EVAL-ADM1073MEBZ [ADI]

Full-Feature −48 V Hot Swap Controller; 全功能的???? 48 V热插拔控制器
EVAL-ADM1073MEBZ
型号: EVAL-ADM1073MEBZ
厂家: ADI    ADI
描述:

Full-Feature −48 V Hot Swap Controller
全功能的???? 48 V热插拔控制器

控制器
文件: 总24页 (文件大小:376K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
Full-Feature −48 V Hot Swap Controller  
Data Sheet  
ADM1073  
FEATURES  
FUNCTIONAL BLOCK DIAGRAM  
Precision inrush linear current limit  
Soft start inrush current limit profiling  
Precision maximum on-time in current limit  
Maximum on-time modulated by FET drain voltage for  
additional SOA protection  
Adjustable PWM retry scheme and multiple device cascading  
capability for charging large capacitive loads  
Limited number of PWM cycles for FET SOA protection under  
short circuit condition  
Ability to configure device as continuous autoretry with a  
5-second cooling period  
Shunt regulator topology to allow very large transient input  
supplies  
V
SPLYGD  
IN  
PWRGD  
DRAIN  
V
AND  
CC  
FOLDBACK  
AND PWRGD  
REFERENCE  
GENERATOR  
OVERVOLTAGE  
DETECTOR  
OV  
UV  
V
IN  
UNDERVOLTAGE  
DETECTOR  
50A  
100mV(MAX)  
GATE  
SOFT START  
CONTROL  
SS  
SENSE  
tON CONTROL  
TIMER  
FAULT TIMER  
AND CONTROL  
V
EE  
5 SECOND  
SHUTDOWN  
Separate UV and OV pins for programming allowable input  
supply window  
PWM  
TIMEOUT  
OSCILLATOR  
Programmable OV hysteresis using current source into pin  
when supply is high  
SHDN  
RESTART  
LATCHED  
Programmable UV hysteresis using current sink from pin  
when supply is low  
Figure 1.  
output indicates when capacitor charging complete  
PWRGD  
APPLICATIONS  
output indicates when supply is within  
Central office switching  
SPLYGD  
valid window  
Telecommunication and data communication equipment  
−48 V distributed power systems  
Negative power supply control  
High availability servers  
output indicates the end of the retry cycle before  
LATCHED  
load capacitance is charged  
input for user-commanded shutdown  
SHDN  
input for user-triggered 5-second shutdown and  
autorestart— virtual card reseat  
RESTART  
−48 V power supply modules  
Disk arrays  
GENERAL DESCRIPTION  
The ADM1073 is a full-feature, negative voltage, hot swap  
controller that allows boards to be safely inserted and removed  
from a live −48 V backplane. The part provides precise and  
robust current limiting, and protection against both transient  
and nontransient short circuits in overvoltage and undervoltage  
conditions. The ADM1073 can operate from a negative voltage  
of −18 V to −80 V and can tolerate transient voltages of up to  
−200 V.  
A built-in soft start function allows control of the inrush  
current profile by an external capacitor on the soft start (SS)  
pin.  
An external capacitor on the TIMER pin determines the time  
for which the FET gate is controlled to be high when maximum  
inrush current flows. The ADM1073 employs a limited consec-  
utive retry scheme, whereby, if the load capacitance is not fully  
charged within one attempt, the FET gate is pulled low and  
retries after a cooling period.  
Inrush current is limited to a programmable value by control-  
ling the gate drive of an external N-channel FET. The maximum  
(continued on Page 3)  
current limit is set by the choice of the sense resistor, RSENSE  
.
Rev. B  
Document Feedback  
Information furnishedby Analog Devices is believedto be accurate andreliable. However, no  
responsibilityisassumedbyAnalog Devices for its use, nor for anyinfringements of patents or other  
rightsofthird partiesthat may result from its use. Specifications subject to change without notice. No  
license isgrantedbyimplication or otherwise under anypatent or patent rights of Analog Devices.  
Trademarks andregisteredtrademarks are the property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700 ©2004–2013 Analog Devices, Inc. All rights reserved.  
Technical Support  
www.analog.com  
ADM1073  
Data Sheet  
TABLE OF CONTENTS  
General Description ......................................................................... 3  
Timing Control—TIMER ......................................................... 15  
Drain ............................................................................................ 16  
Specifications..................................................................................... 4  
Absolute Maximum Ratings............................................................ 6  
Thermal Characteristics .............................................................. 6  
ESD Caution.................................................................................. 6  
Pin Configuration and Function Descriptions............................. 7  
Typical Performance Characteristics ............................................. 8  
Functional Description.................................................................. 13  
Hot Circuit Insertion ................................................................. 13  
Initial Startup .............................................................................. 13  
Board Removal ........................................................................... 14  
Controlling the Current............................................................. 14  
Sense............................................................................................. 15  
Sense Resistor.............................................................................. 15  
Soft Start (SS Pin) ....................................................................... 15  
GATE............................................................................................ 15  
VIN................................................................................................. 15  
VEE................................................................................................. 15  
PWRGD  
....................................................................................... 16  
LATCHED  
................................................................................... 16  
SPLYGD  
RESTART  
....................................................................................... 16  
..................................................................................... 16  
........................................................................................... 16  
SHDN  
Undervoltage/Overvoltage Detection ..................................... 16  
Functionality and Timing.............................................................. 18  
Live Insertion.............................................................................. 18  
Overvoltage and Undervoltage Faults ..................................... 18  
Soft Start ...................................................................................... 19  
Current Faults ............................................................................. 20  
Logic Inputs................................................................................. 21  
Kelvin Sense Resistor Connection ........................................... 21  
Outline Dimensions....................................................................... 22  
Ordering Guide .......................................................................... 22  
REVISION HISTORY  
7/13—Rev. A to Rev. B  
Changes to Figure 15...................................................................... 10  
Changes to Figure 32...................................................................... 13  
Changes to VOV Equation .............................................................. 17  
2/12—Rev. 0 to Rev. A  
Updated Outline Dimensions....................................................... 22  
Changes to Ordering Guide .......................................................... 22  
4/04—Revision 0: Initial Version  
Rev. B | Page 2 of 24  
Data Sheet  
ADM1073  
GENERAL DESCRIPTION  
(continued from Page 1)  
(typically −36 V) is detected on the UV pin, or if greater than  
the overvoltage threshold (typically −80 V) is detected on the  
OV pin. The operating voltage window of the ADM1073 is  
programmable via resistor networks on the UV and OV pins.  
The hysteresis levels on the undervoltage and overvoltage  
detectors can also be altered (see the Undervoltage/Overvoltage  
Further control of the inrush current is provided by modulating  
the width of the pulses, depending on the drain-source voltage  
across the FET. This allows maximum charge transfer to the  
load capacitance while maintaining the FET in its safe operating  
area (SOA).  
The default duty cycle of the pulse train is 6%, decreasing to  
2.5% with maximum FET drain-source voltage, with a  
maximum of seven successive autorestarts. After seven  
successive autorestarts, the fault is latched and the part goes into  
shutdown, with the result that the external FET is disabled until  
SPLYGD  
Detection section). The  
output signal indicates when  
the backplane supply is within the externally programmable  
operating voltage range.  
Other functions include  
LATCHED  
the power is reset. The  
the seven retries are complete.  
output signal indicates when  
PWRGD  
output, which can be used to enable a power  
module (the DRAIN pin is monitored to determine when  
the load capacitance is fully charged)  
Further programmability is offered by allowing alteration of the  
default 6% ratio. An extra resistor between the TIMER pin and  
EE allows the ratio of on-time to off-time to be decreased,  
SHDN  
input to manually disable the GATE drive  
RESTART  
input to remotely initiate a 5 second shutdown  
V
The ADM1073 is fabricated using BiCMOS technology for  
minimal power consumption and is available in a 14-lead  
TSSOP package.  
while a resistor between TIMER and VIN allows the ratio to be  
increased.  
The ADM1073 has separate UV and OV pins for undervoltage  
and overvoltage detection. The FET is turned off, if a  
nontransient voltage less than the undervoltage threshold  
Rev. B | Page 3 of 24  
 
