ADM1173-1AUJ [ADI]
IC 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8, TSOT-8, Power Management Circuit;
| 型号： | ADM1173-1AUJ |
| 厂家： | 
ADI |
| 描述： | IC 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8, TSOT-8, Power Management Circuit 光电二极管 |
| 文件： | 总8页 (文件大小：151K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
2.7V to 16.5V Hot Swap Controller
with Tracking or Slew Rate Control
Preliminary Technical Data
ADM1173
FEATURES
GENERAL DESCRIPTION
The ADM1173 is a Hot Swap controller that allows a board to
be safely inserted and removed from a live backplane.
An internal charge pumped driver controls the GATE of an
external high side N-channel FET for a supply voltage ranging
from 2.7V to 16.5V. The ADM1173 provides the initial timing
cycle and allows the GATE to be ramped up at an adjustable
rate. The Slew rate of the Output is controlled a capacitor or
supply on the SLEW pin.
The ADM1173 features a fast current limit loop providing
active current limiting together with a circuit breaker timer.
The signal at the ON pin turns the part on and off and is also
used for the reset function.
Allows Safe Board Insertion and Removal from a Live
Backplane
Controls Supply Voltages from 2.7 V to 16.5V
Adjustable Analog Current Limit with Circuit Breaker
Fast Response Limits Peak Fault Current
Automatic Retry or Latch-Off On Current Fault
Adjustable Voltage Slew Rate Control
Charge Pumped Gate Drive for External N-FET Switch
TIMER pin allows control over timing functions
Undervoltage Lockout
8-pin TSOT Package
A capacitor connected to the TIMER pin gives the user control
over the duty cycle of the PWM retry ratio during current fault.
This part is available in two options: the ADM1173-1 will
automatic retry for over-current fault and the ADM1173-2 will
latch-off for an over-current fault.
APPLICATIONS
Hot Swap Board Insertion – Line Cards, Raid systems
Electronic Circuit Breaker
Industrial High Side Switch/Circuit Breaker
The ADM1173 is packaged in an 8-lead TSOT package.
APPLICATIONS DIAGRAM
R
SENSE
Q
V
=5V
OUT
LONG
1
V
=5V
IN
C
LOAD
SENSE-
V
cc
R
ON1
GATE
SHORT
ON / CLR
ADM1173
SLEW
C
VOUT
SLEW
TIMER
R
ON2
GND
C
TIMER
GND
GND
LONG
Rev.PrE
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
www.analog.com
Analog Devices, Inc. All rights reserved.
2005
Preliminary Technical Data
ADM1173
SPECIFICATIONS
Table 1. VCC = 2.7V to 16V, TA = -40°C to +85°C, Typical Values at TA = 25°C unless otherwise noted.
Parameter
Min
Typ
Max
Units
Conditions
VCC Pin
Operating Voltage Range, VCC
Supply Current, Icc
Undervoltage Lockout, VUVLO
Undervoltage Lockout Hysteresis, VUVLOHYS
ON Pin
2.7
16.5
1.0
2.65
V
mA
V
0.65
2.525
25
2.4
VCC Rising
mV
ON Pin Input Current, IINON
On Pin Threshold, VON
ON Pin Threshold Hysteresis, VONHYST
RS- Pin
-100
1.26
0
100
nA
V
mV
1.3
80
1.34
ON rising
Hot Swap Voltage
RS- Pin Input Current, IINSENSE
2.7
TBD
10
16.5
TBD
30
V
-200
20
VSENSE = VCC, VHOTSWAP = 0.6 V, Note
VSENSE = VCC, VHOTSWAP > 2.2 V
VCB = (VCC – VSENSE) ,VHOTSWAP = 0.6 V
VCB = (VCC – VSENSE) ,VHOTSWAP > 2.2 V
VHOTSWAP = 0.6 V, Note
µA
µA
Circuit Breaker Limit Voltage, VCB
Over Current Limit Voltage, VOC
34
44
40
50
47
47
53
53
60
53
66
59
mV
mV
mV
mV
VHOTSWAP > 2.2 V
GATE Pin
GATE Drive Voltage, VGATE
GATE Drive Voltage, VGATE
GATE Drive Voltage, VGATE
Gate Pullup Current
Gate Pulldown Current
Gate Pulldown Current
TIMER Pin
5
6
5
6.5
8
6.5
12
2
10
12
10
14
V
V
V
uA
mA
mA
VGATE – VCC, VCC = 2.7V
