Document
LP3997 Micropower 250mA CMOS LDO Regulator with Error Flag / Power-On-Reset
PRELIMINARY
May 2004
LP3997 Micropower 250mA CMOS LDO Regulator with Error Flag / Power-On-Reset
General Description
The LP3997 regulator is designed to meet the requirements of portable, battery-powered systems, providing accurate output voltage, low noise, and low quiescent current. The LP3997 provides 3.3V output at up to 250mA load current. When switched in shutdown mode, the power consumption is virtually zero. The LP3997 is designed to be stable with space saving ceramic capacitors as small as 1µF. The LP3997 also includes an out-of-regulation error flag. When the output is more than 5% below its nominal voltage, the error flag sets to low. If a capacitor is connected to device’s delay pin, a delayed power-on reset signal will be generated. n n n n n Less than 70µA Typical IQ at 250mA. Virtually Zero IQ (Disabled). Themal and Short Circuit Protection. 3.3V Output. For other voltage options, please contact your local NSC sales office.
Package
8 Lead MSOP
For other package options contact your NSC sales office.
Applications
n n n n n Portable Consumer Electronics Cellular Handsets Laptop and Palm Computers PDA’s Digital Cameras
Features
n Low, 140mV, Dropout at 250mA Load. n Stable with Ceramic Capactor. n Low Noise, with Bypass Capacitor.
Typical Application Circuit
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© 2004 National Semiconductor Corporation
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LP3997
Functional Block Diagram
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Pin Descriptions
Pin # 1 2 3 4 5 6 7 Name CNOISE DELAY GND VIN VOUT SENSE ERROR Description Noise bypass pin. For low noise applications a 0.1µF or larger ceramic capacitor should be connected from this pin to ground A capacitor connected from this pin to ground will allow a delayed power-on-reset signal at the ERROR (pin 7) output. Ground pin. Local ground for CNOISE and COUT. Input supply pin. Bypass this with a 1µF capacitor. Output voltage, Connect COUT between this pin and ground. Connect this pin to VOUT (pin 5). This open drain output is an error flag output which goes low when VOUT drops 5% below it nominal voltage. This pin also provides a power-on-reset signal if a capacitor is connected to the DELAY pin. Shutdown. Disables the regulator when less than 0.4V is applied. Enables the regulator when greater than 0.9V. The Shutdown pin is pulled down internally by a 6MΩ resistor.
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SD
Connection Diagram
8 Lead MSOP NS Package Number MUA08A
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LP3997
Ordering Information
For MSOP Package Please contact Sales Office for Availability Output Voltage (V) 3.3 Grade STD LP3997 Supplied as 1000 Units, Tape and Reel LP3997MM-3.3 LP3997 Supplied as 3500 Units, Tape and Reel LP3997MMX-3.3 Package Marking
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LP3997
Absolute Maximum Ratings
(Notes 2, 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage Output Voltage SD Input Voltage Junction Temperature Lead/Pad Temp. MSOP Storage Temperature Continuous Power Dissipation Internally Limited (Note 3) 260˚C -65 to 150˚C -0.3 to 6.5V -0.3 to (VIN + 0.3V) to 6.5V (max) -0.3 to (VIN + 0.3V) to 6.5V (max) 150˚C
ESD (Note 4) Human Body Model Machine Model 2KV 200V
Operating Ratings
(Note 1) Input Voltage Shutdown Input Voltage Junction Temperature Ambient Temperature TA Range (Note 5) 2V to 6V 0 to (VIN + 0.3V) to 6.5V (max) -40˚C to 125˚C -40˚C to 85˚C
Thermal Properties
(Note 1) Junction To Ambient Thermal Resistance (Note 6) θJA (MSOP) 210˚C/W
Electrical Characteristics
Unless otherwise noted, VSD =950mV, VIN = VOUT + 1.0V, CIN = 2.2 µF, IOUT = 1 mA, COUT =2.2 µF and CNOISE = 0.1 µF. Typical values and limits appearing in normal type apply for TJ = 27˚C. Limits appearing in boldface type apply over the full temperature range for operation, −40 to +125˚C. (Note 11) Symbol VIN ∆VOUT Parameter Input Voltage Output Voltage Tolerance Line Regulation Error Load Regulation Error ILOAD IQ Load Current Quiescent Current Over full line and load regulation. VIN = (VOUT(NOM) + 1.0V) to 6.0V, IOUT = 1mA IOUT = 1mA to 250mA (Notes 7, 8) VSD = 950mV, IOUT = 0mA VSD = 950mV, IOUT = 250mA VSD = 0.4V ISC IOUT PSRR eN Short Circuit Current Limit Maximum Output Current Power Supply Rejection Ratio Output noise Voltage (Note 8) f = 1kHz, IOUT = 1mA to 150mA f = 10kHz, IOUT = 150mA BW = 10Hz to 100kHz, VIN = VOUTnom +1V Temperature Hysteresis Enable Control Characteristics ISD VIL VIH VTH Maximum Input Current at VSD Input Low Input Threshold High Input Threshold Power Good Trip Threshold VSD = 0.0V VSD = 6V (Note 10) VIN = 2V to 6V VIN = 2V to 6V VIN Rising 95 0.95 95 97 0.001 1 0.1 2 0.4 µA V V %VOUT w/o CNOISE CNOISE = 0.1µF 64 39 180 µVRMS 100 160 20 ˚C (Note 9) 45 65 0.002 650 250 1000 mA mA dB µA 0.05 20 0 Conditions Typ Limit Min 2 -3 Max 6 +3 Units V % %/V µV/mA µA
TSHUTDOWN Thermal Shutdown
Error Flag Characteristics
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