Rainbow Electronics MAX783 - Manual

_______________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) pulse-
width 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 low-
battery-detection comparators.
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-Mode
TM oper-
ation at light loads. The MAX783 uses physically small
components, thanks to high operating frequencies
(300kHz/200kHz) and a new current-mode PWM architec-
ture 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 frequen-
cy 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 con-
troller provides a low-cost, +15V high-side output that regu-
lates 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 electro-
magnetic pen-based systems and communicating comput-
ers. The MAX783 is similar to the MAX782, except the fly-
back 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
____________________________Features
♦ 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
♦ 5.5V to 30V Input Range
♦ Small SSOP Package
♦ Fixed Output Voltages Available:
3.3V (standard)
3.45V (High-Speed Pentium™)
3.6V (PowerPC™)
______________Ordering Information
MAX783
Triple-Output Power-Supply Controller
for Notebook Computers
________________________________________________________________ Maxim Integrated Products 1
Call toll free 1-800-998-8800 for free samples or literature.
™ Idle-Mode is a trademark of Maxim Integrated Products. Pentium is a trademark of Intel. PowerPC is a trademark of IBM.
19-0045; Rev 1; 5/94
Evaluation Kit
Information Included
MAX783
5.5V
TO
30V
VPP
CONTROL
ON3
ON5
SYNC
POWER
SECTION
SUSPEND POWER
LOW-BATTERY WARNING
VPP (0V/3.3V/5V/12V)
µ P
MEMORY
PERIPHERALS
+3.3V
+5V
DUAL
PCMCIA
SLOTS
4
VPP (0V/3.3V/5V/12V)
SHDN
_______Typical Application Diagram
36
35
34
33
32
31
30
29
28
27
26
25
24
23
1
2
3
4
5
6
7
8
9
10
11
12
13
14
SS3
CS3
FB3
DH3
LX3
BST3
LX5
DL3
V+
VL
FB5
PGND
DL5
BST5
SYNC
REF
GND
VPPB
VDD
VPPA
RDY5
Q1
Q2
VH
D2
D1
SHDN
ON3
SSOP
TOP VIEW
MAX783
22
21
20
19
15
16
17
18 ON5
DH5
CS5
SS5
DB0
DB1
DA0
DA1
__________________Pin Configuration
36 SSOP 0°C to +70°C MAX783RCBX
36 SSOP 0°C to +70°C MAX783CBX
PIN-PACKAGE TEMP. RANGE PART
3.45V
3.3V
V OUT
Ordering Information continued on last page.