LT1614CMS8

LT1614 LINER | Alldatasheet

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1614 is a fixed frequency, inverting mode switch- ing reglator that operates from an input voltage as low as 1V. Utilizing a low noise topology, the LT1614 can gener- ate a negative output down to –24V from a 1V to 5V input. Fixed frequency switching ensures a clean output free from low frequency noise. The device contains a low- battery detector with a 200mV reference and shuts down to less than 10µA. No load quiescent current of the LT1614 is 1mA and the internal NPN power switch handles a 500mA current with a voltage drop of just 295mV. High frequency switching enables the use of small induc- tors and capacitors. Ceramic capacitors can be used in many applications, eliminating the need for bulky tanta- lum types. The LT1614 is available in 8-lead MSOP or SO packages. n Better Regulation Than a Charge Pump n 0.1Ω Effective Output Impedance n –5V at 200mA from a 5V Input n 600kHz Fixed Frequency Operation n Operates with VIN as Low as 1V n 1mA Quiescent Current n Low Shutdown Current: 10µA n Low-Battery Detector n Low VCESAT Switch: 295mV at 500mA Final Electrical Specifications 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. , LTC and LT are registered trademarks of Linear Technology Corporation. n MR Head Bias n LCD Bias n GaAs FET Bias n Positive-to-Negative Conversion APPLICATIONSU TYPICAL APPLICATIONU 5V to – 5V Converter Efficiency5V to –5V Converter VIN SW LT1614 22µHVIN D1NFB SHDN 69.8k 24.9k100k 1nF VOUT –5V 200mA C1, C2: AVX TAJB336M010 C3: AVX 1206CY106 D1: MBR0520 L1, L2: MURATA LQH3C220

1614 TA01

33µF C2 33µFVC GND 22µH 1µF LOAD CURRENT (mA) 31 0 3 0 EFFICIENCY (%) 100 300

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A UGWA WU WARBSOLUTEX I T I S V Operating Temperature Range Extended Commercial Commercial Grade 0°C to 70°C. VIN = 1.5V, VSHDN = VIN, TA = 25°C unless otherwise noted. ELECTRICAL C CHARA TERISTICS PARAMETER CONDITIONS MIN TYP MAX UNITS Quiescent Current 12 m A VSHDN = 0V 5 10 µA Feedback Voltage l –1.21 –1.24 –1.27 V NFB Pin Bias Current (Note 2) V NFB = –1.24V l – 2.5 – 4.5 – 7 µA Reference Line Regulation 1V ≤ VIN ≤ 2V 0.6 1.1 %/V 2V ≤ VIN ≤ 6V 0.3 0.8 %/V Minimum Input Voltage 0.92 1 V Maximum Input Voltage l 6V Error Amp Transconductance ΔI = 5µA1 6 µmhos Error Amp Voltage Gain 100 V/V Switching Frequency l 500 600 750 kHz Maximum Duty Cycle 73 80 % l 70 80 % Switch Current Limit (Note 3) 0.75 1.2 A WU UPACKAGE/ORDER I FOR ATIO TJMAX = 125°C, θJA = 160°C/W Consult factory for Military grade parts. ORDER PART NUMBER LT1614CS8 LT1614IS8 S8 PART MARKING 1614 1614I ORDER PART NUMBER LT1614CMS8 MS8 PART MARKING LTEJ NFB V C SHDN GND LBO LBI V IN SW TOP VIEW MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 120°C/W TOP VIEW LBO LBI V IN SW NFB VC SHDN GND S8 PACKAGE 8-LEAD PLASTIC SO

