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LTC4444-5

44445fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

High Voltage Synchronous

N-Channel MOSFET Driver

The LTC

4444-5 is a high frequency high voltage gate

driver that drives two N-channel MOSFETs in a synchro-

nous DC/DC converter with supply voltages up to 100V.

This powerful driver reduces switching losses in MOSFETs

with high gate capacitance.

The LTC4444-5 is configured for two supply-indepen-

dent inputs. The high side input logic signal is internally

level-shifted to the bootstrapped supply, which may func-

tion at up to 114V above ground.

The LTC4444-5 contains undervoltage lockout circuits that

disable the external MOSFETs when activated. Adaptive

shoot-through protection prevents both MOSFETs from

conducting simultaneously.

For a similar driver in this product family, please refer to

the chart below.

PARAMETER LTC4444-5 LTC4446 LTC4444

Shoot-Through Protection Yes No Yes

Absolute Max TS 100V 100V 100V

MOSFET Gate Drive 4.5V to 13.5V 7.2V to 13.5V 7.2V to 13.5V

4V 6.6V 6.6V

–

3.5V 6.15V 6.15V

Bootstrap Supply Voltage to 114V

Wide V

Voltage: 4.5V to 13.5V

Adaptive Shoot-Through Protection

1.4A Peak Top Gate Pull-Up Current

1.75A Peak Bottom Gate Pull-Up Current

1.5 Top Gate Driver Pull-Down

0.75 Bottom Gate Driver Pull-Down

5ns Top Gate Fall Time Driving 1nF Load

8ns Top Gate Rise Time Driving 1nF Load

3ns Bottom Gate Fall Time Driving 1nF Load

6ns Bottom Gate Rise Time Driving 1nF Load

Drives Both High and Low Side N-Channel MOSFETs

Undervoltage Lockout

Thermally Enhanced 8-Pin MSOP Package

Distributed Power Architectures

Automotive Power Supplies

High Density Power Modules

Telecommunication Systems

High Input Voltage Buck Converter LTC4444-5 Driving a 1000pF Capacitive Load

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

No R

SENSE

is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners. Protected by U.S. Patents, including 6677210.

BOOST

100V

GND

TINP

LTC4444-5

PWM2

(FROM CONTROLLER IC)

PWM1

(FROM CONTROLLER IC)

4.5V TO 13.5V

BINP

OUT

44445 TA01a

BINP

5V/DIV

TINP

5V/DIV

TG-TS

5V/DIV

20ns/DIV

44445 TA01b

Summary of content (14 pages)

