TC1266_13 Datasheet, PDF (1/18 Pages) Microchip Technology – 200mA PCI LDO

TC1266
200mA PCI LDO
Features
• Glitch Free Transition Between Input Sources
• Automatic Input Source Selection
• External PMOS Bypass Switch Control
• Built-in 5V Detector
• 1% Regulated Output Voltage Accuracy
• 200mA Load Current Capability
• Kelvin Sense Input
• Low Dropout Voltage (240mV @ Full Load)
• Low Ground Current, Independent of Load
Applications
• PCMCIA
• PCI
• Network Interface Cards (NICs)
• Cardbus^TM Technology
Device Selection Table
Part Number
Package
Junction
Temp. Range
TC1266VOA 8-Pin SOIC (Narrow) -5°C to +125°C
TC1266VUA
8-Pin MSOP -5°C to +125°C
Package Type
8-Pin SOIC
V_IN 1
NC 2
V_AUX 3
GND 4
TC1266
8 D_R
7 V_OUT
6 SENSE
5 NC
General Description
The TC1266 is an application-specific, low dropout
regulator (LDO), specifically intended for use in PCI
peripheral card applications complying with PCI Power
Management (PCI 2.0). It provides an uninterrupted,
3.3V, 200mA (max) output voltage when the main (5V)
or auxiliary (3.3V) input voltage supplies are present.
The TC1266 consists of an LDO, a voltage threshold
detector, external switchover logic and gate drive
circuitry. It functions as a conventional LDO as long as
the voltage on the main supply input (V_IN) is above the
lower threshold (3.90V typical). Should the voltage on
V_IN fall below the lower threshold, the LDO is disabled
and an external P-channel MOSFET is automatically
turned on, connecting the auxiliary supply input to
V_OUT, and ensuring an uninterrupted 3.3V output. The
main supply is automatically selected, if both the main
and auxiliary input supplies are present, and transition
from one input supply to the other is ensured glitch-
free. High integration, automatic secondary supply swi-
tchover, Kelvin sensing, and small size make the
TC1266 the optimum LDO for PCI 2.0 applications.
Functional Block Diagram
V_IN
V_AUX
Detect
GND
Bandgap
Reference
–
E/A
+
D_R
V_OUT
SENSE
8-Pin MSOP
V_{IN 1}
NC ₂
V_AUX 3
GND ⁴
TC1266
8 ^DR
7 V_OUT
6 SENSE
5 NC
 2001-2012 Microchip Technology Inc.
DS21377C-page 1