LT3782EFE-PBF LINER [Linear Technology], LT3782EFE-PBF Datasheet

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LT3782EFE-PBF

Manufacturer Part Number
LT3782EFE-PBF
Description
2-Phase Step-UP DC/DC Controller
Manufacturer
LINER [Linear Technology]
Datasheet
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FEATURES
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n
n
n
n
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APPLICATIONS
TYPICAL APPLICATION
10V TO 36V
Industrial Equipment
Telecom Infrastructure
Interleaved Isolated Power Supply
2-Phase Operation Reduces Required Input and
Output Capacitance
Programmable Switching Frequency:
150kHz to 500kHz
6V to 40V Input Range
10V Gate Drive with V
High Current Gate Drive (4A)
Programmable Soft-Start and Current Limit
Programmable Slope Compensation for
High Noise Immunity
MOSFET Gate Signals with Programmable
Falling Edge Delay for External Synchronous
Drivers
Programmable Undervoltage Lockout
Programmable Duty Cycle Clamp (50% or Higher)
Thermally Enhanced 28-Lead TSSOP and 4mm × 5mm
QFN Packages
100pF
V
10μF
IN
50V
C
2x
IN
825k
274k
R6
R8
R
R
SLOPE
59k
80k
FREQ
0.1μF
13k
1μF
6.8nF
V
RUN
SLOPE
DELAY
DCL
R
SS
V
CC
C
SET
CC
LT3782
≥13V
GND
50V 4A Boost Converter
SENSE1
SENSE1
SENSE2
SENSE2
BGATE1
BGATE2
GBIAS1
GBIAS2
GBIAS
V
V
EE1
EE2
FB
+
+
10Ω
+
10nF
C3
2μF
0.004Ω
L1
L2
R
S1
10Ω
10nF
M1
Si7852dp
2x
30BQ060
D1
30BQ060
M2
Si7852dp
2x
R
0.004Ω
S2
D2
3782 TA01
DESCRIPTION
The LT
converter controller. Its high switching frequency (up to
500kHz) and 2-phase operation reduce system fi ltering
capacitance and inductance requirements.
With 10V gate drive (V
the LT3782 can drive most industrial grade high power
MOSFETs with high effi ciency. For synchronous applica-
tions, the LT3782 provides synchronous gate signals with
programmable falling edge delay to avoid cross conduc-
tion when using external MOSFET drivers. Other features
include programmable undervoltage lockout, soft-start,
current limit, duty cycle clamp (50% or higher) and slope
compensation.
The LT3782 is available in thermally enhanced 28-lead
TSSOP and 4mm × 5mm QFN packages.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6144194.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
R
475k
F1
L1, L2: PB2020.223
C
IN
R
24.9k
®
, C
C
10μF
50V
2x
F2
3782 is a current mode two phase step-up DC/DC
OUT1
OUT1
+
: X7R, TDK
C
220μF
OUT2
V
50V, 4A
OUT
DC/DC Controller
2-Phase Step-UP
CC
≥13V) and 4A peak drive current,
97
95
93
91
89
87
85
0
Effi ciency and Power Loss
EFFICIENCY
1
vs Load Current
2
I
OUT
V
V
IN
IN
(A)
POWER LOSS
= 12V
= 12V
3
LT3782
V
V
IN
4
IN
= 24V
= 24V
3782 TA01b
5
18
15
12
9
6
3
0
3782ff
1

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LT3782EFE-PBF Summary of contents

Page 1

FEATURES n 2-Phase Operation Reduces Required Input and Output Capacitance n Programmable Switching Frequency: 150kHz to 500kHz 40V Input Range n 10V Gate Drive with V ≥13V CC n High Current Gate Drive (4A) n Programmable Soft-Start ...

Page 2

... RUN EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB PART MARKING PACKAGE DESCRIPTION LT3782EFE 28-Lead Plastic TSSOP LT3782IFE 28-Lead Plastic TSSOP 28-Lead (4mm × 5mm) Plastic QFN 3782 PART MARKING PACKAGE DESCRIPTION LT3782EFE 28-Lead Plastic SSOP LT3782IFE 28-Lead Plastic SSOP 28-Lead (4mm × ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER Overall Supply Voltage ( Supply Current (I ) VCC Shutdown RUN Threshold RUN Threshold Hysteresis Supply Current in Shutdown RUN Pin Input Current Voltage Amplifi ...