PARAMETER CONDITIONS MIN TYP MAX UNITS Switch VCESAT ISW = 500mA (25°C, 0°C) 295 350 mV ISW = 500mA (70°C) 400 mV Shutdown Pin Current V SHDN = VIN 10 20 µA VSHDN = 0V –5 –10 µA LBI Threshold Voltage 190 200 210 mV l 185 215 mV LBO Output Low I SINK = 10µA 0.1 0.25 V LBO Leakage Current V LBI = 250mV, VLBO = 5V 0.01 0.1 µA LBI Input Bias Current (Note 4) V LBI = 150mV 10 50 nA Low-Battery Detector Gain 1M Ω Load 1000 V/V Switch Leakage Current V SW = 5V 0.01 3 µA Commercial Grade 0°C to 70°C. VIN = 1.5V, VSHDN = VIN, TA = 25°C unless otherwise noted. ELECTRICAL C CHARA TERISTICS The l denotes specifications which apply over the full operating temperature range. Note 1: The LT1614C is guaranteed to meet specified performance from 0°C to 70°C and is designed, characterized and expected to meet these extended temperature limits, but is not tested at –40 °C and 85°C. The LT1614I is guaranteed to meet the extended temperature limits. Industrial Grade – 40°C to 85°C. VIN = 1.5V, VSHDN = VIN unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Quiescent Current 12 m A VSHDN = 0V 5 10 µA Feedback Voltage l –1.21 –1.24 –1.27 V NFB Pin Bias Current (Note 2) V NFB = –1.24V l – 2 – 4.5 – 7.5 µA Reference Line Regulation 1V ≤ VIN ≤ 2V 0.6 1.1 %/V 2V ≤ VIN ≤ 6V 0.3 0.8 %/V Minimum Input Voltage –40 °C 1.1 1.25 V 85°C 0.8 1.0 V Maximum Input Voltage l 6V Error Amp Transconductance ΔI = 5µA1 6 µmhos Error Amp Voltage Gain 100 V/V Switching Frequency l 500 600 750 kHz Maximum Duty Cycle l 70 80 % Switch Current Limit (Note 3) 0.75 1.2 A Switch VCESAT ISW = 500mA (–40 °C) 250 350 mV ISW = 500mA (85°C) 330 400 mV Shutdown Pin Current V SHDN = VIN 10 20 µA VSHDN = 0V –5 –10 µA LBI Threshold Voltage l 180 200 220 mV LBO Output Low I SINK = 10µA 0.1 0.25 V LBO Leakage Current V LBI = 250mV, VLBO = 5V 0.1 0.3 µA LBI Input Bias Current (Note 4) V LBI = 150mV 5 30 nA Low-Battery Detector Gain 1M Ω Load 1000 V/V Switch Leakage Current V SW = 5V 0.01 3 µA Note 2: Bias current flows out of NFB pin. Note 3: Switch current limit guaranteed by design and/or correlation to static tests. Duty cycle affects current limit due to ramp generator. Note 4: Bias current flows out of LBI pin.

NFB (Pin 1): Negative Feedback Pin. Reference voltage is –1.24V. Connect resistive divider tap here. The sug- gested value for R2 is 24.9k. Set R1 and R2 according to: R V R OUT1 12 4 12 4 45 1 0 6 +  || ± . . .· ± VC (Pin 2): Compensation Pin for Error Amplifier. Con- nect a series RC from this pin to ground. Typical values are 100kΩ and 1nF. Minimize trace area at V SHDN (Pin 3): Shutdown. Ground this pin to turn off switcher. Must be tied to VIN (or higher voltage) to enable switcher. Do not float the SHDN pin. PIN FUNCTIONSUU U GND (Pin 4): Ground. Connect directly to local ground plane. SW (Pin 5): Switch Pin. Minimize trace area at this pin to keep EMI down. VIN (Pin 6): Supply Pin. Must have 1µF ceramic bypass capacitor right at the pin, connected directly to ground. LBI (Pin 7): Low-Battery Detector Input. 200mV refer- ence. Voltage on LBI must stay between ground and 700mV. Float this pin if not used. LBO (Pin 8): Low-Battery Detector Output. Open collec- tor, can sink 10µA. A 1MΩ pull-up is recommended. Float this pin if not used. BLOCK DIAGRAMW Σ COMPARATOR RAMP GENERATOR R BIAS VC gm ×10 NFB NFB ENABLE 200mV A = 3 FF ERROR AMPLIFIER 0.15Ω DRIVER SW GND 1614 BD Q3Q S 600kHz OSCILLATOR LBO LBI SHDN SHUTDOWN 3 40k 40k (EXTERNAL) 30k 140k VIN VIN VOUT (EXTERNAL)

Figure 1. Shutdown Circuit

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ence can also be accessed as shown in Figure 3.

