AS1851A Datasheet, PDF (1/41 Pages) –

AS1851A/31A — Digital Power PoE PD Controllers w/HV Isolation &
Synchronous DC-DC Converter
GENERAL DESCRIPTION
The AS1851A and AS1831A devices each integrate Akros
GreenEdge™ High Voltage Isolation technology with Power-over-
Ethernet (PoE) PD and Synchronous DC-DC power conversion
technology.
The AS1851A includes a 13W/25W (Type 1 and Type 2)
IEEE^®802.3af/at compliant PD integrated with high-voltage isolation
and a digital power Synchronous DC-DC converter.
The AS1831A includes a 13W (Type 1) IEEE^®802.3af/at compliant
PD integrated with high-voltage isolation and a digital power
Synchronous DC-DC converter.
In addition to enabling digital PoE power conversion, Akros
GreenEdge™ isolation enables direct digital management of both
isolated Primary power and Secondary system power for real time
end-to-end Green Power application capabilities.
TYPICAL APPLICATIONS
 Voice-over-IP (VoIP) phones
 Wireless LAN & WiMAX access points (WAP)
 Pan, Tilt, Zoom (PTZ) Cameras, IP cameras
 Thin-client and notebook computers
 Fiber-to-the-home (FTTH) terminals
 Point-of-sale (PoS) terminals, RFID readers
ORDERING INFORMATION
The AS1851A and AS1831A pin-compatible devices are available in
64-lead QFN Reduction of Hazardous Substance (RoHS) compliant
packages.
Part #
Type 1 Type 2 Hardware
PD
PD
Mode
AS1851A*
x
x
x
AS1831A*
x
x
* Industrial Temperature Range, -40°C to 85°C
Software
Mode
x
x
Pwr In
(W)
13/30
13
SIMPLIFIED APPLICATION DIAGRAM
FEATURES
Digitally Isolated Programmable Power
PoE PD Controller
 Type 1 and Type 2 IEEE^® 802.3af & 802.3at Compliant PD
(AS1851A), Type 1 only (AS1831A)
 Automatic PoE-Plus (Type 2) detection in HW and I²C Modes
(AS1851A only)
 Low Resistance PD Power FET Switch (0.5 typical)
Primary‐Side DC‐DC Controller
 High-efficiency DC-DC Controller with Digital Optimization
 Primary-Secondary High-voltage integrated Digital Isolation
 Programmable Primary Clock Frequency Local-power operation
Down to 9.5V
Secondary‐Side Sync Power Output
 Synchronous Controller with programmable power-FET timing
for high efficiency at both light and full load
 Programmable PWM Frequencies synched to External Clock
Power Management
 Hardware programmable start-up power sequencing
 Primary-side power monitoring & control from Secondary-side
 Individual output Power-Good management
 Voltage margining for each output
 Primary GPIO/ADC controlled via Secondary GPIO or I²C
 5V µC-compatible with interrupt on alarm services
 Programmable watchdog timer
EMC Compliance and Protection
 Slew-rate-controlled power drivers
 External PWM sync clock option
 Optional spread-spectrum clocking, SW controlled
 Over-current, Under/Over-voltage and Short-circuit Protection
 High-temperature warning and shutdown
 Meets IEC 61000-4-2/3/4/5/6, IEC60747, IEC 60950, DIN
EN60747-5-2 (VDE0884), & UL1577 requirements for EMC
compliance and basic isolation to 2120 VDC (1500 VRMS)
 100V Process for PoE transient voltage robustness
Akros Silicon, Inc.
6399 San Ignacio Avenue, Suite 250, San Jose, CA 95119 USA
408.746.9000  http://www.AkrosSilicon.com