LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
LM2717 Dual Step-Down DC/DC Converter
Check for Samples: LM2717
FEATURES
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 feature low RDSON (0.16Ω)
internal switches for maximum efficiency. Operating
frequency can be adjusted anywhere between
300kHz and 600kHz allowing the use of small
external 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 solution.
1
2
•
•
•
•
•
•
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
APPLICATIONS
•
•
•
•
TFT-LCD Displays
Handheld Devices
Portable Applications
Laptop Computers
Typical Application Circuit
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005–2013, Texas Instruments Incorporated
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
Connection Diagram
Top View
Figure 1. 24-Lead TSSOP
See Package Number PW0024A
PIN DESCRIPTIONS
2
Pin
Name
1
PGND
Power ground. PGND and AGND pins must be connected together directly at the part.
Function
2
PGND
Power ground. PGND and AGND pins must be connected together directly at the part.
3
AGND
Analog ground. PGND and AGND pins must be connected together directly at the part.
4
FB1
Fixed buck output voltage feedback input.
5
VC1
Fixed buck compensation network connection. Connected to the output of the voltage error amplifier.
6
VBG
Bandgap connection.
7
VC2
Adjustable buck compensation network connection. Connected to the output of the voltage error
amplifier.
8
FB2
Adjustable buck output voltage feedback input.
9
AGND
Analog ground. PGND and AGND pins must be connected together directly at the part.
10
AGND
Analog ground. PGND and AGND pins must be connected together directly at the part.
11
PGND
Power ground. PGND and AGND pins must be connected together directly at the part.
12
PGND
Power ground. PGND and AGND pins must be connected together directly at the part.
13
SW2
Adjustable buck power switch input. Switch connected between VIN pins and SW2 pin.
14
VIN
Analog power input. VIN pins should be connected together directly at the part.
15
VIN
Analog power input. VIN pins should be connected together directly at the part.
16
CB2
Adjustable buck converter bootstrap capacitor connection.
17
SHDN2
Shutdown pin for adjustable buck converter. Active low.
18
SS2
19
FSLCT
Adjustable buck soft start pin.
20
SS1
21
SHDN1
22
CB1
Fixed buck converter bootstrap capacitor connection.
23
VIN
Analog power input. VIN pins should be connected together directly at the part.
24
SW1
Switching frequency select input. Use a resistor to set the frequency anywhere between 300kHz and
600kHz.
Fixed buck soft start pin.
Shutdown pin for fixed buck converter. Active low.
Fixed buck power switch input. Switch connected between VIN pins and SW1 pin.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
Block Diagram
FSLCT
CB1
VIN
+
95% Duty
Cycle Limit
+
OSC
SS1
Buck Load
Current
Measurement
FB1
36.5k
20.38k
DC
LIMIT
SET
+
PWM
Comp
-
Soft
Start
RESET
BUCK
DRIVE
Buck
Driver
SW1
OVP
Error
Amp
+
+
OVP
Comp
-
TSH
PGND
Thermal
Shutdown
BG
SHDN1
Bandgap
VBG
SD
Fixed Buck Converter
VC1
FSLCT
CB2
VIN
+
OSC
SS2
FB2
SET
+
PWM
Comp
-
Soft
Start
Buck Load
Current
Measurement
DC
LIMIT
RESET
BUCK
DRIVE
Buck
Driver
SW2
OVP
Error
Amp
+
+
OVP
Comp
BG
Bandgap
VBG
95% Duty
Cycle Limit
+
VC2
TSH
SD
PGND
Thermal
Shutdown
SHDN2
Adjustable Buck Converter
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
3
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
Absolute Maximum Ratings (1) (2)
VIN
−0.3V to 22V
SW1 Voltage
−0.3V to 22V
SW2 Voltage
−0.3V to 22V
FB1, FB2 Voltages
−0.3V to 7V
CB1, CB2 Voltages
−0.3V to VIN+7V (VIN=VSW)
VC1 Voltage
1.75V ≤ VC1 ≤ 2.25V
VC2 Voltage
0.965V ≤ VC2 ≤ 1.565V
SHDN1 Voltage
−0.3V to 7.5V
SHDN2 Voltage
−0.3V to 7.5V
SS1 Voltage
−0.3V to 2.1V
SS2 Voltage
−0.3V to 2.1V
FSLCT Voltage
AGND to 5V
Maximum Junction Temperature
150°C
Power Dissipation (3)
Internally Limited
Lead Temperature
300°C
Vapor Phase (60 sec.)
215°C
Infrared (15 sec.)
