MAX1716 Datasheet, PDF (1/33 Pages) Maxim Integrated Products – High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning

19-1758; Rev 0; 8/00
High-Speed, Adjustable, Synchronous Step-Down
Controllers with Integrated Voltage Positioning
General Description
The MAX1716/MAX1854/MAX1855 step-down con-
trollers are intended for core CPU DC-DC converters in
notebook computers. They feature a dynamically
adjustable output (5-bit DAC), ultra-fast transient
response, high DC accuracy, and high efficiency need-
ed for leading-edge CPU core power supplies. Maxim's
proprietary Quick-PWM™ quick-response, constant-on-
time PWM control scheme handles wide input/output
voltage ratios with ease and provides 100ns “instant-on”
response to load transients while maintaining a relative-
ly constant switching frequency.
The MAX1716/MAX1854/MAX1855 are designed
specifically for CPU core applications requiring a volt-
age-positioned supply. The voltage-positioning input
(VPS), combined with a high DC accuracy control loop,
is used to implement a power supply that modifies its
output set point in response to the load current. This
arrangement decreases full-load power dissipation and
reduces the required number of output capacitors.
The 28V input range of the MAX1716/MAX1854/MAX1855
enables single-stage buck conversion from high-volt-
age batteries for the maximum possible efficiency.
Alternatively, the devices’ high-frequency capability
combined with two-stage conversion (stepping down
the +5V system supply instead of the battery) allows
the smallest possible physical size. The output voltage
can be dynamically adjusted through the 5-bit digital-
to-analog converter (DAC) inputs.
The MAX1716/MAX1854/MAX1855 are available in a
24-pin QSOP package. For applications requiring
SpeedStep™ power control (see the MAX1717).
________________________Applications
Notebook Computers
Docking Stations
CPU Core Supply
Single-Stage (BATT to V_CORE) Converters
Two-Stage (+5V to V_CORE) Converters
PART
MAX1716EEG
MAX1854EEG
MAX1855EEG
Ordering Information
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 QSOP
24 QSOP
24 QSOP
Features
o High-Efficiency Voltage Positioning
o Quick-PWM Architecture
o ±1% V_OUT Line-Regulation Accuracy
o Adjustable Output Range (5-Bit DAC)
MAX1716: 0.925V to 1.6V
MAX1854: 0.925V to 2.0V
MAX1855: 0.600V to 1.75V
o 2V to 28V Input Range
o 200/300/400/550kHz Switching Frequency
o Output Undervoltage Protection
o Overvoltage Protection (MAX1716/MAX1855)
o Drive Large Synchronous-Rectifier MOSFETs
o 1.7ms Digital Soft-Start
o 700µA I_CC Supply Current
o 1µA Shutdown Supply Current
o 2V ±1% Reference Output
o V_GATE Transition-Complete Indicator
o Small 24-Pin QSOP Package
+5V INPUT
DAC
INPUTS
Typical Operating Circuit
BATTERY
2V TO 28V
V_CC
V_DD
SHDN
V+
ILIM
BST
REF
DH
MAX1716
CC _MAX1854 LX
SKIP ^MAX1855 DL
GND
CS
TON
VPS
D0
D1
PGND
D2
D3
FB
D4
VGATE
OUTPUT
Quick-PWM is a trademark of Maxim Integrated Products.
SpeedStep is a trademark of Intel Corp.
Pin Configuration appears at end of data sheet.
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