LT1316

LT1316 LINER | Alldatasheet

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n Precise Control of Peak Switch Current n Quiescent Current: 33µA in Active Mode 3µA in Shutdown Mode n Low-Battery Detector Active in Shutdown n Low Switch VCESAT: 300mV at 500mA n 8-Lead MSOP and SO Packages n Operates with VIN as Low as 1.5V n Logic Level Shutdown Pin FEATURES DESCRIPTIONU The LT 1316 is a micropower step-up DC/DC converter that operates from an input voltage as low as 1.5V. A programmable input current limiting function allows pre- cise control of peak switch current. Peak switch current can be set to any value between 30mA and 500mA by adjusting one resistor. This is particularly useful for DC/DC converters operating from high source impedance inputs such as lithium coin cells or telephone lines. The fixed off-time, variable on-time regulation scheme results in quiescent current of only 33µA in active mode. Quiescent current decreases to 3µA in shutdown with the low-battery detector still active. The LT1316 is available in 8-lead MSOP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIONU APPLICATIONSU n Battery Backup n LCD Bias n Low Power – 48V to 5V/3.3V Converters 2-Cell to 5V Step-Up Converter VIN SW RSET GND FBSHDN LBOLBI LT1316 C2 47µF NC NC 10k 47µF2 CELLS 47µH D1 50mA D1: MOTOROLA MBR0520L L1: SUMIDA CD43-470

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LOAD CURRENT (mA) 0.1

60 EFFICIENCY (%)

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3.3VIN 2.5VIN 1.8VIN Efficiency vs Load Current

ABSOLUTE MAXIMUM RATINGSW WW U Operating Temperature Range PACKAGE/ORDER INFORMATIONW UU LT1316CMS8 ORDER PART NUMBER MS8 PART MARKING LTCD ORDER PART NUMBER S8 PART MARKING TOP VIEW LBO LBI RSET GND FB SHDN V IN SW S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 125°C, θJA = 120°C/W LBO LBI R SET GND FB SHDN V IN SW TOP VIEW MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 160°C/W Consult factory for Military grade parts. ELECTRICAL C CHARA TERISTICS Commercial grade 0°C to 70°C, Industrial grade – 40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. (Notes 1, 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 1.5 1.65 V Maximum Operating Voltage 12 V Quiescent Current V SHDN = 2V, Not Switching 33 45 µA l 50 µA Quiescent Current in Shutdown V SHDN = 0V, VIN = 2V l 35 µA VSHDN = 0V, VIN = 5V l 71 0 µA FB Pin Bias Current l 33 0 n A Line Regulation V IN = 1.8V to 12V l 0.04 0.15 %/V LBI Input Threshold Falling Edge l 1.1 1.17 1.25 V LBI Pin Bias Current l 32 0 n A LBI Input Hysteresis l 35 65 mV LBO Output Voltage Low I SINK = 500µA l 0.2 0.4 V LBO Output Leakage Current LBI = 1.7V, LBO = 5V l 0.01 0.1 µA SHDN Input Voltage High l 1.4 V SHDN Input Voltage Low l 0.4 V SHDN Pin Bias Current V SHDN = 5V l 2 5 µA VSHDN = 0V l –1 –3 µA LT1316CS8 LT1316IS8 1316 1316I

ELECTRICAL C CHARA TERISTICS Commercial grade 0°C to 70°C, Industrial grade – 40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. (Notes 1, 2) Load Transient Response Burst Mode TM Operation VOUT 100mV/DIV AC COUPLED VOUT 100mV/DIV AC COUPLED VSW 5V/DIV INDUCTOR CURRENT 200mA/DIV

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Burst Mode IS A TRADEMARK OF LINEAR TECHNOLOGY CORPORATION. Commercial grade 0°C to 70°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Switch OFF Time FB > 1V 1.4 2.0 2.6 µs l 1.1 3.0 µs FB < 1V 3.4 µs Switch ON Time Current Limit Not Asserted 4.4 6.3 8.2 µs 1V < FB < 1.2V l 3.4 9.5 µs Maximum Duty Cycle Current Limit Not Asserted 74 76 90 % 1V < FB < 1.2V l 73 90 % Switch Saturation Voltage I SW = 0.5A l 0.30 0.4 V ISW = 0.1A l 0.06 0.15 V Switch Leakage Switch Off, V SW = 5V l 0.1 5 µA FB Comparator Trip Point l 1.21 1.23 1.25 V Peak Switch Current R SET = 27.4k, TA = 25°C 90 100 110 mA RSET = 27.4k, TA =0°C 90 100 115 mA RSET = 27.4k, TA = 70°C 70 90 110 mA RSET = 10K l 250 290 340 mA RSET = 121k 25 mA FB Comparator Trip Point l 1.205 1.23 1.255 V Peak Switch Current R SET = 27.4k, l 70 100 125 mA RSET = 10k l 200 290 370 mA Industrial grade – 40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. over the –40 °C to 85°C temperature range by design or correlation, but are not production tested. Note 2: I grade device specifications are guaranteed over the –40 °C to 85°C temperature range. TYPICAL PERFORMANCE CHARACTERISTICS UW 0mA 50mA ILOAD The l denotes specifications which apply over the specified temperature range. Note 1: C grade device specifications are guaranteed over the 0°C to 70°C temperature range. In addition, C grade device specifications are assured