VGATE – VCC, VCC = 5V
VGATE – VCC, VCC = 16.5V
VGATE = 0V
VGATE = 3V, Vcc > UVLO
VGATE = 3V, Vcc < UVLO
10
25
TIMER Pin Pull-Up Current, ITIMERUP
-4
-5
-60
2
-6
Initial Cycle, VTIMER = 1V
During Current Fault, VTIMER = 1V
After Current Fault, VTIMER = 1V
Normal Operation, VTIMER = 1V
TIMER rising
µA
µA
µA
µA
V
-48
-72
2.5
TIMER Pin Pull-Down Current, ITIMERDN
100
1.3
0.2
TIMER Pin Threshold High, VTIMERH
TIMER Pin Threshold Low, VTIMERL
CSLEW Pin
1.235
0.18
1.365
0.22
TIMER falling
V
-10
10
1
Slew up Current
µA
µA
V/V
mV
V
Slew down Current
Tracking Gain
Tracking Accuracy
Minimum Tracking Voltage
Maximum Tracking voltage
Slew Rate
VSLEW/VOUTFB
-100
100
100
0.1
Vcc – 0.1
V
V/s
1000
VOUTFB Pin
-100
0
100
Vcc
Input Current
µA
V
Voltage Range
Rev. PrE | Page 2 of 8
Preliminary Technical Data
Absolute Maximum Ratings
ADM1173
Parameter
Rating
VCC Pin
20V
RS+, RS- Pins
-0.3V to 20V
-0.3V to (VCC + 0.3V)
-0.3 to 20V
-0.3V to 20V
VCC + 11V
TBD
TIMER Pin
Slew Pin
ON Pin
GATE Pin
Power Dissipation
Storage Temperature
Operating Temperature Range
Lead Temperature Range (10 sec)
Junction Temperature
–65°C to +125°C
–40°C to +85°C
300°C
150°C
Rev. PrE | Page 3 of 8
Preliminary Technical Data
ADM1173
shunts any potential static charge on the backplane and reduces
the overvoltage stress at the ON pin during live insertion.
Alternatively, an external resistor divider at the ON pin can be
used to program an undervoltage lockout value higher than the
internal UVLO circuit. An RC filter can be added at the ON pin
to increase the delay time at card insertion if the internal glitch
filter delay is insufficient.
HOT CIRCUIT INSERTION
When circuit boards are inserted into live backplanes, the
supply bypass capacitors can draw large transient currents
from the backplane power bus as they charge. Such transient
currents can cause permanent damage to connector pins,
glitches on the system supply or reset other boards in the
system.
The ADM1173 is designed to turn a printed circuit board’s
supply voltage ON and OFF in a controlled manner, allowing
the circuit board to be safely inserted into or removed from a
live backplane. The ADM1173 can reside either on the
backplane or on the daughter board for hot circuit insertion
applications.
GATE FUNCTION
During hot insertion of the PCB, an abrupt application of
supply voltage charges the external FET drain/gate capacitance.
This can cause an unwanted gate voltage spike. An internal
circuit holds GATE low before the internal circuitry wakes up.
This reduces the FET current surges substantially at insertion.
The GATE pin is held low in reset mode and during the initial
timing cycle. In the start-up cycle the GATE pin is pulled up by
a 12µA current source. During an over-current fault condition,
the error amplifier servos the GATE pin to maintain a constant
current to the load until the circuit breaker trips. When the
circuit breaker trips, the GATE pin shuts down abruptly.
OVERVIEW
The ADM1173 is designed to operate over a range of supplies
from 2.7V to 16.5V. Upon insertion, an undervoltage lockout
circuit determines if sufficient supply voltage is present. When
the ON pin goes high an initial timing cycle assures that the
board is fully seated in the backplane before the FET is turned
on. A single timer capacitor sets the periods for all of the timer
functions. After the initial timing cycle the ADM1173 can
either start up in current limit or with a lower load current.
