19-2187; Rev 1; 9/04
Hig h -Effic ie n c y, Qu a d Ou t p u t , Ma in P o w e r-
S u p p ly Co n t ro lle rs fo r No t e b o o k Co m p u t e rs
Ge n e ra l De s c rip t io n
Fe a t u re s
♦ No Current-Sense Resistor Needed (MAX1999)
The MAX1777/MAX1977/MAX1999 d ua l s te p -d own,
switch-mode power-supply (SMPS) controllers generate
logic-supply voltages in battery-powered systems. The
MAX1777/MAX1977/MAX1999 include two pulse-width
modulation (PWM) controllers, adjustable from 2V to 5.5V
or fixed at 5V and 3.3V. These devices feature two linear
regulators providing 5V and 3.3V always-on outputs.
Each linear regulator provides up to 100mA output cur-
rent with automatic linear regulator bootstrapping to the
main SMPS outputs. The MAX1777/MAX1977/MAX1999
include on-board power-up sequencing, a power-good
(PGOOD) output, digital soft-start, and internal soft-stop
output discharge that prevents negative voltages on shut-
down.
♦ Accurate Current Sense with Current-Sense
Resistor (MAX1777/MAX1977)
♦ 1.5% Output Voltage Accuracy
♦ 3.3V and 5V 100mA Bootstrapped Linear
Regulators
♦ Internal Soft-Start and Soft-Stop Output
Discharge
♦ Quick-PWM with 100ns Load Step Response
♦ 3.3V and 5V Fixed or Adjustable Outputs
(Dual Mode™)
♦ 4.5V to 24V Input Voltage Range
♦ Ultrasonic Pulse-Skipping Mode (25kHz min)
♦ Power-Good (PGOOD) Signal
Maxim’s proprietary Quick-PWM™ quick-response, con-
stant on-time PWM control scheme operates without
sense resistors and provides 100ns response to load
transients while maintaining a relatively constant switch-
ing frequency. The unique ultrasonic pulse-skipping
mode maintains the switching frequency above 25kHz,
which eliminates noise in audio applications. Other fea-
tures include pulse skipping, which maximizes efficiency
in light-load applications, and fixed-frequency PWM
mode, which reduces RF interference in sensitive appli-
cations.
♦ Overvoltage Protection Enable/Disable
Ord e rin g In fo rm a t io n
5V/3V
PIN-
PACKAGE
PART
TEMP RANGE
SWITCHING
FREQUENCY
MAX1777EEI -40°C to +85°C 28 QSOP 200kHz/300kHz
MAX1777EEI+ -40°C to +85°C 28 QSOP 200kHz/300kHz
MAX1977EEI -40°C to +85°C 28 QSOP 400kHz/500kHz
MAX1977EEI+ -40°C to +85°C 28 QSOP 400kHz/500kHz
The MAX1777 features a 200kHz/5V and 300kHz/3.3V
SMPS for highest efficiency, while the MAX1977 features
a 400kHz/5V and 500kHz/3.3V SMPS for “thin and light”
applications. The MAX1999 provides a pin-selectable
switching frequency, allowing either 200kHz/300kHz or
400kHz/500kHz operation of the 5V/3.3V SMPSs, respec-
tively. The MAX1777/MAX1977/MAX1999 are available in
28-pin QSOP packages and operate over the extended
temperature range (-40°C to +85°C). The MAX1777/
MAX1977/MAX1999 are available in lead-free packages.
200kHz/300kHz or
MAX1999EEI -40°C to +85°C 28 QSOP
400kHz/500kHz
200kHz/300kHz or
MAX1999EEI+ -40°C to +85°C 28 QSOP
400kHz/500kHz
+Denotes lead-free package.
P in Co n fig u ra t io n s
TOP VIEW
N.C.
PGOOD
ON3
1
2
3
4
5
6
7
8
9
28 BST3
27 LX3
26 DH3
25 LDO3
24 DL3
23 GND
22 OUT3
21 OUT5
20 V+
Ap p lic a t io n s
Notebook and Subnotebook Computers
PDAs and Mobile Communication Devices
3- and 4-Cell Li+ Battery-Powered Devices
ON5
ILIM3
SHDN
FB3
MAX1999
REF
FB5
PRO 10
ILIM5 11
SKIP 12
TON 13
BST5 14
19 DL5
18 LDO5
Quick-PWM and Dual Mode are trademarks of Maxim
Integrated Products, Inc.
17
V
CC
16 DH5
15 LX5
QSOP
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.