View LM2575_3535242.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

1a, 52khz, step-down switching regulator LM2575 features 3.3v, 5.0v, 12v, 15v, and adjustable output versions adjustable version output voltage range, 1.23 to 37v +/- 4% ag10 maximum over line and load conditions guaranteed 1a output current wide input voltage range requires only 4 external components 52khz fixed frequency internal oscillator ttl shutdown capability, low power standby mode high efficiency uses readily available standard inductors thermal shutdown and current limit protection moisture sensitivity level 3 applications simple high-efficiency step-down(buck) regulator efficient pre-regulator for linear regulators on-card switching regulators positive to negative converter(buck-boost) negative step-up converters power supply for battery chargers description ordering information the LM2575 series of regulators are monolithic integrated circuits ideally suited for easy and convenient design of a step-down switching regualtor(buck converter). all circuits of this series are capable of driving a 1a load with excellent line and load regulation. these devices are available in fixed output voltages of 3.3v, 5.0v,12v, 15v, and an adjustable output version. these regulatiors were designed to minimize the number of exter nalcomponents to simplify the power supply design. standard series of inductors optimized fo r use with the LM2575 are offered by several different inductor manufacturers. since the LM2575 converter is a switch-mode power supply, its efficiency is significantly higher in comparison with popular three-terminal limear reguators, especi ally with higher input voltages. available from several different manufacturers. this feature g reatly simplifies the design of switch-mode power supplies. the LM2575 features include a guara nteed +/- 4% tolerance on output voltage within specified input voltages and output lo ad conditions, and +/-10% on the oscillator frequency (+/- 2% over 0 to 125 ). external shutdown is included, featuring 80 ?(typical) standby current. the output switch includes cycle-bycycle current limiting, as well as thermal shutdown for full protection under fault conditions. 2008 - ver. 1.0 htc ? 1 ? device marking package LM2575t-x.x LM2575t-x.x to-220 in many cases, the power dissipated is so low that no heatsink is required or its size could be reduced dramatically. a standard series of inductors optimiz ed for use with the LM2575 are LM2575tv-x.x LM2575t-x.x LM2575r LM2575r-x.x to-263 to-220v 1. vin 2. output 3. ground 4. feedback 5. on/off 1 5 1 5 1 5 to-220 pkg to-263 pkg to-220v pkg
1a, 52khz, step-down switching regulator LM2575 absolute maximum ratings (absolute maximum ratings indicate limits beyond which damage t o the device may occur) maximum junction temperature t j 150 lead temperature (soldering,10seconds) - 260 minimum esd rating(human body model : - 2.0 kv c=100 pf, r=1.5?) storage temperature range t stg -60 to +150 thermal resistance, juntion to case p jc 5.0 /w internally limited w thermal resistance, juntion to ambient p ja 70 /w to-220 5lead p d thermal resistance, juntion to ambient p ja thermal resistance, juntion to case p jc to-263 5lead p d power dissipation internally limited w 65 /w 5.0 /w 45 - - 1.0 v rating symbol value unit htc ? 2 ? v on/off pin input voltage - -0.3v v +vin v output voltage to ground (steady-state) maximum supply voltage vin typical application (fixed output voltage versions) fi g ure 1. block dia g ram and t yp ical a pp lication LM2575 1a load
1a, 52khz, step-down switching regulator LM2575 operating ratings (operating ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. for guaranteed specifications, see the electrical characteristics.) LM2575-3.3v ([note 1] test circuit figure 2) LM2575-5.0v ([note 1] test circuit figure 2) LM2575-12v ([note 1] test circuit figure 2) LM2575-adj ([note 1] test circuit figure 2) % - 1.28 - htc ? 3 ? t j = -40 ~ +125 1.18 feedback voltage(8.0vvin40v, 0.5ai load 1a, vout=5.0v) t j =25 1.193 efficiency (vin=12v, i load =1a, vout=5.0v) -77 1.23 1.267 vout % feedback voltage (vin=12v, i load =0.5a, t j =25) vout 1.217 1.23 1.243 v v - 12.6 efficiency (vin=12v, i load =1a) -88- vout v t j =25 11.52 12 12.48 t j = -40 ~ +125 11.4 output voltage (15vvin40v, 0.5ai load 1a % output voltage (vin = 25v, i load =0.5a, t j =25) vout 11.76 12 12.24 v - 5.25 efficiency (vin=12v, i load =1a) -77- vout v t j =25 4.8 5.0 5.2 t j = -40 ~ +125 4.75 output voltage (8.0vvin40v, 0.5ai load 1a % output voltage (vin = 12v, i load =0.5a, t j =25) vout 4.9 5.0 5.1 v - 3.465 efficiency (vin=12v, i load =1a) -75- vout v t j =25 3.168 3.3 3.432 t j = -40 ~ +125 3.135 output voltage (6.0vvin40v, 0.5ai load 1a 3.366 v characteristics symbol min output voltage (vin = 12v, i load =0.5a, t j =25) vout 3.234 3.3 typ supply voltage vin 40 max v unit operating junction temperature range t j -40 to +125 rating symbol value unit electrical characteristics / system parameters ([note 1] test circuit figure 15) (unless otherwise specified, vin = 12 v for the 3.3 v, 5.0 v, a nd adjustable version, vin = 25 v for the 12 v version, and vin = 30 v for the 15 v version. iload = 500 ma. for typical values tj = 25c, for min/max values tj is the operating junction temperature ran ge that applies [note 2], unless otherwise noted.) 1. external components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. when the LM2575 is used as shown in the figure 15 test circ uit, system performance will be as shown in system parameters section . 2. tested junction temperature range for the LM2575: tlow = C40 c thigh = +125c
