LP2986AIMM-3.3 Schematic ( PDF Datasheet ) - National Semiconductor

Teilenummer	LP2986AIMM-3.3
Beschreibung	Micropower/ 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator
Hersteller	National Semiconductor
Logo
Gesamt 14 Seiten March 1999 LP2986 Micropower, 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator General Description The LP2986 is a 200 mA precision LDO voltage regulator which offers the designer a higher performance version of the industry standard LP2951. Using an optimized VIP™ (Vertically Integrated PNP) pro- cess, the LP2986 delivers superior performance: Dropout Voltage: Typically 180 mV @ 200 mA load, and 1 mV @ 1 mA load. Ground Pin Current: Typically 1 mA @ 200 mA load, and 200 µA @ 10 mA load. Sleep Mode: The LP2986 draws less than 1 µA quiescent current when shutdown pin is pulled low. Error Flag: The built-in error flag goes low when the output drops approximately 5% below nominal. Precision Output: The standard product versions available can be pin-strapped (using the internal resistive divider) to provide output voltages of 5.0V, 3.3V, or 3.0V with guaran- teed accuracy of 0.5% (“A” grade) and 1% (standard grade) at room temperature. Features n Ultra low dropout voltage n Guaranteed 200 mA output current n SO-8 and mini-SO8 surface mount packages n <1 µA quiescent current when shutdown n Low ground pin current at all loads n 0.5% output voltage accuracy (“A” grade) n High peak current capability (400 mA typical) n Wide supply voltage range (16V max) n Overtemperature/overcurrent protection n −40˚C to +125˚C junction temperature range Applications n Cellular Phone n Palmtop/Laptop Computer n Camcorder, Personal Stereo, Camera Block Diagram VIP™ is a trademark of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS012935 DS012935-1 www.national.com Typical Performance Characteristics Unless otherwise specified: TA = 25˚C, COUT = 4.7 µF, CIN = 2.2 µF, S/D is tied to VIN, VIN = VO(NOM) + 1V, IL = 1 mA. VOUT vs Temperature Dropout Voltage vs Temperature Dropout Voltage vs Load Current DS012935-8 Dropout Characteristics DS012935-9 DS012935-10 Ground Pin Current vs Temperature and Load DS012935-13 Ground Pin Current vs Load Current DS012935-12 www.national.com 6 DS012935-11 6 Page Application Hints (Continued) A lead compensation capacitor (CF) must also be used to place a zero in the loop response at about 50 kHz. The value for C F can be found using: CF = 1/(2π x R1 x 50k) A good quality capacitor must be used for CF to ensure that the value is accurate and does not change significantly over temperature. Mica or ceramic capacitors can be used, as- suming a tolerance of ±20% or better is selected. If a ceramic is used, select one with a temperature coeffi- cient of NPO, COG, Y5P, or X7R. Capacitor types Z5U, Y5V, and Z4V can not be used because their value varies more that 50% over the −25˚C to +85˚C temperature range. SHUTDOWN INPUT OPERATION The LP2986 is shut off by driving the Shutdown input low, and turned on by pulling it high. If this feature is not to be used, the Shutdown input should be tied to VIN to keep the regulator output on at all times. To assure proper operation, the signal source used to drive the Shutdown input must be able to swing above and below the specified turn-on/turn-off voltage thresholds listed as VH and VL, respectively (see Electrical Characteristics). It is also important that the turn-on (and turn-off) voltage sig- nals applied to the Shutdown input have a slew rate which is not less than 40 mV/µs. CAUTION: the regulator output state can not be guaranteed if a slow-moving AC (or DC) signal is applied that is in the range between VH and VL. REVERSE INPUT-OUTPUT VOLTAGE The PNP power transistor used as the pass element in the LP2986 has an inherent diode connected between the regu- lator output and input. During normal operation (where the input voltage is higher than the output) this diode is reverse-biased. However, if the output is pulled above the input, this diode will turn ON and current will flow into the regulator output. In such cases, a parasitic SCR can latch which will allow a high current to flow into VIN (and out the ground pin), which can damage the part. In any application where the output may be pulled above the input, an external Schottky diode must be connected from VIN to VOUT (cathode on VIN, anode on VOUT), to limit the re- verse voltage across the LP2986 to 0.3V (see Absolute Maximum Ratings). www.national.com 12 12 Page
Seiten	Gesamt 14 Seiten
PDF Download	[ LP2986AIMM-3.3 Schematic.PDF ]

Link teilen

Besondere Datenblatt

Teilenummer	Beschreibung	Hersteller
LP2986AIMM-3.0	Micropower/ 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator	National Semiconductor
LP2986AIMM-3.0	Micropower/ 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator	National Semiconductor
LP2986AIMM-3.3	Micropower/ 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator	National Semiconductor
LP2986AIMM-3.3	Micropower/ 200 mA Ultra Low-Dropout Fixed or Adjustable Voltage Regulator	National Semiconductor

Teilenummer	Beschreibung	Hersteller
CD40175BC	Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.	Fairchild Semiconductor
KTD1146	EPITAXIAL PLANAR NPN TRANSISTOR.	KEC