ZXLD1615Q
Document overview
- Manufacturer or author: Diodes Incorporated
- PDF pages: 12
Technical content
Features
Internal PWM Filter for Adjustable Output High Efficiency (85% typ.) Wide Input Voltage Range: 2.5V to 5.5V Up to 250mA Output Current at 5V Low 60µA Quiescent Current 100nA Maximum Shutdown Current Up to 1MHz Switching Frequency Low External Component Count Green Molding in Small Package TSOT25 Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Automotive-Compliant Qualified to AEC-Q100 Grade 3 PPAP Capable (Note 4) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated‟s definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. 4. Automotive compliant products are AEC-Q100 qualified and are PPAP capable. Please refer to https://www.diodes.com/quality/product-compliance- definitions/.
Document number: DS37687 Rev. 2 - 2 2 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Typical Application Circuit Pin Description Pin Number Pin Name Function
1 LX Drain of NDMOS Switch
2 GND Ground (0V)
3 FB Feedback Pin for Voltage Control Loop
Nominal Voltage 1.025V
4 EN Enable Input (Active High to Turn on Device)
Also Used to Adjust Output Current by PWM Signal - Connect to VIN for Permanent Operation 5 VIN Input Voltage (2.5V to 5.5V) Decouple with Capacitor Close to Device 4.7F
Document number: DS37687 Rev. 2 - 2 3 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Functional Block Diagram Absolute Maximum Ratings (Note 5) (@TA = +25° C, unless otherwise specified.) Symbol Parameter Rating Unit VIN Input Voltage -0.3 to +7 V VLX LX Output Voltage -0.3 to +30 V ILX Switch Output Current 0.5 A PTOT Power Dissipation (Note 6) 0.3 W TST Storage Temperature -55 to +150 °C TJ MAX Junction Temperature +125 °C ESD Susceptibility HBM Human Body Model 1,500 V MM Machine Model 100 V CDM Charged Device Model 1,000 V Notes: 5. All voltages unless otherwise stated are measured with respect to GND. 6. Derate power dissipation above +25° C ambient temperature at +330° C/W. Caution: Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage t o the device. These are stress ratings only; functional operation of the device at conditions between maximum recommended operating conditions and absolute maximum ratings is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD p recautions should be taken when handling and transporting these devices. The human body model is a 100pF capacitor discharge through a 1.5kΩ resistor pin. The machine model is a 200pF capacitor discharged directly into each pin.
Document number: DS37687 Rev. 2 - 2 4 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Recommended Operating Conditions Symbol Parameter Min Max Unit VIN Input Voltage 2.5 5.5 V VLX LX Pin (MOSFET Switch‟s Drain) Output Voltage 0 28 V VENH EN Pin High Level Input Voltage 1.5 VIN V VENL EN Pin Low Level Input Voltage 0 0.4 V fLX MAX Recommended Maximum Operating Frequency — 1,000 kHz TA Operating Ambient Temperature Range -40 +85 °C Electrical Characteristics (Test conditions: @ VIN = VEN = 3V, TA = +25° C, unless otherwise specified.) Symbol Parameter Condition Min Typ Max Unit IINQ_OFF Quiescent Supply Current - Output Off VEN = 0V — <10 100 nA IINQ_ON Quiescent Supply Current - Output Not Switching VEN = VIN, ILX = 0A — 60 100 µA VFB FB Pin Control Voltage — 0.98 — 1.07 V fLX Operating Frequency L=10µ H, VOUT =28V, 5mA Load — 600 — kHz tOFF LX Output “OFF” Time — 350 500 — ns tON LX Output “ON” Time (Note 7) — — — 5 µs RLX Switch 'ON' Resistance — — 1.75 — Ω ILX_PK Switch Peak Current Limit VLX = 20V — 320 — mA ILX(LEAK) Switch Leakage Current VLX = 20V — — 1 µA IENH EN Pin High Level Input Current VEN = VIN — — -100 nA IENL EN Pin Low Level Input Current VEN = 0V — — 1 µA tEN(HOLD) EN Pin Turn off Delay (Note 8) VEN Switched from High to Low — 120 — µs PWMDC PWM Duty Cycle Range at „EN‟ Input for DC Output Voltage Control 10kHz < f < 100kHz, VENH =VIN 20 — 100 % fLPF Internal PWM Low Pass Filter Cut-Off Frequency — — 4 — kHz ALPF Filter Attenuation f = 30kHz — 52.5 — dB Notes: 7. Nominal „on‟ time (tON_NOM ) is defined by the input voltage (VIN), coil inductance (L) and peak current (ILX_PKDC) according to the expression: tON_NOM = {ILX_PKDC x L/VIN} +200ns. 8. This is the time for which the device remains active after the EN pin has been asserted low. This delay is necessary to allow the output to be maintained during dc PWM mode operation.
