TOP VIEW. OUTPUT PRESET 2.5V TO 5V 200mA SHDN 3 4 BP GND. Maxim Integrated Products 1

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1 ; Rev ; 1/2 Low-Noise, Low-Dropout, 2mA General Description The low-noise, low-dropout linear regulator operates from a 2.5V to 6.5V input and delivers up to 2mA. Typical output noise is 3µV RMS, and typical dropout is only 236mV at 2mA. The output voltage is preset to voltages from 2.5V to 5V in 1mV increments. Designed with an internal P-channel MOSFET pass transistor, the maintains a low 1µA supply current independent of the load current and dropout voltage. Other features include a 1nA logic-controlled shutdown mode, short-circuit and thermal-shutdown protection, and reverse battery protection. The device also includes an autodischarge function, which actively discharges the output voltage to ground when the device is placed in shutdown. The comes in a thin 5-pin SOT23 package. 2mA Output Current Low Output Noise: 3µV RMS Features Low 55mV Dropout at 5mA Output Low 85µA No-Load Supply Current Low 1µA Operating Supply Current, Even in Dropout Thermal-Overload and Short-Circuit Protection Reverse Battery Protection Output Current Limit Preset Output Voltages 1nA Logic-Controlled Shutdown Cellular, Cordless, and PCS Phones PCMCIA Cards Modems Hand-Held Instruments Palmtop Computers Electronic Planners Applications Ordering Information PART TEMP RANGE PIN-PACKAGE EZKxy-T* -4 C to +85 C Thin SOT23-5 *xy is the output voltage code (see the Selector Guide at end of data sheet). Typical Operating Circuit Pin Configuration TOP VIEW INPUT 2.5V TO 6.5V C IN 1µF IN OUT C OUT 2.2µF OUTPUT PRESET 2.5V TO 5V 2mA IN GND 1 5 OUT 2 ON OFF C BP.1µF SHDN BP GND SHDN 3 4 THIN SOT23-5 BP Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at , or visit Maxim s website at

2 Low-Noise, Low-Dropout, 2mA ABSOLUTE MAXIMUM RATINGS IN to GND...-7V to +7V Output Short-Circuit Duration...Infinite SHDN to GND...-7V to +7V SHDN to IN...-7V to +.3V OUT, BP to GND...-.3V to (V IN +.3V) Continuous Power Dissipation (T A = +7 C) 5-Pin Thin SOT23 (derate 9.1mW/ C above +7 C)...727mW Operating Temperature Range...-4 C to +85 C Junction Temperature C θ JB (thin)...11 C/W Storage Temperature C to +15 C Lead Temperature (soldering, 1s)...+3 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 (V IN = ((NOMINAL) +.5V) or 2.5V (whichever is greater), T A = -4 C to +85 C, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage V IN V I OUT =.1mA, T A = +25 C, 2.5V Output Voltage Accuracy I OU T =.1m A to 12m A, T A = - 4 C to + 85 C, 2.5V Maximum Output Current 2 ma Current Limit I LIM ma No load Ground-Pin Current I Q I OUT = 15mA 1 Dropout Voltage (Note 2) I OUT = 1mA 1.1 Line Regulation V LNR V IN = 2.5V or ( +.1V) to 6.5V, I OUT = 1mA I OUT = 5mA I OUT = 2mA 236 % µa mv %/V Load Regulation V LDR I OUT =.1mA to 12mA, C OUT = 1µF.1.4 %/ma f = 1Hz to 1kHz, C OUT = 1µF 3 Output Voltage Noise e n C BP =.1µF C OUT = 1µF 2 SHUTDOWN SHDN Input Threshold V IH V IN = 2.5V to 5.5V 2. V IL V IN = 2.5V to 5.5V.4 T A = +25 C.1 1 SHDN Input Bias Current I SHDN V SHDN = V IN T A = +85 C.5 Shutdown Supply Current I Q(SHDN) = V Shutdown Exit Delay T A = +25 C.1 1 T A = +85 C.2 C BP =.1µF T A = +25 C 3 15 C OUT = 1µF, no load (Note 3) T A = -4 C to +85 C 3 Resistance Shutdown Discharge 3 Ω µv RMS V µa µa µs 2

