19-0990; Rev 2; 2/08 KIT ATION EVALU E L B AVAILA Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package The MAX8902A/MAX8902B low-noise linear regulators deliver up to 500mA of output current with only 16µVRMS of output noise in a 100kHz bandwidth. These regulators maintain their output voltage over a wide input range, requiring only 100mV of input-to-output headroom at full load. These LDOs maintain a low 80µA typical supply current, independent of the load current and dropout voltage. The regulator control circuitry includes a programmable soft-start circuit and short circuit, reverse current, and thermal-overload protection. Other features include an enable input and a power-OK output (MAX8902B only). The MAX8902A output voltage can be set to 1.5V, 1.8V, 2.0V, 2.5V, 3.0V, 3.1V, 3.3V, 4.6V, or 4.7V using the SELA and SELB inputs. The MAX8902B output voltage can be set between 0.6V and 5.3V with an external resistor voltage-divider. Features ♦ 1.7V to 5.5V Input Voltage Range ♦ 0.6V to 5.3V Output Voltage Range ♦ 16µVRMS Output Noise, 10Hz to 100kHz ♦ 80µA Operating Supply Current ♦ 92dB PSRR at 5kHz ♦ Guaranteed 500mA Output Current ♦ ±1.5% Output Accuracy Over Load, Line, and Temperature ♦ 100mV (max) Dropout at 500mA Load ♦ < 1µA Shutdown Supply Current ♦ 700mA Short-Circuit Protection ♦ Thermal-Overload Protection ♦ Output-to-Input Reverse Current Protection ♦ 2mm x 2mm x 0.8mm TDFN Package Applications Ordering Information Notebook Computers PART MP3 and Portable Media Players FEATURES Wireless Headphones GPS Portable Navigation Devices Smartphones TOP MARK PKG CODE MAX8902AATA+ Pin-selectable output voltage ABG T822-1 MAX8902BATA+ Adjustable output voltage ABH T822-1 +Denotes a lead-free, RoHS-compliant package. Note: All devices are in an 8-pin, 2mm x 2mm TDFN package with an exposed paddle and operate over the -40°C to +125°C automotive temperature range. Typical Operating Circuits INPUT 4.7V TO 5.5V INPUT 1.7V TO 5.5V OUTPUT 4.6V OUTPUT ADJUSTABLE 0.6V TO 5.3V OUT IN OUT IN 10μF 10μF 0.01μF MAX8902A EN ON OFF BYP 10μF BYP ON OFF OUTS 0.01μF MAX8902B 10μF R1 EN FB LOGIC SUPPLY R2 SELA R3 100kΩ SELB TO μC EP GND GS POK EP GND Pin Configurations appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX8902A/MAX8902B General Description MAX8902A/MAX8902B Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package ABSOLUTE MAXIMUM RATINGS BYP, EN, IN, OUT, SELA, SELB, POK to GND, GS to GND, FB, OUTS to GND .....................................................-0.3V to +6.0V Output Short-Circuit Duration.....................................Continuous Continuous Power Dissipation (TA = +70°C) 8-Pin, 2mm x 2mm TDFN (derate 11.9mW/°C above +70°C) .............................953.5mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature Range ............................-40°C to +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 (VIN = VEN = 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 5.5 V 1.7 V IN Input Voltage Range Input Undervoltage Lockout 1.7 VIN rising, 100mV typical hysteresis 1.5 1.6 Output Voltage Range VIN ≥ VOUT + 0.1V 0.6 5.3 V Output Voltage Accuracy VIN = 1.7V to 5.5V for VOUT ≤ 1.4V, VIN = (VOUT + 0.3V) to 5.5V for VOUT > 1.4V, IOUT = 0.1mA to 500mA -1.5 +1.5 % Load Regulation IOUT = 0.1mA to 500mA 0.02 % Line Regulation VIN = 1.7V to 5.5V for VOUT ≤ 1.4V, VIN = (VOUT + 0.3V) to 5.5V for VOUT > 1.4V, IOUT = 200mA 0.04 % Dropout Voltage (Note 2) IOUT = 500mA Current Limit VOUT = 95% of regulation, VIN = VOUT + 0.5V Output Noise IOUT = 100mA, f = 10Hz to 