MIC547 5mA Low-Voltage µcap Linear Regulator General Description The MIC547 is an efficient and precise, low-voltage CMOS voltage regulator optimized for ultra-low noise applications. The MIC547 offers better than % initial accuracy and 85µA constant ground current over load (typically 85µA). The MIC547 provides a very low-noise output, ideal for RF applications where quiet voltage sources are required. A noise bypass pin is also available for further reduction of output noise. Designed specifically for handheld and battery-powered devices, the MIC547 provides a logic compatible enable pin. When disabled, power consumption drops nearly to zero. The MIC547 also works with low-esr ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. Key features include current limit, thermal shutdown, a pushpull output for faster transient response, and an active clamp to speed up device turnoff. Available in the 6-pin mm mm MLF package and the IttyBitty SOT--5 package, the MIC547 also offers a range of fixed output voltages. All support documentation can be found on Micrel s web site at www.micrel.com. Features Ultra-low noise Low-voltage outputs Load independent, ultra-low ground current: 85µA 5mA output current Current limiting Thermal shutdown Tight load and line regulation Zero off-mode current Stability with low-esr capacitors Fast transient response Logic-controlled enable input Applications Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers PCMCIA V CC and V PP regulation/switching Consumer/personal electronics SMPS post-regulator/dc-to-dc modules High-efficiency linear power supplies Typical Application Enable Shutdown EN EN (pin ) may be connected directly to IN (pin ). MIC547-x.xBM5 5 4 C BYP (optional) ENABLE SHUTDOWN MIC547-x.xBML EN 6 C BYP 5 4 (optional) Ultra-Low-Noise Regulator Application 8 Fortune Drive San Jose, CA 95 USA tel + (48) 944-8 fax + (48) 474- http://www.micrel.com February 6 M9999-46
Ordering Information Part Number Standard Marking Pb-Free Marking** Voltage* Junction Temp. Range Package MIC547-.5BM5 LU5 MIC547-.5YM5 LU5.5V 4ºC to +5ºC SOT--5 MIC547-.6BM5 LU6 MIC547-.6YM5 LU6.6V 4ºC to +5ºC SOT--5 MIC547-.8BM5 LU8 MIC547-.8YM5 LU8.8V 4ºC to +5ºC SOT--5 MIC547-.85BM5 LUJ MIC547-.85YM5 LUJ.85V 4ºC to +5ºC SOT--5 MIC547-.BM5 LU MIC547-.YM5 LU.V 4ºC to +5ºC SOT--5 MIC547-.BM5 LU MIC547-.YM5 LU.V 4ºC to +5ºC SOT--5 MIC547-.BM5 LU MIC547-.YM5 LU.V 4ºC to +5ºC SOT--5 MIC547-.4BM5 LU4 MIC547-.4YM5 LU4.4V 4ºC to +5ºC SOT--5 MIC547-.8BD5 NU8 MIC547-.8YD5 NU8.8V 4ºC to +5ºC Thin SOT--5 MIC547-.BD5 NU MIC547-.YD5 NU.V 4ºC to +5ºC Thin SOT--5 MIC547-.5BML U5 MIC547-.5YML U5.5V 4ºC to +5ºC 6-Pin mm x mm MLF MIC547-.6BML U6 MIC547-.6YML U6.6V 4ºC to +5ºC 6-Pin mm x mm MLF MIC547-.8BML U8 MIC547-.8YML U8.8V 4ºC to +5ºC 6-Pin mm x mm MLF MIC547-.85BML UJ MIC547-.85YML UJ.85V 4ºC to +5ºC 6-Pin mm x mm MLF * Other voltage options available, please contact Micrel Marketing for details. ** Over and under bar ( ) ( ) symbols may not be to scale. Pin Configuration EN GND IN EN 6 BYP LUxx/ NUxx 4 5 GND IN 5 4 NC OUT BYP OUT MIC547-x.xBM5 / YM5 MIC547-x.xBD5 / YM5 (Top View) MIC547-x.xBML / YML 6-Pin mm mm MLF (ML) (Top View) Pin Description Pin Number Pin Number Pin Name Pin Function SOT--5 MLF -6 IN Supply input. GND Ground. EN Enable/Shutdown (Input): CMOS-compatible input. Logic high = enable; logic low = shutdown. Do not leave open. 4 6 BYP Reference bypass: Connect external.pf capacitor to GND to reduce output noise. May be left open. 5 4 OUT Regulator output. 5 NC No internal connection. EP GND Ground. Internally connected to the exposed pad. Connect to ground pin. M9999-46 February 6
