EL7556BC Просмотр технического описания (PDF) - Elantec -> Intersil
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EL7556BC Datasheet PDF : 13 Pages
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EL7556BC
Integrated Adjustable 6 Amp Synchronous Switcher
Pin Descriptions
I = Input, O = Output, S = Supply
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Pin Name
FB1
CREF
CSLOPE
COSC
VDD
VIN
VSSP
VIN
VSSP
VSSP
VSSP
VSSP
VCC2DET
OUTEN
OT
PWRGD
TEST
VSSP
VSSP
LX
LX
LX
LX
VHI
VSS
C2V
CP
FB2
Pin Type
I
I
I
I
S
S
S
S
S
S
S
S
I
I
O
O
I
S
S
O
O
O
O
I
S
I
O
I
Function
Voltage feedback pin for the buck regulator. Active when VCC2DET is logic low. Normally connected to exter-
nal resistor divider between VOUT and GND. A 2µA pull-up current forces VOUT to VSS in the event that
FB1is floating and VCC2DET is inadvertently connected to GND.
Bandgap reference bypass capacitor. Typically 0.1µF to VSS.
Slope compensation capacitor. Ramp width corresponds to LX duty cycle. CSLOPE to COSC ratio is normally
1:1.5.
Oscillator timing capacitor. FOSC(Hz) can be approximated by: FOSC(Hz) = 0.0001/COSC. COSC in Farads.
Power Supply for PWM control circuitry. Normally the same potential as VIN.
Power supply for the buck regulator. Connected to the drain of the high-side NMOS FET.
Ground return for the buck regulator. Connected to the source of the low-side synchronous NMOS FET.
Same as pin 6.
Same as pin 7.
Same as pin 7.
Same as pin 7.
Same as pin 7.
VCC2DET interface logic input. When driven to logic 1 VOUT = 3.500V. When driven to logic 0 the PWM uses
FB1 to determine VOUT: VOUT = 1.0V*(1+R3/R4).
The switching regulator output is enabled when logic 1. The reference voltage output operates whenever the
power supply is qualified (VDD>VPOR) regardless of the state of this pin.
Over temperature indicator. Normally high. Pulls low when die temperature exceeds 135°C, returns to the high
state when die temperature has cooled to 100°C.
Power good window comparator output. Logic 1 when regulator output is within ±10% of programmed voltage.
Test pin. Must be connected to VSSP in normal operation.
Same as pin 7.
Same as pin 7.
Inductor drive pin. High current switching output whose average voltage equals the regulator output voltage.
Same as pin 20.
Same as pin 20.
Same as pin 20.
Gate drive to high-side driver. Bootstrapped from LX with a 0.1µF capacitor.
Ground return for the control circuitry.
Connected to voltage doubler output. Supplies gate drive to the low-side driver.
Drives the negative side of charge pump capacitor at one-half the oscillator frequency FOSC.
Voltage feedback pin. Active when VCC2DET is logic 1. Internally preset to VOUT = 3.5V.
8
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