July 25, 2000
BLOCK DIAGRAM
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FEATURES
•=Allows u of small surface mount components •=Ultra fast transient recovery time
•=Dramatic reduction of input ripple current and out-put ripple voltage
•=5-bit programmable DAC for the latest, lower output voltage Microprocessors •=Wide, High frequency operating range •=Selectable 2, 3, 4 pha operation秘密英文
•=+5 Volt only operation eliminates the need for +12V supply
•=Precision load current sharing,1%PWM match •=Selectable internal or external clock •=
Soft start/UVLO/Over current protection
APPLICATIONS
•=High end rvers and workstations
•=High current/Ultra-fast transient microprocessors TEL:805-498-2111 FAX:805-498-3804 h.com
DEVICE
(1)
高一英语课文朗读PACKAGE TEMP. (T J )SC1146CSW.TR
SO-24
0 - 85°C
ORDERING INFORMATION
Note:
(1) Only available in tape and reel packaging. A reel contains 1000 devices.
DESCRIPTION
The SC1146 is the latest, high performance, multi-
pha (PWM) controller designed for high power mi-croprocessors requiring ultra fast transient respon.The SC1146 is programmable for the voltage range required by the latest Microprocessors . Utilizing a novel and unique design, the controller distributes the output load across (up to) four converter channels by digitally pha shifting the PWM outputs. This ap-proach greatly reduces the stress and heat on the out-put stage components while lowering input ripple cur-rent by as much as 80%. Accurate current sharing among the four phas is achieved by precision design techniques and trimming of critical elements.
The high speed transconductance error amplifier is ex-ternally initialized using a soft-start capacitor allowing the controller to “wake-up” without overshoot, thus pro-tecting the low voltage microprocessor loads. The out-put drive voltage to the power MOSFETs is pro-grammable to minimize switching loss in the drive circuitry.
The output voltage is digitally programmable by means of a 5 bit DAC (new codes). A single resistor programs the master clock frequency (8MHz max) or the clock can be supplied by an external sourc
e where exact fre-quency control is desired. The number of operating phas is programmed independently of the external clock. The parts features under-voltage lock-out with hysteresis and over-current protection.
July 25, 2000牛津大学简介
ELECTRICAL CHARACTERISTICS
Unless otherwi noted: T A = 25°C, V CC 5V = 5V, V CC2 = 5V, 4-Pha operation.PARAMETER SYMBOL CONDITIONS
MIN TYP MAX UNITS Supply Voltage Range V CC2 3.9 5.015.0V UVLO Range V CC5V 3.9
5.0
6.0
V UVLO Hystersis
V CC5V
TBD
mV
criteriaSupply Voltage Range V CC5V 4.5 5.0 5.5V Supply Current V CC2DRV Outputs open 10
托福成绩查询时间行尸走肉漫画下载mA Supply Current
V CC5V V OUT = 2.00V, I O = 0
40
mA Reference Current Pin Voltage V REF Iref = 250µA 2.05
V VID0-4 Clock Select & Divide V INL Logic Low 0.8
V Select Logic Threshold V INH Logic High 2
anecdote
V VID0-4 Clock Select & Divide I INL Vid0-4 = 0V -20µA Select Input Bias Current I INH Vid0-4 = 4.5V
+50µA Enable Pin
V INL .8
V V INH 2
V Maximum Duty Cycle D MAX FB = 0V 75
%
DRV0-3 Output Voltage V OL I sink = 1mA
.3
V V OH I source = 1mA, PWRGOOD = V cc5v
V CC2-1
V DRV0-3 Source Current I SRC V OUT = 2.00V 40mA DRV0-3 Sink Current
I SNK
V OUT = 2.00V 20
mA
ABSOLUTE MAXIMUM RATINGS
Parameter Symbol Limits Units V CC5V to GND V cc5v -0.3 to + 12
V FBG to GND FBG ± 1V V CC2 to GND
V cc2-0.3 to +20V Operating Temperature Range T A 0 to +70°C Junction Temperature Range T J 0 to +125°C Storage Temperature Range T STG -55 to +150
°C Thermal Resistance Junction to Ca θJC 25°C/W Thermal Resistance Junction to Ambient θJA 80°C/W Lead Temperature (Soldering) 10 c
T LEAD
300
°C
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July 25, 2000
ELECTRICAL CHARACTERISTICS (Cont.)
Unless otherwi noted: T A = 25°C, V CC5V = 5V, V CC2 = 5V, 4-Pha operation.Note:
(1) This device is ESD nsitive. U of standard ESD handling precautions is required.
July 25, 2000
NOTE: (1) All logic inputs and outputs are open collector TTL compatible.
PIN DESCRIPTION
Pin #Pin Name
Pin Function
1V CC 5V Supply voltage input (5V nominal)
2Divl Connect to Gnd for four pha operation and to logic High for three Pha operation.
3Clkl Clock Select: Logic High lects internal clock. Logic Low lects external clock.
4
Extclk
External Clock Input. The output frequency is determined by (Clock Input Freq.)/4. Output freq.= (Clock Input)/4. Pull up to Vcc5v to lect internal clock.
5
R REF
Connects to external reference resistor. Sets the operating frequency of the internal clock and the ramp time for the PWM. Reference voltage at this pin is 2.05V. Trimmed to t 250µA at 8MHz.6VID0(1)Programming Input (LSB)7VID1(1)Programming Input 8VID2(1)Programming Input 9VID3(1)Programming Input 10VID4(1)Programming Input (MSB)
11OC+Over current comparator. Non-Inverting input.12OC-Over current comparator. Inverting input.
13
COMP
Compensation Pin. Compensation is acheived by connecting a capacitor in ries with a resistor between this pin and FBG. A 300K ohm resistor must also be directly connected between this pin and FBG.14FB Feedback input connected to supply output.
15
BG OUT
Bandgap Reference Output. Output resistance = 3Kohm. Must be
bypasd with 4.7nF-100nF capacitor to FBG. This capacitor programs the soft start time.
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16FBG Feedback Ground. This pin must be connected to return side of output caps. This pin is not internally connected to GND.
17ENABLE Connects to 5V to ENABLE. Connect to GND to disable entire device.18GND Ground Pin
19DRV2Pha 2 output, output voltage range ~.3V - V CC2 - 1V.20DRV0Pha 0 output, output voltage range ~.3V - V CC2 - 1V.
21VCC2Supply voltage for the DRV0-3, may be connected to +5V or +12V supply.There is no Undervoltage Lockout on this pin.22DRV1Pha 1 output, output voltage range ~.3V - V CC2 - 1V.23DRV3Pha 3 output, output voltage range ~.3V - V CC2 - 1V.
24
PWRGOOD
Power good should be pulled-up to 5V supply via a 3K - 10K resistor.
July 25, 2000
OUTPUT VOLTAGE
Unless specified: 0 = GND; 1 = High (or Floating).
T A = 25°C, V
CC5V
= 5V, V
CC2
= 5V, 4-Pha operation.
V
CCCORE VID4VID3VID2VID1VID0(VDC) 11111Output Off 11110 1.1 11101 1.125 11100 1.15 11011 1.175 11010 1.2 11001 1.225 11000 1.250 10111 1.275 10110 1.3 10101 1.325 10100 1.35 10011 1.375 10010 1.4 10001 1.425 10000 1.45 01111 1.475 01110 1.5 01101 1.525 01100 1.55 01011 1.575 01010 1.6 01001 1.625 01000 1.65 00111 1.675 00110 1.7 00101 1.725 00100 1.75 00011 1.775 00010 1.8 00001 1.825 00000 1.85
