LT3435EFE#PBF Linear Technology, LT3435EFE#PBF Datasheet

IC REG SW HV 3A 500KHZ 16-TSSOP

LT3435EFE#PBF

Manufacturer Part Number
LT3435EFE#PBF
Description
IC REG SW HV 3A 500KHZ 16-TSSOP
Manufacturer
Linear Technology
Type
Step-Down (Buck)r
Datasheet

Specifications of LT3435EFE#PBF

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.25 ~ 54 V
Current - Output
3A
Frequency - Switching
500kHz
Voltage - Input
3.3 ~ 60 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
Primary Input Voltage
60V
No. Of Outputs
1
Output Voltage
68V
Output Current
2.4A
No. Of Pins
16
Operating Temperature Range
-40°C To +125°C
Msl
MSL 1 - Unlimited
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LT3435EFE#PBFLT3435EFE
Manufacturer:
LT
Quantity:
13
Company:
Part Number:
LT3435EFE#PBF
Manufacturer:
LINEAR/凌特
Quantity:
20 000
FEATURES
TYPICAL APPLICATIO
Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners. *Protected by U.S. Patents including 6498466
**See Burst Mode Operation section for conditions.
APPLICATIO S
4700pF
, LTC and LT are registered trademarks of Linear Technology Corporation.
Wide Input Range: 3.3V to 60V
3A Peak Switch Current
Burst Mode
Low Shutdown Current: I
Power Good Flag with Programmable Threshold
Load Dump Protection to 60V
500kHz Switching Frequency
Saturating Switch Design: 0.1Ω On-Resistance
Peak Switch Current Maintained Over
Full Duty Cycle Range*
1.25V Feedback Reference Voltage
Easily Synchronizable
Soft-Start Capability
Small 16-Pin Thermally Enhanced TSSOP Package
High Voltage Power Conversion
14V and 42V Automotive Systems
Industrial Power Systems
Distributed Power Systems
Battery-Powered Systems
USB Powered Systems
10k
V
IN
14V to 3.3V Step-Down Converter with
1µF
100µA No Load Quiescent Current
4.7µF
100V
CER
470pF
®
Operation: 100µA Quiescent Current**
V
SHDN
C
SYNC
GND
V
IN
T
C
LT3435
U
BOOST
V
PGFB
BIAS
C
SW
PG
SS
FB
0.1µF
Q
0.33µF
27pF
< 1µA
B360A
U
15µH
165k
100k
1%
1%
4148
+
3435 TA01
100µF
10V
TANT
V
3.3V
2A
OUT
Step-Down Switching Regulator
150
125
100
with 100µA Quiescent Current
75
50
25
Supply Current vs Input Voltage
0
0
10
DESCRIPTIO
The LT
regulator that accepts input voltages up to 60V. A high
efficiency 3A, 0.1Ω switch is included on the die along with
all the necessary oscillator, control and logic circuitry.
Current mode topology is used for fast transient response
and good loop stability.
Innovative design techniques along with a new high volt-
age process achieve high efficiency over a wide input
range. Efficiency is maintained over a wide output current
range by employing Burst Mode operation at low currents,
utilizing the output to bias the internal circuitry, and by
using a supply boost capacitor to fully saturate the power
switch. Patented circuitry maintains peak switch current
over the full duty cycle range.* Shutdown reduces input
supply current to less than 1µA. External synchronization
can be implemented by driving the SYNC pin with logic-level
inputs. A single capacitor from the C
provides a controlled output voltage ramp (soft-start). The
device also has a power good flag with a programmable
threshold and time-out and thermal shutdown protection.
The LT3435 is available in a 16-pin TSSOP package with an
exposed pad leadframe for low thermal resistance.
INPUT VOLTAGE (V)
20
High Voltage 3A, 500kHz
30
®
3435 is a 500kHz monolithic buck switching
40
V
OUT
T
A
50
= 25°C
= 3.3V
3435 TA03
60
U
100
90
80
70
60
50
40
30
20
10
0.0001
0
V
V
Efficiency and Power Loss
IN
OUT
= 12V
= 5V
0.001
V
OUT
vs Load Current
EFFICIENCY
LOAD CURRENT (A)
= 3.3V
0.01
SS
pin to the output
0.1
TYPICAL
POWER LOSS
LT3435
1
3435 TA02
10
10
1
0.1
0.01
0.001
3435fa
1

Related parts for LT3435EFE#PBF

LT3435EFE#PBF Summary of contents

Page 1

... USB Powered Systems , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Protected by U.S. Patents including 6498466 **See Burst Mode Operation section for conditions. ...

Page 2

LT3435 ABSOLUTE AXI U RATI GS (Note SHDN, BIAS, PGOOD, SW ............................... 60V IN BOOST Pin Above SW ............................................ 35V BOOST Pin Voltage ................................................. 68V SYNC PGFB, FB ................................................ 6V SS Operating ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T unless otherwise noted. SYMBOL PARAMETER EA Source Current EA Sink Current High Clamp Current Limit PK Switch On Resistance (Note 9) ...