220°C
ESD Susceptibility
(1)
(2)
(3)
(4)
(4)
Human Body Model
2kV
Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the
device is intended to be functional, but device parameter specifications may not be ensured. For ensured specifications and test
conditions, see the Electrical Characteristics.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal
resistance, θJA, and the ambient temperature, TA. See the Electrical Characteristics table for the thermal resistance. The maximum
allowable power dissipation at any ambient temperature is calculated using: PD (MAX) = (TJ(MAX) − TA)/θJA. Exceeding the maximum
allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown.
The human body model is a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin.
Operating Conditions
Operating Junction Temperature Range (1)
−40°C to +125°C
Storage Temperature
−65°C to +150°C
Supply Voltage
4V to 20V
SW1 Voltage
20V
SW2 Voltage
20V
(1)
All limits specified at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are
100% tested or ensured through statistical analysis. All limits at temperature extremes are specified via correlation using standard
Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Electrical Characteristics
Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating
Temperature Range (TJ = −40°C to +125°C). VIN = 5V, IL = 0A, and FSW = 300kHz unless otherwise specified.
Symbol
IQ
Parameter
Total Quiescent Current (both
switchers)
VFB1
Fixed Buck Feedback Voltage
VFB2
Adjustable Buck Feedback
Voltage
(1)
(2)
4
Conditions
Min (1)
Not Switching
Typ (2)
Max (1)
Units
2.7
6
mA
Switching, switch open
6
12
mA
VSHDN = 0V
9
27
µA
3.3
V
1.267
V
All limits specified at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are
100% tested or ensured through statistical analysis. All limits at temperature extremes are specified via correlation using standard
Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Typical numbers are at 25°C and represent the most likely norm.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
Electrical Characteristics (continued)
Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating
Temperature Range (TJ = −40°C to +125°C). VIN = 5V, IL = 0A, and FSW = 300kHz unless otherwise specified.
Symbol
ICL1
(3)
Parameter
Conditions
Fixed Buck Switch Current
Limit
VIN = 8V
ICL2 (3)
Adjustable Buck Switch
Current Limit
IB1
Min (1)
Typ (2)
Max (1)
Units
(4)
2.2
A
VIN = 8V (4)
3.2
A
Fixed Buck FB Pin Bias
Current (5)
VIN = 20V
65
µA
IB2
Adjustable Buck FB Pin Bias
Current (5)
VIN = 20V
65
nA
VIN
Input Voltage Range
gm1
Fixed Buck Error Amp
Transconductance
ΔI = 20µA
gm2
Adjustable Buck Error Amp
Transconductance
ΔI = 20µA
AV1
4
20
V
1340
µmho
1360
µmho
Fixed Buck Error Amp Voltage
Gain
134
V/V
AV2
Adjustable Buck Error Amp
Voltage Gain
136
V/V
DMAX
Maximum Duty Cycle
FSW
Switching Frequency
ISHDN1
Fixed Buck Shutdown Pin
Current
89
93
RF = 46.4k
200
300
400
kHz
RF = 22.6k
475
600
775
kHz
0V < VSHDN1 < 7.5V
−5
5
µA
ISHDN2
Adjustable Buck Shutdown Pin 0V < VSHDN2 < 7.5V
Current
−5
5
µA
IL1
Fixed Buck Switch Leakage
Current
VIN = 20V
0.01
5
µA
IL2
Adjustable Buck Switch
Leakage Current
VIN = 20V
0.01
5
µA
(6)
RDSON1
Fixed Buck Switch RDSON
RDSON2
Adjustable Buck Switch
RDSON (6)
ThSHDN1
Fixed Buck SHDN Threshold
Output High
1.8
Output Low
ThSHDN2
Adjustable Buck SHDN
Threshold
Output High
160
mΩ
160
mΩ
1.36
1.33
1.8
Output Low
%
V
0.7
1.36
1.33
0.7
V
ISS1
Fixed Buck Soft Start Pin
Current
4
9
15
µA
ISS2
Adjustable Buck Soft Start Pin
Current
4
9
15
µA
UVP
On Threshold
4
3.8
Off Threshold
θJA
(3)
(4)
(5)
(6)
(7)
Thermal Resistance (7)
3.6
TSSOP, package only
115
V
3.3
°C/W
Duty cycle affects current limit due to ramp generator.
Current limit at 0% duty cycle. See TYPICAL PERFORMANCE section for Switch Current Limit vs. VIN
Bias current flows into FB pin.
Includes the bond wires, RDSON from VIN pin(s) to SW pin.
