ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B G5ULM2596 Simple Switcher Power converter 150kHz 3A Step-Down Voltage Regulator Description The G5ULM2596 series of regulators are monolithic integrated circuits that provide all active functions for a step-down (buck) switching regulator, capable of driving 3A load with excellent line and load regulation. These devices are available in fixed output voltage of 3.3v, 5v, 12v and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator. The G5ULM2596 series operates at a switching frequency of 150 kHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Available in a standard 5-lead TO-263 package with several different lead bend options. A standard series if inductors are available from several different manufactures optimized for use with the G5ULM2596 series. This feature greatly simplifies the design of switch-mode power supplies. Other feature include a guaranteed ±4% to tolerance on output voltage under specified input voltages and output load conditions, and ±15% on the oscillator frequency. External shutdown is included, featuring 80uA standby current. Self protection features include a two stage frequency reducing current limit for the output switch and an over temperature shutdown for complete protection under fault conditions. Features 3.3V, 5.0V, 12V and adjustable output versions Adjustable version output voltage range , 1.2V to 37V ±4% max over line and load conditions Guaranteed 3A output current Input voltage range up to 40V Efficient pre-regulator for linear regulators Requires only 4 external components 150kHz fixed frequency internal oscillator TTL shutdown capability, low power standby mode High efficiency Uses readily available standard inductors Thermal shutdown and current limit protection Applications Simple high-efficiency step-down (buck) regulator On-card switching regulators Positive to negative converter Package Dimensions REF. A b L4 c L1 E Millimeter Min. Max. 4.40 4.80 0.66 0.91 0.00 0.30 B 0.36 0.5 2.29 2.79 9.80 10.4 REF. c2 L2 D e L Millimeter Min. Max. 1.25 1.45 1.27 REF. 8.6 9.0 1.70 REF. 14.6 15.8 0˚ 8˚ Typical Application (Fixed Output Voltage Version) 12V Unregulated DC Input G5ULM2596-5.0 33 680 G5ULM2596 1N5824 680 220 Page: 1/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B Block Diagram FEEDBACK Pin Function Pin Name Pin# Function This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be present at this pin to minimize voltage transients and to supply the switching current needed by regulator. Internal switch. The voltage at this pin switches between (+V IN – V SAT) and approximately -0.5V, with a duty cycle of approximately V OUT/V IN. To minimize coupling to sensitive circuit, the PC board copper area connected to this pin should be keep to a minimum. +VIN 1 Output 2 Ground Feedback 3 Circuit ground 4 Senses the regulated output voltage to complete the feedback loop 5 Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply current to approximately 80 A. Pulling this pin below a threshold voltage of approximately 1.3V turns the regulator on, and pulling this pin above 1.3V (up to a maximum of 25V) shuts the regulator down. If this shutdown feature is not needed, ON/OFF pin can be wired to the ground pin or it can be left open, in either case the regulator will be in the ON condition. ON/OFF Absolute Maximum Ratings (Note1) Parameter Maximum Supply Voltage ON/OFF pin input Voltage Feedback pin Voltage Output Voltage to ground (steady state) Power dissipation Storage Temperature Maximum junction temperature Minimum ESD rating (C=100pF, R=1.5k ) Lead temperature (soldering, 10seconds) Operating Ratings Temperature range Supply Voltage G5ULM2596 Parameter Ratings 45 -0.3 V +25 -0.3 V +25 -1 Internally Limited -65 ~ +150 +150 2k +260 Ratings -40 TJ +125 4.5 ~ 40 Unit V V V V V Unit V Page: 2/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B G5ULM2596-3.3 Electrical Characteristics