Document number: DS37687 Rev. 2 - 2 5 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Device Description The device is a PFM flyback DC-DC boost converter, working in discontinuous mode. With reference to the chip block diagram and typical application circuit, the operation of the device is as follows: ZXLD1615Q Block-Circuit Diagram Control Loop When 'EN' is high, the control circuits become active and the low side of the coil (L1) is switched to ground via NDMOS transistor (MN). The current in L1 is allowed to build up to an internally defined level (nominally 320mA) before MN is turned off. The energy stored in L1 is then transferred to the output capacitor (C2) via Schottky diode (D1). The output voltage is sensed at pin 'FB' by external resistors R1 and R2 and compared to a reference voltage V REF (1.025V nominal). A comparator senses when the output voltage is above that set by the reference and its output is used to control the 'off' time of the output switch. The control loop is self -oscillating, producing pulses of up to 5 µs maximum duration (switch 'on'), at a fre quency that varies in proportion to the output current. The feedback loop maintains a voltage of VREF at the FB pin and therefore defines a maximum output voltage equal to VREF x (R1+R2)/R1. The minimum 'off' time of the output switch is fixed at 0.5µs nominal, to allow time for the coil's energy to be dissipated before the switch is turned on again. This maintains stable and efficient operation in discontinuous mode. Filtered PWM Operation The input of an internal low -pass filter is switched to V REF when the EN pin is high and switched to ground when the EN pin is low. The output of this filter drives the comparator within the control loop. A continuous high state on EN therefore provides a filtered voltag e of value V REF to the comparator. However, by varying the duty cycle of the EN signal at a suitably high frequency (f>10kHz), the control loop will see a voltage, that has an average value equal to the duty cycle multiplied by VREF. This provides a means of adjusting the output voltage to a lower value. It also allows the device to be both turned on and adjusted with a single signal at the „EN‟ pin. The output during this mode of operation will be a DC voltage equal to: VREF x (R1+R2)/R1 x D Where D is the Duty Cycle Gated PWM Operation The internal circuitry of the ZXLD1615Q is turned off when no signal is present on the 'EN' pin for more than 120µs (Nominal). A low-frequency signal applied to the EN pin will therefore gate the device 'on' and 'off' at the gating frequency and the duty cycle of this signal can be varied to provide an average output equal to: VREF x (R1+R2)/R1 x D For best accuracy, the gating frequency should be made as low as possible (e.g. below 1kHz), such that the turn -off delay of the chip is only a small proportion of the gating period. Further details of setting output current are given in the application notes. 4.7F
Document number: DS37687 Rev. 2 - 2 6 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Typical Characteristics
Document number: DS37687 Rev. 2 - 2 7 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Typical Characteristics (Cont.)