Refer to Texas Instruments packaging website for more detailed thermal information and mounting techniques for the TSSOP package.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
5
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics
Switching IQ
vs.
Input Voltage
(FSW = 300kHz)
16
9
14
8
12
7
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (PA)
Shutdown IQ
vs.
Input Voltage
10
8
6
4
2
6
5
4
3
2
1
0
4
6
8
10
12
14
16
18
20
0
4
INPUT VOLTAGE (V)
6
8
10
12
14
16
18
20
18
20
INPUT VOLTAGE (V)
Figure 2.
Figure 3.
Switching Frequency
vs.
Input Voltage
(FSW = 300kHz)
Fixed Buck RDS(ON)
vs.
Input Voltage
320
200
190
315
180
SWITCH RDS(ON) (m:
SWITCHING FREQUENCY (kHz)
R F = 46.4k
310
305
300
170
160
150
140
130
120
295
110
290
100
4
6
8
10
12
14
16
18
20
4
6
8
12
14
16
Figure 4.
Figure 5.
Adjustable Buck RDS(ON)
vs.
Input Voltage
Fixed Buck Efficiency
vs.
Load Current
200
100
190
90
180
80
170
70
160
150
140
V IN = 5V
V IN = 12V
60
V IN = 18V
50
40
130
30
120
20
110
10
0
100
4
6
8
10
12
14
16
18
20
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
LOAD CURRENT (A)
INPUT VOLTAGE (V)
Figure 6.
6
10
INPUT VOLTAGE (V)
EFFICIENCY (%)
SWITCH RDS(ON) (m:
INPUT VOLTAGE (V)
Figure 7.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Adjustable Buck Efficiency
vs.
Load Current
(VOUT = 5V)
100
100
90
90
80
80
70
70
EFFICIENCY (%)
EFFICIENCY (%)
Adjustable Buck Efficiency
vs.
Load Current
(VOUT = 15V)
60
50
40
30
50
40
30
20
20
V IN = 18V
10
V IN = 18V
10
0
0
0
0.5
1
1.5
2
2.5
0
0.5
1
1.5
2
2.5
LOAD CURRENT (A)
LOAD CURRENT (A)
Figure 8.
Figure 9.
Fixed Buck Switch Current Limt
vs.
Input Voltage
Adjustable Buck Switch Current Limt
vs.
Input Voltage
(VOUT = 5V)
2.4
3.4
2.2
3.2
SWITCH CURRENT LIMIT (A)
SWITCH CURRENT LIMIT (A)
60
2
1.8
1.6
1.4
1.2
3
2.8
2.6
2.4
2.2
1
2
4
6
8
10
12
14
16
18
20
8
10
12
14
16
18
20
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 10.
Figure 11.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
7
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
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 power devices during supply power startup and shutdown to prevent operation at
voltages less than the minimum input voltage. The OVP comparator is used to prevent the output voltage from
rising at no loads allowing full PWM operation over all load conditions. The LM2717 also features a shutdown
mode for each converter decreasing the supply current to approximately 10µA (both in shutdown mode).
CONTINUOUS CONDUCTION MODE
The LM2717 contains current-mode, PWM buck regulators. A buck regulator steps the input voltage down to a
lower output voltage. In continuous conduction mode (when the inductor current never reaches zero at steady
state), the buck regulator operates in two cycles. The power switch is connected between VIN and SW1 and
SW2.
In the first cycle of operation the transistor is closed and the diode is reverse biased. Energy is collected in the
inductor and the load current is supplied by COUT and the rising current through the inductor.
During the second cycle the transistor is open and the diode is forward biased due to the fact that the inductor
current cannot instantaneously change direction. The energy stored in the inductor is transferred to the load and
output capacitor.
The ratio of these two cycles determines the output voltage. The output voltage is defined approximately as:
D=
VOUT
, D' = (1-D)
VIN
(1)
where D is the duty cycle of the switch, D and D′ will be required for design calculations.
DESIGN PROCEDURE
This section presents guidelines for selecting external components.
