SC2542 Datasheet, PDF (1/27 Pages) Semtech Corporation – High Performance Wide Input Range Dual Synchronous Buck Controller

SC2542
High Performance Wide Input Range
Dual Synchronous Buck Controller
POWER MANAGEMENT
Description
Features
SC2542 is a high performance dual PWM controller. It is
designed to convert a widely ranged battery rail down to
two independent output rails. The PWM operation of the
two channels are 180 degrees out of phase which can
greatly reduce the size and the cost of the input capaci-
tors. Synchronous buck PWM topology and voltage mode
control allow fast transient response and flexible com-
ponent selection for easy designs. A 5V standby regula-
tor is integrated. A 10V internal linear regulator provides
the bias for the controller, and this voltage is optimized
for gate drivers to deliver high efficiency.
The light load efficiency can be greatly improved by turn-
ing off the low side MOSFET upon reversal of inductor
current. There is no need for a current sensing resistor
because the MOSFET on resistance is used as the sens-
ing element. Under extreme light load conditions, the
device will operate in a pulse skip mode. The switching
frequency can be dropped significantly to a level pro-
grammed by external resistors. The battery energy is bet-
ter utilized with these efficiency enhancement schemes.
The power sequencing is fully supported including inde-
pendent start up and power good output. In shutdown
mode the controller only draws 100nA from the supply.
The controller also offers full protection features for the
conditions of under voltage, over voltage, and over cur-
rent. The switching frequency is adjustable from 100KHz
to 300KHz. TSSOP-28-EDP package is offered.
Typical Application Circuit
‹ Independent dual-switcher-outputs
‹ Integrated 5V standby output with over 50mA
capability
‹ Wide input voltage range: 6.5V ~ 28V
‹ Adjustable output voltage down to 0.75V
‹ Light load efficiency enhancement
‹ Programmable skip mode operation
‹ Flexible power sequencing with enable and power
good output
‹ Synchronous buck topology with voltage mode
control
‹ Out of phase operation to reduce cost of input
capacitor
‹ 10V internal regulator for gate driver to deliver high
efficiency
‹ Programmable switching frequency:
100KHz ~ 300KHz
‹ Full protection: UVLO, OVP, and programmable OCP
‹ No need for current sense resistor
‹ Low standby operating current (200µA typical)
‹ Low shut down current (100nA typical)
‹ 28 lead TSSOP package with exposed die pad
(EDP)
‹ Fully WEEE package and RoHS Compliant
Applications
‹ Notebook computer system power
‹ Systems with 6.5V ~ 28V input
‹ Network and telecom systems
‹ Other portable devices
ENABLE
STBY MODE
FB1
VIN+
VO1 (3.3V/10A)
FB1
VIN+
VCC
SC2542
1 _VIN
AGND ²⁸
2 _VCC
5VSBY ²⁷
3 _EN
ROSC ²⁶
4 _STBY
PWRGD ²⁵
5 _FB1
FB2 ²⁴
6 _{ERROUT1 ERROUT2} 23
7 _MINSET1
MINSET2 ²²
8 _SS1
SS2 ²¹
9 _ILIM1
ILIM2 ²⁰
10 _BST1
BST2 ¹⁹
11 _DRVH1
DRVH2 ¹⁸
12 _PHASE1
PHASE2 ¹⁷
13 _DRVL1
DRVL2 ¹⁶
14 _{PGND TH-PAD PVCC} 15
5VSBY
VCC
VO1
PWGRD
FB2
VIN+
VO2 (5V/10A)
FB2
Revision: August 24, 2005
1
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