Datasheet
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
DD
DEN
CLS
APD
RT
T2P
SRD
CTL
LED
WAKE
V
SS
Thermal
Pad
RTN
ARTN
GATE
V
C
CS
V
B
SRT
MODE
SLPb
TPS23752
PWP PACKAGE
(TOP VIEW)
P0021-04
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
DEN
CLS
APD
RT
T2P
SRD
CTL
V
SS
Thermal
Pad
RTN
ARTN
GATE
V
C
CS
V
B
SRT
TPS23751
PWP PACKAGE
(TOP VIEW)
P0047-02
TPS23751
TPS23752
SLVSB97C –JULY 2012–REVISED JANUARY 2014
www.ti.com
PIN FUNCTIONS
PIN
NAME I/O DESCRIPTION
TPS23751 TPS23752
V
DD
1 1 I Connect to positive PoE input power rail. Bypass with 0.1 µF to V
SS
.
DEN 2 2 I/O Connect 24.9 kΩ to V
DD
for detection. Pull to V
SS
to disable pass MOSFET.
CLS 3 3 I/O Connect resistor from CLS to V
SS
to program classification current.
APD 4 4 I Raise 1.5 V above ARTN to disable pass MOSFET and force T2P active.
RT 5 5 I Connect a resistor from RT to ARTN to set switching frequency.
T2P 6 6 O Active low indicates type-2 PSE connected or APD active.
SRD 7 7 O Disable external synchronous rectifiers in VFO Mode.
CTL 8 8 I Control loop input to PWM
LED 9 O Open-drain drive for external LED controlled by SLPb, MODE, and WAKE.
WAKE 10 I/O Pull WAKE low to re-enable the DC-DC converter from Sleep Mode.
SLPb 11 I Pull low during normal operation to enter Sleep Mode.
MODE 12 I Enables pulsed MPS when entering Sleep Mode. Control LED in normal operation.
SRT 9 13 I Set the threshold of PWM to VFO transition
V
B
10 14 O 5 V bias supply. Bypass with a minimum of 0.1 µF to ARTN.
CS 11 15 I/O Current sense input. Connect to ARTN-referenced current sense resistor.
V
C
12 16 I/O DC-DC converter bias voltage. Bypass with 0.47 µF or more to ARTN directly at pin.
GATE 13 17 O Gate driver output for DC-DC converter switching MOSFET.
ARTN 14 18 PWR DC-DC converter analog return. Connect to RTN.
RTN 15 19 O Drain of PoE pass MOSFET. Connect to ARTN.
V
SS
16 20 PWR Connect to negative power rail derived from PoE source.
Pad Always connect PowerPAD™ to V
SS
. A large fill area is required to assist in heat dissipation.
8 Submit Documentation Feedback Copyright © 2012–2014, Texas Instruments Incorporated
Product Folder Links: TPS23751 TPS23752