MAX5092 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – 4V to 72V Input LDOs with Boost Preregulator

19-0659; Rev 0; 10/06
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4V to 72V Input LDOs with Boost Preregulator
General Description
The MAX5092A/MAX5092B/MAX5093A/MAX5093B low-
quiescent-current, low-dropout (LDO) regulators contain
simple boost preregulators operating at a high frequency.
The devices seamlessly provide a preset 3.3V
(MAX5092A/MAX5093A) or 5V (MAX5092B/MAX5093B)
LDO output voltage from an automotive cold-crank
through load-dump (3.5V to 80V) input voltage condi-
tions. The MAX5092_/MAX5093_ deliver up to 250mA
with excellent load and line regulation. During normal
operation, when the battery is healthy, the boost preregu-
lator is completely turned off, reducing quiescent current
to 65µA (typ). This makes the devices suitable for
always-on power supplies.
The buck-boost operation achieved by this combination
of LDO and boost preregulator offers the advantage of
using a single off-the-shelf inductor in place of the mul-
tiple-winding custom magnetics needed in typical sin-
gle-ended primary inductor converter (SEPIC) and
transformer-based flyback topologies. The high operat-
ing frequency of the boost regulator significantly
reduces component size. The MAX5092_ integrates a
blocking diode to further reduce the external compo-
nent count. The boost preregulator output voltage is
preset to 7V. Both LDO and boost output voltages are
programmable using external resistors. The boost pre-
regulator output voltage is adjustable up to 11V
(MAX5092_), or up to 12V (MAX5093_). The LDO output
voltage is adjustable from 1.5V to 9V (MAX5092_) or
from 1.5V to 10V (MAX5093_).
The devices feature a shutdown mode with 5µA (typ)
shutdown current, a HOLD input to implement a self-hold-
ing circuit, and a power-on-reset output (RESET) with an
externally programmable timeout period. Additional fea-
tures include output overload, short-circuit, and thermal
protection.
The MAX5092_/MAX5093_ are available in a thermally
enhanced, 16-pin 5mm x 5mm thin QFN package and can
dissipate up to 2.7W at +70°C on a multilayer PC board.
Applications
Automotive—Body Electronics
Automotive—ECU
Industrial
Features
♦ Wide Operating Input Voltage Range: 3.5V to 72V
with a 4V Startup Voltage
♦ LDO Output Regulates to 5V Seamlessly from an
Input Voltage of 3.5V to 72V
♦ Up to 250mA Output Current
♦ Preset 3.3V, 5V, or Externally Programmable LDO
Output Voltage from 1.5V to 9V (MAX5092_) or
from 1.5V to 10V (MAX5093_)
♦ Preset 7V or Externally Programmable Boost
Output Voltage Up to 11V (MAX5092_) or Up to
12V (MAX5093_)
♦ 65µA Quiescent Current in LDO Mode (V_IN ≥8V)
♦ 5µA Shutdown Current
♦ Power-On Reset (RESET) with Programmable
Timeout Period
♦ Output Short-Circuit and Thermal Protection
♦ TQFN Package Capable of Dissipating Up to 2.7W
at +70°C
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX5092AATE+* -40°C to +125°C 16 TQFN-EP** T1655-3
MAX5092BATE+ -40°C to +125°C 16 TQFN-EP** T1655-3
MAX5093AATE+* -40°C to +125°C 16 TQFN-EP** T1655-3
MAX5093BATE+ -40°C to +125°C 16 TQFN-EP** T1655-3
+Denotes lead-free package.
*Future product—contact factory for availability.
**EP = Exposed pad.
Pin Configuration
TOP VIEW
12 11 10 9
BSFB 13
VL 14
CT 15
MAX5092_/
MAX5093_
RESET 16
+
8 OUT
7 OUT_SENSE
6 SET
5 PGND_LDO
1
2
3
4
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
THIN QFN
(5mm x 5mm)
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