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Part: LM3351MM
Category:
Power Management
-> Regulators
-> Switching Regulators
-> Switched Capacitor Converters
Description: LM3351 - Switched Capacitor Voltage Converter, Package: Mini Soic, Pin Nb=8
Company: National Semiconductor Corporation
Datasheet: Download LM3351MM datasheet File size : 113 kB
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Datasheet text preview:
LM3351 Switched Capacitor Voltage Converter
December 1999
LM3351 Switched Capacitor Voltage Converter
General Description
The LM3351 is a CMOS charge-pump voltage converter which efficiently provides a 3.3V to 5V step-up, or 5V to 3.3V step-down. The LM3351 is pin for pin compatible with the LM3350 but consumes 66% less quiescent current. The LM3351 uses four small, low cost capacitors to provide the voltage conversion. It eliminates the cost, size and radiated EMI related to inductor based circuits, or the power loss of a linear regulator. Operating power conversion efficiency greater than 90% provides ideal performance for battery powered portable systems. The architecture provides a fixed voltage conversion ratio of 3/2 or 2/3. Thus it can be used for other DC-DC conversions as well. n n n n n 4.2 typical step-up output impedance 1.8 typical step-down output impedance 95% typical power conversion efficiency at 50 mA 250 nA typical shutdown current Low quiescent current extends battary life
Features
n Conversion of 3.3V to 5V, or 5V to 3.3V n Small Mini SO-8 package n No inductor required
Applications
n n n n Any mixed 5V and 3.3V system Laptop computers and PDAs Handheld instrumentation PCMCIA cards
Key Specifications
n 200 kHz switch frequency allows use of very small, inexpensive capacitors.
Ordering Information
Order Number LM3351MMX LM3351MM Package Type Mini SO-8 Mini SO-8 NSC Package Drawing MUA08A MUA08A Package Marking S05A S05A Supplied As 3500 Units on Tape and Reel 1000 Units on Tape and Reel
Basic Operating Circuits
Step-Up Converter Step-Down Converter
DS100146-1
DS100146-2
Connection Diagram
Mini SO8 Package
DS100146-3
Top View
© 1999 National Semiconductor Corporation DS100146 www.national.com
LM3351
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Maximum Input Voltage, Step-Down Maximum Input Voltage, Step-Up Power Dissipation (PD) (TA=25°C, (Note 2)) ja (Note 2) Tj Max (Note 2) 5.5V 3.65V 500 mW 250°C/W 150°C
Storage Temperature Lead Temperature (Soldering, 10 secs) ESD Susceptibility (Note 3) Not short circuit protected.
-65°C to +150°C 260°C 2kV
Operating Conditions (Note 1)
Ambient Temperature Range -40°C to + 85°C
Electrical Characteristics 3/2 Step-Up Voltage Converter
Specifications in standard type face are for Tj = 25°C, and those with boldface type apply over full operating temperature range. Unless otherwise specified, Vin = 3.3V, VEnable = 3.3V, Iload = 50 mA, C1, C2, Cin and Cout = 1 µF. Symbol VoutNL VoutFL Vin Parameter Output Voltage at No Load Output Voltage at 50 mA Input Supply Voltage Range Quiescent Current Quiescent Current Output Source Impedance Switching Frequency Enable Threshold Voltage Leakage Current Power Efficiency Current into ENABLE pin; ENABLE = 5V and all other pins at ground Shutdown Mode, VEnable = 0V, Iload=0 A; Current into pin Vlow Normal Mode, IIoad = 0A; Current into pin VIow Iload = 50 mA (Note 6) Iload = 0 A Iload = 50 mA Conditions Typ (Note 4) 5.0 4.7 3.3 2.5 3.65 IQ1 IQ2 Zout fSW 0.025 3 1.1 1.5 4.2 6.25 200 125 275 VEnable 1.7 1.0 2.5 IEnable P 0.025 1 95 Limits (Note 5) Units V V V V(Min) V(Max) µA µA(Max) mA mA(Max) (Max) kHz kHz(Min) kHz(Max) V V(Min) V(Max) µA µA(Max) %
Electrical Characteristics 2/3 Step-Down Voltage Converter
Specifications in standard type face are for Tj = 25°C, and those with boldface type apply over full operating temperature range. Unless otherwise specified, Vhigh = 5V, VEnable = 5V, Iload = 50 mA, C1, C2, Cin and Cout = 1 µF. Symbol VoutNL VoutFL Vin Parameter Output Voltage at No Load Output Voltage at 50 mA Input Supply Voltage Range Quiescent Current Shutdown Mode, VEnable = 0V, Iload=0 A; Current into pin Vhigh
2
Conditions Iload = 0 A Iload =50 mA
Typ (Note 4) 3.3 3.2 5
Limits (Note 5)
Units V V V
2.2 5.5 0.25 3
V(Min) V(Max) µA µA(Max)
IQ1
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LM3351
Electrical Characteristics 2/3 Step-Down Voltage Converter
Symbol IQ2 Zout fSW Parameter Quiescent Current Output Source Impedance Switching Frequency Enable Threshold Voltage Leakage Current Power Efficiency
(Continued)
Specifications in standard type face are for Tj = 25°C, and those with boldface type apply over full operating temperature range. Unless otherwise specified, Vhigh = 5V, VEnable = 5V, Iload = 50 mA, C1, C2, Cin and Cout = 1 µF. Conditions Normal Mode, IIoad = 0A; Current into pin Vhigh Iload = 50 mA (Note 6) Typ (Note 4) 0.8 1.0 1.8 3 200 125 275 VEnable 1.7 1.0 2.5 IEnable P Current into ENABLE pin; ENABLE = 5V and all other pins at ground 0.025 1 95 Limits (Note 5) Units mA mA(Max) (Max) kHz kHz(Min) kHz(Max) V V(Min) V(Max) µA µA(Max) %
Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: For operation at elevated temperatures, LM3351 must be derated based on package thermal resistance of ja and Tj max, Tj = TA+ jaPD. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kW resistor into each pin. Note 4: Typical numbers are at 25°C and represent the most likely parametric norm. Note 5: Limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate National's Averaging Outgoing Quality Level (AOQL). Note 6: The internal oscillator runs at 1.6 MHz, the output switches operate at one eighth of the oscillator frequency, fOSC = 8fSW.
Typical Performance Characteristics
Vout vs Iload (Step-Up) P vs Iload (Step-Up) Output Source Impedance vs Temperature (Step-Up)
DS100146-4
DS100146-5 DS100146-6
3
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