ISL6550A, ISL6550C
®
Data Sheet
January 18, 2005
FN9036.4
SAM (Supervisor And Monitor)
Features
• 12V supply operation
The ISL6550 is a precision, flexible, VID-code-controlled
reference and voltage monitor for high-end microprocessor
and memory power supplies. It monitors various input
signals, and supervises the system (typically a DC/DC
converter) with its output signals. See the Block Diagram for
reference.
• 5V reference output
• 5-bit digital-to-analog converter
• Programmable DAC Range, within 0.8–5.0V
• Programmable undervoltage and overvoltage thresholds,
and latched fault detection
The ISL6550 includes a 5-bit DAC (Digital-to-Analog
Converter), which is programmed by the five VID inputs. The
voltage range of the BDAC (Buffered DAC output) is
determined by the DACHI and DACLO voltage levels, which
are externally adjustable through the R1, R2, R3 resistor
divider network. VREF5 is a precision-trimmed 5V reference,
and is used to set the voltage at the top of the resistor
divider.
• Optional delayed undervoltage (programmable with
external capacitor)
• Undervoltage lockout (power-on-reset)
• Status Indicators (START, PGOOD)
• Uncommitted operational amplifier
• Compatible with ISL6551 full bridge controller
• 20 Lead SOIC and 20 lead QFN (5x5) packages
• QFN Package:
- Compliant to JEDEC PUB95 MO-220
QFN - Quad Flat No Leads - Package Outline
- Near Chip Scale Package footprint, which improves
PCB efficiency and has a thinner profile
Programmable window comparators monitor Overvoltage
(OV) and Undervoltage (UV) levels. The OVUVSEN input,
usually coming from the associated power converter device
is monitored and compared with BDAC; an error band is
established via the R4 and R5 resistor setting on the
OVUVTH pin. An optional external capacitor on the UVDLY
pin gives a programmable delay on the UV. A high gain
operational amplifier is available at pins VOPP, VOPM, and
VOPOUT; it can be used as a gain stage to permit
Applications
• Power Supplies for High End Microprocessors and Servers
monitoring voltages that are different from the BDAC levels.
The PEN (Power supply ENable) input, driven from an open-
collector source, enables (when logic high) the external
converter output, via the PGOOD or START outputs (both
open-drain). They both basically indicate that the power
supply is enabled (PEN = high) and there are no fault
conditions. There are two logic options available, which
determine the START and PGOOD states; see the block
diagram or the Logic Options Table for more detail. The two
logic options are identified with a suffix letter A or C in the
ordering information.
• Can be paired with the ISL6551 FBC for a complete full-
bridge 48V-input converter, or used independently
Ordering Information
PART
TEMP. RANGE
NUMBER
(°C)
PACKAGE
PKG. DWG. #
ISL6550AIB
ISL6550CIB
ISL6550AIR
ISL6550CIR
-40 to 85
-40 to 85
-40 to 85
-40 to 85
20 Lead SOIC M20.3
20 Lead SOIC M20.3
20 Lead QFN L20.5x5
20 Lead QFN L20.5x5
NOTE: The same part numbers with a “-T” suffix are available as
Tape and Reel.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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