LTM8040 LINER
Document overview
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Technical content
FEATURES
APPLICATIONS
DESCRIPTION
36V, 1A µModule LED Driver The LTM®8040 is a fi xed frequency 1A step-down DC/DC μModule™ designed to operate as a constant current source. Internal circuitry monitors the output current to provide accurate current regulation, which is ideal for driving high current LEDs. High output current accuracy is maintained over a wide current range, from 35mA to 1A, allowing a wide dimming range over an output volt- age range of 2.4V to 13V. Unique PWM circuitry allows a dimming range of 400:1, avoiding the color shift normally associated with LED current dimming. With its wide input range of 4V to 36V, the LTM8040 regu- lates a broad array of power sources, from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed power supplies. The LTM8040 is packaged in a thermally enhanced, com- pact (15mm × 9mm) and low profi le (2.82mm) molded Land Grid Array (LGA) package suitable for automated assembly by standard surface mount equipment. The LTM8040 is Pb-free and RoHS compliant. n T rue Color PWM™ Delivers Constant Color with 400:1 Dimming Ratio n Wide Input Range: 4V to 36V n Up to 1A LED Current n Adjustable Control of LED Current n High Output Current Accuracy is Maintained Over a Wide Range from 35mA to 1A n Open LED and Short-Circuit Protection n Grounded Cathode Connection n Small Footprint, Low Profi le (15mm × 9mm × 2.82mm) Surface Mount LGA Package n Automotive and Avionic Lighting n Architectural Detail Lighting n Display Backlighting n Constant Current Sources , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. μModule is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. GND L TM8040
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VIN* 4V TO 36V 1μF 215k 650kHz *RUNNING VOL TAGE. SEE APPLICATION INFORMATION FOR START-UP REQUIREMENTS LEDA LPWR TWO WHITE LEDs 6V TO 9V ADJ PWM RT BIAS Effi ciency1A LED Driver μModule OUTPUT CURRENT (mA) EFFICIENCY (%) 100 200 400
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VIN = 12V 3.3V AT 1A LEDs Electrical Specifications Subject to Change
Internal Operating Temperature (Note 2).... –40 to 125°C (Note 1) PIN CONFIGURATION LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE (NOTE 3) L TM8040EV#PBF L TM8040V 60-Lead 15mm × 9mm LGA Package 0°C to 125°C L TM8040IV#PBF L TM8040V 60-Lead 15mm × 9mm LGA Package –40°C to 125°C Consult L TC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container . Consult L TC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: http://www.linear .com/leadfree/
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage l 3.5 4 V Input Quiescent Current Not Switching 2.6 4 mA Shutdown Current SHDN =0.3V , BIAS = 0V , LEDA = 0V 0.01 2 μA LEDA Current ADJ open RADJ = 5.11k l l 0.98 0.965 0.49 0.481 0.5 1.02 1.035 0.51 0.525 A A A A ADJ Bias Current ADJ = 0V , Current fl ows out of pin 24.5 μA ADJ Pull-up Resistor 5 5.11 5.22 kΩ Switching Frequency RT open 470 500 530 kHz SHDN Threshold V IH VIL 2.60 V V PWM Threshold V IH VIL 0.4 1.2 V V The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V , BIAS = LPWR, VOUT = 4V , ADJ open, RT open, VPWM = 5V , unless otherwise noted (Note 3). ORDER INFORMATION VIN BANK 3 LEDA BANK 1 GND BANK 2 PWM SHDN ADJ RT BIAS GND LPWR TJMAX = 125°C, θJA = 250°C/W, WEIGHT = 1.083g 60 Lead (15mm × 9mm × 2.82mm) θJA DERIVED FROM 6.35cm × 6.35cm 4 LAYER PCB
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: This μModule includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specifi ed maximum operating junction temperature may impair device reliability. The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V , BIAS = LPWR, VOUT = 4V , ADJ open, RT open, VPWM = 5V , unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS LEDA Clamp Voltage 13.2 14.5 V Minimum BIAS Voltage 2.0 2.6 V Note 3: The L TM8040E is guaranteed to meet performance specifi cations from 0°C to 125°C internal. Specifi cations over the full –40°C to 125°C internal operating temperature range are assured by design, characterization and correlation with statistical process controls. The L TM8040I is guaranteed to meet specifi cations over the full –40°C to 125°C internal operating temperature range. Note that the maximum internal temperature is determined by specifi c operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors. TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency - Single 3.3V at 1A LED Effi ciency - T wo 3.3V at 1A LEDs Effi ciency - (3 x 3.3V at 1A LEDs) Effi ciency - Single 2.66V at 1A LED Effi ciency - Three 2.66V at 1A LEDs Effi ciency - Four 2.66V at 1A LEDs OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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24 VIN
