LTC4259CGW Linear Technology, LTC4259CGW Datasheet

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LTC4259CGW

Manufacturer Part Number
LTC4259CGW
Description
Manufacturer
Linear Technology
Datasheet

Specifications of LTC4259CGW

Linear Misc Type
Negative Voltage
Operating Supply Voltage (typ)
-48V
Operating Supply Voltage (max)
-57V
Operating Temperature (min)
0C
Operating Temperature (max)
70C
Operating Temperature Classification
Commercial
Mounting
Surface Mount
Pin Count
36
Lead Free Status / Rohs Status
Not Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LTC4259CGW
Manufacturer:
LT/凌特
Quantity:
20 000
FEATURES
TYPICAL APPLICATIO
APPLICATIO S
Hot Swap is a trademark of Linear Technology Corporation. 802 is a registered trademark of
Instutute of Electrical and Electronics Engineers, Inc. I
, LTC and LT are registered trademarks of Linear Technology Corporation.
IP Phone Systems
DTE Power Distribution
IEEE 802.3af Compliant Systems
Controls Four Independent – 48V Powered
Ethernet Ports
Each Channel Includes:
– IEEE 802
– Inrush Control
– Short-Circuit Protection with Current Foldback
– PD Disconnect Using AC or DC Sensing
– Power Good Indication
Operates Autonomously or Controlled by I
Serial Interface
4-Bit Programmable Digital Address Allows Control
of Up to 64 Channels
Programmable INT Pin Eliminates Software Polling
Current Limit Duty Cycle Protects External FETs
–48V
Classification
SCL
SDAIN
SDAOUT
AD0
AD1
AD2
AD3
DGND
®
AGND
.3af Compliant PD Detection and
INT
V
U
EE
SHDN1
RS1 TO RS4: TWO 1 , 1% RESISTORS IN PARALLEL
Q1 TO Q4: IRFM120A
R
S1
SENSE1
SHDN2 SHDN3 SHDN4
GATE1
Q1
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
OUT1 SENSE2 GATE2
2
C is a trademark of Philips Electronics N.V.
R
10k
S2
Figure 1. Complete 4-Port Powered Ethernet Power Source
U
LTC4259
3.3V
V
Q2
DD
0.1 F
OUT2 SENSE3 GATE3 OUT3 SENSE4 GATE4 OUT4
10k
R
2
S3
OSCIN
C
TM
AUTO
Power over Ethernet Controller
Q3
AUXIN
10k
R
S4
RESET DCDISEN
DESCRIPTIO
The LTC
signed for use in IEEE 802.3af compliant Power Sourc-
ing Equipment (PSE). It consists of four independent
channels, each with inrush control, short-circuit protection,
complete powered device (PD) detection and classification
capability, and programmable PD disconnect using AC or
DC sensing. Used with power MOSFETs and passives, as
in Figure 1, the LTC4259 can implement a complete IEEE
802.3af compliant PSE.
The LTC4259 can operate autonomously or be controlled by
an I
the same data bus, allowing up to 64 powered Ethernet ports
to be controlled with only two digital lines. Fault conditions
are signaled with the INT pin to eliminate software polling.
External power switches, current sense resistors and diodes
allow easy scaling of current and power dissipation levels
and provide protection against voltage and current spikes
and ESD events.
The LTC4259 is available in a 36-pin SSOP package.
Linear Technology also provides solutions for 802.3af
powered device (PD) applications with the LTC4257.
2
Q4
C serial interface. Up to 16 LTC4259s may coexist on
DETECT1
DETECT2
DETECT3
DETECT4
Electrical Specifications Subject to Change
®
S1B 4
10k
4259 is a quad – 48V Hot Swap
BAV19WS
4
with AC Disconnect
1k
4
0.22 F
100V
4
Quad IEEE 802.3af
U
0.1 F 100V
4
LTC4259
August 2003
TM
SMAJ58A
controller de-
4
4259 F01
OUT1
OUT2
OUT3
OUT4
1
4259i

Related parts for LTC4259CGW

LTC4259CGW Summary of contents

Page 1

... APPLICATIO S IP Phone Systems DTE Power Distribution IEEE 802.3af Compliant Systems , LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. 802 is a registered trademark of 2 Instutute of Electrical and Electronics Engineers, Inc trademark of Philips Electronics N.V. U ...

