SC1406ACTS Semtech Corporation, SC1406ACTS Datasheet - Page 2

• Manufacturer Part Number: SC1406ACTS
• Description: PORTABLE PENTIUM II & III POWER SUPPLY CONTROLLER
• Manufacturer: Semtech Corporation

January 28, 2000
PIN DESCRIPTION
Pin
© 2000 SEMTECH CORP.
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Pin Name Pin Function
SSCORE Main controller CORE output soft start. During power-up with EN high and not in UVLO, the
PWRGD
BASE25
BASE15
VCOUT
VCBYP
CLSET
SSLR
VCIN
FB25
FB15
VID4
VID3
VID2
VID1
VID0
LBIN
HYS
EN
Core comparator hysteresis settling.
Current limit setting pin.
Voltage clamp output.
Voltage clamp input.
Voltage clamp bypass pin. Needs to have a 1500pF cap from this pin to ground to ensure
proper operation.
VID most significant bit main controller voltage programming DAC input.
VID input
VID input
VID input
VID least significant bit main controller voltage programming DAC input.
2.5V Linear regulator drive.
2.5V Linear regulator output feedback.
1.5V Linear regulator drive.
1.5V Linear regulator output feedback.
Enable. SC1406A is enabled when this signal is High. This is capable of accepting 5.0V signal
level. When used with the SC1405 driver, this pin can be connected to the PWRDY pin of the
SC1405 to include UVLO feature on the V_5 (Intel Smart Driver’s V
Power Good. When the main converter output approaches and stays within ±12% of the VID
DAC setting, and both soft-start circuits periods for the main core controller and linear regulator
controllers have been terminated, this signal is driven high to VCC level. During UVLO, this
signal is undefined.
Low battery input. This pin is used to set the minimum voltage to the converter through an
external resistor divider. When the input to this pin is less than 1.225V, typical, Tamky is held in
an Under-Voltage-Lock-Out mode regardless of the status of EN.
Linear regulators soft start. During power-up with EN high and not in UVLO, the external soft
start capacitor (1200pF, typ) is charged by an internal 1µA current source to set the ramp up
time of the linear regulator outputs, 1.5V and 2.5V. This ramp up time is typically 2ms, 6ms
max. This is discharged through an internal switch when BIASEN is low, EN low or enter UVLO
region. Enabling internal bias and soft start requires the pin voltage to drop below a threshold of
150mV typical (200mV max). Linear regulator soft start current tolerance tracks the core soft
start current within 10%.
external soft start capacitor (1800pF, typ) is charged by an internal 1µA current source to set
the ramp up time of the main converter output. This ramp up time is typically 3ms, 6ms max.
This is discharged by an internal switch when BIASEN is low, EN pin is low or in UVLO.
Enabling internal bias and soft start requires the pin voltage to drop below a threshold of
150mV typical (200mV max). Core soft start current tolerance tracks the LDO soft start current
to within 10%.
PORTABLE PENTIUM
POWER SUPPLY CONTROLLER
652 MITCHELL ROAD
Pentium is a registered trademark of Intel Corporation
®
II & III
NEWBURY PARK CA 91320
CC
).
SC1406A
2