12 VIN
5 VIN
OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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OUTPUT CURRENT (mA) EFFICIENCY (%) 200 400
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TYPICAL PERFORMANCE CHARACTERISTICS Minimum Start Voltage vs Load 3.3V at 1A LEDs SHDN Current vs Voltage BIAS Current vs Load Current 12VIN, Single 2.7V at 1A LED BIAS Current vs Load Current 24VIN, Three 3.3V at 1A LEDs Temp Rise vs Load 2.7V at 1A LEDs, 12VIN Minimum Running Voltage vs Output Voltage 2.7V at 1A LEDs Minimum Running Voltage vs Output Voltage 3.3V at 1A LEDs Minimum Start Voltage vs Load 2.7V at 1A LEDs Input Current vs Input Voltage Output Short Circuited OUTPUT VOL TAGE INPUT VOL TAGE
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0.5A LOAD 0.1A LOAD OUTPUT VOL TAGE INPUT VOL TAGE
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0.5A LOAD 0.1A LOAD ILOAD (mA) INPUT VOL TAGE 400200
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2 LEDs
3 LEDs
4 LEDs
ILOAD (mA) INPUT VOL TAGE 400200
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SHUTDOWN CURRENT (mA) 105
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LOAD CURRENT (mA) BIAS CURRENT (mA) 400200
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VBIAS = 5V VBIAS = 3.2V VBIAS = 12V LOAD CURRENT (mA) BIAS CURRENT (mA) 400200
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VBIAS = 5V VBIAS = 3.2V VBIAS = 12V INPUT VOL TAGE (V) INPUT CURRENT (mA) 105
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ILOAD (mA) TEMPERATURE RISE (°C) 400200
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LEDA (Bank 1): This pin is the regulated current source of the LTM8040. Connect the anode of the LED string to this pin. This voltage must be at least 2.4V for accurate current regulation. SHDN (Pin L4): The SHDN pin is used to shut down the switching regulator and the internal bias circuits. The 2.65V switching threshold can function as an accurate undervoltage lockout. Pull below 0.3V to shut down the LTM8040. Pull above 2.65V to enable the LTM8040. Tie to V IN if the SHDN function is unused. BIAS (Pin L5): The BIAS pin connects through an internal Schottky diode to provide power to internal housekeeping circuits. Connect to a voltage source (usually LPWR or V IN) greater than 3.2V. Note that this pin is adjacent to the LPWR pin to ease layout. If this pi n is powered by an external power source, a decoupling cap may be necessary. LPWR (Pin K5): This is the output of the buck regulator that sources the LED current. If the LEDA voltage is above 3.2V, connect this pin to BIAS. It is pinned out primarily for the convenience of the user. If it is not used, leave this TYPICAL PERFORMANCE CHARACTERISTICS Temp Rise vs Load 3.3V at 1A LEDs, 36VIN LED Current vs Adjust Voltage Temp Rise vs Load 2.7V at 1A LEDs, 36VIN Temp Rise vs Load 3.3V at 1A LEDs, 12V IN ILOAD (mA) TEMPERATURE RISE (°C) 400200
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ILOAD (mA) TEMPERATURE RISE (°C) 400200
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ILOAD (mA) TEMPERATURE RISE (°C) 400200
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LED CURRENT (mA) 200 400200
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80.6k 5.11k INTERNAL 1.25V 0.1μF 4.7μF 8.2μH SENSE RESISTOR LPWR LEDA BIAS INTERNAL COMPENSATION CURRENT MODE CONTROLLER 8040 BD PIN FUNCTIONS pin fl oating. Please refer to the Applications Information section for details. PWM (Pin L7): Input Pin for PWM Dimming Control. A PWM signal above 0.9V (ON threshold) turns the on output current source, while a PWM signal below 0.5V shuts it down. If the application does not require PWM dimming, then the PWM pin can be left either open (an internal 10μA source current pulls PWM high) or pulled up to a voltage source between 1.2V and 10V. V IN (Bank 3): The VIN pin supplies cur-rent to the LTM8040’s internal power converter and other circuitry. It must be lo- cally bypassed with a high quality (low ESR) capacitor. ADJ (Pin L3): Use the ADJ pin to scale the LEDA output current below 1A by either applying a voltage source or by connecting a resistor to GND. This pin is internally pulled up to a 1.25V reference through a 5.11K resistor, so ensure that the voltage source can drive a 5.11K impedance. If applying a voltage to ADJ, the