|
|
Part: EL7551CU-T7
Category:
Power Management
-> DC-DC Converters
Description: Monolithic 1 Amp Dc:dc Step-down (Buck) Converter
Company: Elantec Semiconductor, Inc. (acquired by Intersil)
Datasheet: Download EL7551CU-T7 datasheet File size : 485 kB
Request For quote: Find where to buy EL7551CU-T7
Datasheet text preview:
EL7551C
EL7551C
Monolithic 1 Amp DC:DC Step-down Regulator
Features
· Integrated synchronous MOSFETs and current mode controller · 1A continuous output current · Up to 95% efficiency · 4.5V to 5.5V input voltage · Adjustable output from 1V to 3.8V · Cycle-by-cycle current limit · Precision reference · ±0.5% load and line regulation · Adjustable switching frequency to 1.2MHz · Oscillator synchronization possible · Internal soft start · Over temperature protection · Under voltage lockout · 16-pin QSOP package
General Description
The EL7551C is an integrated, synchronous step-down regulator with output voltage adjustable from 1.0V to 3.8V. It is capable of delivering 1A continuous current at up to 95% efficiency. The EL7551C operates at a constant frequency pulse width modulation (PWM) mode, making external synchronization possible. Patented on-chip resistorless current sensing enables current mode control, which provides cycle-bycycle current limiting, over-current protection, and excellent step load r es po ns e. The EL7551C is available in a fused-lead 16-pin QSOP package. With proper external components, the whole converter fits into a less than 0.4 in2 area. The minimal external components and s m a l l size make this EL7551C ideal for desktop and portable applications. The EL7551C is specified for operation over the -40°C to +85°C temperature range.
Applications
· · · · · DSP, CPU Core and IO Supplies Logic/Bus Supplies Portable Equipment DC:DC Converter Modules GTL + Bus Power Supply
Typical Application Diagram
C3
C4
1 SGND 2 COSC 3 VDD 4 PGND
PGND 16 C5 VREF 15 0.1µF FB 14 VDRV 13 LX 12 LX 11 VHI 10 C6 0.1µF R1 1k L1 R2 2.37k
0. 1µF 270pF
Ordering Information
P a rt No E L 75 51C U E L 75 51C U-T 7 E L 75 51C U-T 13 Pa ck age 16 -P in QSOP 16 -P in QSOP 16 -P in QSOP T a pe & Reel 7" 1 3" Ou tlin e # MDP 00 40 MDP 00 40 MDP 00 40
R3 39
C1 10µF ce ramic VI N (4. 5V5.5V)
5 PGND 6 VIN 7 VIN 8 EN
10µH
C7 VO 47µF (3.3V, 1 A)
January 24, 2002
PGND 9 EL7551C
Manufactured under U.S. Patent No. 57,323,974
Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a "controlled document". Current revisions, if any, to these s peci fica tion s are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation.
© 2002 Elantec Semiconductor, Inc.
EL7551C
EL7551C
Monolithic 1 Amp DC:DC Step-down Regulator
Absolute Maximum Ratings (T
Supply Voltage between VI N or VDD and GND VLX Voltage Input Voltage VHI Voltage
A=
25°C)
+6.5V VIN +0.3V GND -0.3V, VD D +0.3V GND -0.3V, VL X +6V
Storage Temperature Operating Ambient Temperature Operating Junction Temperature
-65°C to +150°C -40°C to +85°C +135°C
Important Note: All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: T J = TC = TA.
DC Characteristics
VDD = VIN = 5V, TA = TJ = 25°C, COSC = 1.2nF, unless otherwise specified. Parameter VRE F VRE FTC VRE FLOA D VRA MP IOSC _C HG IOSC _D IS IVD D +VD RV IVD D_O FF VD D_O FF VD D_O N TOT TH YS IL E A K IL M A X RDSO N RDSO NT C VFB VFB_LI NE VFB_LO A D VFB_TC IF B VEN _HI VEN _LO IE N Description Reference Accuracy Reference Temperature Coefficient Reference Load Regulation Oscillator Ramp Amplitude Oscillator Charge Current Oscillator Discharge Current VDD +VDRV Supply Current VDD Standby Current VDD for Shutdown VDD for Startup Over Temperature Threshold Over Temperature Hysteresis Internal FET Leakage Current Peak Current Limit FET On Resistance RD SO N Tempco Output Initial Accuracy Output Line Regulation Output Load Regulation Output Temperature Stability Feedback Input Pull Up Current EN Input High Level EN Input Low Level Enable Pull Up Current VEN = 0 1 -4 -2.5 ILOA D = 0A VIN = 5V, VI N = 10%, ILO AD = 0A 0.1A < ILOA D < 1A -40°C < TA < 85°C, ILO A D = 0.5A VFB = 0V 0.960 Wafer level test only EN = 0, LX = 5V (low FET), LX = 0V (high FET) 2 45 0.2 0.975 0.5 0.5 ±1 100 3.2 200 4 0.99 95 0.1V < VO SC < 1.25V 0.1V < VO SC < 1.25V VEN = 4V, FOSC = 120kHz EN = 0 3 .5 3.95 135 20 10 0 < IREF < 50µA -1 1.15 200 8 3.5 1 5 1.5 4 4.45 Conditions Min 1.24 Typ 1.26 50 Max 1.28 Unit V ppm/°C % V µA mA mA mA V V °C °C µA A m m/°C V % % % nA V V µA
