MAX8737 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – Dual, Low-Voltage Linear Regulator Controllers with External MOSFETs

19-3705; Rev 0; 5/05
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Dual, Low-Voltage Linear Regulator Controllers
with External MOSFETs
General Description
The MAX8737 dual high-power linear regulator con-
trollers use external n-channel MOSFETs to generate
two independent low-voltage supplies for notebook
computers. The MAX8737 delivers low output voltages
from 0.5V to 2.5V (±5mV no-load accuracy). The exter-
nal components allow scalable current design with
loads up to 5A with excellent load regulation (1%). The
regulator operates from a low input voltage, which also
reduces the power dissipation in the external n-channel
MOSFET. The controller powers the external MOSFET
gate driver from the standard 5V system supply.
The MAX8737 includes current and thermal limits to
prevent damage to the linear regulator. The MAX8737
uses an external resistive divider to fold back the cur-
rent limit, reducing the overall power dissipation. The
MAX8737 uses an external resistive-divider in series
with the current-sense input (CS_), providing foldback
current-limit protection, and effectively reducing the
short-circuit power dissipation.
An output undervoltage timeout is available for low-cost
applications that omit the current-sense resistor. The
output undervoltage (UVP) timing depends on the mag-
nitude of the voltage at V_OUT. The UVP detects and
shuts down the LDO if the output voltage drops out of
regulation. The controller uses an adjustable reference
input (REFIN_) to set the nominal output voltage
(V_{OUT_}), which minimizes the cost and makes the sta-
bility independent of the output voltage.
Each linear regulator features an adjustable soft-start
function, and generates a delayed power-good
(PGOOD) signal that signals when the linear regulator
is in regulation. The MAX8737 is a low-cost solution
requiring few external components and is available in a
small, 4mm x 4mm, 16-pin thin QFN package.
Applications
Notebook and Desktop Computers
Point-of-Load Regulators
V_MCH and V_CCP CPU Supplies
Low-Voltage Bias Supplies
Servers
Features
♦ Low-Cost Dual Linear Regulators
♦ Output Voltage Accuracy ±5mV
♦ Independent 0.5V to 2.5V Reference Inputs
♦ Foldback Current-Limit Protection
♦ Output Undervoltage-Lockout Protection
♦ Thermal Limit (Internal Sensor)
♦ 1.0V to 5.5V Input Supply Voltage (External FET
Drain)
♦ 5V Bias Supply Voltage
♦ Independent Power-Good Open-Drain Outputs
♦ Independent Enable Inputs
♦ Soft-Shutdown Output Discharge
♦ Low Supply Current (0.5mA)
♦ 5µA (max) Shutdown Supply Current
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX8737ETE -40°C to +85°C 16 Thin QFN-EP* 4mm x 4mm
MAX8737ETE+ -40°C to +85°C 16 Thin QFN-EP* 4mm x 4mm
*EP = Exposed pad.
+Denotes lead-free packaging.
Pin Configuration
TOP VIEW
DRV2 13
N.C. 14
GND 15
DRV1 16
12 11 10 9
MAX8737
1
2
3
4
8 EN1
7 EN2
6 PGOOD1
5 PGOOD2
4mm x 4mm TQFN
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