Once the external FET is fully enhanced and the supply has
ramped up, the ADM1173 monitors the load current through
an external sense resistor. Overcurrent faults are actively
limited to 47mV/RSENSE for a specified circuit breaker timer
limit. The ADM1173-1 will automatically retry after a current
limit fault while the ADM1173-2 latches off. The ADM1173-1
timer function limits the retry duty cycle to 3.8% for FET
cooling.
SLEW RATE CONTROL
The slew rate of a rising or falling supply can be controlled by
an external capacitor on the SLEW pin. Alternatively, this pin
can be overdriven with a supply which will result in the output
following this supply. This enables the ADM1173 to behave as a
voltage tracker.
CURRENT LIMIT CIRCUIT BREAKER FUNCTION
The ADM1173 features a current limiting circuit breaker.
When there is a sudden load current surge, such as a low
impedance fault, the bus supply voltage can drop significantly
to a point where the power to an adjacent card is
affected, causing system malfunctions. The ADM1173 fast
response current sense amplifier instantly limits current by
reducing the external FET GATE pin voltage. This
minimizes the bus supply voltage drop and permits power
budgeting and fault isolation without affecting neighboring
cards. A compensation circuit should be connected to
the GATE pin for current limit loop stability.
UNDERVOLTAGE LOCKOUT
An internal undervoltage lockout (UVLO) circuit resets the
ADM1173 if the VCC supply is too low for normal operation.
The UVLO has a low-to-high threshold of 2.525V, a 25mV
hysteresis. Above 2.525V supply voltage, the ADM1173 will
start if the ON pin conditions are met.
ON FUNCTION
The ON pin is the input to a comparator which has a low-to-
high threshold of 1.3V, an 80mV hysteresis and a high-to-
low glitch filter of 30µs. A low input on the ON pin resets
the ADM1173 TIMER status and turns off the external FET by
pulling the GATE pin to ground. A low-to-high transition on
the ON pin starts an initial cycle followed by a start-up cycle.
The output will then start to rise at a rate determined by the
slew rate of the SLEW pin. A 10k pull-up resistor connecting
the ON pin to the supply is recommended. The 10k resistor
Rev. PrE | Page 4 of 8
Preliminary Technical Data
ADM1173
pulls down the TIMER pin until it reaches 0.2V at time point 4.
The initial cycle delay (time point 2 to time point 4) is related to
CTIMER by equation:
CALCULATING CURRENT LIMIT
The nominal fault current limit is determined by a sense
resistor connected between VCC and the SENSE pin as
given by the equation below:
tINITIAL ~= 272.9 x CTIMER ms/uF
(4)
When the initial cycle terminates, a start-up cycle is activated
and the GATE pin ramps high. The TIMER pin continues to be
pulled down towards ground.
ILIMIT(NOM) = VCB(NOM) / RSENSE
(1)
The minimum load current is given by Equation 2:
ILIMIT(MIN) = VCB(MIN) / RSENSE(MAX)
The maximum load current is given by Equation 3:
ILIMIT(MAX) = VCB(MAX) / RSENSE(MIN) (3)
(2)
V
IN
Note: The power rating of the sense resistor should be rated at
the fault current level.
For proper operation, the minimum current limit must exceed
V
ON
the circuit maximum operating load current with margin. The
2
sense resistor power rating must exceed VCB(MAX
)
/RSENSE(MIN).
V
TIMER
V
GATE
TIMER FUNCTION
The TIMER pin handles several key functions with an external
capacitor, CTIMER. There are two comparator thresholds:
COMP1 (0.2V) and COMP2 (1.3V). The four timing current
sources are:
V
OU T
INITIAL
CYCLE
NORMAL
CYCLE
START -UP
CYCLE
RESET
MODE
•
•
•
•
5µA pull-up
Figure 1: Normal Start-up
60µA pull-up
2µA pull-down
100µA pull-down
The 100µA is a non-ideal current source approximating a 7k
resistor below 0.4V.
INITIAL TIMING CYCLE
When the card is being inserted into the bus connector, the
long pins mate first which brings up the supply VIN at time
point 1 of Figure 1. The ADM1173 is in reset mode as the ON
pin is low. GATE is pulled low and the TIMER pin is pulled low
with a 100µA source. At time point 2, the short pin makes
contact and ON is pulled high. At this instant, a start-up check
requires that the supply voltage be above UVLO, the ON pin
beabove1.3Vand the TIMER pin voltage be less than 0.2V.