TYPICAL PERFORMANCE CHARACTERISTICS UW SWITCH CURRENT (mA) SWITCH SATURATION VOLTAGE (mV) 500 400 300 200 100 300 500 800

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100°C –40°C 75°C 25°C Switch Saturation Voltage vs Switch Current TEMPERATURE (°C) –50 LBI PIN CURRENT (nA) –25 0 25 50

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TEMPERATURE (°C) –50 OFF-TIME (µs) –25 0 25 50

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TEMPERATURE (°C) –50 MAXIMUM ON-TIME (µs) –25 0 25 50

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vs Temperature Quiescent Current vs Temperature TEMPERATURE (°C) –50 QUIESCENT CURRENT (µA) –25 0 25 50

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Feedback Voltage vs Temperature TEMPERATURE (°C) –50 FEEDBACK VOLTAGE (V) 1.240 1.235 1.230 1.225 1.220 –25 0 25 50

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PEAK SWITCH CURRENT (mA) 100 1000 TEMPERATURE (°C) –50 –25 0 25 50

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RSET = 4.84k RSET = 27.4k RSET = 97.3k RSET = 10k Shutdown Pin Bias Current vs Shutdown Pin Voltage FB Pin Bias Current vs Temperature Peak Switch Current vs Temperature SHUTDOWN PIN VOLTAGE (V) SHUTDOWN PIN CURRENT (µA) 1234

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TEMPERATURE (°C) –50 FB PIN BIAS CURRENT (nA) –25 0 25 50

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this pin drops below 1.17V, LBO goes low. possible. Do not put capacitance at this pin. GND (Pin 4): Ground. Connect directly to ground plane. traces at this pin as short as possible. logic specification (1.4V for high, 0.4V for low). FB (Pin 8): Feedback Pin. Reference voltage is 1.23V. OUT according to: VOUT = 1.23V(1 + R1/R2). Figure 1. LT1316 Block Diagram

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Figure 2. Switching Waveforms

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Figure 3. DC Current Limit vs RSET Resistor output voltage rises enough to overcome A1’s hysteresis. Current through Q2 is equal to Q1’s current divided by 200. plished by grounding the SHDN pin.

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Table 1. RSET Resistor and Inductor Values Figure 1. Comparator A1 monitors FB voltage which is VOUT divided down by resistor divider network R1/R2. inductor to alternately ramp up and down (see Figure 2).

delay is approximately 300ns. discontinuous mode operation. where tOFF = 2µs and VD = 0.4V. switching will be 40% of the peak current (see Figure 2). if input voltage and output current are tightly controlled. Figure 5. Minimum Inductance vs Peak Current

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Figure 4. Discontinuous Mode Operation

