19-0045; Rev 1; 5/94
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Triple-Output Power-Supply Controller
for Notebook Computers
In
High efficiency (95% at 2A, greater than 80% at loads from
5mA to 3A) is achieved through synchronous rectification
and PWM operation at heavy loads, and Idle-ModeTM operation at light loads. The MAX783 uses physically small
components, thanks to high operating frequencies
(300kHz/200kHz) and a new current-mode PWM architecture that allows for output filter capacitors as small as 30µF
per ampere of load. Line- and load-transient responses
are terrific, with a high 60kHz unity-gain crossover frequency that allows output transients to be corrected within four
or five clock cycles. Low system cost is achieved through
a high level of integration and the use of low-cost external
N-channel MOSFETs. The integral flyback winding controller provides a low-cost, +15V high-side output that regulates even in the absence of a load on the main output.
Other features include low-noise, fixed-frequency PWM
operation at moderate to heavy loads and a synchronizable
oscillator for noise-sensitive applications such as electromagnetic pen-based systems and communicating computers. The MAX783 is similar to the MAX782, except the flyback winding is on the 3.3V inductor instead of the 5V
inductor, the VPP outputs can be optionally programmed to
3.3V, and the device may be completely shut down.
________________________Applications
Notebook Computers
Portable Data Terminals
Communicating Computers
Pen-Entry Systems
ON5
SYNC
SHDN
______________Ordering Information
TEMP. RANGE
PIN-PACKAGE
VOUT
MAX783CBX
PART
0°C to +70°C
36 SSOP
3.3V
MAX783RCBX
0°C to +70°C
36 SSOP
3.45V
Ordering Information continued on last page.
__________________Pin Configuration
TOP VIEW
ON3 1
36 SS3
SHDN 2
35 CS3
D1 3
34 FB3
D2 4
33 DH3
VH 5
32 LX3
Q1 7
31 BST3
MAX783
30 DL3
RDY5 8
µP
MEMORY
POWER
SECTION
+5V
MAX783
29 V+
VPPA 9
28 VL
27 FB5
VDD 10
26 PGND
VPPB 11
+3.3V
VPP
CONTROL
ON3
Dual PWM Buck Controllers (+3.3V and +5V)
Dual PCMCIA VPP Outputs (0V/3.3V/5V/12V)
Two Precision Comparators or Level Translators
Power-Ready Status Output (RDY5)
95% Efficiency
Optimized for 6-Cell Applications
420µA Quiescent Current;
70µA in Standby (linear regulators alive)
25µA Shutdown Current
o 5.5V to 30V Input Range
o Small SSOP Package
o Fixed Output Voltages Available:
3.3V (standard)
3.45V (High-Speed Pentium™)
3.6V (PowerPC™)
Q2 6
_______Typical Application Diagram
5.5V
TO
30V
____________________________Features
o
o
o
o
o
o
o
PERIPHERALS
GND 12
25 DL5
24 BST5
REF 13
23 LX5
DA1 15
22 DH5
DA0 16
4
SYNC 14
21 CS5
SUSPEND POWER
LOW-BATTERY WARNING
VPP (0V/3.3V/5V/12V)
VPP (0V/3.3V/5V/12V)
DB1 17
DUAL
PCMCIA
SLOTS
20 SS5
DB0 18
19 ON5
SSOP
™Idle-Mode is a trademark of Maxim Integrated Products. Pentium is a trademark of Intel. PowerPC is a trademark of IBM.
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX783
_______________General Description
The MAX783 is a system-engineered power-supply controller
for notebook computers or similar battery-powered equipment.
It provides two high-performance step-down (buck) pulsewidth modulators (PWMs) for +3.3V/+5V and dual PCMCIA
VPP outputs powered by an integral flyback winding controller.
Other functions include dual, low-dropout, micropower linear
regulators for CMOS/RTC back up, and two precision lowbattery-detection comparators.
