LT3684 LINER
Document overview
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Technical content
36V, 2A, 2.8MHz Step-Down Switching Regulator The LT®3684 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 34V (36V maximum). A high effi ciency 0.18Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. The LT3684’s high operating frequency allows the use of small, low cost inductors and ceramic capacitors resulting in low output ripple while keeping total solution size to a minimum. The low current shutdown mode reduces input supply current to less than 1µA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good fl ag signals when V OUT reaches 90% of the programmed output voltage. The LT3684 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with Exposed Pads for low thermal resistance. ■ Automotive Battery Regulation ■ Power for Portable Products ■ Distributed Supply Regulation ■ Industrial Supplies ■ Wall Transformer Regulation ■ Wide Input Range: 3.6V to 34V Operating, 36V Maximum ■ 2A Maximum Output Current ■ Adjustable Switching Frequency: 300kHz to 2.8MHz ■ Low Shutdown Current: IQ < 1µA ■ Integrated Boost Diode ■ Power Good Flag ■ Saturating Switch Design: 0.18 Ω On-Resistance ■ 1.265V Feedback Reference Voltage ■ Output Voltage: 1.265V to 20V ■ Soft-Start Capability ■ Small 10-Pin Thermally Enhanced MSOP and (3mm × 3mm) DFN Packages 3.3V Step-Down Converter Effi ciency FEATURES DESCRIPTION
APPLICATIONS
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. SW BIAS FB VC PG RT VIN BD VIN 4.5V TO 34V VOUT 3.3V 4.7µF 0.47µF 330pF 22µF200k 16.2k 60.4k 4.7µH 324k GND OFF ON LT3684
3684 TA01
LOAD CURRENT (A) EFFICIENCY (%) 0.5 1 1.5 2
3684 TA01b
VIN = 12V VOUT = 3.3V L = 4.7µH f = 800kHz
ELECTRICAL CHARACTERISTICS
FB, RT, V (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage ● 3 3.6 V Quiescent Current from VIN VRUN/SS = 0.2V 0.01 0.5 µA VBIAS = 3V, Not Switching ● 0.4 0.8 mA VBIAS = 0, Not Switching 1.2 2.0 mA Quiescent Current from BIAS V RUN/SS = 0.2V 0.01 0.5 µA VBIAS = 3V, Not Switching ● 0.85 1.5 mA VBIAS = 0, Not Switching 00 . 1 mA The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 10V, VRUNS/SS = 10V, VBOOST = 15V, VBIAS = 3.3V unless otherwise noted. (Note 2) Operating Temperature Range (Note 2) Lead Temperature (Soldering, 10 sec) ABSOLUTE MAXIMUM RATINGS TOP VIEW DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN 3 11 1 RT VC FB BIAS PG BD BOOST SW V IN RUN/SS TJMAX = 125°C, θJA = 45°C/W, θJC = 10°C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB BD BOOST SW V IN RUN/SS RT V C FB BIAS PG TOP VIEW MSE PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 45°C/W, θJC = 10°C/W EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER DD PART MARKING* ORDER PART NUMBER MSE PART MARKING* LT3684EDD LT3684IDD LCVT LCVT LT3684EMSE LT3684IMSE LTCVS LTCVS Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. PACKAGE/ORDER INFORMATION
PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Bias Voltage 2.7 3 V Feedback Voltage 1.25 1.24 1.265 1.265 1.28 1.29 V V FB Pin Bias Current (Note 3)
- 30 100 nA FB Voltage Line Regulation 4V < V IN < 34V 0.002 0.02 %/V Error Amp gm 330 µMho Error Amp Gain 1000 VC Source Current 75 µA VC Sink Current 100 µA VC Pin to Switch Current Gain 3.5 A/V VC Clamp Voltage 2V Switching Frequency R T = 8.66k RT = 29.4k RT = 187k 2.7 1.25 250 3.0 1.4 300 3.3 1.55 350 MHz MHz kHz Minimum Switch Off-Time
- 100 150 nS Switch Current Limit Duty Cycle = 5% 3.1 3.6 4.0 A Switch VCESAT ISW = 2A 360 mV Boost Schottky Reverse Leakage V SW = 10V, VBIAS = 0V 0.02 2 µA Minimum Boost Voltage (Note 4) ● 1.6 2.1 V BOOST Pin Current I SW = 1A 18 30 mA RUN/SS Pin Current V RUN/SS = 2.5V 5 10 µA RUN/SS Input Voltage High 2.5 V RUN/SS Input Voltage Low 0.2 V PG Threshold Offset from Feedback Voltage V FB Rising 100 mV PG Hysteresis 10 mV PG Leakage V PG = 5V 0.1 1 µA PG Sink Current V PG = 0.4V ● 100 300 µA Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT3684E is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LT3684I specifi cations are guaranteed over the –40°C to 125°C temperature range. Note 3: Bias current measured in regulation. Bias current fl ows into the FB pin. Note 4: This is the minimum voltage across the boost capacitor needed to guarantee full saturation of the switch. The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 10V, VRUNS/SS = 10V VBOOST = 15V, VBIAS = 3.3V unless otherwise noted. (Note 2)