ADM1073  
Data Sheet  
SPECIFICATIONS  
VDD = 0 V, VEE = −48 V; TA = −40°C to +85°C, unless otherwise noted.  
Table 1.  
Parameter  
Min  
Typ Max  
Unit  
Test Conditions  
BOARD SUPPLY (Not Connected Directly to Device)  
Maximum Voltage Range  
Limited by external components  
−200 −48 −18  
V
V
Typical Operating Voltage Range  
VIN PIN—SHUNT REGULATOR  
Operating Supply Voltage Range  
Quiescent Supply Current  
Maximum Shunt Supply Voltage  
Undervoltage Lockout, VLKO  
Power-On Reset Delay  
−80  
11.7  
−48 −35  
12.3 12.9  
V
μA  
V
V
ms  
IIN = 0.6 mA to 2 mA  
VIN = 11.7 V  
IIN = 10 mA  
300 500  
14  
8
150  
UV, OV PINS—UNDERVOLTAGE AND OVERVOLTAGE DETECTION  
Undervoltage Falling Threshold, VUVF  
Undervoltage Hysteresis Current  
Undervoltage Fault Filter  
Overvoltage Rising Threshold, VOVR  
Overvoltage Hysteresis Current  
Overvoltage Fault Filter  
825  
868 910  
5
0.6  
1.93 2.00  
5
5
mV  
μA  
ms  
V
μA  
μs  
1.86  
Input Current  
0.2  
μA  
GATE PIN—FET DRIVER  
Maximum Gate Voltage  
Minimum Gate Voltage  
Pull-Up Current  
11.5  
VIN(MAX)  
100  
V
IGATE = −1.0 μA  
IGATE = 1.0 μA  
VGATE = 0 V to 8 V; VSS = 2 V  
VGATE = 0 V to 8 V; VSS = 0 V  
VGATE > 2 V  
10  
−50  
−36  
mV  
μA  
μA  
mA  
mA  
Pull-Down Current  
20  
50  
VGATE > 5 V  
SENSE PIN—CURRENT SENSE—SOFT START  
Current Limit Control Loop Threshold, VACL  
Circuit Breaker Limit Voltage, VCB  
Fast Current Limit Voltage, VFCL  
Control Loop Transconductance  
Soft Start Pin Current  
97  
86  
100 103  
mV  
mV  
mV  
μA/mV  
μA  
IGATE = 0 mA  
90  
110  
4.5  
5
TIMER PIN—PWM CONTROL  
Minimum TIMER Pull-Up Current  
18  
16  
37  
34  
19  
19  
39  
39  
1
20  
20  
41  
41  
μA  
μA  
μA  
μA  
IPWRGD < 4 μA; TA = 25°C to 85°C  
IPWRGD < 4 μA  
Maximum TIMER Pull-Up Current  
IPWRGD = 24 μA; TA = 25°C to 85°C  
IPWRGD = 24 μA  
TIMER Pull-Down Current  
TIMER Low Voltage Trip Point  
TIMER High Voltage Trip Point  
μA  
V
V
0.45  
2.34  
0.50 0.55  
2.42 2.50  
Current Limit On-Time, tON  
6
3
7
0.6  
ms  
ms  
IDRAIN = 4 μA; CTIMER = 47 nF  
IDRAIN = 20 μA; CTIMER = 47 nF  
Current Limit On-Time, tON, with Foldback  
Number of Consecutive PWM Retry Cycles  
Continuous Short-Circuit Time before Latched Shutdown  
s
CTIMER = 47 nF  
Rev. B | Page 4 of 24  
 
Data Sheet  
ADM1073  
Parameter  
Min  
Typ Max  
Unit  
Test Conditions  
DRAIN (FOLDBACK) AND PWRGD  
DRAIN Voltage at Which PWRGD Asserts  
Maximum DRAIN Pin Current Allowable, IDRAIN(MAX)  
PWRGD Output Voltage Low  
1.9  
2
2.1  
V
RDRAIN = 3.75 M to 20 M  
36  
1
µA  
V
VDS = 80 V; RDRAIN = 3.25 M  
2
I
I
PWRGD = 2.5 mA  
PWRGD = 0.5 mA  
0.2  
6
0.4  
V
PWRGD Internal Pull-Up Current  
PWRGD Output Voltage High  
µA  
V
VIN  
RESTART  
Time before Restart  
Input Threshold  
Glitch Filter  
Internal Pull-Up Current  
SHDN  
5
s
V
µs  
µA  
1.35  
1.35  
1.45 1.55  
5
6
Glitch Filter  
5
µs  
V
µA  
Input Threshold  
Internal Pull-Up Current  
LATCHED AND SPLYGD  
Output Voltage Low  
1.45 1.55  
6
1
2
V
V
I
I
LATCHED, ISPLYGD = 2.5 mA  
LATCHED, ISPLYGD = 0.5 mA  
0.2  
0.4  
Internal Pull-Up Current  
Output Voltage High  
6
VIN  
µA  
V
Rev. B | Page 5 of 24  
ADM1073  
Data Sheet  
ABSOLUTE MAXIMUM RATINGS  
All voltages referred to VEE, TA = 25°C, unless otherwise noted.  
Table 2.  
Stresses above those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. This is a stress  
rating only and functional operation of the device at these or  
any other conditions above those indicated in the operational  
section of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
Parameter  
Rating  
Supply Voltage (VDD − VEE)  
Maximum Shunt Supply Voltage, VSS  
SENSE Pin  
GATE Pin  
UV Pin  
OV Pin  
SS Pin  
TIMER Pin  
DRAIN Pin  
−0.3 V to −200.0 V  
16 V  
−2 V to +2 V  
−0.3 V to +16 V  
−0.3 V to +6 V  
−0.3 V to +6 V  
−0.3 V to +6 V  
−0.3 V to +6 V  
−0.3 V to +6 V  
−0.3 V to +16 V  
−0.3 V to +16 V  
−0.3 V to +16 V  
−0.3 V to +16 V  
−0.3 V to +16 V  
125°C  
THERMAL CHARACTERISTICS  
14-lead TSSOP Package:  
θJA = 240°C/W  
θ
JC = 43°C/W  
SHDN Pin  
SPLYGD Pin  
LATCHED Pin  
PWRGD Pin  
RESTART Pin  
Maximum Junction Temperature  
Operating Temperature Range  
Continuous Power Dissipation  
Storage Temperature Range  
Lead Temperature (Soldering, 10 s)  
−40°C to +85°C  
180 mW  
−65°C to +150°C  
300°C  
ESD CAUTION  
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on  
the human body and test equipment and can discharge without detection. Although this product features  
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy  
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance  
degradation or loss of functionality.  
Rev. B | Page 6 of 24  
 
