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Details, datasheet, quote on part number:LM2787TPX
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| Part: | LM2787TPX |
| Category: | Power Management => Regulators => Switching Regulators => Switched Capacitor Converters |
| Description: | LM2787 - Low Noise Regulated Switched Capacitor Voltage Inverter in Micro Smd, Package: Microsmd, Pin Nb=8 |
| Company: | National Semiconductor Corporation |
| Datasheet: | Download LM2787TPX datasheet File size : 239 kB |
| Request For quote: | Find where to buy LM2787TPX
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Datasheet text preview:
LM2787 Low Noise Regulated Switched Capacitor Voltage Inverter in micro SMD
April 2003
LM2787 Low Noise Regulated Switched Capacitor Voltage Inverter in micro SMD
General Description
The LM2787 CMOS Negative Regulated Switched Capacitor Voltage Inverter delivers a very low noise adjustable output for an input voltage in the range of +2.7V to +5.5V. Four low cost capacitors are used in this circuit to provide up to 10mA of output current. The regulated output for the LM2787 is adjustable between -1.5V and -5.2V. The LM2787 operates at 260 kHz (typical) switching frequency to reduce output resistance and voltage ripple. With an operating current of only 400 µA (charge pump power efficiency greater than 90% with most loads) and 0.05 µA typical shutdown current, the LM2787 provides ideal performance for cellular phone power amplifier bias and other low current, low noise negative voltage needs. The device comes in small 8-Bump micro SMD and thin micro SMD packages.
Features
n Inverts and regulates the input supply voltage n Small 8-Bump micro SMD and thin micro SMD packages n 91% typical charge pump power efficiency at 10mA n Low output ripple n Shutdown lowers Quiescent current to 0.05 µA (typical)
Applications
n n n n n Wireless Communication Systems Cellular Phone Power Amplifier Biasing Interface Power Supplies Handheld Instrumentation Laptop Computers and PDA's
Typical Application Circuit and Connection Diagram
10131325
8-Bump micro SMD (Top View)
10131302
© 2003 National Semiconductor Corporation
DS101313
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LM2787
Ordering Information micro SMD
Device Order Number LM2787BP LM2787BPX Package Number BPA08CCB BPA08CCB Package Marking* S8 S8 Supplies As Tape and Reel (250 units/reel) Tape and Reel (3000 units/reel)
Thin micro SMD
Device Order Number LM2787TP LM2787TPX Package Number TPA08CCA TPA08CCA Package Marking* S8 S8 Supplies As Tape and Reel (250 units/reel) Tape and Reel (3000 units/reel)
Note: * The small physical size of the micro SMD package does not allow for the full part number marking. Devices will be marked with the designation shown in the column Package Marking.
Pin Descriptions
Pin No. A1 B1 C1 C2 C3 B3 A3 A2 Name Cap+ VIN VOUT VFB SD VNEG Cap- GND Positive terminal for C1. Positive power supply input. Regulated negative output voltage. Feedback input. Connect VFB to an external resistor divider between VOUT and a positive adjust voltage VADJ (0VADJVIN). DO NOT leave unconnected. Active low, logic-level shutdown input. Negative unregulated output voltage. Negative terminal for C1. Ground. Function
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LM2787
Absolute Maximum Ratings
(Note 1)
TJMAX (Note 3) JA (Note 3) Operating Input Voltage Range Operating Output Current Range Operating Ambient Temp. Range Operating Junction Temp. Range Storage Temperature Lead Temp. (Soldering, 10 sec.) ESD Rating (Note 4)
150°C 220°C/W 2.7V to 5.5V 0mA to 10mA -40°C to 85°C -40°C to 110°C -65°C to 150°C 300°C 2kV
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VIN to GND or GND to OUT) SD VNEG and VOUT Continuous Output Current VOUT Short-Circuit Duration to GND (Note 2) Continuous Power Dissipation (TA = 25°C) (Note 3) + 5.8V (GND - 0.3V) to (VIN + 0.3V) 10mA 1 sec. 600mW
Electrical Characteristics
Limits with standard typeface apply for TJ = 25°C, and limits in boldface type apply over the full temperature range. Unless otherwise specified VIN = 3.6V, C1 = C2 = C3 = 1µF. Symbol IQ ISD FSW POWER TSTART RNEG VR VFB VOUT Parameter Supply Current Shutdown Supply Current Switching Frequency (Note 5) Power Efficiency at VNEG Start Up time Output Resistance to VNEG Output Voltage Ripple (Note 7) Feedback Pin Reference Voltage Adjustable Output Voltage (Note 6) IL = 2.5mA, VOUT = -2.7V IL = 10mA, VOUT = -3.8V IL = 2.5mA (Note 8) 5.5V VIN 2.7V, 2.5mA IL 5.5V VIN 3.0V, 10mA IL 0mA 0 to 10mA, VOUT = - 2.4V 5.5V VIN 2.7V, IL = 2.5mA 2.4 0.8 -1.25 - (VIN -0.3V) - (VIN -1.2V) 5 1 VIN = 3.6V IL = 3.6mA IL = 10mA 140 Conditions Open Circuit, No Load Min Typ 400 0.05 260 94 91 120 30 1 -1.20 -1.15 600 Max 950 1 450 Units µA µA kHz % µs mV V V
Load Regulation Line Regulation VIH VIL
mV/mA mV/V V V
Shutdown Pin Input Voltage 5.5V VIN 2.7V High Shutdown Pin Input Voltage 5.5V VIN 2.7V Low
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device beyond its rated operating conditions. Note 2: OUT may be shorted to GND for one second without damage. However, shorting OUT to VIN may damage the device and must be avoided. Also, for temperatures above TA = 85°C, OUT must not be shorted to GND or VIN or device may be damaged. Note 3: The maximum power dissipation must be de-rated at elevated temperatures and is limited by TJMAX (maximum junction temperature), TA (ambient temperature) and JA (junction-to-ambient thermal resistance). The maximum power dissipation at any temperature is:
PDissMAX = (TJMAX -- TA)/JA up to the value listed in the Absolute Maximum Ratings.
Note 4: Rating is for the human body model, a 100pF capacitor discharged through a 1.5 k resistor into each pin. Note 5: The output switches operate at one half the oscillator frequency, fOSC = 2fSW. Note 6: Current drawn from VNEG pin decreases power efficiency and will increase output voltage ripple. Note 7: In the test circuit, capacitors C1, C2, and C3 are 1µF, 0.30 maximum ESR capacitors. Capacitors with higher ESR will increase output resistance, increase output voltage ripple, and reduce efficiency. Note 8: The feedback resistors R1 and R2 are 200k resistors.
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