MAX1735EUK50-T

19-1783; Rev 1; 11/03 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 The MAX1735 negative-output, low-dropout linear regulator operates from a -2.5V to -6.5V input and delivers a guaranteed 200mA with a low 80mV dropout. The highaccuracy (±1%) output voltage is preset or can be adjusted from -1.25V to -5.5V with an external resistive voltage-divider. An internal N-channel MOSFET allows for a low 85µA quiescent current virtually independent of the load, making this device ideal for battery-powered portable equipment, such as PDAs, mobile phones, cordless phones, and wireless data modems. The device is available in several preset output voltage versions: -5.0V, -3.0V, and -2.5V. All versions offer a 1nA low-power shutdown mode, short-circuit protection, and thermal overload protection. The device is offered in a tiny 5-pin SOT23 package. Features ♦ Guaranteed 200mA Output Current ♦ Low 80mV Dropout Voltage at 200mA ♦ Low 85µA Quiescent Supply Current ♦ Low 1nA Current Shutdown Mode ♦ Stable with 1µF COUT ♦ PSRR >60dB at 100Hz ♦ Thermal Overload Protection ♦ Short-Circuit Protection ♦ -5.0V, -3.0V, or -2.5V Output Voltage or Adjustable (-1.25V to -5.5V) ♦ Tiny SOT23-5 Package Applications Ordering Information Disk Drives PART Modems PINPACKAGE TEMP RANGE Instrumentation Amplifiers MAX1735EUK50-T -40°C to +85°C 5 SOT23-5 Notebook Computers MAX1735EUK30-T -40°C to +85°C 5 SOT23-5 Mobile and Cordless Telephones MAX1735EUK25-T -40°C to +85°C 5 SOT23-5 PCMCIA Cards Output-Voltage Selector Guide GaAsFET Bias Mobile Wireless Data Modems PRESET OUTPUT VOLTAGE PART PDAs and Palmtop Computers MAX1735EUK50-T -5.0V or adj ADOZ MAX1735EUK30-T -3.0V or adj ADOY MAX1735EUK25-T -2.5V or adj ADOX Pin Configuration Typical Operating Circuit -5V, -3V, OR -2.5V OUTPUT UP TO 200mA -6.5V TO -2.5V INPUT OUT IN CIN COUT MAX1735 SOT TOP MARK TOP VIEW GND 1 IN 2 5 OUT 4 SET MAX1735 ON GND OFF ON SET SHDN SHDN 3 GND SOT23-5 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX1735 General Description MAX1735 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 ABSOLUTE MAXIMUM RATINGS IN, SET to GND .................................................... -7.0V to +0.3V SHDN to GND ............................................ (VIN - 0.3)V to +7.0V OUT to GND ...............................................(VIN - 0.3)V to +0.3V Output Short-Circuit Duration ........................................Indefinite Continuous Power Dissipation (TA = +70°C) 5-Pin SOT23 (derate 7.1mW/°C above +70°C)........... 571mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range ............................ -65°C to +150°C Lead Temperature (soldering, 10s) ................................ +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 (Circuit of Figure 2, VIN = VOUT - 1V, V SHDN = VIN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Input Voltage SYMBOL CONDITIONS VIN Output Voltage Accuracy MIN Maximum Output Current IOUT Current Limit ILIM Ground-Pin Current IQ Dropout Voltage (Note 2) +1 IOUT = -100µA, TA = 0°C to +85°C -2 +2 ILOAD = -100µA to -200mA -3 +2 -1.225 Circuit of Figure 3, ILOAD = -100µA to -200mA -1.275 -1.2125 VOUT = 0 -1020 IOUT = -100µA -180 -200 -85 40 IOUT = -200mA 80 240 0 +0.15 f = 100Hz TA = +25°C -1 Shutdown Supply Current V SHDN = 0 SHDN Input High Threshold (Note 3) Negative voltage at SHDN -1.6 Positive voltage at SHDN +0.4 TA = +85°C %/mA µVRMS 60 dB -0.001 TA = +25°C Thermal Shutdown Junction Temperature Hysteresis = 15°C (typ) -0.4 -15 V SHDN = +6.5V V SHDN = 0, -6.5V µA +1.6 Negative voltage at SHDN SHDN Input Bias Current %/V 160 -1 -100 mV 0.004 Positive voltage at SHDN VSET = -1.25V, TA = +25°C mA µA IOUT = -100mA 10Hz to 1MHz, COUT = 1µF ISET -250 -125 IOUT from 0mA to -200mA V mA -515 IOUT = -200mA -0.15 % -1.2375 -1.275 Output Voltage Noise Set Input Bias Current -1.25 Circuit of Figure 3, IOUT = -100µA, TA = 0°C to +85°C Load Regulation SHDN Input Low Threshold (Note 3) V -2.5 -1 Circuit of Figure 3, VIN from -6.5V to -2.5V, VOUT = -1.25V PSRR UNITS -6.5 Line Regulation Power-Supply Rejection Ratio MAX TA = +25°C, IOUT = -100µA Circuit of Figure 3, TA = +25°C, IOUT = -100µA -1.2625 SET Regulation Set Point TYP +0.5 160 V nA 3.5 -0.5 V µA °C Note 1: Limits are 100% production tested at TA = +25°C. Limits over operating temperature range are guaranteed by design. Note 2: The dropout voltage is defined as VOUT - VIN, when VOUT is 100mV above the nominal value of VOUT. Note 3: The SHDN logic input can be driven by either a positive voltage or a negative voltage. | V SHDN | < 0.4V puts the device in shutdown, while | V SHDN | > 1.6V enables the device. 2 _______________________________________________________________________________________ 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. LOAD CURRENT 130 SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 140 120 100 80 60 MAX1735 toc02 ILOAD = 200mA 160 140 MAX1735 toc01 180 120 110 100 90 40 80 20 0 70 -1 -2 -3 -4 -5 -6 20 40 60 80 100 120 140 160 180 200 LOAD CURRENT (mA) SUPPLY CURRENT vs. TEMPERATURE DROPOUT VOLTAGE vs. LOAD CURRENT 140 120 100 80 NO LOAD 60 100 MAX1735 toc03 ILOAD = 200mA VOUT = -2.9V DROPOUT VOLTAGE (mV) SUPPLY CURRENT (µA) 0 SUPPLY VOLTAGE (V) 180 160 -7 MAX1735 toc04 0 40 80 TA = +25°C 60 TA = +85°C 40 TA = -40°C 20 20 0 0 -15 10 35 60 0 50 75 100 125 150 175 200 LOAD CURRENT (mA) OUTPUT VOLTAGE CHANGE vs. LOAD CURRENT OUTPUT VOLTAGE CHANGE vs. TEMPERATURE -0.4 TA = -40°C TA = +85°C -0.8 TA = +25°C -1.0 MAX1735 toc06 -0.2 1.00 0.75 OUTPUT VOLTAGE CHANGE (%) VOUT = -3V -0.6 25 TEMPERATURE (°C) 0 OUTPUT VOLTAGE CHANGE (%) 85 MAX1735 toc05 -40 0.50 ILOAD = 200mA 0.25 0 -0.25 NO LOAD -0.50 -0.75 -1.2 -1.00 0 25 50 75 100 125 150 175 200 LOAD CURRENT (mA) -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX1735 Typical Operating Characteristics (Circuit of Figure 2, VIN = -4.0V, VOUT = -3.0V, TA = +25°C, unless otherwise specified.) Typical Operating Characteristics (continued) (Circuit of Figure 2, VIN = -4.0V, VOUT = -3.0V, TA = +25°C, unless otherwise specified.) 50 COUT = 10µF 40 30 COUT = 1.0µF MAX1735 toc09 MAX1735 toc08 60 10 OUTPUT NOISE (µVRMS/√Hz) MAX1735 toc07 70 20 OUTPUT NOISE (10Hz TO 1MHz) OUTPUT NOISE DENSITY vs. FREQUENCY POWER-SUPPLY REJECTION RATIO vs. FREQUENCY PSRR (dB) 500µV/div COUT = 1µF ILOAD = 50mA 1 0.1 10 0.01 0 1 10 100 1k 10k 100k 10 1M 1k TIME (1ms/div) 100k FREQUENCY (Hz) FREQUENCY (Hz) REGION OF STABLE ESR vs. LOAD CURRENT LINE-TRANSIENT RESPONSE MAX1735 toc11 MAX1735 toc10 100 COUT = 1µF REGION OF STABLE ESR COUT (Ω) MAX1735 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 10 VOUT 50mV/div 1 0.1 VIN 1V/div REGION OF STABILITY 0.01 0.001 0 TIME (100µs/div) 20 40 60 80 100 120 140 160 180 200 LOAD CURRENT (mA) LOAD-TRANSIENT RESPONSE (NORMAL OPERATION) LOAD-TRANSIENT RESPONSE (NEAR DROPOUT) MAX1735 toc12 TIME (100µs/div) 4 MAX1735 toc13 ILOAD STEP 0 to 50mA ILOAD STEP 0 to 50mA VOUT 10mV/div VOUT 10mV/div TIME (100µs/div) _______________________________________________________________________________________ 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 SHUTDOWN RESPONSE (DRIVEN BY A NEGATIVE VOLTAGE) SHUTDOWN-PIN BIAS CURRENT vs. SHUTDOWN-PIN VOLTAGE MAX1735 toc14b VSHDN 2V/div 0 0 VSHDN 2V/div 0 VOUT 2V/div 0 VOUT 2V/div 1.5 1.0 0.5 MAX1735 toc15 SHUTDOWN-PIN BIAS CURRENT (µA) 2.0 INVALID LOGIC VOLTAGE MAX1735 toc14a INVALID LOGIC VOLTAGE SHUTDOWN RESPONSE (DRIVEN FROM A POSITIVE VOLTAGE) 0 -0.5 TIME (200µs/div) TIME (200µs/div) -6.5 -5.0 -3.5 -2.0 -0.5 1.0 2.5 4.0 5.5 SHUTDOWN-PIN VOLTAGE (V) Pin Description PIN NAME FUNCTION 1 GND 2 IN Regulator Input. Supply voltage can range from -2.5V to -6.5V. Bypass with a 1µF capacitor to GND (see Capacitor Selection and Regulator Stability). This pin also functions as a heatsink. Solder to a large PC board pad or directly to the PC board power plane to maximize thermal dissipation. 