LTC3414
4A, 4MHz, Monolithic
Synchronous Step-Down Regulator
DESCRIPTIO
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FEATURES
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High Efficiency: Up to 95%
4A Output Current
Low Quiescent Current: 64μA
Low RDS(ON) Internal Switch: 67mΩ
Programmable Frequency: 300KHz to 4MHz
2.25V to 5.5V Input Voltage Range
±2% Output Voltage Accuracy
0.8V Reference Allows Low Output Voltage
Selectable Forced Continuous/Burst Mode® Operation
with Adjustable Burst Clamp
Synchronizable Switching Frequency
Low Dropout Operation: 100% Duty Cycle
Power Good Output Voltage Monitor
Overtemperature Protected
Available in 20-Lead Exposed TSSOP Package
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APPLICATIO S
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Point-of-Load Regulation
Notebook Computers
Portable Instruments
Distributed Power Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP 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, 6724174
The LTC®3414 is a high efficiency monolithic synchronous, step-down DC/DC converter utilizing a constant
frequency, current mode architecture. It operates from an
input voltage range of 2.25V to 5.5V and provides a
regulated output voltage from 0.8V to 5V while delivering
up to 4A of output current. The internal synchronous
power switch with 67mΩ on-resistance increases efficiency and eliminates the need for an external Schottky
diode. Switching frequency is set by an external resistor or
can be synchronized to an external clock. 100% duty cycle
provides low dropout operation extending battery life in
portable systems. OPTI-LOOP® compensation allows the
transient response to be optimized over a wide range of
loads and output capacitors.
The LTC3414 can be configured for either Burst Mode
operation or forced continuous operation. Forced continuous operation reduces noise and RF interference while
Burst Mode operation provides high efficiency by reducing gate charge losses at light loads. In Burst Mode
operation, external control of the burst clamp level allows
the output voltage ripple to be adjusted according to the
requirements of the application.
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TYPICAL APPLICATIO
22μF
LTC3414 Efficiency Curve
VIN
2.7V TO 5.5V
100
PVIN SVIN
RT
95
PGOOD
0.47μH
LTC3414
294k
1000pF
RITH*
470pF
VOUT
2.5V AT 4A
COUT*
SW
RUN/SS
PGND
ITH
SGND
VFB
SYNC/MODE
75k
85
80
75
FORCED
CONTINUOUS
70
65
3414 F01a
110k
Burst Mode OPERATION
90
EFFICIENCY (%)
2.2M
392k
60
55
50
0.001
*Burst Mode OPERATION: COUT = 470μF SANYO POSCAP 4TPB470M, RITH = 20k
FORCED CONTINUOUS: COUT = (2) 100μF TDKC4532X5ROJ107M, RITH = 12.1k
0.01
0.1
1.0
LOAD CURRENT (A)
10
3414 F01b
Figure 1. 2.5V/4A Step-Down Regulator
3414fb
1
LTC3414
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TYPICAL PERFOR A CE CHARACTERISTICS
Switch On-Resistance vs
Temperature, VIN = 3.3V
Switch On-Resistance vs
Input Voltage
VREF vs Temperature, VIN = 3.3V
120
90
0.800
TA = 25°C
80
0.797
ON-RESISTANCE (mΩ)
0.798
100
PFET
70
ON-RESISTANCE (mΩ)
VREF (V)
0.799
60
NFET
50
40
30
80
PFET
NFET
60
40
20
0.796
20
10
0.795
–40 –20
0
0
2.25 2.75 3.25 3.75 4.25 4.75 5.25
INPUT VOLTAGE (V)
20 40 60 80 100 120 140
TEMPERATURE (°C)
Switch Leakage vs Input Voltage
7000
TA = 25°C
PFET
12
10
8
6
5000
4000
3000
2000
NFET
1000
980
960
940
4
920
1000
2
5.25
25 125 225 325 425 525 625 725 825 925
ROSC (k)
3414 G04
350
1090
VIN = 3.3V
ROSC = 294k
Minimum Peak Inductor Current
vs Burst Clamp Voltage
5.0
TA = 25°C
300
QUIESCENT CURRENT (μA)
1030
1010
990
970
950
ACTIVE
250
200
150
100
SLEEP
50
930
910
–40 –20
0
20 40 60 80
TEMPERATURE (°C)
100 120
3414 G07
0
2.25
2.75
3.25 3.75 4.25 4.75
INPUT VOLTAGE (V)
5.25
3414 G06
DC Supply Current vs Input
Voltage
1050
2.75 3.25 3.75 4.25 4.75
INPUT VOLTAGE (V)
3414 G05
Frequency vs Temperature
1070
900
2.25
0
2.75 3.25 3.75 4.25 4.75
INPUT VOLTAGE (V)
MINIMUM PEAK INDUCTOR CURRENT (A)
0
2.25
FREQUENCY (kHz)
ROSC = 294k
TA = 25°C
1020
FREQUENCY (kHz)
16
1040
VIN = 3.3V
TA = 25°C
6000
14
Frequency vs Input Voltage
Frequency vs ROSC
FREQUENCY (kHz)
SWITCH LEAKAGE CURRENT (nA)
18
3414 G03
3414 G02
3414 G01
20
0
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
5.75
5.25
3414 G08
VIN = 3.3V
TA = 25°C
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
0.1
0.2 0.3 0.4 0.5 0.6 0.7
BURST CLAMP VOLTAGE (V)
0.8
3414 G09
3414fb
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