 
 
Data Sheet  
ADM1073  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
RESTART  
1
2
3
4
5
6
7
14 SHDN  
13 TIMER  
12 UV  
V
IN  
PWRGD  
SS  
ADM1073  
11 OV  
TOP VIEW  
(Not to Scale)  
SENSE  
10 DRAIN  
V
9
8
GATE  
EE  
LATCHED  
SPLYGD  
Figure 2. Pin Configuration  
Table 3. Pin Function Descriptions  
Pin Number Mnemonic  
Function  
Input Pin. Edge-triggered 5-second shutdown and automatic restart.  
1
2
RESTART  
VIN  
Shunt Regulated Positive Supply to Chip. Connect to the positive supply rail via shunt resistor. A 1 µF  
capacitor to VEE is recommended on the VIN pin.  
3
4
PWRGD  
SS  
Open Drain Output. Signals that the hot swap is complete.  
Analog Pin for Soft Start. An external capacitor on this pin sets the ramp rate of the inrush current  
profile. This pin can be overdriven to alter the current limit control loop threshold.  
5
6
7
8
SENSE  
VEE  
LATCHED  
SPLYGD  
Voltage Input from External Sense Resistor.  
Ground Supply to Chip (usually a −48 V system supply). Also low-side sense resistor connection.  
Open Drain Output. Signals the end of the PWM retry period after a current fault.  
Open Drain Output. Signals that the device is not in reset and that the supply is in operating voltage  
window.  
9
GATE  
DRAIN  
OV  
UV  
TIMER  
Output to External FET Gate Drive.  
10  
11  
12  
13  
Analog Input for Monitoring of FET Drain Voltage.  
Input Pin for Overvoltage Detection Circuitry.  
Input Pin for Undervoltage Detection Circuitry.  
Analog Pin. An external capacitor on this pin sets the maximum allowable time in current limit, the  
PWM on-time, and the PWM duty cycle.  
14  
SHDN  
Input Pin. Level-triggered device shutdown and reset.  
Rev. B | Page 7 of 24  
 
ADM1073  
Data Sheet  
TYPICAL PERFORMANCE CHARACTERISTICS  
500  
14.5  
14.0  
13.5  
13.0  
12.5  
12.0  
11.5  
11.0  
450  
400  
350  
300  
250  
200  
150  
100  
50  
0
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 3. IIN vs. Temperature  
Figure 6. VIN vs. Temperature  
100.0  
12  
10  
8
10.0  
1.0  
6
4
T
= –40°C  
A
T
= +25°C  
A
2
T
= +85°C  
A
0.1  
0
–50  
1.5  
3.5  
5.5  
4.5  
7.5  
8.5  
9.5  
11.5  
13.5  
–35  
–20  
–5  
–10  
25  
40  
55  
70  
85  
0.5  
2.5  
6.5  
10.5  
12.5  
14.5  
TEMPERATURE (°C)  
V
(V)  
IN  
Figure 4. IIN vs. VIN  
Figure 7. Undervoltage Lockout, VLKO, vs. Temperature  
10  
9
8
7
6
5
4
3
2
1
0
400  
350  
300  
250  
200  
150  
100  
50  
0
–50  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
–35  
–20  
–50  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 8. POR Delay vs. Temperature  
Figure 5. RZ (VIN Forward Voltage) vs. Temperature  
Rev. B | Page 8 of 24  
 