Effi ciency (VOUT = 5.0V) Effi ciency (VOUT = 3.3V) Maximum Load Current Switch Voltage Drop Boost Pin Current Switch Current LimitMaximum Load Current Switch Current Limit Effi ciency LOAD CURRENT (A) EFFICIENCY (%) 100 1.6
3684 G01
VIN = 12V VIN = 24V L: NEC PLC-0745-4R7 f = 800kHz LOAD CURRENT (A) EFFICIENCY (%) 1.6
3684 G02
VIN = 12V VIN = 7V VIN = 24V L: NEC PLC-0745-4R7 f = 800kHz SWITCHING FREQUENCY (MHz) EFFICIENCY (%) 1.5
3684 G03
0.5 1 2 2.5 3 VIN = 12V VIN = 24V VOUT = 3.3V L = 10µH LOAD = 1A INPUT VOLTAGE (V) LOAD CURRENT (A)
3684 G04
2.5 10 20 1.5 1.0 4.0 3.5 3.0 2.0 25 30 TYPICAL MINIMUM VOUT = 3.3V TA = 25°C L = 4.7µH f = 800kHz INPUT VOLTAGE (V) LOAD CURRENT (A)
3684 G05
2.5 10 20 1.5 1.0 4.0 3.5 3.0 2.0 25 30 TYPICAL MINIMUM VOUT = 5V TA = 25°C L = 4.7µH f = 800kHz DUTY CYCLE (%) SWITCH CURRENT LIMIT (A)
3684 G06
2.5 20 60 1.5 1.0 4.0 3.5 3.0 2.0 80 100 TEMPERATURE (°C) –50 SWITCH CURRENT LIMIT (A) 2.0 2.5 3.0 125
3684 G07
1.5 1.0 0–25 50 25 100 75 0.5 4.5
4.0 DUTY CYCLE = 10 %
DUTY CYCLE = 90 % SWITCH CURRENT (mA) 400 500 700 1500 2500
3684 G08
600VOLTAGE DROP (mV) SWITCH CURRENT (mA) BOOST PIN CURRENT (mA) 2000
3684 G09
1000500 2500 30001500 3500 (TA = 25°C unless otherwise noted)TYPICAL PERFORMANCE CHARACTERISTICS
Feedback Voltage Switching Frequency Frequency Foldback Minimum Switch On-Time Soft-Start RUN/SS Pin Current Boost Diode Error Amp Output Current Minimum Input Voltage TEMPERATURE (°C) –50 FEEDBACK VOLTAGE (V) 1.270 1.280 125
3684 G10
1.260 1.250 0 50 100–25 25 75 1.290 1.265 1.275 1.255 1.285 TEMPERATURE (°C) –50 FREQUENCY (MHz) 1.00 1.10 125
3684 G11
0.90 0.80 0 50 100–25 25 75 1.20 RT = 45.3k 0.95 1.05 0.85 1.15 FB PIN VOLTAGE (mV) SWITCHING FREQUENCY (kHz) 800 1000 1200 600 1000
3684 G12
RT = 45.3k TEMPERATURE (˚C) –50 MINIMUM SWITCH ON-TIME (ns) 100 120
3684 G13
–25 0 50 75 100 125 140 RUN/SS PIN VOLTAGE (V) SWITCH CURRENT LIMIT (A) 3.5 1.5
3684 G14
2.0 1.0 0.5 1 2 0.5 4.0 3.0 2.5 1.5 2.5 3 3.5 RUN/SS PIN VOLTAGE (V) RUN/SS PIN CURRENT (µA) 15 25
3684 G15
BOOST DIODE CURRENT (A) BOOST DIODE Vf (V) 0.8 1.0 1.2 2.0
3684 G16
0.6 0.4 0.5 1.0 1.5 0.2 1.6 1.4 FB PIN VOLTAGE (V) 1.065 –80 VC PIN CURRENT (µA) –60 –20 1 .265 1.465 100
3684 G17
–40 1.165 1.365 LOAD CURRENT (A) 0.001 INPUT VOLTAGE (V) 3.0 3.5
3684 G18
2.5 2.0 0.01 0.1 1 4.5 4.0 VOUT = 3.3V TA = 25°C L = 4.7µH f = 800kHz TYPICAL PERFORMANCE CHARACTERISTICS(TA = 25°C unless otherwise noted)
VC VoltagesMinimum Input Voltage Power Good Threshold Switching Waveforms (Discontinuous Operation) Switching Waveforms (Continuous Operation) LOAD CURRENT (A) 0.001 INPUT VOLTAGE (V) 5.0 5.5
3684 G19
4.5 4.0 0.01 0.1 1 6.5 6.0 VOUT = 5V TA = 25°C L = 4.7µH f = 800kHz TEMPERATURE (°C) –50 THRESHOLD VOLTAGE (V) 1.50 2.00 2.50 25 75 125
3684 G20
1.00 0.50 –25 0 50 100 CURRENT LIMIT CLAMP SWITCHING THRESHOLD TEMPERATURE (°C) –50 THRESHOLD VOLTAGE (V) 1.160 1.180 1.200 25 75 125
3684 G21
1.140 1.120 1.100 –25 0 50 100 PG RISING IL 0.5A/DIV VSW 5V/DIV VOUT 10mV/DIV
3684 G221µs/DIV
VIN = 12V, FRONT PAGE APPLICATION ILOAD = 140mA IL 0.5A/DIV VRUN/SS 5V/DIV VOUT 10mV/DIV
3684 G231µs/DIV
VIN = 12V, FRONT PAGE APPLICATION ILOAD = 1A TYPICAL PERFORMANCE CHARACTERISTICS(TA = 25°C unless otherwise noted)
BD (Pin 1): This pin connects to the anode of the boost Schottky diode. BOOST (Pin 2): This pin is used to provide a drive voltage, higher than the input voltage, to the internal bipolar NPN power switch. SW (Pin 3): The SW pin is the output of the internal power switch. Connect this pin to the inductor, catch diode and boost capacitor. VIN (Pin 4): The VIN pin supplies current to the LT3684’s internal regulator and to the internal power switch. This pin must be locally bypassed. RUN/SS (Pin 5): The RUN/SS pin is used to put the LT3684 in shutdown mode. Tie to ground to shut down the LT3684. Tie to 2.3V or more for normal operation. If the shutdown feature is not used, tie this pin to the V IN pin. RUN/SS also provides a soft-start function; see the Applications