LM2717MTX/NOPB National Semiconductor, LM2717MTX/NOPB Datasheet

IC CONV DC/DC DUAL PWM 24-TSSOP

LM2717MTX/NOPB

Manufacturer Part Number
LM2717MTX/NOPB
Description
IC CONV DC/DC DUAL PWM 24-TSSOP
Manufacturer
National Semiconductor
Type
Step-Down (Buck)r
Datasheet

Specifications of LM2717MTX/NOPB

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
2
Voltage - Output
3.3V, 1.27 ~ 18 V
Current - Output
2.2A, 3.2A
Frequency - Switching
300kHz ~ 600kHz
Voltage - Input
4 ~ 20 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
24-TSSOP
For Use With
LM2717MT-ADJEV - BOARD EVALUATION LM2717MT-ADJ
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Other names
LM2717MTX
© 2008 National Semiconductor Corporation
LM2717
Dual Step-Down DC/DC Converter
General Description
The LM2717 is composed of two PWM DC/DC buck (step-
down) converters. The first converter is used to generate a
fixed output voltage of 3.3V. The second converter is used to
generate an adjustable output voltage. Both converters fea-
ture low R
ciency. Operating frequency can be adjusted anywhere
between 300kHz and 600kHz allowing the use of small ex-
ternal components. External soft-start pins for each enables
the user to tailor the soft-start times to a specific application.
Each converter may also be shut down independently with its
own shutdown pin. The LM2717 is available in a low profile
24-lead TSSOP package ensuring a low profile overall solu-
tion.
Typical Application Circuit
DSON
(0.16Ω) internal switches for maximum effi-
200785
Features
Applications
Fixed 3.3V output buck converter with a 2.2A, 0.16Ω,
internal switch
Adjustable buck converter with a 3.2A, 0.16Ω, internal
switch
Operating input voltage range of 4V to 20V
Input undervoltage protection
300kHz to 600kHz pin adjustable operating frequency
Over temperature protection
Small 24-Lead TSSOP package
TFT-LCD Displays
Handheld Devices
Portable Applications
Laptop Computers
20078501
March 4, 2008
www.national.com

Related parts for LM2717MTX/NOPB

LM2717MTX/NOPB Summary of contents

Page 1

... Each converter may also be shut down independently with its own shutdown pin. The LM2717 is available in a low profile 24-lead TSSOP package ensuring a low profile overall solu- tion. Typical Application Circuit © 2008 National Semiconductor Corporation Features ■ Fixed 3.3V output buck converter with a 2.2A, 0.16Ω, internal switch ■ ...

Page 2

Connection Diagram Ordering Information Order Number Spec LM2717MT LM2717MTX LM2717MT NOPB LM2717MTX NOPB www.national.com Top View 20078504 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, ...

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 20078503 ...

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 Fixed Buck Switch Leakage L1 Current I Adjustable Buck Switch L2 Leakage Current R Fixed Buck Switch R DSON1 DSON (Note 9) R Adjustable Buck Switch DSON2 R (Note 9) DSON Th Fixed Buck SHDN Threshold SHDN1 ...

Page 7

Typical Performance Characteristics Shutdown I vs. Input Voltage Q Switching Frequency vs. Input Voltage (F = 300kHz) SW Adjustable Buck R vs. Input Voltage DS(ON) Switching I 20078560 Fixed Buck R 20078562 Fixed Buck Efficiency vs. Load Current 20078564 7 ...

Page 8

Adjustable Buck Efficiency vs. Load Current (V = 15V) OUT Fixed Buck Switch Current Limt vs. Input Voltage www.national.com Adjustable Buck Efficiency vs. Load Current 20078566 Adjustable Buck Switch Current Limt vs. Input Voltage 20078568 5V) OUT ...

Page 9

Buck Operation PROTECTION (BOTH REGULATORS) The LM2717 has dedicated protection circuitry running during normal operation to protect the IC. The Thermal Shutdown circuitry turns off the power devices when the die temperature reaches excessive levels. The UVP comparator protects the ...

Page 10

SOFT-START CAPACITOR (BOTH REGULATORS) The LM2717 does not contain internal soft-start which allows for fast startup time but also causes high inrush current. Therefore for applications that need reduced inrush current the LM2717 has circuitry that is used to limit ...

Page 11

FIGURE 1. 15V, 3.3V Output Application FIGURE 2. 5V, 3.3V Output Application 11 20078558 20078559 www.national.com ...

Page 12

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted TSSOP-24 Pin Package (MTC) For Ordering, Refer to Ordering Information Table NS Package Number MTC24 12 ...

Page 13

Notes 13 www.national.com ...

Page 14

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