Data Sheet  
ADM1073  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
SS = 2V  
SS = 0V  
0
8.0  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
8.5  
9.0  
9.5  
10.0  
10.5  
11.0  
11.5  
12.0  
TEMPERATURE (°C)  
V
(V)  
GATE  
Figure 9. VGATEL vs. Temperature  
Figure 12. IGATE (Source) vs. VGATE  
14.0  
13.5  
13.0  
12.5  
12.0  
11.5  
11.0  
10.5  
10.0  
60  
50  
40  
30  
20  
10  
0
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 10. VGATEH vs. Temperature  
Figure 13. IGATE (FCL, Sink) vs. Temperature (VGATE = 2 V)  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
SS = 2V  
SS = 0V  
1
2
3
4
5
6
7
8
9
10  
11  
12  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
V
(V)  
TEMPERATURE (°C)  
GATE  
Figure 11. IGATE (Source) vs. Temperature  
Figure 14. IGATE (FCL, Sink) vs. VGATE  
Rev. B | Page 9 of 24  
ADM1073  
Data Sheet  
1000  
980  
960  
940  
920  
900  
880  
860  
840  
820  
800  
10  
9
8
7
6
5
4
3
2
1
0
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
70  
70  
85  
85  
85  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 15. UV Threshold vs. Temperature  
Figure 18. OV Voltage Fault Filter Time vs. Temperature  
2.00  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
1.98  
1.96  
1.94  
1.92  
1.90  
1.88  
1.86  
1.84  
1.82  
1.80  
–50  
–35  
–20  
–50  
10  
25  
40  
55  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 16. OV Threshold vs. Temperature  
Figure 19. ISENSE vs. Temperature (VSENSE = 50 mV)  
2.0  
1.8  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
80  
60  
40  
20  
0
–20  
–40  
–60  
–80  
–2  
–1.5  
–1.0  
–0.5  
0
0.5  
1.0  
1.5  
2.0  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
V
(V)  
TEMPERATURE (°C)  
SENSE  
Figure 17. UV Voltage Fault Filter Time vs. Temperature  
Figure 20. ISENSE vs. (VSENSE − VEE)  
Rev. B | Page 10 of 24  
Data Sheet  
ADM1073  
14  
12  
10  
8
120  
82.0nF  
115  
100.0nF  
V
FCL  
68.0nF  
110  
105  
100  
95  
47.0nF  
33.0nF  
V
ACL  
6
1.0nF  
22.0nF  
4
90  
V
CB  
2
85  
10.0nF  
4.7nF  
50  
0
80  
–50  
0
10  
20  
30  
40  
60  
(nF)  
70  
80  
90  
100  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
C
TEMPERATURE (°C)  
TIMER  
Figure 21. Voltage Limits for Load Current Control vs. Temperature  
Figure 24. Current Limit On-Time vs. CTIMER (1 nF − 100 nF)  
3.0  
10  
9
8
7
6
5
4
3
2
1
V
(HIGH)  
TMR  
2.5  
2.0  
1.5  
1.0  
0.5  
0
V
(LOW)  
TMR  
0
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 22. High and Low TIMER Thresholds vs. Temperature  
Figure 25. Current Limit PWM vs. Temperature  
50  
20  
18  
16  
14  
12  
10  
8
45  
40  
35  
30  
25  
20  
15  
10  
5
6
4
2
0
0
–50  
0
1
2
3
4
5
6
7
8
9
10  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
R
(M)  
TEMPERATURE (°C)  
TIMER  
Figure 23. Maximum Current Limit On-Time vs. Temperature  
(IDRAIN = 4 µA, CTIMER = 47 nF)  
Figure 26. Current Limit PWM vs. RTIMER  
Rev. B | Page 11 of 24  
ADM1073  
Data Sheet  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
10.0nF  
6.8nF  
4.7nF  
3.3nF  
2.2nF  
1.5nF  
1.0nF  
0
1
2
3
4
5
(nF)  
6
7
8
9
10  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
C
TEMPERATURE (°C)  
SS  
Figure 27. Continuous Short Circuit Time before Shutdown vs. Temperature  
Figure 29. Soft Start Ramp Time vs. CSS  
10  
9
8
7
6
5
4
3
2
1
0
10  
9
8
7
6
5
4
3
2
1
0
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
–50  
–35  
–20  
–5  
10  
25  
40  
55  
70  
85  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 30. IUV/OV vs. Temperature  
RESTART  
Figure 28.  
Time vs. Temperature  
Rev. B | Page 12 of 24  
Data Sheet  
ADM1073  
FUNCTIONAL DESCRIPTION  
HOT CIRCUIT INSERTION  
INITIAL STARTUP  
Inserting circuit boards into a live −48 V backplane can cause  
large transient currents to be drawn as the board capacitance  
charges up. These transient currents can cause glitches on the  
system power supply and can permanently damage the board  
connectors and components.  
The ADM1073 hot swap controller normally resides on a  
removable circuit board and controls the manner in which  
power is applied to the board upon connection. This is achieved  
using a FET, Q1, in the power path (see Figure 31). By  
controlling the gate voltage of the transistor, the surge of current  
to charge load capacitance can be limited to a safe value when  
the board makes connection. The ADM1073 can also reside on  
the backplane itself and perform the same function from there.  
The ADM1073 is designed to control the manner in which a  
board’s supply voltage is applied so that harmful transient  
currents do not occur and the board can be safely inserted or  
removed from a live backplane. Undervoltage, overvoltage, and  
overcurrent protection are other features of the part. The  
ADM1073 ensures that the input voltage is stable and within  
tolerance before being applied to the power module.  
Figure 32 shows a typical ADM1073 application circuit. When  
the plug-in board is inserted into the live backplane, the −48 V  
and 0 V lines connect to the live supply. This powers up the  
device with the voltage on VIN exceeding VLKO. When the  
voltage on the UV pin exceeds the undervoltage rising  
threshold (0.868 V), it is now inside the programmed operating  
voltage window. It must stay inside this window for the duration  
of the power-on reset delay time, tPOR (150 ms).  
PLUG-IN BOARD  
SHDN  
RESTART  
0V  
V +  
IN  
R
DROP  
R1  
R2  
R3  
R4  
LATCHED  
SPLYGD  
PWRGD  
LIVE  
BACKPLANE  
DC-DC  
CONVERTER  
C
ADM1073  
LOAD  
C
TIMER  
R
C
DRAIN  
SS  
–48V  
V
IN  
R
FET  
SENSE  
Figure 31. ADM1073 Topology  
V
EE  
–48V RTN  
5V  
3.3V  
2.8V  
...etc.  
GND  
R
DROP  
DC-DC  
CONVERTER  
V
SPLYGD  
IN  
PWRGD  
R1  
R3  
V
AND  
CC  
FOLDBACK  
AND PWRGD  
R
DRAIN  
REFERENCE  
GENERATOR  
DRAIN  
OVERVOLTAGE  
DETECTOR  
OV  
UV  
V
IN  
UNDERVOLTAGE  
DETECTOR  
50A  
100mV(MAX)  
FET  
R2  
R4  
SOFT START  
CONTROL  
GATE  
SS  
TIMER CONTROL  
SENSE  
FAULT TIMER  
TIMER  
R
SENSE  
AND CONTROL  
C
SS  
V
5 SECOND  
SHUTDOWN  
EE  
PWM  
TIMEOUT  
OSCILLATOR  
C
SHDN  
RESTART  
LATCHED  
TIMER  
R
*
TIMER  
–48V  
*R  
IS AN OPTIONAL COMPONENT  
TIMER  
Figure 32. ADM1073 Application Diagram  
Rev. B | Page 13 of 24  
 
 
 
 
 
