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Part: LT1611CS5
Category:
Power Management
-> Regulators
-> Switching Regulators
-> Inverting
Description: LT1611, 550mA, Inverting 1.4MHz Switching Regulator in 5-Lead SOT-23
Company: Linear Technology Corporation
Datasheet: Download LT1611CS5 datasheet File size : 550 kB
Request For quote: Find where to buy LT1611CS5
Datasheet text preview:
LT1611 Inverting 1.4MHz Switching Regulator in SOT-23
FEATURES
s s s s s s s s s s
DESCRIPTIO
Very Low Noise: 1mVPP Output Ripple 5V at 150mA from a 5V Input Better Regulation Than a Charge Pump Effective Output Impedance: 0.14 Uses Tiny Capacitors and Inductors Internally Compensated Fixed Frequency 1.4MHz Operation Low Shutdown Current: <1µA Low VCESAT Switch: 300mV at 300mA Tiny 5-Lead SOT-23 Package
The LT®1611 is the industry's first inverting 5-lead SOT-23 current mode DC/DC converter. Intended for use in small, low power applications, it operates from an input voltage as low as 1.1V and switches at 1.4MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. Its small size and high switching frequency enable the complete DC/DC converter function to consume less than 0.25 square inches of PC board area. Capable of generating 5V at 150mA from a 5V supply or 5V at 100mA from a 3V supply, the LT1611 replaces nonregulated "charge pump" solutions in many applications. The LT1611 operates in a dual inductor inverting topology which filters the input side as well as the output side of the DC/DC converter. Fixed frequency switching ensures a clean output free from low frequency noise typically present with charge pump solutions. No load quiescent current of the LT1611 is 3mA, while in shutdown quiescent current drops to 0.5µA. The 36V switch allows VIN to VOUT differential of up to 33V. The LT1611 is available in the 5-lead SOT-23 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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MR Head Bias Digital Camera CCD Bias LCD Bias GaAs FET Bias Positive-to-Negative Conversion
TYPICAL APPLICATIO
VIN 5V VIN L1A 22µH
C2 1µF
L1B 22µH
D1 SW LT1611 NFB GND R2 10k R1 29.4k 1200pF SHDN C1 22µF
+
VOUT 5V 150mA C3 22µF
VOUT 20mV/DIV AC COUPLED
LOAD CURRENT C1: AVX TAJB226M010 C2: TAIYO YUDEN LMK212BJ105MG C3: TAIYO YUDEN JMK325BJ226MM (1210 SIZE) D1: MBR0520 L1: SUMIDA CLS62-220 OR 2× MURATA LQH3C220 (UNCOUPLED)
1611 TA01
150mA 50mA 100µs/DIV
1611 F10
Figure 1. 5V to 5V, 150mA Low Noise Inverting DC/DC Converter
U
Transient Response
U
U
1
LT1611
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW SW 1 GND 2 NFB 3 4 SHDN 5 VIN
VIN Voltage ..... 10V SW Voltage ...... 0.4V to 36V NFB Voltage .... 3V Current into NFB Pin ............ ±1mA SHDN Voltage .......... 10V Maximum Junction Temperature .. 125°C Operating Temperature Range Commercial ............ 0°C to 70°C Extended Commercial (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 LT1611CS5 S5 PART MARKING LTES
S5 PACKAGE 5-LEAD PLASTIC SOT-23
TJMAX = 125°C, JA = 256°C/W
Consult factory for Industrial and Military grade parts.
The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.5V, VSHDN = VIN unless otherwise noted.
PARAMETER Minimum Operating Voltage Maximum Operating Voltage NFB Pin Bias Current Feedback Voltage Quiescent Current Quiescent Current in Shutdown Reference Line Regulation Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Switch Leakage Current SHDN Input Voltage High SHDN Input Voltage Low SHDN Pin Bias Current VSHDN = 3V VSHDN = 0V 25 0 (Note 3) ISW = 300mA VSW = 5V 1 0.3 50 0.1 VSHDN = 1.5V, Not Switching VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V 1.5V VIN 10V
q q
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
TYP 0.9
MAX 1.1 10 6.7 1.255 4.5 0.5 1.0 0.2 1.8
UNITS V V µA V mA µA µA %/V MHz % mA
VNFB = 1.23V
q q
2.7 1.205
4.7 1.23 3 0.01 0.01 0.02
1.0 82 550
1.4 86 800 300 0.01
350 1
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: C grade device specifications are guaranteed over the 0°C to 70°C temperature range. In addition, C grade device specifications are assured over the 40°C to 85°C temperature range by design or correlation, but are not production tested.
Note 3: Current limit guaranteed by design and/or correlation to static test. Slope compensation reduces current limit at higher duty cycle.
2
U
W
U
U
WW
W
mV µA V V µA µA
LT1611 TYPICAL PERFOR A CE CHARACTERISTICS
Efficiency, VOUT = 5V
85 80 75 EFFICIENCY (%) 70 65 60 55 50 0 25 50 75 100 LOAD CURRENT (mA) 125 150
1611 G01
VIN = 5V
1.235
NFB PIN BIAS CURRENT (µA) 25 0 25 50 TEMPERATURE (°C) 75 100
1611 G02
VNFB (V)
VIN = 3V
Switch VCESAT vs Switch Current
700 600 500 TA = 25°C SHDN PIN BIAS CURRENT (µA) 40 50
SWITCH CURRENT LIMIT (mA)
VCESAT (mV)
400 300 200 100 0 0 100 200 300 400 500 SWITCH CURRENT (mA) 600 700
Oscillator Frequency vs Temperature
2.00 1.75 VIN = 5V OPERATING CURRENT (mA) 6.0 5.5
SWITCHING FREQUENCY (MHz)
SWITCH CURRENT LIMIT (mA)
1.50 1.25 1.00 0.75 0.50 0.25 0 50 VIN = 1.5V
25
0 25 50 TEMPERATURE (°C)
* Includes bias current through R1, R2 and Schottky leakage current at T 75°C
UW
1611 G04
VNFB vs Temperature
1.245 1.240 6 5 4 3 2 1
NFB Pin Bias Current vs Temperature
1.230 1.225 1.220 1.215 1.210 50
0 50
25
0 25 50 TEMPERATURE (°C)
75
100
1611 G03
SHDN Pin Bias Current vs VSHDN
900 800 700 600 500 400 300 200 100
Switch Current Limit vs Duty Cycle
TA = 25°C
30
20
10
0 0 1 2 3 4 SHDN PIN VOLTAGE (V) 5
1611 G05
0 10 20 30 40 50 60 DUTY CYCLE (%) 70 80
1611 G06
No-Load Operating Quiescent Current vs Temperature*
900 800 700 600 500 400 300 200 100
Switch Current Limit vs Temperature (Duty Cycle = 30%)
5.0 4.5 4.0 3.5 3.0 2.5
75
100
1611 G07
2.0 50
25
0 25 50 TEMPERATURE (°C)
75
100
1611 G08
0 50
25
0 25 50 TEMPERATURE (°C)
75
100
1611 G09
3
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