°C) SOT23-5 (derate 7.1mW/°C above +70°C) .................571mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C θJA ...............................................................................+140°C/W Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+300°C 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 specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VIN = +3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Input Voltage Output Voltage SYMBOL CONDITIONS VIN VOUT Ground Pin Current Off Supply Current TYP MAX UNITS 6.5 V 1.25 1.37 V 2.5 0.1mA ≤ IOUT ≤ 50mA, SET = OUT Maximum Output Current Current Limit (Note 2) MIN 1.13 120 mA ILIM 280 IQ 80 200 TA = +25°C 0.0001 1 TA = +85°C 0.02 IOFF VOUT = VON = GND mA µA µA ON INPUT ON Input High Threshold VIH ON Input Low Threshold VIL ON Input Bias Current 2.0 V 0.4 ION ON = IN ISET VSET = 1.4V TA = +25°C 0 TA = +85°C 0.05 TA = +25°C 0.03 TA = +85°C 0.5 100 V nA SET INPUT SET Input Leakage Current 10 nA THERMAL PROTECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis TSHDN 170 °C ∆TSHDN 20 °C Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. Note 2: Not tested. For design purposes, the current limit should be considered 120mA minimum to 420mA maximum. 2 _______________________________________________________________________________________ SOT23 Vibrator Motor Driver 90 1.25 1.24 1.23 1.2 OUTPUT VOLTAGE (V) 80 SUPPLY CURRENT (µA) 1.26 1.4 MAX1749toc02 100 MAX1749 TOC01 1.27 70 60 50 40 30 20 1.22 1.0 0.8 0.6 0.4 0.2 10 0 0 40 60 80 100 120 0 20 LOAD CURRENT (mA) 40 60 80 100 0 120 1 2 SUPPLY CURRENT vs. INPUT VOLTAGE 4 5 6 OUTPUT VOLTAGE vs. TEMPERATURE 1.28 MAX1749 toc04 120 ILOAD = 50mA 1.27 OUTPUT VOLTAGE (V) 100 ILOAD = 50mA 80 3 INPUT VOLTAGE (V) LOAD CURRENT (mA) 60 ILOAD = 0 40 20 1.26 1.25 1.24 1.23 1.22 0 1.21 1 2 3 4 5 6 -15 10 35 60 TEMPERATURE (°C) SUPPLY CURRENT vs. TEMPERATURE REGION OF STABLE COUT ESR vs. LOAD CURRENT 100 ILOAD = 50mA 90 -40 INPUT VOLTAGE (V) 10 80 COUT ESR (Ω) 70 60 50 40 85 MAX1749 toc08 0 MAX1749 toc06 20 SUPPLY CURRENT (µA) 0 MAX1749 toc05 1.21 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) OUTPUT VOLTAGE vs. INPUT VOLTAGE SUPPLY CURRENT vs. LOAD CURRENT MAX1749toc03 OUTPUT VOLTAGE vs. LOAD CURRENT 1 STABLE REGION 0.1 30 20 10 0 0.01 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 0 20 40 60 80 100 120 LOAD CURRENT (mA) _______________________________________________________________________________________ 3 MAX1749 __________________________________________Typical Operating Characteristics (VIN = +3.6V, SET = OUT, CIN = 1µF, COUT = 1µF, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VIN = +3.6V, SET = OUT, CIN = 1µF, COUT = 1µF, TA = +25°C, unless otherwise noted.) MAX1749 toc09 1.25V 1.24V VOUT MAX1749 toc10 LOAD-TRANSIENT RESPONSE LINE-TRANSIENT RESPONSE 1.25V 1.24V VOUT 1.23V 1.23V 4.6V ILOAD 20mA/div VIN 3.6V 10µs/div ILOAD = 0 to 50mA, CIN = 10µF, VOUT = AC-COUPLED 50µs/div ILOAD = 50mA, CIN = 10µF, VOUT = AC-COUPLED ON/OFF WAVEFORM (VIN = 3.6V) ON/OFF WAVEFORM (VIN = 5.0V) 5V VON 0V 1V 4V MAX1749 toc14 MAX1749 toc13 MAX1749 SOT23 Vibrator Motor Driver 2V VON 0V 1V VOUT 0V VOUT 0V 200mA 200mA ILOAD 0mA 100ms/div VIBRATOR MOTOR LOAD 4 ILOAD 0mA 100ms/div VIBRATOR MOTOR LOAD _______________________________________________________________________________________ SOT23 Vibrator Motor Driver PIN NAME FUNCTION 1 ON Active-High On/Off Input. Apply a logic high to deliver power to the load. Apply a logic low to disconnect the load and reduce the supply current to 0.1nA. 2 GND Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board ground plane to maximize thermal dissipation. 3 IN Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1µF to GND (see Capacitor Selection and Regulator Stability). 4 OUT Regulator Output. Fixed 1.25V or adjustable from 1.25V to VIN. Sources up to 120mA. Bypass with a 1µF, <0.2Ω typical ESR capacitor to GND. 5 SET Feedback Input for Setting the Output Voltage. Connect to OUT for 1.25V regulated output (see Output Voltage Selection). Connect to an external resistor-divider for adjustable-output operation. Detailed Description The MAX1749 is a low-quiescent-current, vibrator motor driver designed for battery-powered wireless handsets and pagers. The device supplies an adjustable +1.25V to +6.5V output for load currents up to 120mA. The MAX1749 allows for a constant vibration force while operating from a +2.5V to +6.5V input voltage range. The 1.25V bandgap reference is connected to the error amplifier’s inverting input. The error amplifier compares this reference with the feedback voltage and amplifies the difference. The MOSFET driver reads the error signal and applies the appropriate drive to the p-channel pass transistor. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled lower than the IN ON reference, allowing more current to flow and increasing the output voltage. If the feedback voltage is too high, the passtransistor gate is pulled-up, allowing less current to flow to the output. The output voltage is fed back to SET either directly for a 1.25V fixed output or through an external resistor-divider for an adjustable +1.25V to VIN output. Additional blocks include a current limiter, reverse battery protection, a thermal sensor, and ON/OFF logic. Internal P-Channel Pass Transistor The MAX1749 features a 1.1Ω typical P-channel MOSFET pass transistor. This provides several advantages over similar designs using PNP pass transistors, including longer battery life. REVERSE BATTERY PROTECTION ERROR AMP MAX1749 ON/OFF LOGIC MOS DRIVER WITH ILIMIT P OUT SET THERMAL SENSOR 1.25V REF GND Figure 1. Functional Diagram _______________________________________________________________________________________ 5 MAX1749 ______________________________________________________________Pin Description MAX1749 SOT23 Vibrator Motor Driver IN CIN BATTERY 1µF ON OFF Current Limit MAX1749 ON OUTPUT VOLTAGE OUT the regulator turns off; however, inertial energy in the motor exhibits a slow output voltage decline. The MAX1749 is designed to withstand this condition with no negative effects. R1 SET R2 GND COUT 1µF VIBRATOR The MAX1749 includes a current limiter that monitors and controls the pass transistor’s gate voltage, estimating the output current and limiting it to about 280mA. For design purposes, the current limit should be considered 120mA (min) to 420mA (max). The output can be shorted to ground for an infinite time period without damaging the part. Thermal-Overload Protection Figure 2. Adjustable Output Using External Feedback Resistors The P-channel MOSFET requires no base drive current, which reduces quiescent current considerably. PNPbased regulators waste considerable amounts of base current under large loads. The MAX1749 does not suffer from these problems and consumes only 80µA of quiescent current independent of the load (see Typical Operating Characteristics). Output Voltage Selection To select the preset 1.25V output, connect OUT directly to SET. To adjust the output (1.25V to 6.5V), use two external resistors connected as a voltage divider to SET (Figure 2). The output voltage is set by the following equation: VOUT = VSET (1 + R1 / R2) where VSET = 1.25V. To simplify resistor selection: V R1 = R2 OUT VSET − 1 Operating Region and Power Dissipation Maximum power dissipation of the MAX1749 depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The power dissipation across the device is P = IOUT (VIN - VOUT). The resulting maximum power dissipation is: PMAX = (TJ - TA) / θJA where (TJ - TA) is the temperature difference between the MAX1749 die junction and the surrounding air, and θJA is +140°C/W. GND performs the dual function of providing an electrical connection to ground and channeling heat away. Connect GND to a large pad or ground plane. Reverse Battery Protection Choose R2 = 100kΩ to optimize power consumption, accuracy, and high-frequency power-supply rejection. The total current through the external resistive feedback and load should not be less than 10µA. ON/OFF Drive ON high to provide power to the load. Drive ON low to disable power to the load and reduce the supply current to typically 0.1nA (1µA max). Refer to the ON/OFF waveforms in the Typical Operating Characteristics. When ON goes high, output current rises to the current limit until VOUT reaches regulation. While in regulation, the output current drops to a lower value sufficient to maintain motor speed. When ON goes low, 6 Thermal-overload protection limits total power dissipation in the MAX1749. When the junction temperature exceeds TJ = +170°C, the thermal sensor sends a signal to the ON/ OFF logic, turning off the pass transistor and allowing the IC to cool. The thermal sensor will turn the pass transistor on again after the IC’s junction temperature cools by typically 20°C, resulting in a pulsed output during continuous thermal-overload conditions. The MAX1749 has a unique protection scheme that limits the reverse supply current to less than 1mA when either VIN or VON falls below ground. The circuitry monitors the polarity of these two pins, disconnecting the internal circuitry and parasitic diodes when the battery is reversed. This feature prevents the device from overheating and damaging the battery. VIN > 5.5V Minimum Load Current When operating the MAX1749 with an input voltage above 5.5V, the minimum current through the external feedback resistors and load must be 30µA. _______________________________________________________________________________________ SOT23 Vibrator Motor Driver Chip Information TRANSISTOR COUNT: 148 Use a 1µF capacitor on the input and a 1µF capacitor on the output of the MAX1749. A higher-value input capacitor (10µF) may be necessary if large, fast transients are anticipated and the device is located several inches from the power source. Improve load-transient response and stability by using larger output capacitors. For stable operation over the full temperature range with load currents up to 120mA, use a 1µF min capacitor (ESR < 0.2Ω). SOT5L.EPS ________________________________________________________Package Information _______________________________________________________________________________________ 7 MAX1749 Capacitor Selection and _________________Regulator Stability MAX1749 SOT23 Vibrator Motor Driver NOTES Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.