ADM1073  
Data Sheet  
When the device detects that the supply voltage is valid, it  
ramps up the GATE voltage until the FET turns on and the load  
current increases. The ADM1073 monitors the level of the  
current flowing through the FET by sensing the voltage across  
the external sense resistor, RSENSE. When the SENSE voltage  
reaches 100 mV, the GATE pin is actively controlled, limiting  
the load current. In this way, the maximum current permitted  
end of the tON period the load capacitance is still demanding  
maximum current. The ADM1073 now controls the FET gate to  
zero for a time tOFF, determined by the time taken for the on-  
chip current sink to discharge the TIMER capacitance to 0.5 V.  
At the end of time tOFF, the device retries, again following the  
soft start current profile. In this way, a large load capacitance  
can be charged using consecutive current limit periods. The  
external components should be chosen to ensure that the  
capacitance is fully charged within seven TIMER periods, if the  
default limited consecutive retry mode is used.  
to flow through the load is set by the choice of RSENSE  
.
If a change in the level of the supply voltage causes the voltage  
on UV to fall below the undervoltage falling threshold (VUVF),  
or the voltage on OV to rise above the overvoltage rising  
threshold (VOVR), then the gate drive is disabled.  
Startup into a Short Circuit or over Current Fault  
The load might demand large currents at initial connection.  
The ADM1073 follows the Soft Start current profile as  
described for startup into a nominal load. The current is limited  
at IMAX for time tON following which the FET gate is pulled low.  
The FET gate is held low for time tOFF, before retrying, again  
with the soft start current profile. The ADM1073 cycles through  
7 retries, after which it latches the FET off, assuming the default  
limited consecutive retry mode is used.  
BOARD REMOVAL  
If the board is removed from a card cage, the voltage on the UV  
pin falls to zero (that is, outside operating range) and the GATE  
drive is de-asserted, turning off the FET.  
CONTROLLING THE CURRENT  
The ADM1073 features the following current control functions:  
Voltage Step during Normal Operation  
Precision maximum current limit  
Controlled time in current limit  
Limited number of consecutive maximum current events  
Current limit profiling—soft start  
Overcurrent fast limit  
Once the load capacitance is charged at initial board insertion  
PWRGD  
and a  
signal is issued by the ADM1073, the load  
begins to demand current. Therefore, following a step increase  
in the magnitude of the supply voltage, not all the FET current  
is available for charging of the load capacitance. Because the  
FET is fully on following a step in the supply voltage, the  
current increases immediately from ILOAD to supply charge to  
the load capacitance. If the current remains below the fast  
current limit, the FET gate drive amplifier controls it back to  
In the following sections, five distinct system operating  
conditions are described with reference to the current control  
features.  
Startup into Nominal Load Capacitance  
I
MAX. If the current exceeds the fast current limit, the FET gate is  
Once the supply voltage has exceeded the UV threshold, and  
following the 0.6 ms UV filter time, the current to the load  
ramps up linearly as the capacitor on the Soft Start (SS) pin is  
charged to 2.5 V. At the same time, current is sourced into the  
capacitor on the TIMER pin, both from an on-chip source and  
via the drain resistor. Once the soft start voltage has reached  
2.5 V, the current to the load is limited to IMAX (100 mV/RSENSE).  
Assuming that the values of RSENSE and the TIMER capacitance  
have been chosen to allow the load capacitance to charge within  
one ON period (tON period), the load capacitor is fully charged  
before the voltage on TIMER reaches 2.5 V. At this point, the  
current to the load decreases, and the FET gate voltage increases  
to VSS, connecting the supply to the load.  
strongly pulled down and back into regulation with the current  
at IMAX. The size of the voltage step and the headroom between  
the load current and IMAX determine the time required at IMAX to  
charge the load capacitance. External components should be  
chosen to ensure that any expected step size leads to a  
requirement of less than time tON to charge the load capacitance.  
Short Circuit or Overcurrent Fault during Operation  
If a short circuit or an overcurrent fault occurs during normal  
operation, the FET is fully on and initially allows increased  
current to flow. If the current remains below the fast current  
limit, the FET gate drive amplifier controls it back to IMAX. If the  
current exceeds the fast current limit, the FET gate is strongly  
pulled down and back into regulation with the current at IMAX  
Following a period, tON, the ADM1073 pulls the FET gate low  
for a time tOFF, then retries following the soft start current  
profile. If the fault persists, the ADM1073 cycles through 7  
retries before latching off. If the fault clears within the 7-retry  
period, the ADM1073 controls the FET gate high to allow  
normal operation to continue.  
.
Startup into Load with Large Capacitance  
If the load capacitance is sufficiently large that to charge it fully  
in one attempt would compromise the FETs SOA, consecutive  
maximum current events may be used. The use of this tech-  
nique assumes that the load is not yet enabled, so negligible  
load current is demanded. The initial current profiling is  
identical to that for startup into a nominal load capacitance. If  
the charge passed to the load in time tON with maximum current  
flowing is insufficient to fully charge the load capacitance, at the  
Rev. B | Page 14 of 24  
 
 
Data Sheet  
ADM1073  
GATE  
SENSE  
Analog output for driving the external FET gate. This pin is  
switched to VEE when the FET is off, is linearly controlled when  
the FET is at the programmed inrush current limit, and is  
switched to VIN when the FET is fully enhanced. The source  
current capability is small to provide slow controlled turn-on,  
and the sink current capability is large to provide fast turn-off.  
The SENSE pin is used for sensing the voltage across an  
external power sense resistor. This voltage is differentially  
measured with respect to VEE, and used to control the GATE.  
If SENSE is lower than 100 mV (after the soft start time), the  
GATE pin is allowed to increase up to 12 V to provide  
maximum FET enhancement. If the current increases such that  
the SENSE pin tries to go above 100 mV, the GATE pin is  
controlled in a feedback loop to ensure that the voltage across  
the sense resistor is regulated at exactly 100 mV.  
VIN  
Positive supply pin. This current-driven supply is shunt-  
regulated at 12.3 V internally, and should be connected to the  
most positive input supply terminal (usually −48 V RTN or 0 V)  
through a dropper resistor. The resistor should be chosen such  
that it always supplies enough current to overcome the  
SENSE RESISTOR  
The ADM1073s current limiting function can operate at  
different current levels. The current limit is determined by  
selection of the sense resistor, RSENSE. Table 4 shows how the  
maximum allowable load current (ILOAD(MAX)) and the minimum  
and maximum inrush currents (ILIMIT(MIN) and ILIMIT(MAX)) are  
maximum quiescent supply current of the chip. Default RDROP  
=
30 kΩ.  
VEE  
related to the value of RSENSE  
.
Negative supply input. This pin should be connected directly to  
the most negative input supply terminal (−48 V). This pin is  
also used for differentially sensing across the external power  
resistor, and should, therefore, be connected as close to the  
sense resistor as possible. (See the Kelvin Sense Resistor  
Connection section.)  
Table 4. Minumum and Maximum Inrush Current and Load  
Current Levels for Different Values of RSENSE  
RSENSE (mΩ)  
ILOAD(MAX) (A)  
17.20  
8.60  
5.73  
4.78  
3.91  
2.61  
1.83  
1.69  
ILIMIT(MIN) (A) ILIMIT(MAX) (A)  
5
19.40  
9.70  
6.47  
5.39  
4.41  
2.94  
2.06  
1.90  
1.43  
1.29  
1.08  
20.60  
10.30  
6.87  
5.72  
4.68  
3.12  
2.19  
2.02  
1.51  
1.37  
1.14  
10  
15  
18  
22  
33  
47  
51  
68  
75  
90  
TIMING CONTROL—TIMER  
The TIMER pin is an analog pin that determines the maximum  
on-time when the FET is in linear current limit, and controls  
the PWM duty cycle for pulsed load capacitor charging. A  
capacitor should be attached to this pin. When the FET is in  
current limit, a 19 µA current source charges the external  
capacitor. If the FET is still in current limit when the TIMER  
capacitor reaches 2.5 V, the GATE driver is turned off and a  
1 µA discharge current sink is turned on. The GATE remains  
low until the TIMER capacitor is reduced to 0.5 V. At this point,  
the GATE pin is turned on again. If the FET goes back into  
current limit, the TIMER recharging starts again.  
1.26  
1.15  
0.96  
SOFT START (SS PIN)  
The SS pin is used to determine the inrush current profile.  
A capacitor should be attached to this pin. Whenever the FET  
is requested to turn on, the SS pin is held at ground until the  
SENSE pin reaches a few mV. A current source is then turned  
on, which linearly ramps the capacitor up to 2.5 V. The  
reference voltage for the GATE linear control amplifier is  
derived from the soft start voltage, such that the inrush linear  
current limit is defined as  
The PWM duty cycle is set at 6% default level by the size of  
these two current sources. Adding a resistor from TIMER to VEE  
decreases the duty cycle. Adding a resistor from TIMER to VIN  
increases the duty cycle.  
In addition, a current proportional to the current into the  
DRAIN pin is added to the charging current. The additional  
current varies linearly with DRAIN voltage. This reduces the  
maximum on-time and the percentage PWM duty cycle when  
there is a large voltage across the FET.  
ILIMIT = VSOFT _ START /20× RSENSE  
Overdriving the SS Pin  
The SS pin can be overdriven externally from 0.360 V to 1.95 V  
to offset the current limit control loop threshold from 18 mV to  
100 mV. This allows different current limits to be selected at  
different points of operation without using multiple sense  
resistors. The current limit voltage is clamped at 100 mV  
maximum.  
Rev. B | Page 15 of 24  
 
