Document
STHS4257A, STHS4257A1 STHS4257L, STHS4257L1
IEEE 802.3af PoE Powered Device (PD) interface controller with integrated signature resistor
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Features
■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
IEEE 802.3af-compliant interface for Powered Devices (PDs) Integrated 100V, 450mA power MOSFET low side switch Inrush current limit Normal operation current limit Integrated 25kΩ signature resistor Signature disable (STHS4257A1/L1) Resistor-programmable classification current (Class 0-4) Power Good output, open drain Undervoltage Lockout (UVLO) Thermal overload protection (two-step for the STHS4257A/L) Latch (L) or auto-retry (A) after repetitive thermal overload Industrial temperature range: –40 to +85°C SO8 and DFN8 (3mm x 3mm) packages RoHS compliant
8 1
SO8 (M)
DFN8 3mm x 3mm (DB)
Applications
■ ■ ■
Voice over IP (VoIP) phones
Table 1.
Device options
Signature disable
Order code
s b O
STHS4257A
t e ol
o r eP
✔
) s t( c du
39.2 36.0 39.2 30.5 30.5 30.5 30.5
-O
■ ■
■
l o bs
Web cameras
WLAN access points Internet appliances POS terminals RFID readers
P e et
c u d o r
) s t(
UVLO threshold, rising (V)
UVLO threshold, falling (V)
Protection mode
Thermal overload protection 2 steps 1 step 2 steps 1 step
Inrush current limit (mA, typ)
Normal operation current limit (mA, typ)
Auto Auto Latch Latch
350/188 (1) 140 350/188 (1) 140 375 375
STHS4257A1 STHS4257L STHS4257L1
✔
36.0
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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Contents
STHS4257A, STHS4257A1, STHS4257L, STHS4257L1
Contents
1
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Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.1 1.1.2 1.1.3 1.1.4 1.1.5 1.1.6 Classification (RCLASS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Power supply (GND) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Signature disable input (SIGDISA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Power Good output (PWRGD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Negative power output (VOUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2
IEEE802.3af PD power classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 3 4 5 6
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
s b O
c u d o Package mechanical data . . . . . . . . . . . . . . . . . . . . . . .r . . . . . . . . . . . . . 14 P Part numbering . . . . . . . . . . . . . . . . . . . . . . . .t .e . . . . . . . . . . . . . . . . . . . 16 e l o Revision history . . . . . . . . . . . . . .b . .s . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 O ) s t( c u d o r P e t e ol
Electrical parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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STHS4257A, STHS4257A1, STHS4257L, STHS4257L1
List of tables
List of tables
Table 1. Table 2. Table 3. www.datasheet4u.com Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Device options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 IEEE802.3af PD power classes and corresponding RCLASS values. . . . . . . . . . . . . . . . . . . 7 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Electrical parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 SO8 – 8-lead plastic small outline, 150mils width, mechanical data. . . . . . . . . . . . . . . . . . 14 DFN8 – 8-lead dual flat no-lead outline, package mechanical data . . . . . . . . . . . . . . . . . . 15 Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
s b O
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List of figures
STHS4257A, STHS4257A1, STHS4257L, STHS4257L1
List of figures
Figure 1. Figure 2. Figure 3. www.datasheet4u.com Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pin connections (STHS4257A/L, top view) . . . . . . . . . . . . . . . . . . . . . . . . .