LEDA current follows the formula: I LED = 1A • ADJ/1.25V. If connecting a resistor to GND, the resistor value should be R = 5.11 • ILED /(1Amp – ILED), where R is in KΩ and ILED is the desired current out of LEDA in Amps. Make sure that the voltage at LEDA is at least 2.4V. RT (Pin L2): The RT pin is used to set the internal oscillator frequency. An 80.6k resistor has already been installed inside the LTM8040 to default switching frequency to 500kHz. If no modifi cation of the switching frequency is necessary, leave this pin fl oating. Otherwise, a parallel resistor applied from RT to GND will raise the switching frequency. See table 2 for details. GND (Bank 2): Tie all GND pins directly to a local ground plane. These pins serve as both signal and power return to the LTM8040 μModule, as well as providing the primary thermal path for heat dissipation within the unit. See the Applications Information section for more information about heat-sinking and printed circuit board layout.
The LTM8040 is a constant frequency, current mode converter capable of generating a constant 1A output intended to drive LEDs or other applications where a constant current is required. Operation can be best understood by referring to the Block Diagram. The power stage is step down converter that regulates the output current by reading the voltage across a power sense resistor that is in series with the output. If the SHDN pin is tied to ground, the LTM8040 is shut down and draws minimal current from the input source tied to V IN. If the SHDN pin exceeds 1.5V, the internal bias circuits turn on, including the internal regulator, reference, and oscillator. When the SHDN pin exceeds 2.65V, the switching regulator will begin to operate. There are two means to dim a LED with the LTM8040. The fi rst is to adjust the current on the LEDA output via a voltage on the ADJ pin. The ADJ pin is internally pulled up to a precision 1.25V reference through a 1% 5.11K resistor. Leaving the ADJ pin fl oating sets the LED pin current to 1A. Reducing the voltage below 1.25V on the ADJ pin proportionally reduces the current fl owing out of LEDA. This can be accomplished by connecting a resistor from the ADJ pin to GND, forming a divider network with the internal 5.11K resistor. LED pin current can also be programmed by tying the ADJ pin directly to a voltage source. For proper operation, make sure that LEDA is at least 2.4V at the desired operating point. The other means by which the LTM8040 can dim a LED is with pulse width modulation using the PWM pin and an optional external NFET. If the PWM pin is unconnected or pulled high, the part operates nominally. If the PWM pin is pulled low, the LTM8040 stops switching and the internal control circuitry is held in its present state. Cir- cuitry drawing current from the LPWR pin is also disabled. This way, the LTM8040 “remembers” the current sourced from the LEDA output until PWM is pulled high again. This leads to a highly linear relationship between pulse width and output light, allowing for a large and accurate dimming range. The RT pin allows programming of the switching fre- quency. The LTM8040 is shipped with 80.6K on this pin to GND, yielding a default switching frequency of 500KHz. For applications requiring a faster switching frequency, apply another resistor in parallel, from RT to GND. Refer to table 2 for the frequencies that correspond to the applied external resistor values. An external voltage is required at the BIAS pin to power internal circuitry. For proper operation, BIAS must be at least 3.2V. For many applications, BIAS should be tied to LWPR; if LWPR is below 3.2V, BIAS may be tied to V IN or some other voltage source. The switching regulator performs frequency foldback d u r i n g o v e r l o a d c o n d i t i o n s . A n a m p l i fi e r s e n s e s w h e n LWPR is less than 2V and begins decreasing the oscillator frequency down from full frequency to 20% of the nominal frequency when V OUT = 0V. The LPWR pin is less than 2V during startup, short circuit, and overload conditions, so the BIAS pin will be below the specifi ed limit for effi cient operation if the two pins are tied together. Frequency foldback helps limit internal power and thermal stresses under these conditions. The LTM8040 is equipped with thermal protection that reduces the output LED current if the internal operating temperature is too high. This thermal protection is active above the 125°C temperature rating of the LTM8040, so continuous operation under this operating condition may impair reliability.