Information section. PG (Pin 6): The PG pin is the open collector output of an internal comparator. PG remains low until the FB pin is within 10% of the fi nal regulation voltage. PG output is valid when V IN is above 3.5V and RUN/SS is high. BIAS (Pin 7): The BIAS pin supplies the current to the LT3684’s internal regulator. Tie this pin to the lowest available voltage source above 3V (typically V OUT). This architecture increases effi ciency especially when the input voltage is much higher than the output. FB (Pin 8): The LT3684 regulates the FB pin to 1.265V. Connect the feedback resistor divider tap to this pin. V C (Pin 9): The VC pin is the output of the internal error amplifi er. The voltage on this pin controls the peak switch current. Tie an RC network from this pin to ground to compensate the control loop. RT (Pin 10): Oscillator Resistor Input. Connecting a resistor to ground from this pin sets the switching frequency. Exposed Pad (Pin 11): Ground. The Exposed Pad must be soldered to PCB. PIN FUNCTIONS
300kHz–2.8MHz VC CLAMPSOFT-START SLOPE COMP INTERNAL 1.265V REF R VINVIN BIAS RUN/SS BOOST SW SWITCH LATCH VC VOUT CF CC RC BD RT GND ERROR AMP FB RT PG 1.12V S Q Σ 3684 BD 11 8
The LT3684 is a constant frequency, current mode step- down regulator. An oscillator, with frequency set by RT, enables an RS fl ip-fl op, turning on the internal power switch. An amplifi er and comparator monitor the current fl owing between the V IN and SW pins, turning the switch off when this current reaches a level determined by the voltage at V C. An error amplifi er measures the output voltage through an external resistor divider tied to the FB pin and servos the V C pin. If the error amplifi er’s output increases, more current is delivered to the output; if it decreases, less current is delivered. An active clamp on the V C pin provides current limit. The VC pin is also clamped to the voltage on the RUN/SS pin; soft-start is implemented by generating a voltage ramp at the RUN/SS pin using an external resistor and capacitor. An internal regulator provides power to the control cir- cuitry. The bias regulator normally draws power from the V IN pin, but if the BIAS pin is connected to an external voltage higher than 3V bias power will be drawn from the external source (typically the regulated output voltage). This improves effi ciency. The RUN/SS pin is used to place the LT3684 in shutdown, disconnecting the output and reducing the input current to less than 1µA. The switch driver operates from either the input or from the BOOST pin. An external capacitor and diode are used to generate a voltage at the BOOST pin that is higher than the input supply. This allows the driver to fully saturate the internal bipolar NPN power switch for effi cient operation. The oscillator reduces the LT3684’s operating frequency when the voltage at the FB pin is low. This frequency foldback helps to control the output current during startup and overload. The LT3684 contains a power good comparator which trips when the FB pin is at 90% of its regulated value. The PG output is an open-collector transistor that is off when the output is in regulation, allowing an external resistor to pull the PG pin high. Power good is valid when the LT3684 is enabled and V IN is above 3.6V. OPERATION
Reference designators refer to the Block Diagram. the inductor and capacitor values small. IN and BOOST pins, and on operating mode. Figure 1. Switching Frequency vs RT Value
36V are acceptable regardless of the switching frequency. maximum duty cycle (see equation in previous section). switching frequency should be used. and switching frequency will determine the ripple current. must be lower than the LT3684’s switch current limit (ILIM). suffi cient maximum output current (IOUT(MAX)). Table 1. Inductor Vendors