100kHz, CBYP = 0.01µF OUT Power-Supply Rejection Ratio VIN ≥ 3.6V, TA ≤ +85°C IOUT = 10mA 50 VIN ≥ 3.6V, TA ≤ +125°C VIN = 1.7V 100 120 mV 150 600 700 800 16 f = 5kHz 92 f = 10kHz 85 f = 100kHz 62 mA µVRMS dB OUTS (MAX8902A only) OUTS Input Bias Current In regulation 0.5 7.0 µA V FB (MAX8902B only) FB Threshold Accuracy VIN = 1.7V to 5.5V, IOUT = 0.1mA to 500mA FB Input Bias Current VFB = 0.6V TA = +25°C 0.591 0.600 0.609 -0.1 0.02 +0.1 TA = -40°C 0.03 µA BYP BYP Capacitor Range Regulator remains stable BYP Startup Current From BYP to GND during startup 2 1 100 50 _______________________________________________________________________________________ nF µA Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package (VIN = VEN = 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX 80 120 160 +1 UNITS GND GND Supply Current IOUT = 0mA GND Shutdown Current VIN = 5.5V, EN = 0V TA < +85°C TA < +125°C TA = +25°C 0.001 TA = +85°C 0.01 µA µA SELA/SELB (MAX8902A only) Select Input Resistance Select Input Capacitance When shorted to GND or VIN 500 When open 1 Ω MΩ When open 10 pF EN EN rising Enable Input Threshold VIN = 1.7V to 5.5V Enable Input Bias Current VEN = 0V to 5.5V EN falling, TA < +85°C EN falling, TA < +125°C TA = +25°C 0.8 0.4 0.38 0.7 0.7 -1 0.001 TA = +85°C 1.2 V +1 0.01 µA POK (MAX8902B only) POK Threshold OUT voltage when POK switches POK Voltage, Low IPOK = 1mA POK Leakage Current POK = 5.5V, VEN = 0V OUT rising 88 OUT falling TA = +25°C TA = +85°C 91 94 % 10 100 mV 0.001 +1 88 -1 0.01 % µA THERMAL SHUTDOWN TJ rising 165 TJ falling 150 Load Transient IOUT = 50mA to 500mA to 50mA, tRISE = tFALL= 1µs 25 mV/P-P Line Transient VIN = 4V to 5V to 4V, tRISE = tFALL = 5µs, IOUT = 500mA 3 mV/P-P IN-to-OUT Reverse Voltage Turnoff Threshold IN falling below OUT 10 mV Thermal Shutdown Threshold °C OUTPUT TRANSIENT Note 1: All devices are production tested at TA = +25°C. Specifications over the operating temperature range are guaranteed by design and characterization. Note 2: The dropout voltage is defined VIN - VOUT, when VOUT is 5% lower than the value of VOUT when VIN = VOUT + 0.5V. _______________________________________________________________________________________ 3 MAX8902A/MAX8902B ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (MAX8902A, VIN = 3.6V, VOUT = 2.5V, TA = +25°C, unless otherwise noted.) 80 60 40 2.504 2.503 2.502 20 2.501 0 2.500 2.510 200mA LOAD 2.508 2.506 OUTPUT VOLTAGE (V) 3.6V INPUT 2.505 OUTPUT VOLTAGE (V) 100 MAX8902A/02B toc02 2.506 MAX8902A/02B toc01 120 INPUT CURRENT (μA) LINE REGULATION LOAD REGULATION 140 MAX8902A/02B toc03 QUIESCENT CURRENT EN = HIGH, NO LOAD 2.504 2.502 2.500 2.498 2.496 2.494 2.492 0 1 2 3 4 2.490 0 5 100 200 300 400 500 1.5 2.5 LOAD CURRENT (mA) INPUT VOLTAGE (V) LOAD TRANSIENT RESPONSE 50mA TO 500mA TO 50mA 3.5 4.5 5.5 INPUT VOLTAGE (V) STARTUP WAVEFORM LOAD TRANSIENT RESPONSE MAX8902A/02B toc05 MAX8902A/02B toc04 MAX8902A/02B toc06 2V/div 5V 100mV/div VOUT 5V VEN 500mV/div 2V/div VIN 4V 200mA/div 2mV/div VOUT VOUT 200mA/div IOUT 5Ω LOAD CBYP = 0.01μF 40ms/div 10μs/div 100μs/div DROPOUT VOLTAGE vs. LOAD CURRENT PSRR vs. FREQUENCY MAX8902A LDO OUTPUT-NOISE SPECTRAL DENSITY vs. FREQUENCY -30 PSRR (dB) 50 -20 40 30 -40 -50 -60 1E+3 100E+0 -70 20 10E+3 MAX8902A/02B toc09 60 MAX8902A/02B toc08 70 0 -10 NOISE DENSITY (nV √Hz) 3.6V INPUT, 4.6V OUTPUT PRESET THE SLOPE OF THE LINE INDICATES A 129mΩ ON-RESISTANCE IN DROPOUT MAX8902A/02B toc07 80 -80 10 -90 -100 0 0 100 200 300 LOAD CURRENT (mA) 4 IIN 2.5V OUTPUT 5Ω LOAD tRISE = tFALL = 1μs DROPOUT VOLTAGE (mV) MAX8902A/MAX8902B Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package 400 500 10E+0 10 100 1k FREQUENCY (Hz) 10k 100k 10 100 1k 10k FREQUENCY (Hz) _______________________________________________________________________________________ 100k 1M Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package PIN NAME FUNCTION MAX8902A MAX8902B 1 IN IN 2 GND GND 3 EN EN Enable Input. A logic-low drives the output low through a 3kΩ resistor and reduces the supply current to less than 1µA. Drive logic-high or connect to IN for normal operation. SELA — Output Voltage Select Input. Connect SELA to GND, IN, or leave unconnected. The states of SELA and SELB are sampled when the regulator turns on and the output voltage is set as shown in Table 2. — GS Internally Used. Connect GS to GND. SELB — Output Voltage Select Input. Connect SELB to GND, IN, or leave unconnected. The states of SELA and SELB are sampled when the regulator turns on and the output voltage is set as shown in Table 2. — POK Power-OK Output. Open-drain output that goes low when the output is above 91% of the nominal regulation voltage. POK is high impedance in shutdown or when the output is below the regulation voltage. OUTS — Output Sense Input. Connect OUTS to the load at a point where accurate regulation is required, or connect OUTS directly to OUT. — FB Feedback Input. Connect FB to the center of a resistor voltage-divider connected between OUT and GND to set the output voltage. VFB regulates to 0.6V. 4 Regulator Power Input. Connect IN to a supply from 1.7V to 5.5V. Bypass IN with a 10µF ceramic capacitor to GND. Ground 5 6 7 BYP BYP Bypass Input. Connect a 0.01µF ceramic capacitor from BYP to OUT to achieve 16µVRMS output noise. Adjust the value of this capacitor to control the output slew rate during startup. Slew Rate = (5V / ms) x (0.01µF / CBYP) 8 OUT OUT — EP EP Regulator Output. Sources up to 500mA at the output regulation voltage. Bypass with a 10µF (< 0.03Ω ESR) capacitor to GND. Exposed Paddle. Connect the exposed paddle to a ground plane to provide heat sinking. Detailed Description The MAX8902A/MAX8902B low-noise, low-dropout linear regulators deliver up to 500mA of output current with only 16µVRMS of output noise in a 100kHz bandwidth. These regulators maintain their output voltage over a wide input range, requiring only 100mV of inputto-output headroom at full load. The MAX8902 maintains a low 80µA typical supply current, independent of the load current and dropout voltage. The regulator control circuitry includes a programmable soft-start circuit and short circuit, reverse current, and thermal-overload protection. Other features include an enable input and a power-OK (POK) output (MAX8902B only). A simplified functional diagram is shown in Figure 1. The MAX8902A output voltage can be set to 1.5V, 1.8V, 2.0V, 2.5V, 3.0V, 3.1V, 3.3V, 4.6V, or 4.7V using the SELA and SELB inputs. The MAX8902B output voltage can be set between 0.6V and 5.3V with an external resistor voltage-divider. Enable (EN) The MAX8902A/MAX8902B include an enable input, EN. Pull EN low to shut down the output, or drive EN high to enable the output. If shutdown is not needed, connect EN to IN. _______________________________________________________________________________________ 5 MAX8902A/MAX8902B Pin Description MAX8902A/MAX8902B Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package THERMAL PROTECTION IN CURRENT LIMIT EN REVERSE CURRENT PROTECTION CONTROL OUT BYP BYP GND REF 0.6V EA POK MAX8902A MAX8902B 0.54V FB MAX8902B ONLY OUTS