For most applications, the design process is straight forward, summarized as follows: 1. Look at Table 1 and fi nd the row that has the desired input voltage range LED string voltage range and output current. 2. Apply the recommended C IN, RT and RADJ values. 3. Connect BIAS as indicated. 4. Connect LEDA to the anode of the LED string. 5. Connect the remaining pins as needed by the system requirements. While these component combinations have been tested for proper operation, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions. Open LED Protection The LTM8040 has internal open LED circuit protection. If the LED is absent or fails open, the LTM8040 clamps the voltage on the LEDA pin to 14V. The switching regulator then skips cycles to limit the input current. The input current and output voltage during an open LED condition is shown in the Typical Performance Characteristics section. Undervoltage Lockout U n d e r v o l t a g e l o c ko u t (U V LO) i s t y p i c a l l y u s e d i n s i t u a t i o n s where the input supply is current limited, or has high source resistance. A switching regulator draws constant power from the source, so the source current increases as the source voltage drops. This looks like a negative resistance load to the source and can cause the source to current limit or latch low under low source voltage conditions. UVLO prevents the regulator from operating at source voltages where this might occur. An internal comparator w i l l f o r c e t h e p a r t i n t o s hu t d o w n w h e n V IN falls below 3.5V. An adjustable UVLO threshold is also realized through the SHDN pin, as the internal comparator that performs this function has a 2.65V threshold. An internal resistor pulls 10.3μA to ground from the SHDN pin at the UVLO threshold in order to provide hysteresis. Choose resistors according to the following formula: R2= 2.65V VUVLO −2.65V R1 – 10.3µA where VUVLO is the desired UVLO Threshold Suppose that the output needs to stay off until the input is above 8V. VTH = 8V Let R1 = 100k R2= 2.65V 8V −2.65V 100k – 10.3µA = 61.9
APPLICATION INFORMATION
Figure 1. Undervoltage Lockout
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pling problems from switching nodes. single external timing resistor from the RT pin to ground.
