STHS4257A Datasheet, PDF (1/18 Pages) STMicroelectronics – IEEE 802.3af PoE Powered Device (PD) interface controller with integrated signature resistor

STHS4257A, STHS4257A1
STHS4257L, STHS4257L1
IEEE 802.3af PoE Powered Device (PD)
interface controller with integrated signature resistor
Features
■ IEEE 802.3af-compliant interface for Powered
Devices (PDs)
■ Integrated 100V, 450mA power MOSFET low
side switch
8
1
SO8 (M)
■ Inrush current limit
■ Normal operation current limit
■ Integrated 25kΩ signature resistor
) _{■ Signature disable (STHS4257A1/L1)}
t(s ■ Resistor-programmable classification current
c _{(Class 0-4)}
du _{■ Power Good output, open drain}
ro _{■ Undervoltage Lockout (UVLO)}
P _{■ Thermal overload protection (two-step for the}
te _STHS4257A/L)
le _{■ Latch (L) or auto-retry (A) after repetitive}
so thermal overload
b _{■ Industrial temperature range: –40 to +85°C}
- ^O ■ SO8 and DFN8 (3mm x 3mm) packages
) _{■ RoHS compliant}
DFN8 3mm x 3mm (DB)
Applications
■ Voice over IP (VoIP) phones
■ Web cameras
■ WLAN access points
■ Internet appliances
■ POS terminals
■ RFID readers
duct(s _{Table 1. Device options}
lete ^{Pro Order code}
Signature
disable
UVLO
threshold,
rising (V)
so _STHS4257A
39.2
ObSTHS4257A1
✔
36.0
UVLO
threshold,
falling (V)
30.5
30.5
Protection
mode
Thermal
overload
protection
Inrush
current limit
(mA, typ)
Normal
operation
current limit
(mA, typ)
Auto
2 steps
350/188 ⁽¹⁾
Auto
1 step
140
375
STHS4257L
39.2
30.5
Latch
2 steps
350/188 ⁽¹⁾
STHS4257L1
✔
36.0
30.5
Latch
1 step
140
375
1. Current limit is common for both modes and gets reduced only in case of thermal overload. See Table 5: Electrical parameters.
July 2007
Rev 4
1/18
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1