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Figure 2. Setting Low-Battery Detector Trip Point

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Figure 3. Accessing 200mV Reference

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Figure 4. 5V to –5V Converter with Coupled Inductor

5V to –15V/80mA DC/DC Converter 5V to – 15V Converter Efficiency LOAD CURRENT (mA) EFFICIENCY (%) 10 100

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22µHVIN D1NFB SHDN 255k 24.9k100k 1nF VOUT –15V 80mA C1: 25V, Y5V D1: MBR0520 L1, L2: MURATA LQH3C220

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22µF 10µF 25VVC GND 22µH 1µF

Dimensions in inches (millimeters) unless otherwise noted.PACKAGE DESCRIPTIONU 1 2 3 4 0.150 – 0.157** (3.810 – 3.988) 8 7 6 5 0.189 – 0.197* (4.801 – 5.004) 0.228 – 0.244 (5.791 – 6.197) 0.016 – 0.050 0.406 – 1.270 0.010 – 0.020 0°– 8° TYP 0.008 – 0.010 (0.203 – 0.254) SO8 0996 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) TYP DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) MSOP (MS8) 1197 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 0.021 – 0.006 (0.53 – 0.015) 0° – 6° TYP SEATING PLANE 0.007 (0.18) 0.040 – 0.006 (1.02 – 0.15) 0.012 (0.30) REF 0.006 – 0.004 (0.15 – 0.102) 0.034 – 0.004 (0.86 – 0.102) 0.0256 (0.65) TYP 12 3 4 0.192 – 0.004 (4.88 – 0.10) 8 7 6 5 0.118 – 0.004* (3.00 – 0.102) 0.118 – 0.004** (3.00 – 0.102) 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610)

Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l TELEX: 499-3977  LINEAR TECHNOLOGY CORPORA TION 1998 1614i LT/GP 0798 4K • PRINTED IN THE USA TYPICAL APPLICATIONU 3.3V to – 3.1V/200mA DC/DC Converter PART NUMBER DESCRIPTION COMMENTS LTC

1174 High Efficiency Step-Down and Inverting DC/DC Converter Selectable I PEAK = 300mA or 600mA

LT1307 Single Cell Micropower 600kHz PWM DC/DC Converter 3.3V at 75mA from 1 Cell, MSOP Package LT1308 Single Cell High Current Micropower 600kHz Boost Converter 5V at 1A from a Single Li-Ion Cell, SO-8 Package LT1316 Micropower Boost DC/DC Converter Programmable Peak Current Limit, MSOP Package LT1317 Micropower 600kHz PWM DC/DC Converter 2 Cells to 3.3V at 200mA, MSOP Package LTC1474 Low Quiescent Current High Efficiency DC/DC Converter I Q = 10µA, Programmable Peak Current Limit, MSOP LT1610 1.7MHz Single Cell Micropower DC/DC Converter 5V at 200mA from 3.3V, MSOP Package RELATED PARTS VIN SW LT1614 22µHVIN 3.3V D1FB SHDN 18.7k 12.7k100k 1nF VOUT –3.1V 200mA C1: AVX1206CY106 D1: MBR0520 L1, L2: MURATA LQH3C220

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22µF 22µFVC GND 22µH 1µF 3.3V to – 3.1V Converter Efficiency LOAD CURRENT (mA) 31 0 3 0 EFFICIENCY (%) 100 300

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