Specifications with standard type face are for TJ=25 Parameter Symbol , and those with boldface type apply over full operating temperature range Conditions System Parameters (Note5) Test Circuit Figure 2 4.75V VIN 40V Output Voltage VOUT 0.2A ILOAD 3A Efficiency VIN=12V, ILOAD=3A (Note4) Min (Note3) Typ (Note4) Max Unit 3.168/3.135 3.3 3.432/3.465 V 73 % G5ULM2596-5.0 Electrical Characteristics Specifications with standard type face are for TJ=25 Parameter Symbol , and those with boldface type apply over full operating temperature range Conditions System Parameters (Note5) Test Circuit Figure 2 7V VIN 40V Output Voltage VOUT 0.2A ILOAD 3A Efficiency VIN=12V, ILOAD=3A (Note4) Min (Note3) Typ (Note4) Max Unit 4.80/4.75 5.0 5.20/5.25 V 80 % G5ULM2596-12 Electrical Characteristics Specifications with standard type face are for TJ=25 Parameter Symbol , and those with boldface type apply over full operating temperature range Conditions System Parameters (Note5) Test Circuit Figure 2 15V VIN 40V Output Voltage VOUT 0.2A ILOAD 3A Efficiency VIN=15V, ILOAD=3A (Note4) Min (Note3) Typ (Note4) Max Unit 11.52/11.40 12 12.48/12.60 V 90 % G5ULM2596 Electrical Characteristics Specifications with standard type face are for TJ=25 Parameter Symbol , and those with boldface type apply over full operating temperature range Conditions System Parameters (Note5) Test Circuit Figure 2 4.5 VIN 40V, 0.2A ILOAD 3A Output Voltage VOUT VOUT=3V, Circuit of Figure 2 Efficiency VIN=12V, ILOAD=3A, VOUT=3V (Note4) Min (Note3) Typ (Note4) Max Unit 1.180/1.168 1.230 1.280/1.292 V 77 % All Output Voltage Version Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range. Unless otherwise specified, V IN=12V for the 3.3V, 5.0V and Adjustable versions, V IN=24V for 12V version. ILOAD=0.5A Parameter Symbol Feedback bias current Oscillator frequency Saturation voltage Ib Conditions VFB=1.3V (adjustable version only) (Note4) Min (Note3) Typ (Note4) Max Unit 127/110 10 50/00 nA 150 173/173 1.4/1.5 kHz V fO VSAT (Note 6) ILOAD=3A (Note 7, 8) - 1.16 Maximum duty cycle (ON) DC (Note 8) (Note 9) - 100 0 - % Current limit ICL Output leakage current IL Peak Current (Note 7, 8) Output=0V(Note 7, 9) Output=-1V (Note 10) Quiescent current Standby quiescent current IQ 3.6/3.4 - 4.5 2 5 6.9/7.5 50 30 10 A uA mA mA - 80 200/250 uA (OFF) Thermal Resistance G5ULM2596 (Note 9) ISTBY ON/OFF pin=5V (OFF)(Note 10) JC Junction to Case - 2 - JA Junction to Ambient (Note 11) Junction to Ambient (Note 12) Junction to Ambient (Note 13) - 50 30 20 - /W Page: 3/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B ON/OFF Control Test Circuit Figure 2 - 1.3 - 2.0 - - 0.6 ON/OFF pin logic input Threshold Voltage VIH VIL High (Regulator OFF) Low (Regulator ON) ON/OFF pin input IH VLOGIC=2.5V ( Regulator OFF) - 5 15 current IL VLOGIC=0.5V ( Regulator ON) - 0.02 5 V uA Note 1: Absolute Maximum Rating indicate limits beyond which damage to the device may occur. Operating Rating indicate conditions for which the device is intended to be functional, but do not guaranteed specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: The human body mode is a 100pF capacitor discharged through a 1.5k Note 3: Typical number are at 25 and represent the most likely norm. resistor into each pin. Note 4: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100% production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) method. All limits are used to calculate Average Outgoing Quality Level (AOQL). Note 5: External component such as the catch diode, inductor, input and output capacitors, and voltage programming resistor can affect switching regulator system performance. When the G5ULM2596 is used as shutdown in the Figure 1 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics. Note 6: The switching frequency is reduced when the second stage current limit is activated. The amount of reduction is determined by the severity of current over-load. Note 7: No diode, inductor or capacitor connected to output pin. Note 8: Feedback pin removed from output and connected to 0V to force the output transistor switch ON. Note 9: Feedback pin removed from output and connected to 12V for the Adjustable, 3.3V and 5V versions, and 15V for the 12V version, to force the output transistor switch OFF. Note 10: V IN=40V. 2 Note 11: Junction to ambient thermal resistance with the TO -263 package tab soldered to a single sided printed circuit board with 0.5 in of (1 oz.) copper area. 2 Note 12: Junction to ambient thermal resistance with the TO -263 package tab soldered to a single sided printed circuit board with 2.5 in of (1 oz.) copper area. Note 13: Junction to ambient thermal resistance with the TO -263 package tab soldered to a double sided printed circuit board with 3.0 in 2 of (1 oz.) copper area on the G5ULM2596 side of the board, and approximately 16in of copper on the other side of the p-c board. Typical Performance Characteristics (circuit of Figure 2) Normalized Output Voltage G5ULM2596 Line Regulator Page: 4/8 2 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B Efficiency Switch Saturation Voltage Switch Current Limit Dropout Voltage Operating Quiescent Current G5ULM2596 Shutdown Quiescent Current Page: 5/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B Minimum Operating Supply Voltage ON/OFF Threshold Voltage ON/OFF Pin Current (Sinking) Switching Frequency Feedback Pin Bias Current G5ULM2596 Page: 6/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B Horizontal Time Base: 2 s/div Continuous Mode Switching Waveforms G5ULM2596 Horizontal Time Base: 2 s/div Discontinuous Mode Switching Waveforms Horizontal Time Base: 100 s/div Horizontal Time Base: 200 s/div Load Transient Response for Continuous Mode Load Transient Response for Discontinuous Mode Page: 7/8 ISSUED DATE :2005/04/15 REVISED DATE :2006/06/26B Test Circuit and layout Guidelines As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance generate voltage transients which can cause problems. For minimal inductance and ground loops, the wires indicated by heavy lines should be wide printed circuit traces and should be kept as short as possible. For best results, external components should be located as close to the switcher IC as possible using ground plane construction or single point grounding. If open core inductors are used, special care must be taken as to the location and positioning of this type of inductor. Allowing the inductor flux to intersect sensitive feedback, IC groundpath and C OUT wiring can cause problems. When using the Adjustable version, special care must be taken as to the location of the feedback resistors and the associated wiring. Physically locate both resistors near the IC, and route the wiring away from the inductor, especially an open core type of inductor. Cin-- 470uF, 50V, Aluminum Electrolytic Cout-- 220uF, 25V Aluminum Electrolytic D1-- 5A, 40V Schottky Rectifer, 1N5825 L1-- 68uH Vout=VREF*(1+R2/R1) Where VREF=1.23V R2=R1*(Vout/VREF-1) Select R1 to be approximately 1k , use a 1% resistor for best stability. Cin-- 470uF, 50V, Aluminum Electrolytic Cout-- 220uF, 35V Aluminum Electrolytic D1-- 5A, 40V Schottky Rectifer, 1N5825 L1-- 68uH Figure 2 Standard Test Circuits and Layout Guides Important Notice: All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of GTM. GTM reserves the right to make changes to its products without notice. GTM semiconductor products are not warranted to be suitable for use in life-support Applications, or systems. GTM assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. Head Office And Factory: Taiwan: No. 17-1 Tatung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, Taiwan, R. O. C. TEL : 886-3-597-7061 FAX : 886-3-597-9220, 597-0785 China: (201203) No.255, Jang-Jiang Tsai-Lueng RD. , Pu-Dung-Hsin District, Shang-Hai City, China TEL : 86-21-5895-7671 ~ 4 FAX : 86-21-38950165 G5ULM2596 Page: 8/8