3 Low-Noise, Low-Dropout, 2mA ELECTRICAL CHARACTERISTICS (continued) (V IN = ((NOMINAL) +.5V) or 2.5V (whichever is greater), T A = -4 C to +85 C, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS THERMAL PROTECTION Thermal-Shutdown Temperature T SHDN 155 C Thermal-Shutdown Hysteresis T SHDN 15 C Note 1: Limits are 1% production tested at T A = +25 C. Limits over the operating temperature range are guaranteed through correlation using guaranteed by design (GBD) methods. Note 2: The dropout voltage is defined as V IN -, when is 1mV below the value of for V IN = +.5V. Note 3: Time needed for to reach 95% of final value. Typical Operating Characteristics (V IN = ((NOMINAL) +.5V) or 2.5V (whichever is greater), C IN = 1µF, C OUT = 2.2µF, C BP =.1µF, T A = +25 C, unless otherwise noted.) OUTPUT VOLTAGE vs. LOAD CURRENT (EZK25) OUTPUT VOLTAGE vs. LOAD CURRENT (EZK5) -2 GROUND-PIN CURRENT (µa) GROUND-PIN CURRENT vs. LOAD CURRENT EZK25 EZK GROUND-PIN CURRENT (µa) GROUND-PIN CURRENT vs. INPUT VOLTAGE (EZK25) I LOAD = 5mA NO LOAD -4 GROUND-PIN CURRENT (µa) GROUND-PIN CURRENT vs. INPUT VOLTAGE (EZK5) I LOAD = 5mA NO LOAD OUTPUT VOLTAGE vs. INPUT VOLTAGE NO LOAD EZK5 EZK INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 3

4 Low-Noise, Low-Dropout, 2mA Typical Operating Characteristics (continued) (V IN = ((NOMINAL) +.5V) or 2.5V (whichever is greater), C IN = 1µF, C OUT = 2.2µF, C BP =.1µF, T A = +25 C, unless otherwise noted.) OUTPUT VOLTAGE vs. TEMPERATURE (EZK25) I LOAD = 5mA TEMPERATURE ( C) OUTPUT VOLTAGE vs. TEMPERATURE (EZK5) I LOAD = 5mA TEMPERATURE ( C) -8 GROUND-PIN CURRENT (µa) GROUND-PIN CURRENT vs. TEMPERATURE EZK5 I LOAD = 5mA EZK TEMPERATURE ( C) DROPOUT VOLTAGE vs. LOAD CURRENT (EZK25) T A = +25 C DROPOUT VOLTAGE vs. LOAD CURRENT (EZK5) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY C OUT = 1µF -12 DROPOUT VOLTAGE (mv) T A = +85 C T A = -4 C DROPOUT VOLTAGE (mv) T A = +85 C T A = +25 C T A = -4 C PSRR (db) I LOAD = 5mA C BP =.1µF C OUT = 1µF FREQUENCY (khz) OUTPUT NOISE SPECTRAL DENSITY (µv/ Hz) OUTPUT NOISE SPECTRAL DENSITY vs. FREQUENCY FREQUENCY (khz) C BP =.1µF I LOAD = 1mA C OUT = 1µF C OUT = 1µF -13 OUTPUT NOISE (µvrms) OUTPUT NOISE vs. BP CAPACITANCE BP CAPACITANCE (µf) C OUT = 1µF I LOAD = 1mA f = 1Hz to 1kHz EZK5 EZK3 EZK25-14 OUTPUT NOISE (µvrms) OUTPUT NOISE vs. LOAD CURRENT C OUT = 1µF C BP =.1µF f = 1Hz to 1kHz EZK5 EZK3 EZK