Page 4

LT3782 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER Gate Driver V GBIAS BGATE1, BGATE2 High Voltage BGATE1, BGATE2 Source Current (Peak) BGATE1, BGATE2 Low Voltage BGATE1, BGATE2 Sink Current (Peak) SGATE1, SGATE2 High Voltage SGATE1, SGATE2 ...

Page 5

TYPICAL PERFORMANCE CHARACTERISTICS GBIAS GBIAS 11.0 10.9 10.8 10.7 10.6 10.5 10.4 10.3 10.2 10.1 10 (mA) GBIAS 3782 G01 Switching Frequency vs R FREQ 600 500 400 300 200 100 ...

Page 6

LT3782 PIN FUNCTIONS (FE/UFD) SGATE2 (Pin 1/Pin 26): Second Phase Synchronous Drive Signal. An external driver buffer is needed to drive the top synchronous power FET. SGATE1 (Pin 2/Pin 27): First Phase Synchronous Drive Signal. An external driver buffer is ...

Page 7

BLOCK DIAGRAM – 1V AND CLAMPED AT 11V C GBIAS REGULATOR 20μF + LOW POWER SHUTDOWN R6 A5 RUN – 0. – + 2.44V BGATE1 ...

Page 8

LT3782 APPLICATIONS INFORMATION Operation The LT3782 is a two phase constant frequency current mode boost controller. Switching frequency can be programmed up to 500kHz. During normal switching cycles, the two channels are controlled by internal fl ip-fl ops and are ...

Page 9

APPLICATIONS INFORMATION With a 200ns one-shot timer on chip, the LT3782 provides fl exibility on the external sync pulse width. The sync pulse threshold is about 1.2V (Figure 1). Current Limit Current limit is set by the 60mV threshold across ...

Page 10

LT3782 APPLICATIONS INFORMATION then should be 80k and V FREQ1 FREQ2 be 1V, with V = 2.3V then R RSET FREQ1 = 32.5k (see Figure 3). Duty Cycle Limit When DCL pin is shorted to R pin ...

Page 11

APPLICATIONS INFORMATION The Peak and Average Input Currents The control circuit in the LT3782 measures the input current by using a sense resistor in each MOSFET source, so the output current needs to be refl ected back to the input ...

Page 12

LT3782 APPLICATIONS INFORMATION The gate drive voltage is set by the 10V GBIAS regulator. Consequently, 10V rated MOSFETs are required in most high voltage LT3782 applications. Pay close attention to the BV DSS MOSFETs relative to the maximum actual switch ...

Page 13

APPLICATIONS INFORMATION From a known power dissipated in the power MOSFET, its junction temperature can be obtained using the following formula • FET TH(JA) The used in this equation ...

Page 14

LT3782 APPLICATIONS INFORMATION For a given V and can calculate the duty cycle D IN OUT and then derive the output RMS ripple current from Figure 6. After choosing output capacitors with suffi cient RMS ripple current ...

Page 15

APPLICATIONS INFORMATION 2. Power MOSFET switching and conduction losses O(MAX • FET DS(ON) 1– D MAX I O(MAX • V • • RSS 1– D MAX 2 3. ...

Page 16

LT3782 APPLICATIONS INFORMATION For best electrical performance, the LT3782 circuit should be laid out as follows: Place all power components in a tight area. This will minimize the size of high current loops. Orient the input and output capacitors and ...

Page 17

TYPICAL APPLICATIONS 1 SGATE2 2 SGATE1 GND 5 SYNC 6 DELAY 7 DCL 10Ω CS1 SENSE1 10nF 9 – SENSE1 59k 10 SLOPE 82k 11 R SET 12 – SENSE2 10nF 10Ω CS2 ...

Page 18

LT3782 PACKAGE DESCRIPTION 4.75 (.187) 6.60 ±0.10 4.50 ±0.10 SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 0.50 – 0.75 (.0035 – .0079) (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. ...

Page 19

PACKAGE DESCRIPTION 4.50 ± 0.05 3.10 ± 0.05 2.50 REF 2.65 ± 0.05 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 5.00 ± ...

Page 20

LT3782 TYPICAL APPLICATIONS 28V Output Base Station Power Converter with Redundant Input 1 SGATE2 2 SGATE1 GND 5 SYNC 6 DELAY 7 DCL 10Ω 8 CS1 SENSE1 10nF 9 SENSE1 59k 10 SLOPE 82k 11 R SET ...

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