LM2717MTX-ADJ/NOPB National Semiconductor, LM2717MTX-ADJ/NOPB Datasheet

Page 1

... Each converter may also be shut down indepen- dently with its own shutdown pin. The LM2717-ADJ is available in a low profile 24-lead TSSOP package ensuring a low profile overall solution. Typical Application Circuit © 2008 National Semiconductor Corporation Features ■ Adjustable buck converter with a 2.2A, 0.16Ω, internal switch (Buck 1) ■ ...

Page 2

... Connection Diagram Ordering Information Order Number Spec LM2717MT-ADJ LM2717MTX-ADJ LM2717MT-ADJ NOPB LM2717MTX-ADJ NOPB www.national.com Top View 20167904 24-Lead TSSOP Package Type NSC Package Drawing TSSOP-24 MTC24 TSSOP-24 MTC24 TSSOP-24 MTC24 TSSOP-24 MTC24 2 Supplied As 61 Units, Rail 2500 Units, Tape and Reel ...

Page 3

Pin Descriptions Pin Name 1 PGND Power ground. PGND and AGND pins must be connected together directly at the part. 2 PGND Power ground. PGND and AGND pins must be connected together directly at the part. 3 AGND Analog ground. ...

Page 4

Block Diagram www.national.com 4 20167903 ...

Page 5

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications SW1 Voltage SW2 Voltage FB1, FB2 Voltages CB1, CB2 Voltages V Voltage C1 V Voltage 0.965V C2 SHDN1 Voltage SHDN2 Voltage SS1 Voltage SS2 Voltage ...

Page 6

Symbol Parameter I Buck 1 Shutdown Pin Current 0V < V SHDN1 I Buck 2 Shutdown Pin Current 0V < V SHDN2 I Buck 1 Switch Leakage L1 Current I Buck 2 Switch Leakage L2 Current R Buck 1 Switch ...

Page 7

Typical Performance Characteristics Shutdown I vs. Input Voltage Q Switching Frequency vs. Input Voltage (F = 300kHz) SW Buck 2 R vs. Input Voltage DS(ON) Switching I 20167960 Buck 1 R 20167962 Buck 1 Efficiency vs. Load Current 20167964 7 ...

Page 8

Buck 2 Efficiency vs. Load Current (V = 15V) OUT Buck 1 Switch Current Limit vs. Input Voltage Buck 1 Switch Current Limit vs. Temperature (V = 12V) IN www.national.com Buck 2 Efficiency vs. Load Current 20167966 Buck 2 Switch ...

Page 9

Buck 1 Switch ON Resistance vs. Temperature Switching Frequency vs. R Buck Operation PROTECTION (BOTH REGULATORS) The LM2717-ADJ has dedicated protection circuitry running during normal operation to protect the IC. The Thermal Shut- down circuitry turns off the power devices ...

Page 10

PWM operation. Note that the OVP function mon- itors the FB pin so it will not function if the feedback resistor is disconnected from the output. ...

Page 11

The soft-start time de- scribed above is the time it takes for the current limit to ramp to maximum value. When this function is used the current limit starts at a low value and ...

Page 12

Once the fp range is determined, R using: Where B is the desired gain in V (fz1 the transconductance of the error amplifier, and R1 and R2 are the feedback resistors as shown in Figure 3. ...

Page 13

Application Information Some Recommended Inductors (Others May Be Used) Manufacturer Coilcraft TDK Pulse Sumida Some Recommended Input And Output Capacitors (Others May Be Used) Manufacturer Vishay Sprague Taiyo Yuden Cornell Dubilier MuRata Inductor DO3316 and DT3316 series SLF10145 series P0751 ...

Page 14

FIGURE 5. 5V, 3.3V Output Application FIGURE 6. 3.3V, 1.8V Output Application 14 20167959 20167915 ...

Page 15

Physical Dimensions inches (millimeters) unless otherwise noted For Ordering, Refer to Ordering Information Table TSSOP-24 Pin Package (MTC) NS Package Number MTC24 15 www.national.com ...

Page 16

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock Conditioners www.national.com/timing Data Converters www.national.com/adc Displays www.national.com/displays Ethernet www.national.com/ethernet Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www ...