LTC3786EUD#PBF Linear Technology, LTC3786EUD#PBF Datasheet

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LTC3786EUD#PBF

Manufacturer Part Number
LTC3786EUD#PBF
Description
IC, DC-DC CONV, 550kHz, QFN16
Manufacturer
Linear Technology
Datasheet

Specifications of LTC3786EUD#PBF

Primary Input Voltage
38V
No. Of Outputs
1
Output Voltage
60V
No. Of Pins
16
Operating Temperature Range
-40°C To +125°C
Peak Reflow Compatible (260 C)
Yes
Switching Frequency Max
550kHz
Msl
MSL 1 - Unlimited
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LTC3786EUD#PBFLTC3786EUD
Manufacturer:
LT
Quantity:
10 000
Company:
Part Number:
LTC3786EUD#PBF
Manufacturer:
LINEAR/凌特
Quantity:
20 000
APPLICATIONS
FEATURES
TYPICAL APPLICATION
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
15nF
Synchronous Operation For Highest Efficiency and
Reduced Heat Dissipation
Wide V
Operates Down to 2.5V After Start-Up
Output Voltages Up to 60V
±1% 1.2V Reference Voltage
R
100% Duty Cycle Capability for Synchronous MOSFET
Low Quiescent Current: 55μA
Phase-Lockable Frequency (75kHz to 850kHz)
Programmable Fixed Frequency (50kHz to 900kHz)
Adjustable Output Voltage Soft-Start
Power Good Output Voltage Monitor
Low Shutdown Current I
Internal 5.4V LDO for Gate Drive Supply
Thermally Enhanced 16-Pin 3mm × 3mm QFN and
MSOP Packages
Industrial and Automotive Power Supplies
Automotive Start-Stop Systems
Medical Devices
High Voltage Battery-Powered Systems
SENSE
8.66k
12.1k
220pF
0.1μF
IN
or Inductor DCR Current Sensing
12V to 24V/5A Synchronous Boost Converter
232k
Range: 4.5V to 38V (40V Abs Max) and
PGOOD
PLLIN/MODE
RUN
FREQ
SS
ITH
VFB
LTC3786
SENSE
SENSE
BOOST
INTV
VBIAS
GND
SW
Q
TG
BG
CC
+
: <8μA
0.1μF
4.7μF
V
IN
4.5V TO 24V
3.3μH
4mΩ
220μF
220μF
3786 TA01a
V
24V
5A
OUT
DESCRIPTION
The LTC
converter controller that drives all N-channel power
MOSFETs. Synchronous rectification increases efficiency,
reduces power losses and eases thermal requirements,
allowing the LTC3786 to be used in high power boost
applications.
A 4.5V to 38V input supply range encompasses a wide
range of system architectures and battery chemistries.
When biased from the output of the boost converter or
another auxiliary supply, the LTC3786 can operate from
an input supply as low as 2.5V after start-up. The 55μA
no-load quiescent current extends operating run time in
battery-powered systems.
The operating frequency can be set for a 50kHz to 900kHz
range or synchronized to an external clock using the internal
PLL. The LTC3786 also features a precision 1.2V reference
and a power good output indicator. The SS pin ramps the
output voltage during start-up. The PLLIN/MODE pin selects
among Burst Mode
continuous inductor current mode at light loads.
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP , Linear Technology and the Linear logo are
registered trademarks and No R
trademarks are the property of their respective owners. Protected by U. S. Patents, including
5408150, 5481178, 5705919, 5929620, 6177787, 6498466, 6580258, 6611131.
®
3786 is a high performance synchronous boost
100
0.00001
90
80
70
60
50
40
30
20
10
0
Low I
EFFICIENCY
0.0001
Efficiency and Power Loss
BURST
SENSE
®
OUTPUT CURRENT (A)
0.001
operation, pulse-skipping mode or
vs Load Current
is a trademark of Linear Technology Corporation. All other
Boost Controller
Q
0.01
V
V
Burst Mode OPERATION
FIGURE 8 CIRCUIT
IN
OUT
BURST
Synchronous
= 12V
LOSS
= 24V
0.1
1
3786 TA01b
LTC3786
10
10000
1000
100
10
1
0.1
1
3786f

Related parts for LTC3786EUD#PBF

LTC3786EUD#PBF Summary of contents

Page 1

... The PLLIN/MODE pin selects among Burst Mode continuous inductor current mode at light loads. L, LT, LTC, LTM, Burst Mode, OPTI-LOOP , Linear Technology and the Linear logo are registered trademarks and No R trademarks are the property of their respective owners. Protected Patents, including 5408150, 5481178, 5705919, 5929620, 6177787, 6498466, 6580258, 6611131 ...