the value of RT for a given operating frequency is shown in the Typical Performance Characteristics section. Table 2 shows suggested RT selections for a variety of switch- ing frequencies. Table 2. RT vs Frequency
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For proper operation, The BIAS pin must be powered by at least 3.2V. Figure 2 shows three ways to arrange the circuit. For outputs of 3.2V or higher, the standard circuit (Figure 2a) is best, because the circuit’s effi ciency is better for lower voltages above 3.2V. For output voltages below 3.2V, the BIAS pin can be tied to the input (Figure 2b) at the cost of some effi ciency. Finally, the BIAS pin can be tied to another source that is at least 3.2V (Figure 2c). For example, if a 3.3V source is on whenever the LED is on, the BIAS pin can be connected to the 3.3V output. In all cases, be sure that the maximum voltage at the BIAS pin is both less than 25V and the sum of V IN and BIAS is less than 51V. If BIAS is powered by a source other than LPWR, a local decoupling capacitor may be necessary. The value of the decoupling cap is dependent upon the source and PCB layout. Programming LED Current The LED current can be set by adjusting the voltage on the ADJ pin. The ADJ pin is internally pulled up to a pre-
cision 1.25V voltage source through a 5.11K 1% resistor. This resistor makes it easy to adjust the LED current with a single external resistor. For a 1A LED current, leave the ADJ pin fl oating. For lower output currents, apply a re- sistor from ADJ to GND as shown in Figure 3, using the following formula: R ADJ = 5.11 • ILED /(1Amp – ILED), where RADJ is in kΩ and I LED is the desired current out of LEDA. In order to have accurate LED current, a precision 1% resistor is recommended. can be calculated from the maximum LED current (IMAX) and the minimum LED current (I MIN) as follows: IMAX IMIN =IRATIO Another dimming control circuit (Figure 5) uses the PWM pin and an external NFET tied to the cathode of the LED. When the PWM signal goes low, the NFET turns off, dis- connecting the LED from the internal current source and “freezing” the state of LTM8040 internal control and drive circuitry, but leaving the output capacitor of the internal step down converter charged. When the PWM pin goes high again, the LED current returns rapidly to its previous on state. This fast settling time allows the L TM8040 to maintain LED current regulation with PWM pulse widths as short as 40μs. It is also possible to not use an external NFET, but the output capacitor of the internal regulator will be discharged by the LED(s) and have to be charged up again when the current source turns back on. This will lengthen the minimum dimming pulse width, in turn reducing the PWM dimming frequency. Figure 4. Dimming with an NFET and Resistor
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Figure 5. Dimming Using PWM Signal
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The LEDA voltage must be at least 2.4V for proper current regulation. Dimming Control There are several different types of dimming control circuits. One dimming control circuit (Figure 4) changes the voltage on the ADJ pin by tying a low on-resis- tance FET to the resistor divider string. This allows the selection of two different LED currents. For reliable operation, program an LED current of no less than 35mA. The maximum current dimming ratio (IRATIO) The maximum PWM dimming ratio (PWM RATIO) can be calculated from the maximum PWM period (t MAX) and minimum PWM pulse width (t MIN) as follows: tMAX tMIN =PWMRATIO Figure 3. Setting ADJ with a Resistor
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Ceramic capacitors are also piezoelectric. While the LTM8040 is a fi xed frequency device, the internal regulators may skip cycles at light loads and extend the switching cycle on time as the input voltage falls towards the to output. Under either of these conditions, the LTM8040 can excite a ceramic capacitor at audio frequencies, generating audible noise. If this audible noise is unacceptable, use a high performance electrolytic capacitor at the output. The input capacitor can be a parallel combination of a 4.7μF ceramic capacitor and a low cost electrolytic capacitor. A fi nal precaution regarding ceramic capacitors concerns