Document number: DS37687 Rev. 2 - 2 8 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Applications Information Setting Output Voltage The ZXLD1615Q has an adjustable output voltage allowing the end user maximum flexibility. To set the output voltage, a potential divider network is needed (see R1 and R2 in typical applications circuit). The output voltage is determined by the equation: VOUT VF 1+ 1 Where VFB = 1.025V The following table gives suggested values for various output voltages. Required Output Voltage R1 R2 5V 270kΩ 1MΩ 12V 91kΩ 1MΩ 18V 60kΩ 1MΩ 21V 51kΩ 1MΩ 25V 43kΩ 1MΩ 28V 39kΩ 1MΩ Output voltage can be adjusted from VIN + VF to the maximum output voltage rating of the internal switch, 30V. Once the nominal output voltage has been set, it can be adjusted to a lower value by applying a pulse width modulated (PWM) c ontrol signal to the EN pin. PWM adjustment permits the device to be turned on and the output voltage set by a single logic signal applied to the EN pin. No external resistors are required and the amplitude of the control signal is not critical, providing it conforms to the limits defined in the electrical characteristics. 1) PWM Output Voltage Adjustment (Analog Mode) During this mode of operation the device operation is continuous, providing a low ripple output voltage (VOUT) directly proportional to the Duty Cycle (D) of the logic signal applied to the EN pin according to the relationship: VOUT = D x VOUT(NOM) Square wave signals applied to the EN pin, for example, will turn the device on and produce a nominal regulated output of 13.5V. The ZXLD1615Q contains a timing circuit that switches the device on a few microseconds after the application of a rising edge to EN and turns it back off again nominally 120μs after the falling edge of EN. For continuous PWM mode operation, the frequency of the control signal must therefore be maintained above 10kHz at all times, to prevent the internal delay circuit from timing out and switching the device into standby mode. The maximum frequency applied to EN should be limited to 100kHz to minimize errors due to internal switching delays. 2) PWM Output Voltage Adjustment (Gated Mode) This method of adjustment can be used in applications where the output ripple is less important than the supply current. The method of adjustment is the same as in 1) above, however, during this mode of operation, the device is gated on and off, providing an average output voltage (V OUT) directly proportional to the Duty Cycle (D) of the logic signal applied to the EN pin according to the relationship: VOUT(AVG) = D x VOUT(NOM) The ripple on this voltage will be determined by the size of the output capacitor. The output voltage can be adjusted all the way down to the input voltage by either method of PWM control, but for best results, the duty cycle range should be kept within the specified range. Lower duty cycles will result in increased out put ripple and non-linearity in the relationship between duty cycle and output voltage. If a greater control range is required, the nominal output can be reduced by the use of external resistors before the PWM signal is applied. Minimizing Output Voltage Ripple For applications requiring lower output ripple it may be necessary to add a small ceramic capacitor in parallel with R2. A value of 4.7pF is suitable for most output ranges.
Document number: DS37687 Rev. 2 - 2 9 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Applications Information (Cont.) Capacitor Selection A ceramic capacitor grounded close to the GND pin of the package is recommended at the output of the device. Surface mount ty pes offer the best performance due to their lower inductance. A minimum value of 0.22µ F is advised, although higher values will low er switching frequency and improve efficiency especially at lower load currents. A higher value will also minimize ripple when using the device to p rovide an adjustable DC output current. A good quality, low ESR capacitor should also be used for input de coupling, as the ESR of this capacitor is effectively in series with the source impedance and lowers overall efficiency. This capacitor has to supply the relatively high peak current to the coil and smooth the current ripple on the input supply. A minimum value of 4.7µ F is acceptable if the input source is close to the device, but higher values will improve performance at lower input voltages, when the source impedance is high. The input capacitor should be mounted as close as possible to the IC. Inductor Selection The choice of inductor will depend on available board space as well as required performance. Small value inductors have the advantage of smaller physical size and may offer lower series resistance and higher saturation current compared to larger values. A disadvantage of lower inductor values is that they result in higher frequency switching, which in turn