Page 4

LT3435 W U TYPICAL PERFOR A CE CHARACTERISTICS FB Voltage 1.30 1.29 1.28 1.27 1.26 1.25 1.24 1.23 1.22 1.21 1.20 – 125 –25 100 TEMPERATURE (°C) 3435 G01 SHDN Pin Current 5 25°C ...

Page 5

W U TYPICAL PERFOR A CE CHARACTERISTICS Switch Peak Current Limit 6.0 5.5 5.0 4.5 4.0 3.5 3.0 –50 –25 – 100 125 TEMPERATURE (°C) 3435 G10 Switch On Voltage (V ) CESAT 500 450 400 T ...

Page 6

LT3435 W TYPICAL PERFOR A CE CHARACTERISTICS Dropout Operation 4 3.3V OUT BOOST DIODE = DIODES INC DFLS160 3.5 3.0 2.5 2.0 1.5 LOAD CURRENT = 2.5A 1.0 LOAD CURRENT = 250mA 0 2.5 3 3.5 ...

Page 7

CTIO S When the PGFB pin rises above V PGFB from the C pin into the external capacitor. When the volt- T age on the external capacitor reaches an internal clamp (V ), the PG ...

Page 8

LT3435 W BLOCK DIAGRA V IN INTERNAL REF 4 UNDERVOLTAGE LOCKOUT BIAS THERMAL 10 SHUTDOWN SYNC 14 SHDN + 15 SHDN COMP – 1. SOFT-START 9 FOLDBACK DETECT FB – 12 ERROR AMP + 1.25V ...

Page 9

W BLOCK DIAGRA power from the V pin, but if the BIAS pin is connected external voltage higher than 3V bias power will be drawn from the external source (typically the regulated output voltage). This improves efficiency. ...

Page 10

LT3435 U U APPLICATIO S I FOR ATIO and Soft-Start Current graphs in Typical Performance Characteristics). Frequency foldback is done to control power dissipation in both the IC and in the external diode and inductor during short-circuit conditions. A shorted ...

Page 11

U U APPLICATIO S I FOR ATIO taken to ensure the ripple and surge ratings are not exceeded. The AVX TPS and Kemet T495 series are surge rated AVX recommends derating capacitor operating volt- age by 2:1 for high surge ...

Page 12

LT3435 U U APPLICATIO S I FOR ATIO V OUT 20mV/DIV AC-COUPLED C = 100µF OUT TANTALUM ESR 100mΩ V OUT 20mV/DIV AC-COUPLED C = 100µF OUT CERAMIC V SW 5V/DIV V = 12V 500ns/DIV 3.3V OUT ...

Page 13

U U APPLICATIO S I FOR ATIO To calculate actual peak switch current in continuous mode with a given set of conditions, use – V OUT IN OUT = + ( )( )( ) ...

Page 14

... After making an initial choice, consider the secondary things like output voltage ripple, second sourcing, etc. Use the experts in the Linear Technology’s applications department if you feel uncertain about the final choice. They have experience with a wide range of inductor types and can tell you about the latest developments in low profile, surface mounting, etc ...

Page 15

U U APPLICATIO S I FOR ATIO ramp rate. When the current through the C exceeds the C threshold (I ), the voltage ramp of the SS CSS output capacitor is limited by reducing the V The C threshold is ...

Page 16

LT3435 U U APPLICATIO S I FOR ATIO load condition can be anticipated, the supply current can be further reduced by cycling the SHDN pin at a rate higher than the natural no load burst frequency. Figure ...

Page 17

U U APPLICATIO S I FOR ATIO output voltage is less than 3. recommended that an alternate boost supply is used. The boost diode can be connected to the input (Figure 7b) but care must be taken to ...

Page 18

LT3435 U U APPLICATIO S I FOR ATIO Example – Ω µ Ω Ω ...

Page 19

U U APPLICATIO S I FOR ATIO threshold during normal operation, the C discharged and PG inactive, resulting in a non Power Good cycle when SHDN is taken above its threshold. Figure 9 shows the power good operation with PGFB ...

Page 20

LT3435 U U APPLICATIO S I FOR ATIO parasitic inductance produces a flyback spike across the LT3435 switch. When operating at higher currents and input voltages, with poor layout, this spike can generate voltages across the LT3435 that may exceed ...

Page 21

U U APPLICATIO S I FOR ATIO Example: with V = 25V and I IN OUT ( )( ) ( ) – ...

Page 22

LT3435 U U APPLICATIO S I FOR ATIO catch diode and connecting the V ground track carrying significant switch current. In addi- tion the theoretical analysis considers only first order non- ideal component behavior. For these reasons important ...

Page 23

... DIMENSIONS ARE IN 3. DRAWING NOT TO SCALE 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights Package 16-Lead Plastic TSSOP (4 ...

Page 24

... I = 100µA, TSSOP-16E IN OUT Q : 3.3V to 60V 100µA, I < 1µ 36V 0.8V 670µ OUT(MIN 0306 REV A • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2005 < 15µA, < 6µA, < 1µA, < 1µA, SD < 1µA, < 1µA, SD < 20µA, 3435fa ...

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