Absolute Maximum Ratings () Supply Input Voltage ( )...V to +7V Enable Input Voltage (V EN )...V to Junction Temperature (T J )... +5 C Storage Temperature (T S )... 65 C to +5 C Lead Temperature (soldering, 5 sec.)... 6 C ESD Rating () Operating Ratings () Input Voltage ( )... +.7V to +6V Enable Input Voltage (V EN )...V to Junction Temperature (T J )... 4 C to +5 C Package Thermal Resistance SOT--5 (θ JA )... 5 C/W mm mm MLF (θ JA )... 9 C/W Electrical Characteristics (4) = +.V; = V EN ; I OUT = µa; T J = 5 C, bold values indicate 4 C T J +5 C; unless noted. Symbol Parameter Conditions Min Typ Max Units V O Output Voltage Accuracy I OUT = ma % % ΔV LNR Line Regulation =.7V to 6V. +. %/V ΔV LDR Load Regulation I OUT =.ma to 5mA (5) % Load Regulation for.5v and.6v I OUT =.ma to 5mA, =.5V or.6v 4 % Dropout Voltage I OUT = 5mA (6) 5 mv I Q Quiescent Current V EN.4V (shutdown). µa I GND Ground Pin Current (7) I OUT = ma 85 5 µa I OUT = 5mA 85 5 µa PSRR Power Supply Rejection f khz 5 db I LIM Current Limit = V 6 ma e n Output Voltage Noise = µf, C BYP =.µf, µvrms f = Hz to khz Enable Input V IL Enable Input Logic-Low Voltage =.7V to 5.5V, regulator shutdown.8.4 V V IH Enable Input Logic-High Voltage =.7V to 5.5V, regulator enabled.6 V I EN Enable Input Current V IL.4V. µa V IH.6V. µa Shutdown Resistance Discharge 5 Ω Thermal Protection Thermal Shutdown Temperature 5 C Thermal Shutdown Hysteresis C Notes:. Exceeding the absolute maximum ratings may damage the device.. The device is not guaranteed to function outside its operating ratings.. Devices are ESD sensitive. Handling precautions recommended. 4. Specification for packaged product only. 5. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from.ma to 5mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 6. Dropout voltage is defined as the input-to-output differential at which the output voltage drops % below its nominal value measured av differential. For outputs below.7v, dropout voltage is the input-to-output voltage differential with the minimum input voltage.7v. Minimum input operating voltage is.7v. 7. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the load current plus the ground pin current. February 6 M9999-46
Typical Characteristics PSRR (db) Power Supply Rejection Ratio 9 8 C BYP = µf C BYP =.µf 7 6 C BYP = 5 4 I L = µa =.4V =.4V = µf Ceramic PSRR (db) 7 6 5.µF 4 Power Supply Rejection Ratio µf C BYP = I L = 5mA =.4V =.4V =µf Ceramic PSRR (db) 6 5 µf 4 I L = ma =.4V =.4V = µf Ceramic Power Supply Rejection Ratio C BYP =.µf 4 5 6 x x x 4 x 5 x FREQUENCY (Hz) 6 x x x x 4 x 5 x FREQUENCY (Hz) 6 x FREQUENCY (Hz) PSRR (db) 6 5 F 4 Power Supply Rejection Ratio. F C BYP = I L = 5mA =.4V =.4V = F Ceramic k k k M FREQUENCY (Hz) Hz) V/rt OUTPUT SPECTRAL NOISE DENSITY ( -5-6 Noise Performance C BYP = C -7 BYP =. F =.8V =.8V C -8 OUT = 4.7 F I LOAD = 5mA k k k M FREQUENCY (Hz) G ROUND CURRENT ( µ A ) 75 74 7 7 7 = + 7 - Ground Current vs. Output Current OUTPUT CURRENT (ma) Ground Pin Current Ground Pin Current Ground Pin Current G ROUND CURRENT ( µ A ) 8 6 4 I LOAD = µa -4-5 8 4 TEMPERATURE ( C) G ROUND CURRENT ( µ A ) 8 6 4 I LOAD = 5mA -4-5 8 4 TEMPERATURE ( C) G ROUND CURRENT ( µ A ) 8 6 4 I LOAD = µa 4 INPUT VOLTAGE (V) G ROUND CURRENT ( µ A ) 8 6 4 Ground Pin Current I LOAD = 5mA 4 INPUT VOLTAGE (V) VOLTAGE OUT (V) Dropout Characteristics I LOAD = µa I LOAD = 5mA 4 INPUT VOLTAGE (V) SHORT CIRCUIT CURRENT (ma) 5 4 Short Circuit Current vs. Temperature = -4-5 8 4 TEMPERATURE ( C) M9999-46 4 February 6
Typical Characteristics, cont. OUTPUT VOLTAGE (V).5.4 Output Voltage vs. Temperature I LOAD = µa. -4-5 8 4 TEMPERATURE ( C) T IME ( µ s ) 5 Rise Time 5 Prop Delay -5 Turn-On Time vs. Bypass Capacitance -4 - - = µf I LOAD = ma - BYPASS CAPACITOR(µF) February 6 5 M9999-46
Functional Characteristics Load Transient Response Line Transient Response = µf C BYP = =.4V =.4V.4V 4.4V ma µa = µf =.4V I LOAD = µa TIME (µs/div.) TIME (5µs/div.) M9999-46 6 February 6
Block Diagram IN Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation EN B Y P Thermal Sensor Undervoltage Lockout FAULT Error Amplifier Current Amplifier PULL UP PULL DOWN OUT ACTIVE SHUTDOWN GND February 6 7 M9999-46