5 Low-Noise, Low-Dropout, 2mA Typical Operating Characteristics (continued) (V IN = ((NOMINAL) +.5V) or 2.5V (whichever is greater), C IN = 1µF, C OUT = 2.2µF, C BP =.1µF, T A = +25 C, unless otherwise noted.) OUTPUT NOISE 1Hz TO 1kHz REGION OF STABLE C OUT ESR vs. LOAD CURRENT C OUT = 1µF -17 5µV/div COUT ESR (Ω) 1 C OUT = 2.2µF.1 STABLE REGION 1ms/div EZK25, C OUT = 1µF, I LOAD = 1mA, C BP =.1µF LINE-TRANSIENT RESPONSE -18 LOAD-TRANSIENT RESPONSE -19 LOAD-TRANSIENT RESPONSE NEAR DROPOUT -2 4V 3V V IN 3.1V 3.V 2.99V 3.1V 3.V 2.99V 3.1V 3.V 2.999V 5mA I LOAD 5mA I LOAD 1µs/div EZK3, I LOAD = 5mA 1µs/div EZK3, V IN = +.5V, C IN = 1µF, I LOAD = TO 5mA 1µs/div EZK3, V IN = +.1V, C IN = 1µF, I LOAD = TO 5mA EZK25 SHUTDOWN EXIT DELAY -21 EZK5 SHUTDOWN EXIT DELAY -22 ENTERING SHUTDOWN -23 V C BP =.1µF V SHDN V C BP =.1µF V SHDN V 5V V SHDN 4V C BP =.1µF 1V C BP =.1µF V V V 5µs/div I LOAD = 5mA 5µs/div I LOAD = 5mA 5µs/div NO LOAD 5

6 Low-Noise, Low-Dropout, 2mA Pin Description PIN NAME FUNCTION 1 IN 2 GND 3 SHDN Regulator Input. Supply voltage can range from 2.5V to 6.5V. Bypass with a 1µF capacitor to GND (see the Capacitor Selection and Regulator Stability section). Ground. This pin also functions as a heatsink. Solder to a large pad or the circuit-board ground plane to maximize power dissipation. Active-Low Shutdown Input. A logic low reduces the supply current to 1nA and causes the output voltage to discharge to GND. Connect to IN for normal operation. 4 BP Reference-Noise Bypass. Bypass with a low-leakage,.1µf ceramic capacitor for reduced noise at the output. 5 OUT Regulator Output. Sources up to 2mA. Bypass with a 2.2µF (<.2Ω typical ESR) capacitor to GND. Detailed Description The is a low-noise, low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications. The part is available with preset output voltages from 2.5V to 5V in 1mV increments. This device can supply loads up to 2mA. As illustrated in Figure 1, the consists of a 1.25V reference, error amplifier, P-channel pass transistor, and internal feedback voltage-divider. 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. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled lower, which allows more current to pass to the output and increases the output voltage. If the feedback voltage is too high, the pass-transistor gate is pulled up, allowing less current to pass to the output. The output voltage is fed back through an internal resistor voltagedivider connected to the OUT pin. An external bypass capacitor connected to the BP pin reduces noise at the output. Additional blocks include a current limiter, reverse battery protection, thermal sensor, and shutdown logic. The also includes an autodischarge function, which actively discharges the output voltage to ground when the device is placed in shutdown mode. IN SHDN REVERSE BATTERY PROTECTION SHUTDOWN AND POWER-ON CONTROL ERROR AMP MOS DRIVER WITH I LIMIT P N OUT THERMAL SENSOR 1.25V REF GND BP Figure 1. Functional Diagram 6