Closed Loop AC Electrical Characteristics
VS = VIN = 5V, TA = TJ = 25°C, COSC = 1.2nF, unless otherwise specified. Parameter FOSC tSY NC MSS tBR M tLEB DMA X Description Oscillator Initial Accuracy Minimum Oscillator Sync Width Soft Start Slope FET Break Before Make Delay High Side FET Minimum On Time Maximum Duty Cycle Conditions Min 105 Typ 117 25 0.5 15 150 95 Max 130 Unit kHz ns V/ms ns ns %
2
EL7551C
EL7551C
Monolithic 1 Amp DC:DC Step-down Regulator
Pin Descriptions
Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pin Name SGND COSC VDD PGND PGND V IN V IN EN PGND VHI LX LX VDRV FB VREF PGND Control circuit negative supply. Oscillator timing capacitor. FOSC can be approximated by: FOSC (kHz) = 0.1843/COSC, COSC in µF. Control circuit positive supply. Ground return of the regulator. Connected to the source of the low-side synchronous NMOS power FET. Ground return of the regulator. Connected to the source of the low-side synchronous NMOS power FET. Power supply input of the regulator. Connected to the drain of the high-side NMOS power FET. Power supply input of the regulator. Connected to the drain of the high-side NMOS power FET. Chip Enable, active high. A 2µA internal pull-up current enables the device if the pin is left open. Ground return of the regulator. Positive supply of the high-side driver. Inductor drive pin. High current digital output whose average voltage equals the regulator output voltage. Inductor drive pin. High current digital output whose average voltage equals the regulator output voltage. Positive supply of the low-side driver and input voltage for the high-side boot strap. Voltage feedback input. Connected to an external resistor divider between VOUT and GND. A 125nA pull-up current forces VOUT to VS in the event that FB is floating. Bandgap reference bypass capacitor. Typically 0.1µF to GND. Ground return of the regulator. Pin Function
3
EL7551C
EL7551C
Monolithic 1 Amp DC:DC Step-down Regulator
Typical Performance Curves
Efficiency vs IO VIN =5V 100 VO=2.5V 95 90 85 VO =1.2V 80 75 70 65 60 0.1 0.2 0.4 FS=500k Hz L=Coilcraft DO3316P-472 0 0.6 0.8 1 VO =3.3V VO =1V Power Loss (W) Efficiency (%) 0.2 VO =1.8V VO=1.5V 0.25
Power Loss vs IO VIN =5V
0.15 VO =3.3V 0.1
0.05 VO=1V 0 0.2 0.4 0.6 0.8 1
Loa d Current IO (A) Efficiency vs IO VO=3.3V 100 VIN=4.5V 95 90 Output Voltage (%) VIN =5V Efficiency (%) 85 80 75 70 65 60 0 0.2 0.4 0.6 0.8 1 Loa d Current IO (A) Line Regulation VO=3.3V 0.6 0.5 0.4 0.3 VO (%) 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 4.5 4.7 4.9 VIN (V) 5.1 5.3 5.5 IO=1A IO=0.1A VREF (V) 1.258 1.256 1.254 1.252 1.25 1.248 1.246 1.244 1.242 -40 10 FS=500k Hz L=Coilcraft DO3316P-472 -0.6 0 0.2 -0.4 VIN=5.5V 0.2 0.4 0.6 Load Regulation VO=3.3V
Output Current IO (A)
VIN=5.5V
VIN =5V 0 -0.2 VIN=4.5V
0.4
0.6
0.8
1
Load Current IO (A) VREF vs Temperature
60 Temperature (°C)
110
160
4
EL7551C
EL7551C
Monolithic 1 Amp DC:DC Step-down Regulator
Typical Performance Curves
Oscillator Frequency vs Temperature 390 385 Oscillator Frequency (kHz) 380 375 370 365 360 -40 Input Current (mA) 0.96 0.94 0.92 0.9 0.88 0.86 0.84 0.82 0 40 Te mpe rature (°C) Switching Frequency vs COSC 1400 1200 1000 FS (kHz) 800 600 400 200 0 0 200 400 600 800 1000 COS C (pF) Transient Response VIN =5V, VO=3.8V, I O=0A-1A Power-Up VIN=5V, V O=3.8V, IO=1A VO iL VI VLX 80 120 0.8 -40 10 60 Temperature (°C) Switching Waveforms VIN =5V, VO=3.8V, I O=1A 110 160 VIN =5V VIN =4.5V VIN =5.5V Input Current vs Temperature (Enable connected to GND)
iO
VIN
VO
VO
5
Others parts begin by el
EL-1 EL-2 EL-3 EL-4 EL-5 EL-6 EL-7 EL-8 EL-9 EL-10 EL-11 EL-12 EL-13 EL-14 EL-15 EL-16 EL-17 EL-18
|
|
|