SETTING THE OUTPUT VOLTAGE (ADJUSTABLE REGULATOR)
The output voltage is set using the feedback pin and a resistor divider connected to the output as shown in
Figure 12. The feedback pin voltage is 1.26V, so the ratio of the feedback resistors sets the output voltage
according to the following equation:
RFB1 = RFB2 x
VOUT - 1.267
:
1.267
(2)
INPUT CAPACITOR
A low ESR aluminum, tantalum, or ceramic capacitor is needed betwen the input pin and power ground. This
capacitor prevents large voltage transients from appearing at the input. The capacitor is selected based on the
RMS current and voltage requirements. The RMS current is given by:
(3)
The RMS current reaches its maximum (IOUT/2) when VIN equals 2VOUT. This value should be calculated for both
regulators and added to give a total RMS current rating. For an aluminum or ceramic capacitor, the voltage rating
should be at least 25% higher than the maximum input voltage. If a tantalum capacitor is used, the voltage rating
required is about twice the maximum input voltage. The tantalum capacitor should be surge current tested by the
manufacturer to prevent being shorted by the inrush current. The minimum capacitor value should be 47µF for
lower output load current applications and less dynamic (quickly changing) load conditions. For higher output
current applications or dynamic load conditions a 68µF to 100µF low ESR capacitor is recommended. It is also
recommended to put a small ceramic capacitor (0.1µF to 4.7µF) between the input pins and ground to reduce
high frequency spikes.
8
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
INDUCTOR SELECTION
The most critical parameters for the inductor are the inductance, peak current and the DC resistance. The
inductance is related to the peak-to-peak inductor ripple current, the input and the output voltages (for 300kHz
operation):
(4)
A higher value of ripple current reduces inductance, but increases the conductance loss, core loss, and current
stress for the inductor and switch devices. It also requires a bigger output capacitor for the same output voltage
ripple requirement. A reasonable value is setting the ripple current to be 30% of the DC output current. Since the
ripple current increases with the input voltage, the maximum input voltage is always used to determine the
inductance. The DC resistance of the inductor is a key parameter for the efficiency. Lower DC resistance is
available with a bigger winding area. A good tradeoff between the efficiency and the core size is letting the
inductor copper loss equal 2% of the output power.
OUTPUT CAPACITOR
The selection of COUT is driven by the maximum allowable output voltage ripple. The output ripple in the constant
frequency, PWM mode is approximated by:
(5)
The ESR term usually plays the dominant role in determining the voltage ripple. Low ESR ceramic, aluminum
electrolytic, or tantalum capacitors (such as Taiyo Yuden MLCC, Nichicon PL series, Sanyo OS-CON, Sprague
593D, 594D, AVX TPS, and CDE polymer aluminum) is recommended. An electrolytic capacitor is not
recommended for temperatures below −25°C since its ESR rises dramatically at cold temperature. Ceramic or
tantalum capacitors have much better ESR specifications at cold temperature and is preferred for low
temperature applications.
BOOTSTRAP CAPACITOR
A 4.7nF ceramic capacitor or larger is recommended for the bootstrap capacitor. For applications where the input
voltage is less than twice the output voltage a larger capacitor is recommended, generally 0.1µF to 1µF to
ensure plenty of gate drive for the internal switches and a consistently low RDS(ON).
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
the inrush current on start-up of the DC/DC switching regulators. This inrush current limiting circuitry serves as a
soft-start. The external SS pins are used to tailor the soft-start for a specific application. A current (ISS) charges
the external soft-start capacitor, CSS. The soft-start time can be estimated as:
TSS = CSS*0.6V/ISS
(6)
When programming the softstart time simply use the equation given in the Soft-Start Capacitor section above.
SHUTDOWN OPERATION (BOTH REGULATORS)
The shutdown pins of the LM2717 are designed so that they may be controlled using 1.8V or higher logic signals.
If the shutdown function is not to be used the pin may be left open. The maximum voltage to the shutdown pin
should not exceed 7.5V. If the use of a higher voltage is desired due to system or other constraints it may be
used, however a 100k or larger resistor is recommended between the applied voltage and the shutdown pin to
protect the device.
SCHOTTKY DIODE
The breakdown voltage rating of D1 and D2 is preferred to be 25% higher than the maximum input voltage. The
current rating for the diode should be equal to the maximum output current for best reliability in most
applications. In cases where the input voltage is much greater than the output voltage the average diode current
is lower. In this case it is possible to use a diode with a lower average current rating, approximately (1-D)*IOUT
however the peak current rating should be higher than the maximum load current.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
9
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
LAYOUT CONSIDERATIONS
The LM2717 uses two separate ground connections, PGND for the drivers and boost NMOS power device and
AGND for the sensitive analog control circuitry. The AGND and PGND pins should be tied directly together at the
package. The feedback and compensation networks should be connected directly to a dedicated analog ground
plane and this ground plane must connect to the AGND pin. If no analog ground plane is available then the
ground connections of the feedback and compensation networks must tie directly to the AGND pin. Connecting
these networks to the PGND can inject noise into the system and effect performance.