the maximum input voltage rating of the LTM8040. A ceramic input capacitor combined with trace or cable inductance forms a high Q (under damped) tank circuit. If the LTM8040 circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possi- bly exceeding the device’s rating. This situation is easily avoided by introducing a small series damping resistance into the circuit. This is most often taken care of by the presence of an electrolytic bulk capacitor in the board. High Temperature Considerations The internal operating temperature of the LTM8040 must be lower than 1 25°C rating, so care should be taken in the layout of the circuit to ensure good heat sinking of the LTM8040. To estimate the junction temperature, ap- proximate the power dissipation within the LTM8040 by applying the typical effi ciency stated in this datasheet to the desired output power, or, if you have and actual module, by taking a power measurement. Then calculate the tem- perature rise of the LTM8040 junction above the surface of the printed circuit board by multiplying the module’s power dissipation by the thermal resistance. The actual thermal resistance of the LTM8040 to the printed circuit board depends on the layout of the circuit board, but the thermal resistance given on page 2, which is based upon a 40.3cm 2 4 layer FR4 PC board, can be used a guide. The LTM8040 is equipped with thermal protection that reduces the output LED current if the internal operating temperature is too high. This thermal protection is active above the 125°C temperature rating of the LTM8040, so Total dimming ratio (DIM RATIO) is the product of the PWM dimming ratio and the current dimming ratio. Example: I MAX = 1A, I MIN = 0.1A, t MAX = 1.0ms, tMIN = 25μs IRATIO = 1A 0.1A =10:1 PWMRATIO = 10ms 25µs = 400:1 DIMRATIO =10 400= 4000:1 Minimum Input Voltage The LTM8040 is a step down converter, so a minimum am o u nt of head room is req u i red to k eep the o utp ut i n regulation. For most applications at full load, the input needs to be at least 1.5V above the desired output. In addition, it takes more input voltage to initially start than is required for continuous operation. This start voltage is also dependent on whether turn-on is controlled by the LTM8040’s SHDN pin or UVLO (that is, the SHDN pin is tied to V IN). See Typical Performance Characteristics for details. Capacitor Selection Considerations The CIN and capacitor values in tables 1 and 2 are the minimum recommended values for the associated oper- ating conditions. Applying capacitor values below those indicated in table 1 is not recommended, and may result in undesirable operation. Using larger values is generally acceptable, and can yield improved performance, if it is necessary. Again, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions. Ceramic capacitors are small, robust and have very low ESR. However, not all ceramic capacitors are suitable. X5R and X7R types are stable over temperature and ap- plied voltage and give dependable service. Other types, including Y5V and Z5U have very large temperature and voltage coeffi cients of capacitance. In an application cir- cuit they may have only a small fraction of their nominal capacitance resulting in much higher output voltage ripple than expected.
Figure 6. Suggested Layout
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continuous operation under this operating condition may impair reliability. Layout Hints Most of the headaches associated with PCB layout have been alleviated or even eliminated by the high level of in- tegration of the LTM8040. The LTM8040 is nevertheless a switching power supply, and care must be taken to minimize EMI and ensure proper operation. Even with the high level of integration, you may fail to achieve specifi ed operation with a haphazard or poor layout. See Figure 6 for a sug- gested layout. Ensure that the grounding and heatsinking are acceptable. A few rules to keep in mind are: 1. Place the C IN capacitor as close as possible to the VIN and GND connection of the LTM8040. 2. Connect all of the GND connections to as large a cop- per pour or plane area as possible on the top layer. Avoid breaking the ground connection between the external components and the LTM8040. 3. Use vias to connect the GND copper area to the board’s internal ground plane. Liberally distribute these GND vias to provide both a good ground connection and thermal path to the internal planes of the printed circuit board. 4. If the application requires BIAS to be connected to the input voltage potential, tie BIAS to V IN, but be careful not to break up the ground plane.
