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Part: LT1618
Category:
Power Management
-> Regulators
-> Switching Regulators
Description: LT1618, 8+ Leds, 1.4MHz Constant-current/constant-voltage Step-up DC/DC Converter
Company: Linear Technology Corporation
Datasheet: Download LT1618 datasheet File size : 550 kB
Request For quote: Find where to buy LT1618
Datasheet text preview:
LT1618 Constant-Current/ Constant-Voltage 1.4MHz Step-Up DC/DC Converter
FEATURES
s s s s s s s
DESCRIPTIO
Accurate Input/Output Current Control: ±5% Over Temperature Accurate Output Voltage Control: ±1% Wide VIN Range: 1.6V to 18V 1.4MHz Switching Frequency High Output Voltage: Up to 35V Low VCESAT Switch: 200mV at 1A Tiny 10-Pin MSOP Package
APPLICATIO S
s s s s
The LT®1618 step-up DC/DC converter combines a traditional voltage feedback loop and a unique current feedback loop to operate as a constant-current, constant-voltage source. This fixed frequency, current mode switcher operates from a wide input voltage range of 1.6V to 18V, and the high switching frequency of 1.4MHz permits the use of tiny, low profile inductors and capacitors. The current sense voltage is set at 50mV and can be adjusted using the IADJ pin. Available in the 10-Pin MSOP package, the LT1618 provides a complete solution for constant-current applications.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
USB to 12V Boost Converter (with Selectable 100mA/500mA Input Current Limit)
VIN 5V 0.1 L1 10µH D1 VOUT 12V 7 SW LT1618 8 3.3V OFF ON 0V 20k 9 VIN SHDN IADJ GND 4 3.3V 100mA 500mA 0V 5 VC 10 2k 13k 10nF FB
90 85
2 C1 4.7µF 3 ISN ISP
1 R2 107k
C2 4.7µF
EFFICIENCY (%)
R1 909k
80 75 70 65 60
0
20
C1: TAIYO YUDEN JMK212BJ475 C2: TAIYO YUDEN EMK316BJ475 D1: ON SEMICONDUCTOR MBR0520 L1: SUMIDA CR43-100
1618 TA01a
U
Efficiency Curve
60 80 100 120 140 160 40 LOAD CURRENT (mA)
1618 TA01b
U
U
1
LT1618
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW FB ISN ISP IADJ GND 1 2 3 4 5 10 9 8 7 6 VC SHDN VIN SW N/C
VIN, SHDN Voltage ......... 18V SW Voltage ..... 36V ISP, ISN Voltage ...... 36V IADJ Voltage ...... 6V FB Voltage ..... 1.5V VC Voltage ..... 1.5V Junction Temperature .......... 125°C Operating Temperature Range (Note 2) .. 40°C to 85°C Storage Temperature Range ........ 65°C to 150°C Lead Temperature (Soldering, 10 sec)......... 300°C
ORDER PART NUMBER LT1618EMS MS10 PART MARKING LTNH
MS10 PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 125°C, JA = 160°C/W
Consult LTC marketing for parts specified with wider operating temperature ranges.
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.6V, VSHDN = 1.6V, unless otherwise noted.
PARAMETER Input Voltage Quiescent Current Reference Voltage Reference Voltage Line Regulation FB Pin Bias Current Error Amplifier Voltage Gain Error Amplifier Transconductance Error Amplifier Sink Current Error Amplifier Source Current Current Sense Voltage (ISP, ISN) ISP , ISN Pin Bias Currents (Note 3) (ISP , ISN) Common Mode Minimum Voltage Switching Frequency Maximum Switch Duty Cycle Switch Current Limit Switch VCESAT ISW = 1A VFB = 1V VFB = 0V
q
ELECTRICAL CHARACTERISTICS
CONDITIONS VSHDN = 1.6V, Not Switching VSHDN = 0V Measured at FB Pin
q
MIN 1.6
TYP 1.8 0.1
MAX 18 2.7 1 1.276 1.283 0.03 ±12
UNITS V mA µA V V %/V nA V/V µmho µA µA
1.250 1.243
1.263 1.263 0.01 ±2 180 160 15 30
1.6V < VIN < 18V VFB = 1.263V, VIN = 1.8V IC = ± 5µA VFB = 1.35V, VC = 1V VFB = 1.10V, VC = 1V VFB = 0V, VIADJ = 0V VISP = 1.85V, VISN = 1.80V, VIADJ = 0V 1.25 88 1.5
q q
47.5
50 50 1.4 550 92 2.1 200
52.5 80 1.8 1.6
MHz kHz % A mV
2.8 260
2
U
mV µA V
W
U
U
WW
W
LT1618
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.6V, VSHDN = 1.6V, unless otherwise noted.
PARAMETER Switch Leakage Current SHDN Pin Current Shutdown Threshold (SHDN Pin) Start-Up Threshold (SHDN Pin) Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT1618 is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the 40°C to 85°C operating 1 CONDITIONS Switch Off, VSW = 5V VSHDN = 1.6V MIN TYP 0.01 5 MAX 5 20 0.3 UNITS µA µA V V
ELECTRICAL CHARACTERISTICS
temperature range are assured by design, characterization, and correlation with statistical process controls. Note 3: Bias currents flow into the ISP and ISN pins.
TYPICAL PERFOR A CE CHARACTERISTICS
Switch Saturation Voltage (VCE, SAT)
500
1.270
SATURATION VOLTAGE (mV)
400 TJ = 125°C 300 TJ = 25°C 200 TJ = 50°C
FEEDBACK VOLTAGE (V)
VOLTAGE
PEAK CURRENT (A)
100
0
0
1.0 0.5 1.5 SWITCH CURRENT (A)
Current Sense Voltage (IADJ Pin = 0V)
52 CURRENT SENSE VOLTAGE (mV)
CURRENT SENSE VOLTAGE (mV) 60 50 40 30 20 10
51
QUIESCENT CURRENT (mA)
50
49
48 50 25
25 50 75 0 TEMPERATURE (°C)
UW
2.0
1618 G01
FB Pin Voltage and Bias Current
4
Switch Current Limit
2.5
1.265
2
2.0
FB PIN BIAS CURRENT (nA)
1.5
1.260 CURRENT
0
1.0
1.255
2
0.5
1.250 50 25
75 25 50 0 TEMPERATURE (°C)
100
4 125
0 50 25
75 25 50 0 TEMPERATURE (°C)
100
125
1618 G02
1618 G03
Current Sense Voltage (VISP, ISN)
2.5
Quiescent Current
2.0
VIN = 18V VIN = 1.6V
1.5
1.0
0.5
100
125
0 0.0
0.2
0.4 0.6 0.8 1.0 1.2 IADJ PIN VOLTAGE (V)
1.4
1.6
0 50 25
25 50 75 0 TEMPERATURE (°C)
100
125
1618 G04
1618 G05
1618 G06
3
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