7 Low-Noise, Low-Dropout, 2mA Output Voltage The is supplied with factory-set output voltages from 2.5V to 5V in 1mV increments. Except for the EZK29 and the EZK32 (which have an output voltage preset at 2.84V and 3.15V, respectively), the two-digit suffix allows the customer to choose the output voltage in 1mV increments. For example, the EZK33 has a preset output voltage of 3.3V (see the Selector Guide). Internal P-Channel Pass Transistor The 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. The P-channel MOSFET requires no base drive, which reduces quiescent current considerably. PNP-based regulators waste considerable current in dropout when the pass transistor saturates. They also use high base-drive currents under large loads. The does not suffer these problems and consumes only 1µA of quiescent current whether in dropout, lightload, or heavy-load applications (see the Typical Operating Characteristics). Current Limit The includes a current limiter, which monitors and controls the pass transistor s gate voltage, limiting the output current to 458mA. For design purposes, consider the current limit to be 22mA minimum to 1.1A maximum. The output can be shorted to ground indefinitely without damaging the part. Thermal-Overload Protection Thermal-overload protection limits total power dissipation in the. When the junction temperature exceeds T J = +155 C, the thermal sensor signals the shutdown logic, turning off the pass transistor and allowing the IC to cool. The thermal sensor turns the pass transistor on again after the IC s junction temperature cools by 15 C, resulting in a pulsed output during continuous thermal-overload conditions. Thermal-overload protection is designed to protect the in the event of fault conditions. For continual operation, do not exceed the absolute maximum junction-temperature rating of T J = +15 C. Operating Region and Power Dissipation The maximum power dissipation 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 = I OUT (V IN - ). The maximum power dissipation is: P MAX = (T J - T A ) / (θ JB + θ BA ) where T J - T A is the temperature difference between the die junction and the surrounding air, θ JB (or θ JC ) is the thermal resistance of the package, and θ BA is the thermal resistance through the PC board, copper traces, and other materials to the surrounding air. The GND pin of the performs the dual functions of providing an electrical connection to ground and channeling heat away. Connect the GND pin to ground using a large pad or ground plane. Reverse Battery Protection The has a unique protection scheme that limits the reverse supply current to 1mA when either V IN or V SHDN falls below ground. Their circuitry monitors the polarity of these two pins and disconnects the internal circuitry and parasitic diodes when the battery is reversed. This feature prevents device damage. Noise Reduction An external.1µf bypass capacitor at BP, in conjunction with an internal 2kΩ resistor, creates an 8Hz lowpass filter for noise reduction. The exhibits 3µV RMS of output voltage noise with C BP =.1µF and C OUT = 1µF. This is negligible in most applications. Startup time is minimized by a power-on circuit that precharges the bypass capacitor. The Typical Operating Characteristics section shows graphs of Noise vs. BP Capacitance, Noise vs. Load Current, and Output Noise Spectral Density. Applications Information Capacitor Selection and Regulator Stability Under normal conditions, use a 1µF capacitor on the input and a 2.2µF to 1µF capacitor on the output. Larger input capacitor values and lower ESRs provide better supply-noise rejection and line-transient response. Reduce noise and improve load-transient response, stability, and power-supply rejection by using large output capacitors. For stable operation over the full temperature range and with load currents up to 2mA, a 2.2µF (min) ceramic capacitor is recommended. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. With dielectrics such as Z5U and Y5V, it may be necessary to increase the capacitance by a factor of 2 or more to ensure stability at temperatures below -1 C. With X7R or X5R dielectrics, 2.2µF should be sufficient at all operating temperatures. A graph of the Region of Stable C OUT ESR vs. Load Current is shown in the Typical Operating Characteristics. 7

8 Low-Noise, Low-Dropout, 2mA Use a.1µf bypass capacitor at BP for low output voltage noise. Increasing the capacitance slightly decreases output noise but increases startup time. Values above.1µf provide no performance advantage and are not recommended (see the Shutdown Exit Delay graphs in the Typical Operating Characteristics). PSRR and Operation from Sources Other than Batteries The are designed to deliver low dropout voltages and low quiescent currents in battery-powered systems. Power-supply rejection is 63dB at low frequencies and rolls off above 1kHz. See the Power- Supply Rejection Ratio Frequency graph in the Typical Operating Characteristics. When operating from sources other than batteries, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors, and through passive filtering techniques. The Typical Operating Characteristics show the s line- and load-transient responses. Load-Transient Considerations The load-transient response graphs (see the Typical Operating Characteristics) show two components of the output response: a DC shift from the output impedance due to the load current change, and the transient response. Typical transient for a step change in the load current from to 5mA is 12mV. Increasing the output capacitor s value and decreasing the ESR attenuates the overshoot. Input-Output (Dropout) Voltage The regulator s minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the uses a P-channel MOSFET pass transistor, their dropout voltage is a function of drain-to-source on-resistance (R DS(ON) ) multiplied by the load current (see the Typical Operating Characteristics). Chip Information TRANSISTOR COUNT: 247 SUBSTRATE CONNECTED TO GND _ Selector Guide OUTPUT VOLTAGE (xy) CODE THIN SOT23 PRESET OUTPUT VOLTAGE (V) SOT TOP MARK THIN EZK25-T 2.5 ADRM EZK28-T 2.8 ADRJ EZK29-T 2.84 ADRN EZK3-T 3. ADRO EZK32-T 3.15 ADRP EZK33-T 3.3 ADRQ EZK36-T 3.6 ADRR EZK5-T 5. ADRS Other xy** x.y **Other xy between 2.5V and 5V are available in 1mV increments. Contact factory for other versions. Minimum order quantity is 25, units. 8

9 Low-Noise, Low-Dropout, 2mA Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to THIN SOT23.EPS 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. Maxim Integrated Products, 12 San Gabriel Drive, Sunnyvale, CA Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.