Page 2

... TAPE AND REEL LTC3786EMSE#PBF LTC3786EMSE#TRPBF LTC3786IMSE#PBF LTC3786IMSE#TRPBF LTC3786EUD#PBF LTC3786EUD#TRPBF LTC3786IUD#PBF LTC3786IUD#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. ...

Page 3

ELECTRICAL CHARACTERISTICS junction temperature range, otherwise specifications are at T SYMBOL PARAMETER Main Control Loop VBIAS Chip Bias Voltage Operating Range V Regulated Feedback Voltage FB I Feedback Current FB V Reference Line Voltage Regulation REFLNREG V Output Voltage Load ...

Page 4

LTC3786 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER INTV Linear Regulator CC V Internal V Voltage INTVCC(VIN INT INTV Load Regulation LDO CC Oscillator and Phase-Locked Loop f Programmable Frequency PROG f Lowest Fixed ...

Page 5

TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Output Current 100 CCM EFFICIENCY 30 CMM LOSS BURST EFFICIENCY 20 BURST LOSS PULSE-SKIPPING EFFICIENCY 10 PULSE-SKIPPING LOSS 0 0.01 0.1 OUTPUT CURRENT (A) Efficiency vs ...

Page 6

LTC3786 TYPICAL PERFORMANCE CHARACTERISTICS Regulated Feedback Voltage vs Temperature 1.212 1.209 1.206 1.203 1.200 1.197 1.194 1.191 1.188 –45 – 105 TEMPERATURE (°C) 3786 G09 Shutdown Current vs Input Voltage ...

Page 7

TYPICAL PERFORMANCE CHARACTERISTICS INTV vs Load Current CC 5. 12V IN 5.45 5.40 5.35 5.30 5.25 5.20 5. 100 120 140 160 LOAD CURRENT (mA) 3786 G18 Oscillator Frequency vs Input Voltage 360 ...

Page 8

LTC3786 TYPICAL PERFORMANCE CHARACTERISTICS Charge Pump Charging Current vs Operating Frequency 110 V = 16.5V BOOST 100 V = 12V 150 250 350 450 550 650 OPERATING FREQUENCY ...

Page 9

PIN FUNCTIONS (MSOP/QFN) FREQ (Pin 7/Pin 9): The Frequency Control Pin for the Internal VCO. Connecting the pin to GND forces the VCO to a fixed low frequency of 350kHz. Connecting the pin to INTV forces the VCO to a ...

Page 10

LTC3786 BLOCK DIAGRAM PGOOD + 1.32V – – 1.08V 20μA FREQ CLK VCO PFD PLLIN/ MODE SYNC DET 100k VBIAS SHDN 5.4V – LDO INTV GND SHDN + 0.425V SLEEP – – ...

Page 11

OPERATION (Refer to the Block Diagram) Main Control Loop The LTC3786 uses a constant-frequency, current mode step-up control architecture. During normal operation, the external bottom MOSFET is turned on when the clock sets the RS latch, and is turned off ...

Page 12

LTC3786 OPERATION (Refer to the Block Diagram) In sleep mode, much of the internal circuitry is turned off and the LTC3786 draws only 55μA of quiescent current. In sleep mode, the load current is supplied by the output capacitor. As ...

Page 13

OPERATION (Refer to the Block Diagram) The typical capture range of the LTC3786’s PLL is from approximately 55kHz to 1MHz, and is guaranteed to lock to an external clock source whose frequency is between 75kHz and 850kHz. The typical input ...

Page 14

LTC3786 APPLICATIONS INFORMATION The Typical Application on the first page is a basic LTC3786 application circuit. LTC3786 can be configured to use either inductor DCR (DC resistance) sensing or a discrete sense resistor (R ) for current sensing. The choice ...

Page 15

APPLICATIONS INFORMATION less half the peak-to-peak ripple current, ΔI the sense resistor value, use the equation: V SENSE(MAX SENSE Δ MAX 2 When using the controller in low V IN output applications, the maximum inductor ...

Page 16

LTC3786 APPLICATIONS INFORMATION Inductor Value Calculation The operating frequency and inductor selection are inter- related in that higher operating frequencies allow the use of smaller inductor and capacitor values. Why would anyone ever choose to operate at lower frequencies with ...