PAGE 1
LTC4444-5 High Voltage Synchronous N-Channel MOSFET Driver FEATURES DESCRIPTION n The LTC®4444-5 is a high frequency high voltage gate driver that drives two N-channel MOSFETs in a synchronous DC/DC converter with supply voltages up to 100V. This powerful driver reduces switching losses in MOSFETs with high gate capacitance. n n n n n n n n n n n n n Bootstrap Supply Voltage to 114V Wide VCC Voltage: 4.5V to 13.5V Adaptive Shoot-Through Protection 1.4A Peak Top Gate Pull-Up Current 1.
PAGE 2
LTC4444-5 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage VCC......................................................... –0.3V to 14V BOOST – TS ........................................... –0.3V to 14V TINP Voltage ................................................. –2V to 14V BINP Voltage ................................................. –2V to 14V BOOST Voltage .........................................–0.3V to 114V TS Voltage ..................................................
PAGE 3
LTC4444-5 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VCC = VBOOST = 6V, VTS = GND = 0V, unless otherwise noted. SYMBOL PARAMETER ITINP(BINP) Input Pin Bias Current CONDITIONS MIN TYP MAX ±0.01 ±2 UNITS μA High Side Gate Driver Output (TG) VOH(TG) TG High Output Voltage ITG = –10mA, VOH(TG) = VBOOST – VTG 0.
PAGE 4
LTC4444-5 TYPICAL PERFORMANCE CHARACTERISTICS VCC Supply Quiescent Current vs Voltage 400 325 TINP = 6V, BINP = 0V 320 350 TINP = BINP = 0V 350 QUIESCENT CURRENT (μA) QUIESCENT CURRENT (μA) 400 TA = 25°C BOOST = 6V TS = GND VCC Supply Current vs Temperature 300 TINP (BINP) = 6V 250 200 150 100 TINP = 0V, BINP = 6V 300 250 200 150 100 50 50 0 0 TINP = BINP = 0V TA = 25°C VCC = 6V TS = GND 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 VCC SUPPLY VOLTAGE (V) 44445 G01 0 1 2 3 4 5 6 7 8 9 10 11 12 13
PAGE 5
LTC4444-5 TYPICAL PERFORMANCE CHARACTERISTICS 4.2 VCC = BOOST = 6V TS = GND 450 425 400 4.0 RISING THRESHOLD 3.9 3.8 3.7 FALLING THRESHOLD 3.6 3.5 375 –55 –25 5 35 65 95 TEMPERATURE (°C) 3.4 –55 125 150 5 35 65 95 TEMPERATURE (°C) 125 150 44445 G11 70 3.0 PULL-UP CURRENT (A) 60 tr(TG) 50 tr(BG) 40 tf(TG) 30 tf(BG) 20 OUTPUT DRIVER PULL-DOWN RESISTANCE (Ω) TA = 25°C VCC = BOOST = 6V TS = GND IPU(BG) VCC = 12V IPU(TG) BOOST–TS = 12V 2.5 2.0 IPU(BG) VCC = 6V 1.
PAGE 6
LTC4444-5 TYPICAL PERFORMANCE CHARACTERISTICS Switching Supply Current vs Input Frequency SUPPLY CURRENT (mA) 1000 TA = 25°C VCC = BOOST = 6V TS = GND 1.6 1.4 1.2 IBOOST (TG SWITCHING) 1.0 IVCC (BG SWITCHING) 0.8 0.6 IVCC (TG SWITCHING) 0.4 SUPPLY CURRENT (mA) 1.8 Switching Supply Current vs Load Capacitance IVCC (BG SWITCHING AT 1MHz) 100 IBOOST (TG SWITCHING IBOOST AT 1MHz) (TG SWITCHING AT 1MHz) IVCC IVCC 1 (TG SWITCHING AT 500kHz) (TG SWITCHING AT 1MHz) 10 IBOOST (BG SWITCHING) 0.
PAGE 7
LTC4444-5 BLOCK DIAGRAM 6 4.5V TO 13.
PAGE 8
LTC4444-5 OPERATION Overview Output Stage The LTC4444-5 receives ground-referenced, low voltage digital input signals to drive two N-channel power MOSFETs in a synchronous buck power supply configuration. The gate of the low side MOSFET is driven either to VCC or GND, depending on the state of the input. Similarly, the gate of the high side MOSFET is driven to either BOOST or TS by a supply bootstrapped off of the switching node (TS).
PAGE 9
LTC4444-5 OPERATION pull-down on the driver outputs is the prevention of crossconduction current. For example, when BG turns the low side (synchronous) power MOSFET off and TG turns the high side power MOSFET on, the voltage on the TS pin will rise to VIN very rapidly. This high frequency positive voltage transient will couple through the CGD capacitance of the low side power MOSFET to the BG pin.
PAGE 10
LTC4444-5 APPLICATIONS INFORMATION At a particular switching frequency, the internal power loss increases due to both AC currents required to charge and discharge internal node capacitances and cross-conduction currents in the internal logic gates. The sum of the quiescent current and internal switching current with no load are shown in the Typical Performance Characteristics plot of Switching Supply Current vs Input Frequency.
PAGE 11
LTC4444-5 TYPICAL APPLICATION LTC3780 High Efficiency 36V to 72V VIN to 48V/6A Buck-Boost DC/DC Converter VBIAS 6V VBIAS 10k 0.022μF SENSE+ 1000pF 100pF 0.1μF 100V 1 68pF SENSE– 100Ω 2 8.25k 1% 47pF D5 2.2μF 100V s4 SW1 – VIN 6 7 9 VIN 11 12 SENSE ITH EXTVCC VOSENSE INTVCC SGND RUN PGND FCB BG2 PLLFLTR SW2 PLLIN TG2 STBYMD 21 4 0.1μF 16V 20 19 18 10μF 10V 17 BG TS 8 + VIN 36V TO 72V C1 100μF 100V 0.22μF 16V VOS+ GND 1μF 16V 10W 9 L1 10μH D3 16 D4 2.
PAGE 12
LTC4444-5 PACKAGE DESCRIPTION MS8E Package 8-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1662 Rev I) BOTTOM VIEW OF EXPOSED PAD OPTION 1.88 (.074) 1 1.88 t 0.102 (.074 t .004) 0.29 REF 1.68 (.066) 0.889 t 0.127 (.035 t .005) 0.05 REF 5.23 (.206) MIN DETAIL “B” CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY NO MEASUREMENT PURPOSE 1.68 t 0.102 3.20 – 3.45 (.066 t .004) (.126 – .136) 8 3.00 t 0.102 (.118 t .004) (NOTE 3) 0.65 (.0256) BSC 0.42 t 0.038 (.
PAGE 13
LTC4444-5 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 06/10 Updates to Description 1 Updates to temperature ranges in Order Information 2 Updates to Notes 2 and 3 in Electrical Characteristics 3 Updates to graphs G03, G04, G08, G10, G11, G14, G15, G17 C 01/11 4, 5, 6 Updates to Pin 9 text in Pin Functions 6 Updates to Block Diagram 7 Updates to Timing Diagram section 7 Updates to “Adaptive Shoot-Through Protection” paragraph 9 Updates to R
PAGE 14
LTC4444-5 TYPICAL APPLICATION LTC3780 High Efficiency 8V to 80V VIN to 12V/5A Buck-Boost DC/DC Converter VBIAS 0.1μF 0.01μF SENSE+ 100pF VOS+ 113k 1% 0.1μF 1 68pF SENSE– 100Ω 2 8.06k 1% SENSE– 6 7 220k 10 11 2.2μF, 100V, TDK C4532X7R2A225MT 100μF, 100V SANYO 100ME 100AX C1: SANYO 16ME330WF D1: DIODES INC. BAV19WS D2: DIODES INC. 1N5819HW-7-F D3: DIODES INC. B320A-13-F D4: DIODES INC. MMBZ5230B-7-F D5: DIODES INC.