Of course, such a simple design guide will not always re- sult in the optimum inductor for your application. A larger value inductor provides a slightly higher maximum load current and will reduce the output voltage ripple. If your load is lower than 2A, then you can decrease the value of the inductor and operate with higher ripple current. This allows you to use a physically smaller inductor, or one with a lower DCR resulting in higher effi ciency. There are several graphs in the Typical Performance Characteristics section of this data sheet that show the maximum load current as a function of input voltage and inductor value for several popular output voltages. Low inductance may result in discontinuous mode operation, which is okay but further reduces maximum load current. For details of maximum output current and discontinuous mode opera- tion, see Linear Technology Application Note 44. Finally, for duty cycles greater than 50% (V OUT/VIN > 0.5), there is a minimum inductance required to avoid subharmonic oscillations. See AN19. Input Capacitor Bypass the input of the LT3684 circuit with a ceramic capaci- tor of X7R or X5R type. Y5V types have poor performance over temperature and applied voltage, and should not be used. A 4.7µF to 10µF ceramic capacitor is adequate to bypass the LT3684 and will easily handle the ripple current. Note that larger input capacitance is required when a lower switching frequency is used. If the input power source has high impedance, or there is signifi cant inductance due to long wires or cables, additional bulk capacitance may be necessary. This can be provided with a low performance electrolytic capacitor. Step-down regulators draw current from the input sup- ply in pulses with very fast rise and fall times. The input capacitor is required to reduce the resulting voltage ripple at the LT3684 and to force this very high frequency switching current into a tight local loop, minimizing EMI. A 4.7µF capacitor is capable of this task, but only if it is placed close to the LT3684 and the catch diode (see the PCB Layout section). A second precaution regarding the ceramic input capacitor concerns the maximum input voltage rating of the LT3684. A ceramic input capacitor combined with trace or cable inductance forms a high quality (under damped) tank circuit. If the LT3684 circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the LT3684’s voltage rating. This situation is easily avoided (see the Hot Plugging Safety section). For space sensitive applications, a 2.2µF ceramic capaci- tor can be used for local bypassing of the LT3684 input. However, the lower input capacitance will result in in- creased input current ripple and input voltage ripple, and may couple noise into other circuitry. Also, the increased voltage ripple will raise the minimum operating voltage of the LT3684 to ~3.7V. Output Capacitor and Output Ripple The output capacitor has two essential functions. Along with the inductor, it fi lters the square wave generated by the LT3684 to produce the DC output. In this role it determines the output ripple, and low impedance at the switching frequency is important. The second function is to store energy in order to satisfy transient loads and stabilize the LT3684’s control loop. Ceramic capacitors have very low equivalent series resistance (ESR) and provide the best ripple performance. A good starting value is: C VfOUT OUT SW = 100 where f SW is in MHz, and C OUT is the recommended output capacitance in µF. Use X5R or X7R types. This choice will provide low output ripple and good transient response. Transient performance can be improved with a higher value capacitor if the compensation network is also adjusted to maintain the loop bandwidth. A lower value of output capacitor can be used to save space and cost but transient performance will suffer. See the Fre- quency Compensation section to choose an appropriate compensation network. APPLICATIONS INFORMATION
operating conditions (applied voltage and temperature). electrolytic capacitors can be used for the output capacitor. several Schottky diodes and their manufacturers. Table 3. Diode Vendors output capacitor has high ESR. Table 2. Capacitor Vendors
the compensation network to optimize the performance. shows an equivalent circuit for the LT3684 control loop. frequency is much lower than the switching frequency. Figure 3. Transient Load Response of the LT3684 Front Page Figure 2. Model for Loop Response
3684 F02
500mA to 1500mA and back to 500mA. pin quiescent current comes from a lower voltage source. of the BOOST and BIAS pins are not exceeded.