1a, 52khz, step-down switching regulator LM2575 all output voltage versions ? t j = 0 to +125 47 - 58 % a ma i cl i l na khz v ? 11 50 30 6.9 9 min typ 94 98 1.2 42 - -52 max duty cycle ("0") [note 5] dc ma - 7.5 - output = -1.0v - 1.7 feedback bias current (vout=5.0v [adjustable version only]) i b 1.4 - on/off pin = 0v (regulator on), tj=25 i il - 0 5.0 on/off pin = 5.0v (regulator off), tj=25 i ih -1530 on/off pin input current (test circuit figure 15) 1 t j = -40 to +125 - - 0.8 t j =25 - 1.2 - vout=nominal output voltage v ih v il - t j = -40 to +125 2.4 - t j =25 2.2 1.4 vout=0v 400 on/off pin logic input level (test circuit figure 15) t j = -40 to +125 -- t j =25 - 80 200 standby quiescent current (on/off pin = 5.0v ("off")) i stby t j = -40 to +125 -- t j =25 -5 quiescent current [note 6] i q 6 output = 0v - 0.8 output leakage current [note 6 and 7], t j =25 t j = -40 to +125 3.5 5.8 current limit (peak current [note 3 and 4]) t j =25 4.2 63 t j = -40 to +125 -- vsat t j =25 - saturation voltage (iout=1a [note 4]) t j = -40 to +125 -- fosc t j = -40 to +125 unit max characteristics symbol htc ? 4 ? t j =25 - 25 100 200 oscillator frequency [note 3] v t j =25 v electrical characteristics / device parameters (unless otherwise specified, vin = 12 v for the 3.3 v, 5.0 v, and adjustable version, vin = 25 v for the 12 v version, and vin = 30 v for the 15 v version. iload = 500 ma. for typical values tj = 25c, for min/ma x values tj is the operating junction temperature range that applies [note 2], unless otherwise noted.) 3. the oscillator frequency reduces to approximately 18 khz in the event of an output short or an overload which causes the regulated output voltage to drop approximat ely 40% from the nominal output voltage. this self protection feature lowers the average dissipation of the ic by lowering the minimum duty cycle from 5% down to approximately 2%. 4. output (pin 2) sourcing current. no diode, inductor or capac itor connected to output pin. 5. feedback (pin 4) removed from output and connected to 0 v. 6. feedback (pin 4) removed from output and connected to +12 v for the adjustable, 3.3 v, and 5.0v ersions, and +25 v for the 12 v and15 v versions, to force the outpu t transistor off. 7. vin = 40 v.
1a, 52khz, step-down switching regulator LM2575 htc ? 5 ? typical performance characteristics (circuit of figure 15)
1a, 52khz, step-down switching regulator LM2575 ? 6 ? htc typical performance characteristics (circuit of figure 15)
1a, 52khz, step-down switching regulator LM2575 ? 7 ? htc LM2575 LM2575
1a, 52khz, step-down switching regulator LM2575 this pin is the positive input supply for the LM2575 step?down switching regulator.in order to minimize voltage transients and to supply the switching currents needed by the regulator, a suitable input bypass capacitor must be present .(cin in figure 1). this is the emitter of the internal switch. the saturation voltage vsat of this output switch is typically 1.5 v. it should be kept in mind that the pcb area connected to this pin should be kept to a minimum in order to minimize coupling to sensitive circuitry. circuit ground pin. see the information about the printed circuit board layout. this pin senses regulated output voltage to complete the feedback loop. the signal is divided by the internal resistor divider network r2, r1 and applied to the non?inverting input of the internal error amplifier. in the adjustable version of the LM2575 switching regulator this pin is the direct input of the error amplifier and the resistor network r2, r1 is connected externally to allow programming of the output voltage. it allows the switching regulator circuit to be shut down using logic level signals, thus dropping the total input supply current to approximately 80 ma. the threshold voltage is typically 1.4 v. applying a voltage above this value (up to +vin) shuts the regulator off. if the voltage applied to this pin is lower than 1.4v or if this pin is left open, the regulator will be in the "on" condition feedback htc ? 8 ? 4 5 on/off 2 gnd 3 description symbol 1 vin output pin function description
1a, 52khz, step-down switching regulator LM2575 ? 9 ? htc LM2575-5.0
1a, 52khz, step-down switching regulator LM2575 htc ? 10 ? LM2575-adj LM2575
1a, 52khz, step-down switching regulator LM2575 htc ? 11 ? LM2575-adj
1a, 52khz, step-down switching regulator LM2575 htc ? 12 ? LM2575-3.3v LM2575-5.0v LM2575-12v LM2575-15v LM2575-adj
1a, 52khz, step-down switching regulator LM2575 ? 13 ? htc

▲Up To Search▲

Price & Availability of LM2575

	To Download LM2575 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .