Not Recommended for New Design

Transcription

1 Features - voltage:. and adjustable output version - Adjustable version output voltage range, 1.2 to 18+4% - 150KHz +15% fixed switching frequency - oltage mode non-synchronous PWM control - Thermal-shutdown and current-limit protection - Operating voltage can be up to 22 - load current: 1.5A - SIP-4L, SOP-8 Pb-Free package - Low power standby mode - Built-in switching transistor on chip - ery Low Cost Applications - Simple High-efficiency step-down regulator - On-card switching regulators - Positive to negative converter Pin Assignments General Description The series are monolithic IC designed for a step-down DC/DC converter, and own the ability of driving a 1.5A load without additional transistor component. Due to reducing the number of external component, the board space can be saved easily. The external shutdown function can be controlled by logic level and then come into standby mode. The internal compensation makes feedback control have good line and load regulation without external design. Regarding protected function, thermal shutdown is to prevent over temperature operating from damage, and current limit is against over current operating of the output switch. If current limit function occurred and is down to 0.5 below, the switching frequency will be reduced. The series operates at a switching frequency of 150KHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Other features include a guaranteed +4% tolerance on output voltage under specified input voltage and output load conditions, and +15% on the oscillator frequency. The output version included fixed. and an adjustable type. Pin Descriptions SIP-4L (Front iew) 1 : IN 2 : : 4 : Name IN Description Operating voltage input Switching output voltage feedback control ON/OFF Shutdown Ground IN (Top iew) SOP-8L This datasheet contains new product information. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. 1/9

2 Ordering Information XX X X version Package Packing Block Diagram Blank : Adjustable - :. P: SIP-4L(Bulk) S: SOP-8L Blank : Tube A : Taping IN 200m 220m Current Source bias 1.25 Reference 2.5 Regulator Start up + Comp _ Comp + _ + Amp _ Frequecy compensation Comp + _ Pre-driver 1.5A Switch 150KHz OSC. Thermal Shutdown Gnd 2/9

3 Absolute Maximum Ratings Symbol Parameter Rating Unit CC Supply oltage +24 ON/OFF Pin input voltage -0. to +18 Feedback Pin voltage -0. to +18 OUT oltage to Ground -1 P D Power Dissipation Internally limited W T ST Storage temperature -65 to +150 o C T OP Operating temperature -40 to +125 o C OP Operating voltage +4.5 to +22 Electrical Characteristics (All oltage ersions) Unless otherwise specified, IN= 12 for., 5, adjustable version and IN=18 for the 12 version. I LOAD = 0.5A Symbol Parameter Conditions Min. Typ. Max. Unit I -50 Feedback bias current = (Adjustable version only) -100 na F OSC Oscillator frequency KHz F SCP Oscillator frequency of When current limit occurred and short circuit protect < 0.5, Ta=25 o C KHz I OUT =2A 1.4 SAT Saturation voltage No outside circuit =0 force driver on 1.5 DC Max. Duty Cycle (ON) =0 force driver on Min. Duty Cycle (OFF) =12 force driver off % I CL Current limit Peak current SIP No outside circuit =0 force driver SOP on A No outside circuit = 0 I L leakage =12 force driver off ua = -1 current IN = ma I Q Quiescent Current =12 force driver off ma I STBY Standby Quiescent ON/OFF pin= Current IN = ua θ JC Thermal Resistance Junction to case SIP SOP-8 15 o C/W θ JA Note 1 Junction to ambient SIP SOP-8 70 o C/W Part Number Symbol Parameter Conditions Typ. Limit Unit 4.5 < IN < A < I Feedback LOAD < 1.5A /1.18 -ADJ MIN OUT programmed for 1.267/1.28 MAX η Efficiency IN = 12, I LOAD =1.5A 78 % -. OUT voltage 4.75 < IN < A < I LOAD < 1.5A..168/.15.42/.465 η Efficiency IN = 12, I LOAD =1.5A 80 % Specifications with boldface type are for full operating temperature range, the other type are for T J=25ºC. Note 1: Pin 4() (< 1 mm length) & direct connect to internal layer (for SIP-4 only). MIN MAX /9

4 Typical Application Circuit (1) Fixed Type Circuit 12 DC Input in 1-2 L1 56uH Inductor./1.5A Load Cin 4 D1 Schottky Diode Co Cin in Gnd GndGndGnd L1 47uH Inductor D1 Schottky Diode Co./1.5A Load (2) Adjustable Type Circuit R2 R1 12 DC Input Cin in D1 Schottky Diode L1 47uH Inductor 2.5/1.5A Load Co R1 out = (1 + ) R2 = 1.2 R2 = 1K ~ K 4/9

5 Typical Application Circuit (Continued) (2) Adjustable Type Circuit R2 1K R1 1K 12 DC Input Cin in Gnd Gnd Gnd Gnd D1 Schottky Diode L1 9uH Inductor 2.5/1.5A Load Co R1 out = (1 + ) R2 = 1.2 R2 = 1K ~ K Typical Performance Characteristics out () oltage v.s. Temperature (in=12,io=1.5a) Efficiency (%) Efficiency v.s. Temperature (in=12,out=.,io=1.5a) /9

6 Typical Performance Characteristics (Continued) Saturation oltage v.s. Temperature (cc=12,fb=0,=0) Switch Current Limit v.s. Temperature (cc=12,fb=0) Saturation oltage () A 1A 1.5A Switch Current Limit (A) Supply Current v.s. Temperature (cc=12, No Load,on/off =0(Switch ON),on/off =5(Switch OFF)) Supply Current (ma) Switch ON Supply Current (ua) Switch OFF Frequency v.s. Temperature (cc=12, Io=500mA,out=5) Feedback Current v.s. Temperature (cc=12, out=5,fb=1.) Frequency (KHz) Feedback Current (na) /9

7 Function Description Pin Functions + IN 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 currents needed by the regulator. Ground Circuit ground. Internal switch. The voltage at this pin switches between (+ IN SAT ) and approximately 0.5, with a duty cycle of approximately OUT / IN. To minimize coupling to sensitive circuitry, the PC board copper area connected to this pin should be kept a minimum. Feedback Senses the regulated output voltage to complete the feedback loop. Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply current to approximately 150uA. Pulling this pin below a threshold voltage of approximately 1. turns the regulator on, and pulling this pin above 1. (up to a maximum of 18) shuts the regulator down. If this shutdown feature is not needed, the pin can be wired to the ground pin. Marking Information (1) SIP-4L ( Top iew ) 1515 Part Number: Type: Adjustable Y WW X Date Code X: Internal code WW: Nth week: 01~52 Y: Year: "1" = 2001 "2" = 2002 ( Top iew ) 15- Part Number : -: Type:. Y WW X Date Code X: Internal code WW: Nth week: 01~52 Y: Year: "1" = 2001 "2" = 2002 (2) SOP-8L (Top view) Part Number Type: Blank: Adjustable : XX YY WW X Logo Date Code X: Internal code WW: Nth week YY: Year 7/9

8 Package Information (1) Package Type: SIP-4L 1.55mm 1.0mm +/ o -7 o o o mm +/-1.25mm 0.8mm +/-0.0mm 0.0mm.65mm 0.46mm +/-0.0mm 0.41mm +/-0.0mm 5.22mm 4.20mm.81mm +/-0.0mm 5 o -7 o o o mm Max. 1.42mm 1.27mm +/-0.0mm 8/9

9 Package Information (Continued) (2) Package Type: SOP-8L E H L IEW "A" 7 (4X) D 0.015x45 7 (4X) A2 A e B A1 y C IEW "A" Symbol Dimensions In Millimeters Dimensions In Inches Min. Nom. Max. Min. Nom. Max. A A A B C D E e H L y θ 0 O - 8 O 0 O - 8 O 9/9