Page 2

... Measured at DETECT n Pin CLASS PORT Class 0-1 Class 1-2 Class 2-3 Class 3-4 Class 4-Overcurrent U W ORDER PART TOP VIEW 1 36 OSCIN NUMBER 2 35 AUTO 3 OUT1 INT 34 LTC4259CGW 4 GATE1 SCL SENSE1 6 31 OUT2 AD3 7 30 GATE2 AD2 8 29 SENSE2 9 V AD1 ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER Gate Driver I GATE Pin Current GON I GATE Pin Current GOFF I GATE Pin Short-Circuit Pull-Down GPD V External Gate Voltage (V – V GATE GATE n Output ...

Page 4

LTC4259 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER DC Maximum Current Limit Duty Cycle CLMAX t Disconnect Delay DIS t DC Disconnect Minimum Pulse VMIN Width Sensitivity Timing f Clock Frequency SCLK t ...

Page 5

W U TEST PORT GATE n INT Figure 2. Detect, Class and Turn-On Timing in Auto or Semiauto Modes V SENSE n V SENSE n V MIN INT t VMIN ...

Page 6

LTC4259 DIAGRA S SCL SDA AD3 AD2 AD1 AD0 START BY MASTER FAULT FRAME 1 SERIAL BUS ADDRESS BYTE SCL SDA AD3 AD2 AD1 AD0 R/W ACK ...

Page 7

CTIO S RESET (Pin 1): Chip Reset, Active Low. When the RESET pin is low, the LTC4259 is held inactive with all channels off and all internal registers reset to their power-up states. When RESET ...

Page 8

LTC4259 CTIO S SHDN2 (Pin 18): Shutdown Channel 2, Active Low. See SHDN1. SHDN3 (Pin 19): Shutdown Channel 3, Active Low. See SHDN1. SHDN4 (Pin 20): Shutdown Channel 4, Active Low. See SHDN1. AGND (Pin ...

Page 9

W TABLE 1. REGISTER AP LTC4259 4259i 9 ...

Page 10

LTC4259 U U REGISTER FU CTIO S Interrupt Registers Interrupt (Address 00h): Interrupt Register, Read Only. A transition to logical 1 of any bit in this register will assert the INT pin (Pin 3) if the corresponding bit in the ...

Page 11

U U REGISTER FU CTIO S –26V). Bit 5 signals that the V supply has dropped be- DD low the V UVLO threshold. Bit 7 indicates that the DD LTC4259 die temperature has exceeded its thermal shut- down (TSD) limit. ...

Page 12

LTC4259 U U REGISTER FU CTIO S Detect/Class Enable (Address 14h): Detection and Clas- sification Enable, Read/Write. The lower four bits of this register enable the detection circuitry at the correspond- ing port if that port is in Auto or ...

Page 13

U U APPLICATIO S I FOR ATIO OVERVIEW Over the years, twisted-pair Ethernet has become the most commonly used method for local area networking. The IEEE 802.3 group, the originator of the Ethernet standard, has defined an extension to the ...

Page 14

LTC4259 U U APPLICATIO S I FOR ATIO OPERATING MODES Each LTC4259 port can operate in one of four modes: Manual, Semiauto, Auto or Shutdown. The operating mode for a port is set by the appropriate bits in the Operating ...

Page 15

U U APPLICATIO S I FOR ATIO 275 25k SLOPE 165 SECOND DETECTION POINT VALID PD 0V-2V VOLTAGE OFFSET Figure 13. PD Detection 17k and 29k (between 19k and 26.5k guaranteed valid PD and report Detect Good (100 ...

Page 16

LTC4259 U U APPLICATIO S I FOR ATIO 60 OVER CURRENT 50 40 CLASS 4 CLASS CLASS 2 TYPICAL CLASS 3 CLASS CLASS VOLTAGE (V ) CLASS Figure ...

Page 17

U U APPLICATIO S I FOR ATIO Dual-Level Current Limit permitted to draw up to 350mA continuously and up to 400mA for 50ms. The LTC4259 has two correspond- ing current limit thresholds, I (350mA to 400mA, 375mA ...

Page 18

LTC4259 U U APPLICATIO S I FOR ATIO Foldback Foldback is designed to limit power dissipation in the MOSFET during short-circuit conditions and during power- up. At low port output voltages, the voltage across the MOSFET is high, and power ...

Page 19

U U APPLICATIO S I FOR ATIO Before designing a MOSFET into your system, carefully compare its safe operating area (SOA) with the worst case conditions (like powering on a defective PD) the device will face. Using transient suppressors, polyfuses ...

Page 20

LTC4259 U U APPLICATIO S I FOR ATIO 300mV 600mA 250mV 500mA 200mV 400mA 150mV 300mA 100mV 200mA 50mV 100mA 0mV 0mA SENSE n CURRENT DC DIS- CUT LIMIT VOLTAGE R = 0.5 CONNECT ( CUT ...

Page 21

U U APPLICATIO S I FOR ATIO When choosing C and C , carefully consider voltage DET PSE derating of the capacitors. Capacitors built around an X7R dielectric will have about 60% of the specified capacitance at their rated voltage. ...

Page 22

LTC4259 U U APPLICATIO S I FOR ATIO the OSCIN pin is driven with either a sine wave or a smoothed trapezoid wave, the LTC4259 is able to distin- guish between capacitive impedance and resistive imped- ance on the Power ...

Page 23

U U APPLICATIO S I FOR ATIO disconnect itself is a more thorough test of the OSCIN signal. When the OSCIN signal is either absent or cor- rupted, powered channels with AC disconnect enabled (and DC disconnect not enabled) will ...

Page 24

LTC4259 U U APPLICATIO S I FOR ATIO V CPU DD SCL SDA TO CONTROLLER SMBELRT GND CPU U1: FAIRCHILD NC7WZ17 U2, U3: AGILENT HCPL-063L 0 200 U1 200 HCPL-063L U3 200 200 0.1 F ...

Page 25

U U APPLICATIO S I FOR ATIO The START and STOP Conditions When the bus is idle, both SCL and SDA must be high. A bus master (typically the host system) signals the begin- ning of a communication to a ...

Page 26

LTC4259 U U APPLICATIO S I FOR ATIO asserting the INT pin, it acknowledges and sends its 7-bit bus address (010A and a 1 (see Figure 10 While it is sending its ...

Page 27

... LTC4259 to make an 802.3af complaint PSE. Each para- graph below addresses a component which is critical for PSE compliance as well as possible pitfalls that can cause a PSE to be noncompliant. For further assistance please contact Linear Technology’s Applications department. L4 100 H R38 510 ...

Page 28

LTC4259 U U APPLICATIO S I FOR ATIO Sense Resistors The 0.5 resistors (R ) used to sense the current through S a port affect the current limit and all thresholds for a powered port. An error in the value ...

Page 29

U U APPLICATIO S I FOR ATIO handle dissipating at least 0.5W should not be stressed in this application. Other component leakages can have a similar affect on AC disconnect and affect DC disconnect if the leakage becomes more severe. ...

Page 30

... In addition, consider checking for IEEE 802.3af compliance after subjecting the PSE to real-world fault conditions: ESD and cable discharge events, shorted ports, connecting to an already powered port, power supply glitches and so on. Linear Technology’s Applica- tions department can also provide additional support. 4259i ...

Page 31

PACKAGE DESCRIPTIO 10.668 MIN 0.520 0.0635 RECOMMENDED SOLDER PAD LAYOUT 7.417 – 7.595** (.292 – .299) 0.254 – 0.406 45 (.010 – .016) 0.231 – 0.3175 0.610 – 1.016 (.024 – .040) (.0091 – .0125) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS ...

Page 32

... DET 0.22 F 100V X7R D DET BAV19WS D TSS 58V 10k SMAJ58A D AC S1B CONNECTOR 1/2 PULSE H2009 0.01 F 0.01 F 200V 200V 1:1 0.01 F 0.01 F 200V 200V 1000pF 1:1 2000V LT/TP 0803 1K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2003 RJ45 4258 F20 4259i ...

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