MAX8902A ONLY SELA 990kΩ VOLTAGE SELECT SELB Figure 1. Simplified Functional Diagram Bypass (BYP) The capacitor connected from BYP to OUT filters the noise of the reference, feedback resistors, and regulator input stage and provides a high-speed feedback path for improved transient response. A 0.01µF capacitor rolls off input noise at approximately 32Hz. 6 The slew rate of the output voltage during startup is also determined by the BYP capacitor. A 0.01µF capacitor sets the slew rate to 5V / ms. This startup rate results in a 50mA slew current drawn from the input at startup to charge the 10µF output capacitance. _______________________________________________________________________________________ Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package Table 1. 2mm x 2mm TDFN Package Thermal Characteristics CONTINUOUS POWER DISSIPATION 953.5mW DERATE 11.9mW/°C ABOVE +70°C θJA* 83.9°C/W θJC 36.6°C/W *θJA is specified according to the JESD51 standard with the part mounted on a multilayer PCB. Table 2. MAX8902A Output Voltages Protection Features The MAX8902A/MAX8902B are fully protected from an output short circuit by a current-limiting and thermaloverload circuit. If the output is shorted to GND, the output current is limited to 700mA (typ). Under these conditions, the part quickly heats up. When the junction temperature reaches +165°C, a thermal-limit circuit shuts off the output device. When the junction cools to +150°C, the output turns back on in an attempt to reestablish regulation. While the fault persists, the output current cycles on and off, as the junction temperature slews between +150°C and +165°C. The MAX8902A/MAX8902B are also protected against reverse current when the output voltage is higher than the input. In the event that extra output capacitance is used at the output, a power-down transient at the input would normally cause a large reverse current through a conventional regulator. The MAX8902A/MAX8902B include a reverse voltage detector that trips when IN drops 10mV below OUT, shutting off the regulator and opening the pMOS body diode connection, preventing any reverse current. Thermal Considerations The MAX8902A/MAX8902B are packaged in an 8-pin, 2mm x 2mm TDFN package with an exposed paddle. The exposed paddle is the main path for heat to leave the IC, and therefore, must be connected to a ground plane with thermal vias to allow heat to dissipate from the device. Thermal properties of the IC package are given in Table 1. OUTPUT VOLTAGE (V) SELA STATE SELB STATE 1.5 IN Unconnected 1.8 Unconnected GND 2.0 Unconnected IN 2.5 Unconnected Unconnected 3.0 GND GND 3.1 GND IN 3.3 GND Unconnected 4.6 IN GND 4.7 IN IN are sampled only at startup. The regulation voltage can be set to a different level by cycling EN or IN momentarily to GND. Setting the Output Voltage (MAX8902B) The MAX8902B uses external feedback resistors to set the output regulation voltage as shown in Figure 3. The output can be set from 0.6V to 5.3V. Set the lower feedback resistor (R2) to 120kΩ or less to minimize FB input bias current error. Then calculate the value of the upper feedback resistor (R1) as follows: ⎛V ⎞ R1 = R2 × ⎜ OUT − 1⎟ ⎝ VFB ⎠ where VFB is the feedback regulation voltage of 0.6V. Selecting the Output Voltage (MAX8902A) Power-OK (MAX8902B) The MAX8902A output can be set to one of nine voltages by shorting or opening the SELA and SELB inputs, as shown in Table 2. SELA and SELB should be connected to GND, IN, or left unconnected. Alternatively, they may be driven high, low, or open with external