3684 F03
to start will be the same as the minimum input to run. input voltage to maintain regulation. Figure 4. Three Circuits For Generating The Boost Voltage Figure 5. The Minimum Input Voltage Depends on
3684 FO4
3684 F05
reducing the maximum input current during start-up. up and shut-down waveforms with the soft-start circuit. protects against a shorted or reversed input. a local, unbroken ground plane below these components. The SW and BOOST nodes should be as small as possible. traces will shield them from the SW and BOOST nodes. board and on the bottom side. Figure 6. To Soft-Start the LT3684, Add a Resisitor
3481 F06
Figure 7. Diode D4 Prevents a Shorted Input from
3684 F07
Figure 8. A Good PCB Layout Ensures Proper, Low EMI Operation
3684 F08
a 5V output at full load operating from 24V. 100 LFPM airfl ow, this resistance can fall by another 25%.
temperature approaches 125°C. Figure 9. A Well Chosen Input Network Prevents Input Voltage Overshoot and
3684 F09
3.3V Step-Down Converter SW BIAS FB VC PG RT VIN BD VIN 6.3V TO 34V VOUT 4.7µF 0.47µF 22µF200k f = 800kHz D: DIODES INC. DFLS240L L: TAIYO YUDEN NP06DZB6R8M D 20k 60.4k L 6.8µH 590k GND 330pF ON OFF LT3684
3684 TA02
4.4V TO 34V VOUT 3.3V 4.7µF 0.47µF 22µF200k f = 800kHz D: DIODES INC. DFLS240L L: TAIYO YUDEN NP06DZB4R7M D 16.2k 60.4k L 4.7µH 324k GND 330pF ON OFF LT3684
3684 TA03
2.5V Step-Down Converter 5V, 2MHz Step-Down Converter SW BIAS FB VC PG RT VIN BD VIN 4V TO 34V VOUT 2.5V 4.7/K6D F 1/K6D F 47/K6D F200k f = 600kHz D1: DIODES INC. DFLS240L D2: MBR0540 L: TAIYO YUDEN NP06DZB4R7M 22.1k 84.5k L 4.7/K6D H 196k GND 220pF ON OFF LT3684
3684 TA04
8.6V TO 22V TRANSIENT TO 36V VOUT 2.2/K6D F 0.47/K6D F 10/K6D F200k f = 2MHz D: DIODES INC. DFLS240L L: SUMIDA CDRH4D22/HP-2R2 D 20k 16.9k L 2.2/K6D H 590k GND 330pF ON OFF LT3684
3684 TA05
1.8V Step-Down Converter 12V Step-Down Converter SW BIAS FB VC PG RT VIN BD VIN 15V TO 34V VOUT 12V 10µF 0.47µF 22µF100k f = 800kHz D: DIODES INC. DFLS240L L: NEC/TOKIN PLC-0755-100 D 30k 60.4k L 10µH 845k GND 330pF ON OFF LT3684
3684 TA06
3.5V TO 27V VOUT 1.8V 4.7µF 0.47µF 47µF200k f = 500kHz D: DIODES INC. DFLS240L L: TAIYO YUDEN NP06DZB3R3M D 15.4k 105k L 3.3µH 84.5k GND 330pF ON OFF LT3684
3684 TA07
10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) PACKAGE DESCRIPTION 3.00 ±0.10 (4 SIDES) NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 0.38 ± 0.10 BOTTOM VIEW—EXPOSED PAD 1.65 ± 0.10 (2 SIDES) 0.75 ±0.05 R = 0.115 TYP 2.38 ±0.10 (2 SIDES) 106 PIN 1 TOP MARK (SEE NOTE 6)
0.200 REF
0.00 – 0.05 (DD) DFN 1103 0.25 ± 0.05 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.65 ±0.05 (2 SIDES)2.15 ±0.05 0.50 BSC 0.675 ±0.05 3.50 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05
0.50 BSC