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APPLICATIONS INFORMATIONWU UU Discontinuous Mode Operation A boost converter with a high VOUT:VIN ratio operates with a high duty cycle in continuous mode. For duty cycles exceeding the LT1316’s guaranteed minimum specifica- tion of 0.73, the circuit will need to be designed for discontinuous operation. Additionally, very low peak cur- rent limiting below 50mA may necessitate operating in this mode unless high inductance values are acceptable. When operating in discontinuous mode, a different equation governs available output power. For each switch cycle, the inductor current ramps down to zero, completely releas- ing the stored energy. Energy stored in the inductor at any time is equal to 1/2 LI 2. Because this energy is released each cycle, the equation for maximum power out is: POUT(MAX) = 1/2L(IPEAK2)f Where f = + tOFF IPEAK(L) VIN – VSAT When designing for very low peak currents (< 50mA), the inductor size needs to be large enough so that on-time is a least 1µs. On-time can be calculated by the equation: On-Time = IPEAK • L (VIN – VSAT) )) where VSAT = 0.2V. Also, at these low current levels, current overshoot due to power transistor turn-off delay will be a significant portion of peak current. Increasing inductor size will keep this to a minimum. Design Example 1 Requirements: V IN = 2V, VOUT = 5V and ILOAD = 10mA. 1. Find duty cycle DC = VOUT – VIN + VD VOUT – VSAT + VD)) = = 0.654 5 – 2 + 0.4 5 – 0.2 + 0.4)) Because duty cycle is less than the LT1316 minimum specification (0.73), the circuit can be designed for continuous operation. IPEAK = 2(IOUT) 1 – DC = = 58mA 2(10mA) 1 – 0.654 3. Find L L = VOUT – VIN + VD 0.4(IPEAK) )) = 293µH 5 – 2 + 0.4 0.4(58mA) )) tOFF 2µs 4. Find RSET resistor Overshoot = 300nsVIN L )) = = 1.8mA2 330µH )) Find RSET from Figure 3 for 58mA – 1.8mA = 56.2mA RSET ≈ 47k Design Example 2 Requirements: VIN = 3.3V, VOUT = 28V and ILOAD = 5mA. 1. Find duty cycle: DC = VOUT – VIN + VD 28 – 0.2 + 0.4)) Because duty cycle exceeds LT1316 minimum specifi- cation of 73%, the circuit must be designed for discon- tinuous operation. 2. Find P OUT(MAX) Multiply POUT by 1.4 to give a safe operating margin POUT(MAX) = POUT(1.4) = (5mA)(28V)(1.4) = 0.196W 3. Set the on-time to the data sheet minimum of 3.4µs and find L L = (tON2)(VIN – VSAT)2 2POUT(MAX)(tON + tOFF)

1. Find IPEAK for 3.4µs on-time

have low ESR along with high surge current ratings. although output voltage ripple may increase. the Motorola MBR0520L surface mount Schottky diode.

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Figure 6. 2-Cell to 5V Step-Up Converter

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Figure 7. Switching Waveforms for the Circuit

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Figure 8. By Adding C1, Output Ripple Voltage

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Figure 9. Suggested PC Layout

Efficiency vs Load Current LOAD CURRENT (mA) EFFICIENCY (%) 10 100

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– 48V 1.30M 69.8k 121k 432k, 1% MPSA928 1.3M 0.1µF 0.022µF 47µF 1N4148 47µF 1N5817T1 10:1:1 V OUT 50mA 1N4148 VIN SW RSET GND T1 = DALE LPE-4841-A313 (605-665-9301) L PRI: 2mH R DS(ON): 4.3Ω AT VGS = 2.5V R6, Q2,R7 MUST BE PLACED NEXT TO THE FB PIN I IN = 190µA WHEN VIN = 48V, ILOAD = 1mA VA 1316 • TA03 Nonisolated – 48V to 5V Flyback Converter

Positive-to-Negative Converter for LCD Bias VIN VIN SW RSET FB MMBD914 SHDN LT1316 GND 1µF 35V 15k 33µF 10V

2 CELLS

33µH C4: SPRAGUE 293D105X9035B2T C5: SPRAGUE 293D225X0035B2T L1: SUMIDA CD43-330

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2.2µF 35V 3.3M 2.2M 0.01µF 50V 210k CONTRAST ADJUST MBR0530L V OUT –20V 6mA 100pF 50V 0.33µF 50V MMBD914 Battery-Powered Solenoid Driver CAP GOOD 5V/DIV VENERGIZE 5V/DIV IL1 200mA/DIV VCAP 10V/DIV

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When Solenoid Is Energized (VENERGIZE High) Peak Input Current Remains Low and Controlled, Maximizing Battery Life VIN VIN SW RSET FB BAT-85 VCAP ZTX949 VENERGIZE SHDN LBILBO LT1316 GND 20k 470k 47µF 16V 47µH C1: AVX TPS 47µF, 16V C2: SANYO 50MV470GX L1: SUMIDA CD43-470

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5k 1.3k 2N3904 6.8M 324K 47k SOLENOID 1N4148 470µF 50V 50k

