POWER LOSS (mW)
LTC3826-1
30A I , Dual, 2-Phase
Q
Synchronous Step-Down Controller
FEATURES DESCRIPTION
n
Wide Output Voltage Range: 0.8V V 10V The LTC 3826-1 is a high performance dual step-down
OUT
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Low Operating I : 30A (One Channel On) switching regulator controller that drives all N-channel
Q
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Out-of-Phase Controllers Reduce Required Input synchronous power MOSFET stages. A constant frequency
current mode architecture allows a phase-lockable fre-
Capacitance and Power Supply Induced Noise
n
quency of up to 650kHz. Power loss and noise due to the
OPTI-LOOP Compensation Minimizes C
OUT
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ESR of the input capacitor ESR are minimized by operating
1% Output Voltage Accuracy
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the two controller output stages out of phase.
Wide V Range: 4V to 36V Operation
IN
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Phase-Lockable Fixed Frequency 140kHz to 650kHz
The 30A no-load quiescent current extends operating
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Selectable Continuous, Pulse Skipping or Low Ripple
life in battery powered systems. OPTI-LOOP compensa-
Burst Mode Operation at Light Loads
tion allows the transient response to be optimized over
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Dual N-Channel MOSFET Synchronous Drive
a wide range of output capacitance and ESR values. The
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Very Low Dropout Operation: 99% Duty Cycle
LTC3826-1 features a precision 0.8V reference and a power
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Adjustable Output Voltage Soft-Start or Tracking
good output indicator. A wide 4V to 36V input supply range
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Output Current Foldback Limiting
encompasses all battery chemistries.
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Power Good Output Voltage Monitor
Independent TRACK/SS pins for each controller ramp the
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Output Overvoltage Protection
output voltage during start-up. Current foldback limits
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Low Shutdown I : 4A
Q
MOSFET heat dissipation during short-circuit conditions.
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Internal LDO Powers Gate Drive from V or V
IN OUT
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The PLLIN/MODE pin selects among Burst Mode opera-
Small 28-Lead SSOP Package
tion, pulse skipping mode, or continuous inductor cur-
rent mode at light loads. For a leadless package version
APPLICATIONS
(5mm 5mm QFN) with additional features, see the
n LTC3826 data sheet.
Automotive Systems
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L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Battery-Operated Digital Devices
Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.
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Distributed DC Power Systems
All other trademarks are the property of their respective owners. Protected by U.S. Patents
including 5481178, 5929620, 6177787, 6144194, 5408150, 6580258, 6304066, 5705919.
TYPICAL APPLICATION
High Ef ciency Dual 8.5V/3.3V Step-Down Converter
V
IN Ef ciency and Power Loss
4V TO 36V
22F vs Load Current
4.7F
50V
V INTV 100 10000
IN CC
TG1 TG2
90
0.1F
BOOST1 BOOST2 80 1000
7.2H
3.3H
0.1F
SW1 SW2 70
BG1 BG2 60 100
LTC3826-1
50
PGND
+ + 40 10
SENSE1
SENSE2
30
0.015 0.015
20 1
SENSE2
SENSE1
V V
OUT1 OUT2
10
3.3V V V 8.5V
FB1 FB2
FIGURE 13 CIRCUIT
5A 62.5k 3.5A
192.5k 0
0.1
I I
TH1 TH2
0.00001 0.0001 0.001 0.01 0.1 1 10
220pF 220pF
150F 150F
TRACK/SS1 SGND TRACK/SS2
20k OUTPUT CURRENT (A)
20k
15k 15k 38261 TA01b
0.1F 0.1F
38261 TA01
38261fb
1
EFFICIENCY (%)LTC3826-1
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
Input Supply Voltage (V ) ......................... 36V to 0.3V
IN
1 28 TRACK/SS1
I
TH1
Topside Driver Voltages
2 27 PGOOD1
V
FB1
BOOST1, BOOST2 .................................. 42V to 0.3V
+
3 26 TG1
SENSE1
Switch Voltage (SW1, SW2) ......................... 36V to 5V
4 25 SW1
SENSE1
(BOOST1-SW1), (BOOST2-SW2) ............. 8.5V to 0.3V
5 24 BOOST1
PLLLPF
RUN1, RUN2 ............................................... 7V to 0.3V
6 23 BG1
PLLIN/MODE
+ +
SENSE1 , SENSE2 , SENSE1 , 7 22 V
SGND IN
8 21 PGND
SENSE2 Voltages ..................................... 11V to 0.3V RUN1
9 20 EXTV
RUN2 CC
PLLIN/MODE, PLLLPF, TRACK/SS1, TRACK/SS2
10 19 INTV
SENSE2 CC
Voltages ........................................... INTV to 0.3V
CC
+
11 18 BG2
SENSE2
EXTV ...................................................... 10V to 0.3V
CC
12 17 BOOST2
V
FB2
I , I , V , V Voltages ................. 2.7V to 0.3V
TH1 TH2 FB1 FB2
13 16 SW2
I
TH2
PGOOD1 Voltage ....................................... 8.5V to 0.3V
14 15 TG2
TRACK/SS2
Peak Output Current <10s (TG1, TG2, BG1, BG2) .....3A
G PACKAGE 28-LEAD PLASTIC SSOP
Operating Temperature Range (Note 2).... 40C to 85C
T = 125C, Q = 95C/W
JMAX JA
Junction Temperature (Note 3) ............................. 125C
Storage Temperature Range ................... 65C to 150C
Lead Temperature (Soldering, 10 sec) .................. 300C
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3826EG-1#PBF LTC3826EG-1#TRPBF LTC3826EG-1 28-Lead Plastic SSOP 40C to 85C
LTC3826IG-1#PBF LTC3826IG-1#TRPBF LTC3826IG-1 28-Lead Plastic SSOP 40C to 85C
LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3826EG-1 LTC3826EG-1#TR LTC3826EG-1 28-Lead Plastic SSOP 40C to 85C
LTC3826IG-1 LTC3826IG-1#TR LTC3826IG-1 28-Lead Plastic SSOP 40C to 85C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges.
For more information on lead free part marking, go to: