MAX1999EEI-T Maxim Integrated Products, MAX1999EEI-T Datasheet - Page 16

• Manufacturer Part Number: MAX1999EEI-T
• Description: DC/DC Switching Controllers
• Manufacturer: Maxim Integrated Products

Specifications of MAX1999EEI-T

• Number Of Outputs: 1
• Output Voltage: 3.3 V, 2 V to 5.5 V
• Output Current: 0.95 A
• Input Voltage: 6 V to 24 V
• Mounting Style: SMD/SMT
• Package / Case: QSOP-28
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

High-Efficiency, Quad Output, Main Power-
Supply Controllers for Notebook Computers
MAX1977 is optimized for “thin and light” applications with a
5V/400kHz SMPS and a 3.3V/500kHz SMPS. The MAX1999
provides a pin-selectable switching frequency, allowing
either 200kHz/300kHz or 400kHz/500kHz operation of the
5V/3.3V SMPSs, respectively.
Light-load efficiency is enhanced by automatic Idle
Mode™ operation, a variable-frequency pulse-skipping
mode that reduces transition and gate-charge losses.
Figure 3. Detailed Functional Diagram
Idle Mode is a trademark of Maxim Integrated Products, Inc.
16
______________________________________________________________________________________
(MAX1999 ONLY)
(MAX1777/
TON
MAX1977)
CS3
BST3
SHDN
ILIM3
OUT3
LDO3
DH3
LX3
ON3
ON5
PRO
DL3
FB3
LDO5
MAX1777/
MAX1977/
MAX1999
POWER-ON SEQUENCE/
CLEAR FAULT LATCH
LINEAR
REG
3V
EN3
CONTROLLER
SMPS PWM
3.3V
2.91V
GND
V+
Each step-down, power-switching circuit consists of two
N-channel MOSFETs, a rectifier, and an LC output filter.
The output voltage is the average AC voltage at the
switching node, which is regulated by changing the duty
cycle of the MOSFET switches. The gate-drive signal to
the N-channel high-side MOSFET must exceed the
battery voltage, and is provided by a flying-capacitor
boost circuit that uses a 100nF capacitor connected to
BST_.
SHUTDOWN
THERMAL
4.56V
CONTROLLER
PGOOD3
SMPS PWM
5V
PGOOD5
LINEAR
EN5
REG
5V
REFERENCE
2V
LDO5
BST5
DH5
LX5
PGOOD
DL5
(MAX1777/
ILIM5
FB5
OUT5
LDO5
V
REF
MAX1977)
CC
CS5