50V to 6V Isolated Flyback Converter 47µH 0.5A

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READY 1.00M 100pF 10k CIN 33µF 10V 1.00M 357k 324k ++ COUT 33µF 10V TAJB330M010R PANASONIC EEC-S5R5V104 C IN, COUT: CSUP: +CSUP 0.1F 5.5V 75Ω MBR0520LT3 SUMIDA CD43-470 D1: L1: VIN SW LT1316 SHDN LBI LBO FB7 RSET GND LT1316 LBI LB0 FB SHDN7 604k 2N3904 1.30M 69.8k 12.7k 50k 510k +VIN 25V TO 50V 0.1µF 0.022µF 100V CERAMIC 1µF 16V CERAMIC 1N4148 100µF 16V 1N5817 L PRI: 2mH 10:1:1 VOUT 6V/20mA 75% EFFICIENCY 1N4148 VIN SW RSET GND C1 = SANYO OS-CON 100µF, 16V Q1 = ZETEX ZVN 4424A T1 = DALE LPE-4841-A313 (605-665-9301)

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LCD Bias Generator with Output Disconnect in Shutdown VIN VIN 3.3V SW RSET MBR0540LT1 OPTIONAL CONNECTION VBAT 1.6V TO 3.5V VADJ (VOUT ADJUST) 0V TO 3.3V SHDN FB LT1316 GND 11k 22µH 22µF 6.3V C1: AVX TAJA226M006R C2: AVX TAJB335M035R L1: MURATA LQH3C220K04 Q1: MMBT3906LT3

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4.7M 150k 100pF 50V CERAMIC V OUT 17.1V TO 19.8V 4mA 3.32M 1%232k 3.3µF 35V 0.33µF 50V CERAMIC Universal Serial Bus (USB) to 5V/100mA DC/DC Converter VIN VIN 4V TO SW RSET 3 8 SHDN FB LT1316 GND 10k RB 100Ω 33µH 10µF 10V C1: 10µF 10V AVX TAJB106M010 C2: 33µF 10V AVX TPSC336M010 C3: 10µF ALUMINUM ELECTROLYTIC D1: MBR0520LT1 L1: 33µH SUMIDA CD43 (OR COILCRAFT DO1608) Q1: MPS1907A

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+ R2 1.00M 324k 100pF V OUT 100mA 33µF 10V + C3 10µF 10V

Dimensions in inches (millimeter) unless otherwise noted. 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) TYPDIMENSION 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) 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 circuits as described herein will not infringe on existing patent rights.

1316f LT/TP 0298 4K • PRINTED IN USA  LINEAR TECHNOLOGY CORPORATION 1 997 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 l (408) 432-1900 FAX: (408) 434-0507 l TELEX: 499-3977 l www.linear-tech.com TYPICAL APPLICATIONS N U Low Profile 2 Cell-to-28V Converter for LCD Bias VIN SW RSET FB SHDN LBI LBO LT1316 GND 1µF 35V 10k 10µF2 CELLS VIN 22µH VOUT 28V 5mA C1: MURATA GRM235Y5V106Z010 C2: SPRAGUE 293D105X9035B2T C3: 0.33µF CERAMIC, 50V C4: 100pF CERAMIC, 50V D1: BAT-54 L1: MURATA LQH3C220K04

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4.32M 100pF 50V 204k 0.33µF 50V Bipolar LCD Bias Supply VIN VIN 3.3V TO 4.2V SW RSET 1N914 SHDN FBLT1316 GND 47k 47µH 22µF 16V C4 3.3µF 35V

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1.00M 88.7k (BAT54 = TWO DIODES IN SOT23)BAT54 × 2 100pF 13V 0.5mA –15V 1.5mA 1µF 35V 1µF 35V 2N3904 22k 10k C1: AVX TAJB226M016R C2, C3: AVX TAJA105K035R C4: AVX TAJB335M035R L1: MURATA LQH3C470 PART NUMBER DESCRIPTION COMMENTS LTC 1163 Triple High Side Driver for 2-Cell Inputs 1.8V Minimum Input, Drives N-Channel MOSFETs LTC1174 Micropower Step-Down DC/DC Converter 94% Efficiency, 130 µA IQ, 9V to 5V at 300mA LT1302 High Output Current Micropower DC/DC Converter 5V/600mA from 2V, 2A Internal Switch, 200 µA IQ LT1304 2-Cell Micropower DC/DC Converter Low-Battery Detector Active in Shutdown, 5V at 200mA for 2 Cells LT1307 Single Cell Micropower 600kHz PWM DC/DC Converter 3.3V at 75mA from 1 Cell LTC1440/1/2 Ultralow Power Single/Dual Comparators with Reference 2.8 µA IQ, Adjustable Hysteresis LTC1516 2-Cell to 5V Regulated Charge Pump 12 µA IQ, No Inductors, 5V at 50mA from 3V Input LT1521 Micropower Low Dropout Linear Regulator 500mV Dropout, 300mA Current, 12 µA IQ RELATED PARTS