When these three conditions are fulfilled, the initial cycle
begins and the TIMER pin is pulled high with 5µA. At time
point 3, the TIMER reaches the COMP2 threshold and the first
portion of the initial cycle ends. The 100µA current source then
Rev. PrE | Page 5 of 8
Preliminary Technical Data
ADM1173
KELVIN SENSE RESISTOR CONNECTION
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 18 below shows the correct way to connect the sense
resistor between the VCC and RS- pins of the ADM1173.
V
IN
60µA
5µA
V
ON
2µA
100µA
100µA
V
TIMER
SENSE RESISTOR
V
GATE
V
TH
V
OUT
Current Flow
Current Flow to
Load
fro
m
so
urce
I
RSENSE
KELVIN SENSE TRACES
NORMAL
CYCLE
INITIAL
CYCLE
START-UP
CYCLE
RESET
MODE
Figure 2: Current Limiting at Start-up
SENSE
VCC
V
RS-
Figure 2: Current Sense Kelvin connection
Rev. PrE | Page 6 of 8
Preliminary Technical Data
PIN CONFIGURATIONS
ADM1173
TIMER
8
VCC
TIMER
8
VCC
1
1
ADM1173-1AUJ
ADM1173-2AUJ
GND
ON
GND
ON-CLR
VOUTFB
RS-
2
3
4
2
3
4
RS-
7
6
5
7
6
5
TOP VIEW
(Not to Scale)
TOP VIEW
(Not to Scale)
SLEW
GATE
SLEW
GATE
VOUTFB
PIN FUNCTIONAL DESCRIPTIONS
Pin No.
Name
Description
1
TIMER
Timer Input Pin. An external capacitor CTIMER sets a 272.9ms/µF initial timing delay and a
21.7ms/µF circuit breaker delay. The GATE pin turns off whenever the TIMER pin is pulled
beyond the upper threshold, such as for overvoltage detection with an external zener.
2
3
GND
Chip Ground Pin
UP/STOP
ON (ON-CLR)
Input Pin. The ON pin comparator has a low-to-high threshold of 1.3V with 80mV
hysteresis and a glitch filter. When the ON pin is low, the ADM1173 is reset. When the
ON pin goes high, the GATE turns on after the initial timing cycle. On the ADM1173-2, a
rising edge on this pin has the added function of clearing a fault and restarting the
device
4
5
VOUTFB
GATE
Monitors the Source of the external FET
GATE Output Pin. This pin is the high side gate drive of an external N-channel FET. An
internal charge pump provides a 12µA pull-up current with Zener clamps to RS+ and
ground. In overload, the error amplifier (EA) controls the external FET to maintain a
constant load current.
6
7
SLEW
R S-
Connect to an external capacitor to control the slew rate of the of the GATE at turn on
and turn-off.
Current Limit Sense Input Pin. A sense resistor between the Vcc and RS- pins sets the
analog current limit. In overload, the EA controls the external FET gate to maintain the
SENSE voltage at 50mV. When the EA is maintaining current limit, the TIMER circuit
breaker mode is activated. The current limit loop/circuit breaker mode can be disabled
by connecting the Vcc pin and RS- pin together.
8
VCC
Positive Supply Input Pin. The operating supply voltage range is between 2.7V to 16.5V.
An undervoltage lockout (UVLO) circuit with a glitch filter resets the ADM1173 when a
low supply voltage is detected.
Rev. PrE | Page 7 of 8
ADM1173
Preliminary Technical Data
OUTLINE DIMENSIONS
Figure 3. 8-Lead TSOT Package (UJ-8)—Dimensions shown in millimeters
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.
Table 2. Ordering Guide
Part Number
Version
Temperature Package Package Description
Package Outline
ADM1173-1AUJ
ADM1173-2AUJ
Automatic Retry Version
Latched Off Version
–40°C to +85°C
–40°C to +85°C
TSOT
TSOT
UJ-8
UJ-8
2
0
0
5
Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Printed in the U.S.A.
PR05127-0-2/05(PrE)
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