Page 17

APPLICATIONS INFORMATION which accounts for the loss caused by reverse recovery current, is inversely proportional to the gate drive current and has an empirical value of 1.7. 2 Both MOSFETs have I R losses while the bottom N-channel equation includes ...

Page 18

LTC3786 APPLICATIONS INFORMATION Soft-Start (SS Pin) The start-up of the V is controlled by the voltage on the OUT SS pin. When the voltage on the SS pin is less than the internal 1.2V reference, the LTC3786 regulates the VFB ...

Page 19

APPLICATIONS INFORMATION the INTV supply to collapse and effectively shut down CC the entire LTC3786 chip. Once the junction temperature drops back to approximately 155°C, the INTV back on. Long-term overstress (T J avoided as it can degrade the performance ...

Page 20

LTC3786 APPLICATIONS INFORMATION In forced continuous mode, if the duty cycle falls below what can be accommodated by the minimum on-time, the controller will begin to skip cycles but the output will continue to be regulated. More cycles will be ...

Page 21

APPLICATIONS INFORMATION The ITH series R -C filter sets the dominant pole-zero C C loop compensation. The values can be modified slightly to optimize transient response once the final PCB layout is complete and the particular output capacitor type and ...

Page 22

LTC3786 APPLICATIONS INFORMATION C is chosen to filter the square current in the output. OUT The maximum output current peak is: ⎛ RIPPLE • 1+ ⎜ OUT(PEAK) OUT(MAX) ⎝ ⎛ ⎞ 31 • 1+ ⎟ ...

Page 23

APPLICATIONS INFORMATION Reduce V from its nominal level to verify operation with IN high duty cycle. Check the operation of the undervoltage lockout circuit by further lowering V the outputs to verify operation. Investigate whether any problems exist only at ...

Page 24

LTC3786 APPLICATIONS INFORMATION C 0.1μ 15nF ITH R 8.66k ITH C 220pF ITHA R 12. 232k OUTB D: BAS140W L: PULSE PA1494.362NL MBOT, MTOP: RENESAS HAT2169H *WHEN V C 0.1μF ...

Page 25

APPLICATIONS INFORMATION C 0.1μ 15nF ITH R 8.66k ITH C 220pF ITHA R 12. 357k OUTB D: BAS170W L: PULSE PA2050.103NL MBOT, MTOP: RENESAS RJIC0652DPB *WHEN V C 0.1μ 100nF ITH ...

Page 26

LTC3786 APPLICATIONS INFORMATION 60.4k RUN f = 400kHz SW FREQ C SS 0.1μ ITH R ITH 10nF 4.64k ITH C ITHA 100pF R A 12.1k VFB R B 88. TDK C4532X5R1E226M IN OUTA C ...

Page 27

APPLICATIONS INFORMATION PLLIN/MODE RUN FREQ C SS 0.1μ ITH R ITH 6.8nF 5.11k ITH C ITHA 100pF R A 150k VFB R B 475k TDK C3225X5R1A476M IN OUT L: TOKO FDV0840-R67M MBOT, MTOP: INFINEON ...

Page 28

LTC3786 APPLICATIONS INFORMATION C SS 0.1μF C ITH R ITH 15nF 8.87k C ITHA 220pF R A 12. 232k C1: TDK C1005X7R1C104K OUTB L: PULSE PA2050.103NL MBOT, MTOP: RENESAS RJK0305 D: INFINEON BAS140W ...

Page 29

APPLICATIONS INFORMATION DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY 25k f = 105kHz SW C ITH R 22nF 8.66k C ITHA 100pF 16. 22nF ITH R ITH C ITHA 12.1k 1% Figure 16. ...

Page 30

LTC3786 PACKAGE DESCRIPTION 2.845 0.102 (.112 .004) 5.23 (.206) MIN 0.305 0.038 (.0120 .0015) TYP RECOMMENDED SOLDER PAD LAYOUT DETAIL “A” 0.254 (.010) GAUGE PLANE DETAIL “A” 0.18 (.007) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. ...

Page 31

... ON THE TOP AND BOTTOM OF PACKAGE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. UD Package 16-Lead Plastic QFN (3mm × ...

Page 32

... OUT ≤ 38V 60V, 50kHz to 900kHz, 5mm × 5mm OUT ≤ 38V, Boost Output Voltage Up to 60V, 50kHz to 900kHz, ≤ 36V, Burst Mode IN ≤ 30V, SSOP-24, 5mm × 5mm QFN-32 OUT LT 1010 • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2010 3786f ...

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