 
 
 
 
 
 
 
ADM1073  
Data Sheet  
shutdown function is triggered by a low pulse of at least 5 µs at  
the pin. This pin has an internal pull-up of approximately 6 µA,  
allowing it to be driven by an open collector pull-down output  
or a push-pull output. The input threshold is 1.5 V.  
DRAIN  
Analog input fed by a resistor connected to the drain of the  
FET. This pin is clamped to go no higher than 4 V with respect  
to VEE. Below this level, the voltage on the pin is monitored so  
PWRGD  
that, if it falls below 2 V, the  
output can be set. Above  
SHDN  
the 4 V level, the current into the pin is detected and used to  
modulate the maximum on-time for the linear FET driver. This  
is done by summing a proportion of the drain input current  
with the charging current for the TIMER timing capacitor,  
thereby reducing the allowable on-time.  
Level-triggered input. Allows the user to command a shutdown  
of the hot swap function. When this input is set low, the GATE  
output is switched to VEE to turn the FET off. This pin has an  
internal pull-up of approximately 6 µA, allowing it to be driven  
by an open collector pull-down output or a push-pull output.  
The input threshold is 1.5 V.  
PWRGD  
UNDERVOLTAGE/OVERVOLTAGE DETECTION  
Output to indicate when the load capacitor is fully charged.  
This is an open collector output with internal pull-up to VIN.  
The ADM1073 incorporates dual pin undervoltage and  
overvoltage detection, with a programmable operating voltage  
window. When the voltage on the UV pin falls below the UV  
falling threshold or the voltage on the OV pin rises above the  
OV rising threshold, a fault signal is generated that disables the  
linear current regulator and results in the GATE pin being  
pulled low. The voltage fault signal is time filtered so that faults  
of a duration less than the UV glitch filter time (0.6 ms) and OV  
glitch filter time (5 µs) do not force the gate drive low. The filter  
operates only on the faulting edge, that is, on a high-to-low  
transition on the undervoltage monitor and on a low-to-high  
transition on the overvoltage monitor.  
PWRGD  
When a normal startup is initiated, the  
output is  
latched low when the DRAIN pin falls below 2 V. The latch is  
reset, if either the input supply goes out of range or a current  
limit time-out event occurs. The second of these cases ensures  
that, if a voltage step of greater than 2 V is presented at the  
PWRGD  
input, the  
flag does not go high while the load  
capacitor is being charged up to the additional voltage.  
LATCHED  
Output to indicate when the device has completed the maxi-  
mum number (7) of PWM cycles. This is an open collector  
output with an internal current source pull-up. If this PWM  
time-out event occurs, the GATE pin is latched low and the  
–48V RTN  
V
LATCHED  
IN  
output is set low. This condition can then be reset  
by either a power cycling event or a low signal to either the  
SHDN RESTART  
OVERVOLTAGE  
DETECTOR  
input or the  
LATCHED  
input. By connecting the  
SHDN  
1.93V  
signal directly to  
be put into a continuous PWM mode. By connecting the  
LATCHED RESTART  
, the device can effectively  
R1  
R2  
R3  
R4  
OV  
UV  
SPLYGD  
signal directly to  
, the device can  
effectively be put into autoretry mode, with a 5-second cooling  
period.  
868mV  
UNDERVOLTAGE  
DETECTOR  
SPLYGD  
FET DRIVE  
ENABLE  
ADM1073  
Output to indicate when the input supply is within the pro-  
grammed voltage window. This is an open collector output with  
an internal pull-up current source. For very large capacitive  
loads where multiple FETs and controllers are required to meet  
the inrush requirements, this output can be used to drive  
directly into the UV pin of a second controller. This allows the  
second FET to start 1 ms after the first one, with the added  
advantage that the input supply UV detection is done on one  
–48V IN  
Figure 33. Undervoltage and Overvoltage Circuitry  
(Standard 4-Resistor Configuration)  
The operating voltage window is determined by selecting the  
resistor ratios R1/R2 and R3/R4. These resistor networks form  
two resistor dividers that generate the voltages at the UV and  
OV pins, which are proportional to the supply voltage. By  
choosing these ratios carefully, the user can program the  
ADM1073 to apply the supply voltage to the load only when it is  
within specific thresholds. Note that 1% tolerance resistors  
should always be used to maintain the accuracy of the pro-  
grammed thresholds.  
controller only. The  
output is asserted only when the  
SPLYGD  
ADM1073 is not in reset mode.  
RESTART  
Edge-triggered input. Allows the user to remotely command a  
5-second shutdown and restart of the hot swap function,  
effectively simulating a board removal and replacement. The  
Rev. B | Page 16 of 24  
 
 
 
 
 
 
 
Data Sheet  
ADM1073  
UV (Undervoltage)  
In this manner, the user can program the value of the voltage  
hysteresis by varying the parallel impedance of the resistor  
divider. The OV comparator has an internal 5 µs time delay.  
The voltage on the UV pin is compared to an internal 0.868 V  
reference. For the implementation in Figure 33, the undervolt-  
age level is then set as  
If the voltage on UV or OV goes out of range (below 0.868 V on  
UV or above 1.93V on OV), GATE is pulled low. If the supply  
subsequently reenters the operating voltage window, the  
ADM1073 restores the GATE drive.  
VUV = 0.868 × (R1 + R2)/R2  
If the UV pin voltage is less than 0.868 V and the comparator  
trips, an internal 5 µA current sink is turned on. This pulls the  
UV voltage down by  
Hysteresis must be considered when reentering the operating  
window, that is, VUV must increase above  
V
UVHYST(PIN) = 5 µA × R1 × R2/(R1 + R2)  
at the UV pin, or by  
UVHYST(SUPPLY) = 5 µA × R1  
0.868 V + VUVHYST(SUPPLY)  
when recovering from an undervoltage fault, and VOV must  
drop below  
V
at the supply.  
1.93 V − VOVHYST(SUPPLY)  
In this manner, the user can program the value of the voltage  
hysteresis by varying the parallel impedance of the resistor  
divider. The UV comparator has an internal 0.6 ms time delay  
to prevent nuisance shutdowns under noisy supply conditions.  
when recovering from an overvoltage fault for GATE to be  
restored.  
Alternative UV and OV Configurations  
A 2-resistor or a 3-resistor implementation can also be used to  
set the UV and OV levels (see Figure 34 and Figure 35).  
OV (Overvoltage)  
The voltage on the UV pin is compared to an internal 1.93 V  
reference. For the implementation in Figure 33, the overvoltage  
level is then set as  
–48V RTN  
V
OV = 1.93 × (R3 + R4)/R4  
R1  
OV  
UV  
If the OV pin voltage exceeds 1.93 V and the comparator trips,  
an internal 5 µA current source is turned on. This pulls the OV  
voltage up by  
ADM1073  
R2  
–48V IN  
V
OVHYST(PIN) = 5 µA × R3 × R4/(R3 + R4)  
at the OV pin, or by  
OVHYST(SUPPLY) = 5 µA × R3  
at the supply.  
Figure 34. 2-Resistor UV/OV Implementation  
V
–48V RTN  
R1  
OV  
ADM1073  
R2  
UV  
R3  
–48V IN  
Figure 35. 3-Resistor UV/OV Implementation  
Rev. B | Page 17 of 24  
 
 
ADM1073  
Data Sheet  
FUNCTIONALITY AND TIMING  
LIVE INSERTION  
The timing waveforms associated with the live insertion of a  
plug-in board using the ADM1073 are shown in Figure 36. The  
long connector pins are the first to make connection, and the  
GND − VEE potential climbs to 48 V. As this voltage is applied,  
the voltage at the VIN pin ramps to a constant 12.3 V and is held  
at this level with the shunt resistor and external resistor  
combination at the VIN pin. In this case, the connection pins are  
staggered so that the R1/R2 and R3/R4 resistor dividers are the  
last to connect to the backplane. This means that VUV and VOV  
begin to ramp after the other pins connect. Note that staggered  
connector pins are optional, because an internal time filter is  
included on the UV pin.  
Figure 37. Typical Startup Sequence  
PWRGD  
SPLYGD  
)
(Ch1 = GATE; Ch2 = SENSE; Ch3 =  
; Ch4 =  
When VUV crosses the undervoltage rising threshold, it is now  
inside the operating voltage window and the −48 V supply must  
OVERVOLTAGE AND UNDERVOLTAGE FAULTS  
SPLYGD  
be applied to the load. The  
output is asserted and after  
a time delay, tPOR, the ADM1073 begins to ramp up the gate  
drive. When the voltage on the SENSE pin reaches 100 mV (the  
analog current limit level), the gate drive is held constant. When  
the board capacitance is fully charged, the sense voltage begins  
to drop below the analog current limit voltage and the gate  
voltage is free to ramp up further. The gate voltage eventually  
The waveforms for an overvoltage glitch are shown in Figure 38.  
When VOV glitches above the overvoltage threshold of 1.93 V, an  
overvoltage condition is detected and the GATE voltage is  
pulled low. VOV begins to drop back toward the operating  
voltage window, and the GATE drive is restored when the  
overvoltage falling threshold (1.93 V minus preset OV  
hysteresis level) is reached. Figure 38 illustrates the ADM1073s  
reactions to an overvoltage condition.  
PWRGD  
climbs to its maximum value of 12.3 V and the  
output  
is asserted. Figure 37 shows some typical startup waveforms.  
–48V RTN – VEE  
V
LKO  
V
IN  
V
UVR  
V
UV  
tPOR  
GATE  
SENSE  
V
OUT  
Figure 38. Timing Waveforms Associated with an Overvoltage Fault  
PWRGD  
SPLYGD  
(Ch1 = GATE; Ch2 = OV; Ch3 =  
; Ch 4 =  
)
SPLYGD  
PWRGD  
Figure 36. Timing Waveforms Associated with a Live Insertion Event  
Rev. B | Page 18 of 24  
 
 
 
 
 
 
Data Sheet  
ADM1073  
An undervoltage glitch is dealt with in a similar way. When VUV  
falls below the undervoltage threshold of 0.868 V, the GATE  
voltage is pulled low. VUV begins to rise back toward the  
operating voltage window, and the GATE drive is restored when  
the undervoltage rising threshold (0.868 V plus preset UV  
hysteresis level) is reached. Figure 39 illustrates the ADM1073s  
operation in an undervoltage situation.  
Figure 41. Soft Start Profile with a 1.5 nF Capacitor  
(Ch1 = GATE; Ch2 = SENSE)  
Figure 39. Timing Waveforms Associated with an Undervoltage Fault  
PWRGD  
SPLYGD  
(Ch1 = GATE; Ch2 = UV; Ch3 =  
; Ch4 =  
)
SOFT START  
The ADM1073 offers a variable soft start feature. The value of  
the capacitor on the SS pin sets the ramp rate of the inrush  
current profile at startup. Figure 40 to Figure 42 show different  
inrush current ramp rates for three SS capacitors.  
Figure 42. Soft Start Profile with an 8.2 nF Capacitor  
(Ch1 = GATE; Ch2 = SENSE)  
Figure 40. Soft Start Profile with a 0.1 nF Capacitor  
(Ch1 = GATE; Ch2 = SENSE)  
Rev. B | Page 19 of 24  
 
 
 