Table 1. Recommended Confi guration
Step Down 1A Drive with Single Red or White LED Step Down 350mA Drive with Three Series Red LEDs Step Down 1A Drive with Three White Series LEDs GND L TM8040
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VIN* 5.5V TO 25V 1μF *RUNNING VOL TAGE. SEE APPLICATION INFORMATION FOR START-UP REQUIREMENTS LEDA LPWR 2.5V TO 4V VIN SHDN BIAS ADJ PWM RT GND L TM8040
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VIN* 10.5V TO 36V 1μF 2.87k 137k 750kHz *RUNNING VOL TAGE. SEE APPLICATION INFORMATION FOR START-UP REQUIREMENTS LEDA LPWR BIAS 6V TO 9V 350mA VIN SHDN ADJ PWM RT GND L TM8040
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VIN* 15.5V TO 36V 1μF 137k 750kHz *RUNNING VOL TAGE. SEE APPLICATION INFORMATION FOR START-UP REQUIREMENTS LEDA LPWR BIAS 8V TO 12V VIN SHDN ADJ PWM RT
Information furnished by Linear Technology Corpor ation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- t i o n t h a t t h e i n t e r c o n n e c t i o n o f i t s c i r c u i t s a s d e s c r i b e d h e r e i n w i l l n o t i n f r i n g e o n e x i s t i n g p a t e n t r i g h t s . PACKAGE DESCRIPTION 66-Lead (15mm × 9mm × 2.82mm) (Reference L TC DWG # 05-08-1810 Rev Ø) NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS LAND DESIGNATION PER JESD MO-222, SPP-010 AND SPP-020 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. THE TOTAL NUMBER OF PADS: 66 DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER MAY BE EITHER A MOLD OR A MARKED FEATURE SYMBOL aaa bbb TOLERANCE 0.15 0.10 9.000 BSC PACKAGE TOP VIEW LGA 66 0407 REV Ø 15.000 BSC PAD 1 CORNER PADS SEE NOTES X Y aaa Z aaa Z 2.670 – 2.970 DETAIL A PACKAGE SIDE VIEW DETAIL A SUBSTRATEMOLD CAP 0.27 – 0.37 2.40 – 2.60 bbb Z Z 1.270 BSC 0.605 – 0.665 0.605 – 0.665 12.700 BSC 7.620 BSC PAD 1 C (0.30)HB A DC EF PACKAGE BOTTOM VIEW PACKAGE IN TRAY LOADING ORIENTATION GLJ K 2.540 2.540 1.270 5.080 5.080 6.350 6.350 3.810 3.810 0.000 1.270 3.810 3.810 2.540 2.540 1.270 1.270 0.000 1.5875 0.9525 SUGGESTED PCB LAYOUT TOP VIEW LTMXXXXXX μModule TRAY PIN 1 BEVEL COMPONENT PIN 1 0.9525 1.5875
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com © LINEAR TECHNOLOGY CORPORATION 2008 LT 0808 • PRINTED IN USA RELATED PARTS TYPICAL APPLICATION Step Down 1A Drive with Four Series Red LEDs GND L TM8040
8040 TA05
VIN* 15.5V TO 36V 1μF 137k 750kHz *RUNNING VOL TAGE. SEE APPLICATION INFORMATION FOR START-UP REQUIREMENTS LEDA LPWR BIAS 8V TO 12V VIN SHDN ADJ PWM RT PART NUMBER DESCRIPTION COMMENTS L TM4600 10A DC/DC μModule Basic 10A DC/DC μModule, 15mm × 15mm × 2.8mm LGA L TM4600HVMPV Military Plastic 10A DC/DC μModule –55°C to 125°C Operation, 15mm × 15mm × 2.8mm LGA L TM4601/ L TM4601A 12A DC/DC μModule with PLL, Output T racking/Margining and Remote Sensing Synchronizable, PolyPhase® Operation, L TM4601-1 Version Has No Remote Sensing L TM4602 6A DC/DC μModule Pin-Compatible with the L TM4600 L TM4603 6A DC/DC μModule with PLL and Output T racking/ Margining and Remote Sensing Synchronizable, PolyPhase Operation, L TM4603-1 Version Has No Remote Sensing, Pin-Compatible with the L TM4601 L TM4604 4A Low V IN DC/DC μModule 2.375V ≤ V IN ≤ 5V , 0.8V ≤ VOUT ≤ 5V , 9mm × 15mm × 2.3mm LGA L TM4605 5A to 12A Buck-Boost μModule High Effi ciency, Adjustable Frequency, 4.5V ≤ V IN ≤ 20V , 0.8V ≤ VOUT ≤ 16V , 15mm × 15mm × 2.8mm L TM4607 5A to 12A Buck-Boost μModule High Effi ciency, Adjustable Frequency, 4.5V ≤ V IN ≤ 36V , 0.8V ≤ VOUT ≤ 25V , 15mm × 15mm × 2.8mm L TM4608 8A Low V IN DC/DC μModule 2.375V ≤ V IN ≤ 5V , 0.8V ≤ VOUT ≤ 5V , 9mm × 15mm × 2.8mm LGA L TM8020 36V , 200mA DC/DC μModule 4V ≤ V IN ≤ 36V , 1.25V ≤ VOUT ≤ 5V , 6.25mm × 6.25mm × 2.3mm LGA L TM8022 1A, 36V DC/DC μModule Adjustable Frequency, 0.8V ≤ V OUT ≤ 5V , 11.25mm × 9mm × 2.82mm, Pin-Compatible to the L TM8023 L TM8023 2A, 36V DC/DC μModule Adjustable Frequency, 0.8V ≤ V OUT ≤ 5V , 11.25mm × 9mm × 2.82mm, Pin-Compatible to the L TM8022 PolyPhase is a trademark of Linear Technology Corporation