The input bypass capacitor CIN, as shown in Figure 12, must be placed close to the IC. This will reduce copper
trace resistance which effects input voltage ripple of the IC. For additional input voltage filtering, a 0.1µF to 4.7µF
bypass capacitors can be placed in parallel with CIN, close to the VIN pins to shunt any high frequency noise to
ground. The output capacitors, COUT1 and COUT2, should also be placed close to the IC. Any copper trace
connections for the COUTX capacitors can increase the series resistance, which directly effects output voltage
ripple. The feedback network, resistors RFB1 and RFB2, should be kept close to the FB pin, and away from the
inductor to minimize copper trace connections that can inject noise into the system. Trace connections made to
the inductors and schottky diodes should be minimized to reduce power dissipation and increase overall
efficiency. For more detail on switching power supply layout considerations see Application Note AN-1149:
Layout Guidelines for Switching Power Supplies (SNVA021).
Application Information
Table 1. Some Recommended Inductors (Others May Be Used)
Manufacturer
Inductor
Contact Information
Coilcraft
DO3316 and DO5022 series
www.coilcraft.com
Coiltronics
DRQ73 and CD1 series
www.cooperet.com
Pulse
P0751 and P0762 series
www.pulseeng.com
Sumida
CDRH8D28 and CDRH8D43 series
www.sumida.com
Table 2. Some Recommended Input And Output Capacitors (Others May Be Used)
10
Manufacturer
Capacitor
Contact Information
Vishay Sprague
293D, 592D, and 595D series tantalum
www.vishay.com
Taiyo Yuden
High capacitance MLCC ceramic
www.t-yuden.com
Cornell Dubilier
ESRD seriec Polymer Aluminum Electrolytic
SPV and AFK series V-chip series
www.cde.com
Panasonic
High capacitance MLCC ceramic
EEJ-L series tantalum
www.panasonic.com
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
LM2717
www.ti.com
SNVS253D – MAY 2005 – REVISED MARCH 2013
L1
22 PH
CBOOT1
4.7 nF
U1
CSS1
CC1
47 nF
20k
4.7 nF
RC1
CBG
1 nF
CC2
2k
4.7 nF
RC2
CSS2
RF
20.5k
47 nF
AGND
CB1
SW1
FB1
SHDN1
SS1
VC1
VIN
VBG
VIN
VC2
SHDN2
CB2
*Connect CINA (pin
23) and CINB (pins
14,15) as close as
possible to the VIN
pins.
VIN
SS2
FSLCT
FB2
AGND
AGND
SW2
PGND
AGND
PGND
PGND
PGND
CBOOT2
*CINB
4.7 PF
ceramic
3.3V OUT1
D1
MBRS240
COUT1A
1 PF
ceramic
17V to 20V IN
*CINA
4.7 PF
ceramic
CIN
68 PF
L2
22 PH
1 PF
COUT1
68 PF
15V OUT2
RFB1
D2
MBRS240
221k
COUT2A
1 PF
ceramic
COUT2
68 PF
LM2717
RFB2
20k
PGND
Figure 12. 15V, 3.3V Output Application
L1
22 PH
CBOOT1
1 PF
U1
CSS1
CC1
47 nF
20k
4.7 nF
RC1
CBG
1 nF
CC2
10k
4.7 nF
RC2
CSS2
RF
20.5k
47 nF
AGND
CB1
SW1
FB1
SHDN1
SS1
VC1
VIN
VBG
VIN
VC2
SHDN2
CB2
*Connect CINA (pin
23) and CINB (pins
14,15) as close as
possible to the VIN
pins.
VIN
SS2
FSLCT
FB2
AGND
AGND
SW2
PGND
AGND
PGND
PGND
PGND
CBOOT2
*CINB
4.7 PF
ceramic
1 PF
3.3V OUT1
D1
MBRS240
COUT1A
1 PF
ceramic
COUT1
68 PF
8V to 20V IN
*CINA
4.7 PF
ceramic
CIN
68 PF
L2
22 PH
D2
MBRS240
5V OUT2
RFB1
59k
COUT2A
1 PF
ceramic
COUT2
68 PF
LM2717
RFB2
20k
PGND
Figure 13. 5V, 3.3V Output Application
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
11
LM2717
SNVS253D – MAY 2005 – REVISED MARCH 2013
www.ti.com
REVISION HISTORY
Changes from Revision C (March 2013) to Revision D
•
12
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 11
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM2717
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM2717MT/NOPB
ACTIVE
TSSOP
PW
24
61
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM2717MT
LM2717MTX/NOPB
ACTIVE
TSSOP
PW
24
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM2717MT
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