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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1664) PACKAGE DESCRIPTION MSOP (MSE) 0603 0.53 ± 0.152 (.021 ± .006) SEATING PLANE 0.18 (.007) 1.10 (.043) MAX 0.17 – 0.27 (.007 – .011) TYP 0.86 (.034) REF 0.50 (.0197) BSC 12 3 45 4.90 ± 0.152 (.193 ± .006) 0.497 ± 0.076 (.0196 ± .003) REF8910 7 6 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 3.00 ± 0.102 (.118 ± .004) (NOTE 4) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 0.254 (.010) 0° – 6° TYP DETAIL “A” DETAIL “A” GAUGE PLANE 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 0.889 ± 0.127 (.035 ± .005) RECOMMENDED SOLDER PAD LAYOUT 0.305 ± 0.038 (.0120 ± .0015) TYP 2.083 ± 0.102 (.082 ± .004) 2.794 ± 0.102 (.110 ± .004) 0.50 (.0197) BSC BOTTOM VIEW OF EXPOSED PAD OPTION 1.83 ± 0.102 (.072 ± .004) 2.06 ± 0.102 (.081 ± .004) 0.127 ± 0.076 (.005 ± .003)
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007 LT 0207 • PRINTED IN USA PART NUMBER DESCRIPTION COMMENTS LT1933 500mA (I OUT), 500kHz Step-Down Switching Regulator in SOT-23 VIN: 3.6V to 36V, VOUT(MIN) = 12V, IQ = 1.6mA, ISD < 1µA, ThinSOTTM Package LT3437 60V, 400mA (I OUT), MicroPower Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.3V to 80V, VOUT(MIN) = 1.25V, IQ = 100µA, ISD < 1µA, DFN Package LT1936 36V, 1.4A (I OUT), 500kHz High Effi ciency Step-Down DC/DC Converter VIN: 3.6V to 36V, VOUT(MIN) = 1.2V, IQ = 1.9mA, ISD < 1µA, MS8E Package LT3493 36V, 1.2A (I OUT), 750kHz High Effi ciency Step-Down DC/DC Converter VIN: 3.6V to 40V, VOUT(MIN) = 0.8V, IQ = 1.9mA, ISD < 1µA, DFN Package LT1976/LT1977 60V, 1.2A (I OUT), 200kHz/500kHz, High Effi ciency Step- Down DC/DC Converter with Burst Mode Operation VIN: 3.3V to 60V, VOUT(MIN) = 1.20V, IQ = 100µA, ISD < 1µA, TSSOP16E Package LT1767 25V, 1.2A (I OUT), 1.1MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3V to 25V, VOUT(MIN) = 1.20V, IQ = 1mA, ISD < 6µA, MS8E Package LT1940 Dual 25V, 1.4A (I OUT), 1.1MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3.6V to 25V, VOUT(MIN) = 1.20V, IQ = 3.8mA, ISD < 30µA, TSSOP16E Package LT1766 60V, 1.2A (I OUT), 200kHz, High Effi ciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN) = 1.20V, IQ = 2.5mA, ISD < 25µA, TSSOP16E Package LT3434/LT3435 60V, 2.4A (I OUT), 200/500kHz, High Effi ciency Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.3V to 60V, VOUT(MIN) = 1.20V, IQ = 100µA, ISD < 1µA, TSSOP16E Package LT3481 36V, 2A (I OUT), Micropower 2.8MHz, High Effi ciency Step-Down DC/DC Converter VIN: 3.6V to 36V, VOUT(MIN) = 1.265V, IQ = 5µA, ISD < 1µA, 3mm × 3mm DFN and MS10E Packages 1.265V Step-Down Converter SW BIAS FB VC PG RT VIN BD VIN 3.6V TO 27V VOUT 1.265V 4.7/K6D F 0.47/K6D F 47/K6D F f = 500kHz D: DIODES INC. DFLS240L L: TAIYO YUDEN NP06DZB3R3M D 13k 105k L 3.3/K6D H GND 330pF ON OFF LT3648