logic; however, the states of SELA and SELB The MAX8902B includes an additional open-drain output, POK, that pulls low to indicate the output voltage is in regulation. During startup, POK is high impedance until the output voltage rises to 91% of its regulation level. If an overload occurs at the output, or the output is shut down, POK is high impedance. _______________________________________________________________________________________ 7 MAX8902A/MAX8902B The BYP capacitor value can be adjusted from 0.001µF to 0.1µF to change the startup slew rate according to the following formula: Startup slew rate = (5V / ms) x (0.01µF / CBYP) Note that this slew rate applies only at startup, and that recovery from a short circuit occurs at a slew rate approximately 500 times slower. Also note that, being a low-frequency filter node, BYP is sensitive to leakage. BYP leakage currents above 10nA cause measurable inaccuracy at the output and should be avoided. MAX8902A/MAX8902B Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package INPUT 4.7V TO 5.5V INPUT 1.7V TO 5.5V OUTPUT 4.6V OUTPUT ADJUSTABLE 0.6V TO 5.3V OUT IN OUT IN 10μF 10μF 0.01μF MAX8902A EN ON OFF 10μF BYP OFF 10μF R1 BYP ON EN FB LOGIC SUPPLY OUTS 0.01μF MAX8902B R2 SELA R3 100kΩ SELB TO μC EP GS POK GND EP Figure 2. MAX8902A Fixed-Output Application Circuit Figure 3. MAX8902B Adjustable-Output Application Circuit Pin Configurations Input Capacitor A 10µF ceramic capacitor is recommended for the input. Select a capacitor that maintains its capacitance over temperature and DC bias. Capacitors with X5R or X7R temperature characteristics generally perform well. Output Capacitor A minimum of 10µF of capacitance is required at OUT to ensure stability. Select a ceramic capacitor that maintains its capacitance over temperature and DC bias. Capacitors with X5R or X7R temperature characteristics generally perform well. GND TOP VIEW MAX8902A IN 1 + GND 2 EN 3 SELA 4 EP MAX8902B 8 OUT IN 1 7 BYP GND 2 6 OUTS EN 3 5 SELB GS 4 TDFN-EP 2mm x 2mm + 8 OUT 7 BYP 6 FB EP 5 POK TDFN-EP 2mm x 2mm EP = EXPOSED PADDLE. Chip Information PROCESS: BiCMOS 8 _______________________________________________________________________________________ Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package 8L TDFN EXPOSED PADS.EPS PACKAGE OUTLINE 8L TDFN EXPOSED PAD, 2x2x0.80mm 21-0168 E 1 2 _______________________________________________________________________________________ 9 MAX8902A/MAX8902B 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 www.maxim-ic.com/packages.) MAX8902A/MAX8902B Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) COMMON DIMENSIONS SYMBOL A MIN. MAX. 0.70 0.80 D 1.90 2.10 E 1.90 2.10 A1 0.00 0.05 L 0.20 0.40 k 0.25 MIN. A2 0.20 REF. PACKAGE VARIATIONS PKG. CODE N D2 E2 e b r [(N/2)-1] x e T822-1 8 0.70±0.10 1.30±0.10 0.50 TYP. 0.25±0.05 0.125 1.50 REF T822-2 8 0.80±0.10 1.20±0.10 0.50 TYP. 0.25±0.05 0.125 1.50 REF PACKAGE OUTLINE 8L TDFN EXPOSED PAD, 2x2x0.80mm 21-0168 10 ______________________________________________________________________________________ E 2 2 Low-Noise 500mA LDO Regulators in a 2mm x 2mm TDFN Package PAGES CHANGED REVISION NUMBER REVISION DATE 0 9/07 Initial release 1 1/08 Changed input capacitor value from 4.7µF to 10µF. 1, 5, 8 2 2/08 Changed BP to BYP 2, 4–8 DESCRIPTION — 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, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11 © 2008 Maxim Integrated Products Boblet is a registered trademark of Maxim Integrated Products, Inc. MAX8902A/MAX8902B Revision History