 
ADM1073  
Data Sheet  
CURRENT FAULTS  
Some timing waveforms associated with overcurrent faults are  
shown in the following figures. Figure 43 shows how a perma-  
SPLYGD  
nent current fault is dealt with after startup.  
going low  
indicates when the supply voltage is good. Because the output is  
shorted, the sense voltage immediately rises through the 90 mV  
circuit breaker threshold, and the fault timer is started. The  
linear current control loop then goes into regulation at VSENSE  
=
100 mV, accurately limiting the load current at the preset level.  
The limited consecutive retry scheme PWMs the GATE pin  
seven times. When the seventh retry occurs, the permanent  
fault is deemed permanent and the part latches off. The  
LATCHED  
output asserts at this time. Power must now be  
Figure 44. Timing Waveforms Associated with a Temporary Current Fault  
Followed by a Permanent Current Fault  
cycled to restart the device. This can be achieved via a manual  
card reseating event (which cycles the power) or with an  
(Ch1 = GATE; Ch2 = SENSE)  
Figure 45 shows the behavior of the TIMER pin during a retry  
cycle. Different current sources are switched in during the  
on-time (TIMER ramping up) and off-times (TIMER ramping  
down). This can be seen in the varying ramp-up and ramp-  
down rates of TIMER below. The default ratio of tON to tOFF is  
6%. This ratio can be reduced with a resistor from TIMER to  
RESTART SHDN  
external  
or  
signal.  
V
EE or increased with a resistor from TIMER to VIN. The total  
retry period can be extended or reduced by changing the value  
of the TIMER capacitor.  
Figure 43. Timing Waveforms Associated with a Current Fault at Startup,  
Using Limited Consecutive Retry (Ch1 = GATE; Ch2 = SENSE;  
SPLYGD  
LATCHED  
Ch3 =  
; Ch4 =  
)
LATCHED  
Note that the  
output can also be tied back to the  
RESTART  
input, giving an infinite retry during current fault  
with a 5-second cool-down period after every seven retries. The  
waveforms for this event are similar to those in Figure 43, but  
repeats every five seconds.  
Figure 45. Timing Waveforms during a Retry Cycle for CTIMER = 0.82 nF  
(Ch1 = GATE; Ch2 = SENSE; Ch3 = TIMER)  
Figure 44 shows the behavior of ADM1073 when a temporary  
current fault occurs followed by a permanent current fault.  
When the first overcurrent fault occurs, the first 97.5 mV spike  
on the SENSE line can be seen. The ADM1073 retries a number  
of times, and during the fifth tOFF time this current fault corrects  
itself. After this time period, a no-fault condition is detected  
and the limited consecutive counter is reset. GATE is reasserted.  
When the overcurrent fault returns permanently, the limited  
consecutive retry counter detects seven consecutive faults and  
the part latches off. In this way, the ADM1073 prevents  
nuisance shutdowns caused by transient shorts of a  
programmable duration (typically ~0.6 s, set via TIMER, as  
follows), but provides latched shutdown protection from  
permanently shorted loads.  
Rev. B | Page 20 of 24  
 
 
 
 
Data Sheet  
ADM1073  
LOGIC INPUTS  
KELVIN SENSE RESISTOR CONNECTION  
SHDN  
When using a low-value sense resistor for high current  
measurement, the problem of parasitic series resistance can  
arise. The lead resistance can be a substantial fraction of the  
rated resistance, making the total resistance a function of lead  
length. This problem can be avoided by using a Kelvin sense  
connection. This type of connection separates the current path  
through the resistor and the voltage drop across the resistor.  
Figure 48 shows the correct way to connect the sense resistor  
between the SENSE and VEE pins of the ADM1073.  
Figure 46 shows assertion of the level-triggered  
signal  
for 150 ms, causing the ADM1073 to shut down for this  
duration.  
SENSE RESISTOR  
CURRENT  
FLOW FROM  
LOAD  
CURRENT  
FLOW TO –48V  
BACKPLANE  
KELVIN SENSE TRACES  
Figure 46. Timing Waveforms Associated with a RESET Event  
SHDN  
PWRGD  
SPLYGD  
; Ch4 = )  
(Ch1 = GATE; Ch2 =  
; Ch3 =  
RESTART  
Figure 47 shows the assertion of the edge-triggered  
SENSE  
V
EE  
signal, causing the ADM1073 to shut down for approximately  
five seconds before restarting automatically.  
ADM1073  
Figure 48. Kelvin Sensing with the ADM1073  
RESTART  
; Ch4 =  
Figure 47. Timing Waveforms Associated with a  
RESTART PWRGD  
Event  
SPLYGD  
(Ch1 = GATE; Ch2 =  
; Ch3 =  
)
Rev. B | Page 21 of 24  
 
 
 
 
 
ADM1073  
Data Sheet  
OUTLINE DIMENSIONS  
5.10  
5.00  
4.90  
14  
8
7
4.50  
4.40  
4.30  
6.40  
BSC  
1
PIN 1  
0.65 BSC  
1.05  
1.00  
0.80  
1.20  
MAX  
0.20  
0.09  
0.75  
0.60  
0.45  
8°  
0°  
0.15  
0.05  
COPLANARITY  
0.10  
SEATING  
PLANE  
0.30  
0.19  
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1  
Figure 49. 14-Lead Thin Shrink Small Outline Package [TSSOP]  
(RU-14)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Model1  
ADM1073ARUZ  
ADM1073ARUZ-REEL  
ADM1073ARUZ-REEL7  
EVAL-ADM1073MEBZ  
Temperature Range  
Package Description  
14-Lead TSSOP  
14-Lead TSSOP  
14-Lead TSSOP  
Micro Evaluation Board  
Package Option  
RU-14  
RU-14  
−40°C to +85°C  
−40°C to +85°C  
−40°C to +85°C  
RU-14  
1 Z = RoHS Compliant Part.  
Rev. B | Page 22 of 24  
 
 
 
Data Sheet  
NOTES  
ADM1073  
Rev. B | Page 23 of 24  
ADM1073  
NOTES  
Data Sheet  
©2004–2013 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D04488–0–7/13(B)  
Rev. B | Page 24 of 24  

相关型号:

EVAL-ADM1075EBZ

−48 V Hot Swap Controller and Digital
ADI

EVAL-ADM1087EB

Simple Sequencers in 6-Lead SC7
ADI

EVAL-ADM1168LQEBZ

Super Sequencer and Monitor with Nonvolatile Fault Recording
ADI

EVAL-ADM1184

Evaluation Kit for ADM1184 ±0.8% Accurate Quad Voltage Monitor
ADI

EVAL-ADM1184EBZ

Evaluation Kit for ADM1184 ±0.8% Accurate Quad Voltage Monitor
ADI

EVAL-ADM1186-1EBZ

Quad Voltage Up and Down Sequencer and Monitor with Programmable Timing
ADI

EVAL-ADM1186-1MBZ

Quad Voltage Up and Down Sequencer and Monitor with Programmable Timing
ADI

EVAL-ADM1186-2EBZ

Quad Voltage Up and Down Sequencer and Monitor with Programmable Timing
ADI

EVAL-ADM1186-2MBZ

Quad Voltage Up and Down Sequencer and Monitor with Programmable Timing
ADI

EVAL-ADM1191EBZ

Digital Power Monitor with Convert Pin and ALERTB Output
ADI

EVAL-ADM1191EBZ1

Digital Power Monitor with Convert Pin and ALERTB O
ADI

EVAL-ADM1192EBZ

Digital Power Monitor with Clear Pin and ALERT Output
ADI