3 SHDN Shutdown Input. Drive SHDN to GND to turn the regulator off, reducing the input current to less than 1nA. Drive SHDN above +1.6V or below -1.6V to enable the regulator. Connect SHDN to IN for always-on operation. 4 SET Dual Mode™ Regulator Feedback Input. Connect SET to GND for the preset output voltage. Use a resistive voltage-divider from OUT to SET to set the output voltage between -1.25V and -5.5V. Regulation setpoint is -1.25V. 5 OUT Regulator Output. OUT supplies up to 200mA in regulation. Bypass to GND with a 1µF ceramic capacitor. Ground Dual Mode is a trademark of Maxim Integrated Products, Inc. _______________________________________________________________________________________ 5 MAX1735 Typical Operating Characteristics (continued) (Circuit of Figure 2, VIN = -4.0V, VOUT = -3.0V, TA = +25°C, unless otherwise specified.) MAX1735 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 IN THERMAL SENSOR CIN SHUTDOWN LOGIC NMOS PASS TRANSISTOR OUT ON GND SHDN OFF MAX1735 ON COUT ERROR AMPLIFIER R1 VREF -1.25V SET Dual Mode COMPARATOR R2 -270mV GND Figure 1. Functional Diagram Detailed Description The MAX1735 is a low-dropout negative linear voltage regulator. It features Dual Mode operation, allowing a fixed -5.0V, -3.0V, or -2.5V output voltage or an adjustable output from -1.25V to -5.5V. The regulator is guaranteed to supply 200mA of output current. It features 60dB power-supply rejection for noise-sensitive applications and a low 85µA operating current that optimizes it for battery-operated devices. As Figure 1 illustrates, the device consists of an internal -1.25V reference, an error amplifier, an N-channel MOSFET, an internal precision-trimmed feedback voltage-divider, and a Dual Mode comparator. The -1.25V reference is connected to the inverting input of the error amplifier. The error amplifier compares the reference voltage with the selected feedback voltage and amplifies the difference. The error amplifier drives the MOSFET to control the output voltage. The feedback voltage for regulation is generated by either an internal or external resistive voltage-divider connected from OUT to SET. The internal Dual Mode 6 comparator selects the feedback path based on VSET. Connect SET to GND to use the internal feedback path, setting the output voltage to the preset value. If an external voltage-divider is used, see Output Voltage Selection. Internal N-Channel MOSFET The MAX1735 features an N-channel MOSFET pass transistor. Unlike similar designs using NPN bipolar pass transistors, N-channel MOSFETs require extremely low drive currents, reducing overall quiescent current. Also, NPN-based regulators consume still more base current in dropout conditions when the pass transistor saturates. The MAX1735 does not suffer from these problems, consuming only 125µA total current at full load and in dropout. Output Voltage Selection The MAX1735 features Dual Mode operation, allowing for a preset or adjustable output voltage. In preset voltage mode, the output of the MAX1735 is set to -5.0V, -3.0V, or -2.5V (see Ordering Information). Select this mode by connecting SET to GND (Figure 2). _______________________________________________________________________________________ 200mA, Negative-Output, Low-Dropout Linear Regulator in SOT23 OUT IN CIN 1µF CERAMIC COUT 1µF CERAMIC MAX1735 -6.5V TO -2.5V INPUT -5.5V TO -1.25V ADJUSTABLE OUTPUT -6.5V TO -2.5V INPUT -5.0V,-3.0V, OR -2.5V FIXED OUTPUT OUT IN CIN 1µF CERAMIC R1 COUT 1µF CERAMIC MAX1735 MAX1735 ON ON GND OFF ON GND SET SHDN OFF ON SET SHDN GND GND R2 VOUT = VSET Figure 2. Typical Application Circuit with Preset Output Voltage In adjustable mode, an output voltage between -5.5V and -1.25V is selected using two external resistors connected as a voltage-divider from OUT to SET (Figure 3). The output voltage is determined by the following equation:   R1   VOUT = VSET 1 +      R2   where VSET = VREFERENCE = -1.25V when in regulation. Since the input bias current at SET is