Applications Information Enable/Shutdown The MIC547 comes with an active-high enable pin that can disable the regulator. Forcing the enable pin low disables the regulator and sends it into a zero off-mode-current state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor An input capacitor is not required for stability. A µf input capacitor is recommended when the bulk AC supply capacitance is more than inches away from the device, or when the supply is a battery. Output Capacitor The MIC547 requires an output capacitor for stability. The design requires µf or greater on the output to maintain stability. The capacitor can be a low-esr ceramic chip capacitor. The MIC547 has been designed to work specifically with low-cost, small chip capacitors. Tantalum capacitors can also be used for improved capacitance over temperature. The value of the capacitor can be increased without bound. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A.µF capacitor is recommended for applications that require low-noise outputs. The bypass capacitor can be increased without bound, further reducing noise and improving PSRR. Turn-on time remains constant with respect to bypass capacitance. Refer to the Typical Characteristics section for a graph of turn-on time vs. bypass capacitor. Transient Response The MIC547 implements a unique output stage to dramatically improve transient response recovery time. The output is a totem-pole configuration with a P-Channel MOSFET pass device and an N-Channel MOSFET clamp. The N-Channel clamp is a significantly smaller device that prevents the output voltage from overshooting when a heavy load is removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load (ma) to light load (85µA). Active Shutdown The MIC547 also features an active shutdown clamp, which is an N-Channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. Thermal Considerations The MIC547 is designed to provide 5mA of continuous current in a very small package. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. To determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: TJ( max) T A PD ( max) = θ JA T J (max) is the maximum junction temperature of the die, 5 C, and T A is the ambient operating temperature. θ JA is layout dependent; Table shows examples of junction-toambient thermal resistance for the MIC547. Package θ JA Recommended θ JA Square θ JC Minimum Footprint Copper Clad SOT--5 (M5) 5 C/W 85 C/W 45 C/W Table. SOT--5 Thermal Resistance The actual power dissipation of the regulator circuit can be determined using the equation: ( ) + PD = VIN VOUT IOUT VIN IGND Substituting P D (max) for P D and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC547-.4BM5 at room temperature with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: 5 C 5 C PD ( max) = 5 C/W P ( max) = 45mW D The junction-to-ambient thermal resistance for the minimum footprint is 5 C/W, from Table. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of.4v and an output current of 5mA, the maximum input voltage can be determined. Because this device is CMOS and the ground current is typically µa over the load range, the power dissipation contributed by the ground current is < % and can be ignored for this calculation. 45mW = (.4V) 5mA 45mW = 5mA 6mW 785mW = 5mA (max) = 5.V Therefore, a.4v application at 5mA of output current can accept a maximum input voltage of 5.V in a SOT--5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the Regulator Thermals section of Micrel s Designing with Low-Dropout Voltage Regulators handbook. Fixed Regulator Applications MIC547-x.xBM5 5 4 µf.µf Figure. Ultra-Low-Noise Fixed Voltage Application M9999-46 8 February 6
Figure includes a.µf capacitor for low-noise operation and shows EN (pin ) connected to IN (pin ) for an application where enable/shutdown is not required. = µf minimum. Enable Shutdown EN MIC547-x.xBM5 5 4.µF Figure. Low-Noise Fixed Voltage Application Figure is an example of a low-noise configuration where C BYP is not required. = µf minimum. February 6 9 M9999-46
Package Information SOT--5 (M) TSOT--5 (D5) M9999-46 February 6
6-Pin MLF (ML) MICREL, INC. 849 FORTUNE DRIVE SAN JOSE, CA 95 USA TEL + (48) 944-8 FAX + (48) 944-97 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser s use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. 4 Micrel, Incorporated. February 6 M9999-46