LTC3417A-2
1
3417a2fa
Dual Synchronous
1.5A/1A 4MHz
Step-Down DC/DC Regulator
The LTC
®
3417A-2 is a dual constant frequency, synchro-
nous step-down DC/DC converter. Intended for medium
power applications, it operates from a 2.25V to 5.5V input
voltage range and has a constant programmable switching
frequency, allowing the use of tiny, low cost capacitors
and inductors 2mm or less in height. Each output voltage
is adjustable from 0.8V to 5V. Internal synchronous, low
R
DS(ON)
power switches provide high effi ciency without
the need for external Schottky diodes.
A user selectable mode input allows the user to trade
off ripple voltage for light load effi ciency. Burst Mode
operation provides high effi ciency at light loads, while
Pulse Skip mode provides low ripple noise at light loads.
A phase mode pin allows the second channel to operate
in-phase or 180° out-of-phase with respect to channel 1.
Out-of-phase operation produces lower RMS current on
V
IN
and thus lower stress on the input capacitor.
To further maximize battery life, the P-channel MOSFETs
are turned on continuously in dropout (100% duty cycle)
and both channels draw a total quiescent current of only
100µA. In shutdown, the device draws <1µA.
V
OUT2
Effi ciency
(Burst Mode Operation)
FEATURES
n
High Effi ciency: Up to 95%
n
1.5A/1A Guaranteed Minimum Output Current
n
Synchronizable to External Clock
n
No Schottky Diodes Required
n
Programmable Frequency Operation: 1.5MHz or
Adjustable From 0.6MHz to 4MHz
n
Low Ripple (<35mV
P-P
) BurstMode
®
Operation
I
Q
: 125μA in Sleep
n
Low R
DS(ON)
Internal Switches
n
Short-Circuit Protected
n
V
IN
: 2.25V to 5.5V
n
Current Mode Operation for Excellent Line and Load
Transient Response
n
Ultralow Shutdown Current: I
Q
< 1µA
n
Low Dropout Operation: 100% Duty Cycle
n
Power Good Ouput
n
Phase Pin Selects 2nd Channel Phase Relationship
with Respect to 1st Channel
n
Internal Soft-Start with Individual Run Pin Control
n
Available in Small Thermally Enhanced
(5mm × 3mm) DFN and 20-Lead TSSOP Packages
APPLICATIONS
n
GPS/Navigation Systems
n
Automotive Instrumentation
n
PC Cards
n
Industrial Power Supplies
n
General Purpose Point of Load DC/DC
DESCRIPTION
L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents
including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 6144194.
FREQ
SW1
RUN1
V
FB1
I
TH1
SW2
RUN2
V
FB2
I
TH2
V
IN
LTC3417A-2
GND
10µF
1.5µH
2.2µH
22pF
511k
22pF
866k
V
IN
V
IN
412k
412k
22µF
5.9k 2.87k
2200pF
6800pF
3417A-2 TA01
47µF
V
OUT1
1.8V
1.5A
V
OUT2
2.5V
1A
V
IN
2.5V TO 5.5V
LOAD CURRENT (A)
0.001
70
EFFICIENCY (%)
90
95
100
0.01 0.1 1
3417A-2 TA01a
85
80
75
POWER LOSS (W)
0.001
0.01
0.1
1
10
0.0001
EFFICIENCY
REFER TO FIGURE 4
POWER LOSS
V
IN
= 3.6V
V
OUT
= 2.5V
FREQ = 1MHz
TYPICAL APPLICATION
LTC3417A-2
2
3417a2fa
ABSOLUTE MAXIMUM RATINGS
V
IN1
, V
IN2
Voltages ......................................0.3V to 6V
SYNC/MODE, SW1, SW2, RUN1,
RUN2, V
FB1
, V
FB2
, PHASE, FREQ,
I
TH1
, I
TH2
Voltages......... –0.3V to ((V
IN1
or V
IN2
)+ 0.3V)
V
IN1
– V
IN2
, V
IN2
– V
IN1
.......................................... 0.3V
(Note 1)
PGOOD Voltage ........................................... –0.3V to 6V
Operating Temperature Range (Note 2)
LTC3417AE-2 ....................................... –40°C to 85°C
LTC3417AI-2 ...................................... –40°C to 125°C
Junction Temperature (Notes 7, 8) ...................... 125°C
Storage Temperature Range ................... –65°C to 150°C
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3417AEDHC-2#PBF LTC3417AEDHC-2#TRPBF 3417A2 16-Lead (3mm × 5mm) Plastic DFN –40°C to 85°C
LTC3417AIDHC-2#PBF LTC3417AIDHC-2#TRPBF 3417A2 16-Lead (3mm × 5mm) Plastic DFN –40°C to 125°C
LTC3417AEFE-2#PBF LTC3417AEFE-2#TRPBF LTC3417AFE-2 20-Lead Plastic TSSOP –40°C to 85°C
LTC3417AIFE-2#PBF LTC3417AIFE-2#TRPBF LTC3417AFE-2 20-Lead Plastic TSSOP –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
16
15
14
13
12
11
10
9
17
1
2
3
4
5
6
7
8
PGND1
SW1
PHASE
GNDA
FREQ
PGOOD
SW2
SYNC/MODE
RUN1
V
IN1
I
TH1
V
FB1
V
FB2
I
TH2
RUN2
V
IN2
TOP VIEW
DHC PACKAGE
16-LEAD (3mm × 5mm) PLASTIC DFN
T
JMAX
= 125°C, θ
JA
= 43°C/ W
EXPOSED PAD (PIN 17) IS PGND2/GNDD
MUST BE SOLDERED TO PCB
FE PACKAGE
20-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
9
10
TOP VIEW
20
19
18
17
16
15
14
13
12
11
GNDD
RUN1
V
IN1
I
TH1
V
FB1
V
FB2
I
TH2
RUN2
V
IN2
PGND2
GNDD
PGND1
SW1
PHASE
GNDA
FREQ
PGOOD
SW2
SYNC/MODE
PGND2
21
T
JMAX
= 125°C, θ
JA
= 38°C/ W
EXPOSED PAD (PIN 21) IS PGND2/GNDD
MUST BE SOLDERED TO PCB
LTC3417A-2
3
3417a2fa
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 3.6V unless otherwise specifi ed (Note 2).