causes reduced effic iency due to switching losses. Higher inductor values can provide better performance at lower supply voltages. However, if the inductance is too high, the output power will be limited by the internal oscillator, which will prevent the coil current from reaching its peak value. Th is condition will arise whenever the ramp time (ILX(PEAK) x L/VIN) exceeds the nominal 5µ s maximum 'on' time limit for the LX output. For maximum stability over temperature, capacitors with X7R dielectric are recommended, as these have a much smaller temperat ure coefficient than other types. A table of recommended manufacturers is provided below: Manufacturer Website Murata www.murata.com Taiyo Yuden www.t-yuden.com Kemet www.kement.com AVX www.avxcorp.com Recommended inductor values for the ZXLD1615Q are in the range 6.8 µH to 22 µH. The inductor should be mounted as close to the device as possible with low resistance connections to the LX and VIN pins. Suitable coils for use with the ZXLD1615Q are shown in the table below: Part No. L(µ H) DCR (Ω) ISAT(A) Manufacturer CMD4D11-100MC 10 0.457 0.5 Sumida www.sumida.com DO1608-103 10 0.16 1.1 Coilcraft www.coilcraft.com LQH31CN100 10 1.3 0.23 Murata www.murata.com LB2012Y100MR 10 0.5 0.1 Taiyo Yuden www.tyuden.com Diode Selection The rectifier diode (D1) should be a fast low capacitance Schottky diode with low reverse leakage at the working voltage. It should also have a peak current rating above the peak coil current and a continuous current rating higher than the maximum output load current. The table below gives some typical characteristics for diodes that can be used with the ZXLD1615Q: Diode VF @ 100mA (mV) IF (mA) IR at 40V (µA) Package DFLS140LQ 360 1,000 100 PowerDI®123 (Note 9) DFLS160LQ 360 1,000 100 PowerDI®123 (Note 9) Note 9: PowerDI is a registered trademark of Diodes Incorporated. Layout Considerations PCB tracks should be kept as short as possible to minimize ground bounce, and the ground pin of the device should be soldered dir ectly to the ground plane. It is particularly important to mount the coil and the input/output capacitors close to the device to mi nimize parasitic resistance and inductance, which will degrade efficiency. The FB pin is a high -impedance input, so PCB track lengths to this should also be kept as short as possible to reduce noise pickup. Excess capacitance from the FB pin to ground should be avoided.
Document number: DS37687 Rev. 2 - 2 10 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Applications Information (Cont.) General Boost Converter VIN =2.5V to 5.5V, VOUT up to 28V
Ordering Information
Product Name Qualification ET5: TSOT25 TA:Tape & Reel Package Packing Q: Automotive compliant Part Number Packaging (Note 10) Pack Code 7” Tape & Reel Qualification Grade (Note 11) Reel Width (mm) Quantity Per Reel Part Number Suffix ZXLD1615QET5TA TSOT25 ET5 8 3,000 TA Automotive-Compliant Notes: 10. For packaging details, go to our website at https://www.diodes.com/design/support/packaging/diodes -packaging/. 11. ZXLD1615Q has been qualified to AEC-Q100 grade 3 and is classified as “Automotive-Compliant” which supports PPAP documentation. See ZXLD1615 datasheet for commercial qualified versions. Marking Information 1 2 3 (Top View) XXX : Identification Code (615) W : Week : A to Z : 1 to 26 week; X : Internal Code Y : Year 0 to 9 a to z : 27 to 52 week; z represents 52 and 53 week XXX Y W X 4.7F
Document number: DS37687 Rev. 2 - 2 11 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. D E1/2 E E/2 e A Seating Plane0 L Gauge Plane 01(4x) 01(4x) c b Seating Plane TSOT25 Dim Min Max Typ A - 1.00 - A1 0.01 0.10 - A2 0.84 0.90 - b 0.30 0.45 - c 0.12 0.20 - D - - 2.90 E - - 2.80 E1 - - 1.60 e 0.95 BSC e1 1.90 BSC L 0.30 0.50 - L2 0.25 BSC θ 0° 8° 4° θ1 4° 12° - All Dimensions in mm Dimensions Value (in mm) C 0.950 X 0.700 Y 1.000 Y1 3.199 C X Y TSOT25 TSOT25
Document number: DS37687 Rev. 2 - 2 12 of 12 www.diodes.com November 2017 © Diodes Incorporated ZXLD1615Q IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license unde r its patent or trademark rights, nor the rights of others. Any Cust omer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diod es Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising ou t of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Product name s and markings noted herein may also be covered by one or more United States, international or foreign trademarks. This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or system s without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided i n the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support d evices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety -critical, life support devices or systems, notwithstanding any devices - or systems -related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2017, Diodes Incorporated www.diodes.com