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN1
, V
IN2
Operating Voltage Range V
IN1
= V
IN2
2.25 5.5 V
I
FB1
, I
FB2
Feedback Pin Input Current V
IN
= 6V Pin Under Test = 3V ± 0.1 µA
V
FB1
, V
FB2
Feedback Voltage (Note 3)
l
0.784 0.8 0.816 V
ΔV
LINEREG
Reference Voltage Line Regulation. %/V
is the Percentage Change in V
OUT
with a
Change in V
IN
V
IN
= 2.25V to 5V (Note 3) 0.02 0.2 %/V
ΔV
LOADREG
Output Voltage Load Regulation I
TH1
, I
TH2
= 0.36V (Note 3)
I
TH1
, I
TH2
= 0.84V (Note 3)
0.02
–0.02
0.2
–0.2
%
%
g
m(EA)
Error Amplifi er Transconductance I
TH1
, I
TH2(PINLOAD)
= ±5µA (Note 3) 1400 µS
I
S
Input DC Supply Current (Note 4)
Active Mode V
FB1
= V
FB2
= 0.75V, V
SYNC/MODE
= V
IN
,
V
RUN1
= V
RUN2
= V
IN
400 600 µA
I
S
Half Active Mode (V
RUN2
= 0V, 1.5A Only) V
FB1
= 0.75V, V
SYNC/MODE
= V
IN
, V
RUN1
= V
IN
260 400 µA
Half Active Mode (V
RUN1
= 0V, 1A Only) V
FB2
= 0.75V, V
SYNC/MODE
= V
IN
, V
RUN2
= V
IN
260 400 µA
Both Channels in Sleep Mode V
FB1
= V
FB2
= 1V, V
SYNC/MODE
= V
IN
, V
RUN1
=
V
RUN2
= V
IN
125 250 µA
Shutdown V
RUN1
= V
RUN2
= 0V 0.01 1 µA
f
OSC
Oscillator Frequency V
FREQ
= V
IN
V
FREQ
: R
T
= 143k
V
FREQ
: Resistor (Note 6)
1.2
0.85
1.5
1
1.8
1.25
4
MHz
MHz
MHz
I
LIM1
Peak Switch Current Limit on SW1 (1.5A) 2.1 2.5 A
I
LIM2
Peak Switch Current Limit on SW2 (1A) 1.4 1.7 A
R
DS(ON)1
SW1 Top Switch On-Resistance (1.5A)
SW1 Bottom Switch On-Resistance
V
IN1
= 3.6V (Note 5)
V
IN1
= 3.6V (Note 5)
0.088
0.084
R
DS(ON)2
SW2 Top Switch On-Resistance (1A)
SW2 Bottom Switch On-Resistance
V
IN2
= 3.6V (Note 5)
V
IN2
= 3.6V (Note 5)
0.16
0.15
I
SW1(LKG)
Switch Leakage Current SW1 (1.5A) V
IN1
= 6V, V
ITH1
= 0V, V
RUN1
= 0V 0.01 1 µA
I
SW2(LKG)
Switch Leakage Current SW2 (1A) V
IN2
= 6V, V
ITH2
= 0V, V
RUN2
= 0V 0.01 1 µA
V
UVLO
Undervoltage Lockout Threshold V
IN1
, V
IN2
Ramping Down
V
IN1
, V
IN2
Ramping Up
1.9
1.95
2.07
2.12
2.2
2.25
V
V
T
PGOOD
Threshold for Power Good. Percentage
Deviation from V
FB
Steady State
(Typically 0.8V)
V
FB1
or V
FB2
Ramping Up
V
FB1
or V
FB2
Ramping Down
–6
–6
%
%
R
PGOOD
Power Good Pull-Down On-Resistance 120 300
V
RUN1,
V
RUN2
RUN1, RUN2 Threshold 0.3 0.85 1.5 V
V
PHASE
PHASE Threshold High-CMOS Levels V
IN
–0.5 V
PHASE Threshold Low-CMOS Levels 0.5 V
I
RUN1,
I
RUN2,
I
PHASE,
I
SYNC/MODE
RUN1, RUN2, PHASE and SYNC/MODE
Leakage Current
V
IN
= 6V, Pin Under Test = 3V ±0.01 ±1 µA
VTL
SYNC/MODE
SYNC/MODE Threshold Voltage Low 0.5 V
VTH
SYNC/MODE
SYNC/MODE Threshold Voltage High V
IN
–0.5 V
VTH
FREQ
FREQ Threshold Voltage High V
IN
–0.5 V

LTC3417AEFE-2#TRPBF

Mfr. #:
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 2x Sync 1.5A/1A 4MHz Buck DC/DC Reg
Lifecycle:
New from this manufacturer.
Delivery:
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Payment:
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