Datasheet

ManualsBrandsANALOG DEVICES ManualsPMICsPMIC - hot swap controller Multi-purpose TSOT 23 8 Surface-mount

2.7 V to 16.5 V Hot Swap Controller

with Current Sense Output

Data Sheet

ADM1171

Rev. A Document Feedback

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FEATURES

Controls supply rails from 2.7 V to 16.5 V

Allows protected board removal and insertion to a live

backplane

External sense resistor provides adjustable analog current

limit with circuit breaker

Peak fault current limited with fast response

Charge pumped gate drive for external N-FET switch

Current sense output

Soft start inrush current control

Automatic retry or latch-off during current fault

Undervoltage lockout

8-lead, TSOT package

APPLICATIONS

Hot swap board insertion: line cards, raid systems

Industrial high-side switches/circuit breakers

Electronic circuit breakers

GENERAL DESCRIPTION

The ADM1171 is a hot swap controller that safely enables a

printed circuit board to be removed and inserted to a live

backplane. This is achieved using an external N-channel power

MOSFET with a current control loop that monitors the load

current through a sense resistor. An internal charge pump is

used to enhance the gate of the N-channel FET. When an

overcurrent condition is detected, the gate voltage of the FET is

reduced to limit the current flowing through the sense resistor.

During an overcurrent condition, the TIMER cap determines

the amount of time the FET remains at a current limiting mode

of operation until it is shut down. The ON (ON-

CLR

) pin is the

enable input for the device and can be used to monitor the

input supply voltage. The ADM1171 operates with a supply

voltage ranging from 2.7 V to 16.5 V.

The ADM1171 features soft start to provide the user with a

capacitor programmable ramping reference to the internal

current sense comparator. This provides a linearly increasing

current limit at startup at a rate set by C

. This helps to reduce

and limit large inrush currents.

The ADM1171 also features a current sense output (CSOUT)

pin. The voltage on the CSOUT pin represents the voltage drop

across the sense resistor gained up by a factor of 20.

This device is available in two options: the ADM1171-1 with

automatic retry for overcurrent fault and the ADM1171-2 with

latch-off for an overcurrent fault. Toggling the ON (ON-

CLR

)

pin resets a latched fault. The ADM1171 is packaged in an

8-lead TSOT.

FUNCTIONAL BLOCK DIAGRAM

LONG

= 5V V

OUT

= 5V

SENSE

TIMER

LONG

SHORT

SENSE

GATE

TIMER

ADM1171-1

GND

GND GND

ON1

ON2

LOAD

CSOUT

05125-001

Figure 1.

Summary of content (16 pages)

PAGE 1
2.7 V to 16.5 V Hot Swap Controller with Current Sense Output ADM1171 Data Sheet FEATURES GENERAL DESCRIPTION Controls supply rails from 2.7 V to 16.
PAGE 2
ADM1171 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 ON (ON-CLR) Pin ..................................................................... 12 Applications ....................................................................................... 1 GATE ........................................................................................... 12 General Description ...................................................
PAGE 3
Data Sheet ADM1171 SPECIFICATIONS VCC = 2.7 V to 16.5 V, TA = −40°C to +85°C, typical values at TA = 25°C, unless otherwise noted. Table 1. Parameter VCC PIN Operating Voltage Range Supply Current Undervoltage Lockout Undervoltage Lockout Hysteresis ON (ON-CLR) PIN Input Current Threshold Threshold Hysteresis SENSE PIN Hot Swap Operating Range Input Current Circuit Breaker Limit Voltage GATE PIN Drive Voltage Symbol Min VCC ICC VUVLO VUVLOHYS 2.7 IINON VON VONHYST −1 1.22 IINSENSE VCB 2.4 2.
PAGE 4
ADM1171 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 2. Parameter VCC Pin SENSE Pin VCC − SENSE TIMER Pin ON (ON-CLR) Pin SS Pin CSOUT Pin GATE Pin Storage Temperature Range Operating Temperature Range Lead Temperature (10 sec) Junction Temperature Rating −0.3 V to +20 V −0.3 V to +20 V ±5 V −0.3 V to (VCC + 0.3 V) −0.3 V to +20 V –0.3 V to (VCC + 0.3 V) –0.3 V to (VCC + 0.3 V) −0.
PAGE 5
Data Sheet ADM1171 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS ADM1171-2AUJ ADM1171-1AUJ 8 TIMER 1 VCC ON 4 5 GATE 05125-006 7 SENSE TOP VIEW SS 3 (Not to Scale) 6 CSOUT 8 VCC 7 SENSE TOP VIEW SS 3 (Not to Scale) 6 CSOUT GND 2 GND 2 ON-CLR 4 Figure 2. Pin Configuration, 1AUJ Model 5 GATE 05125-007 TIMER 1 Figure 3. Pin Configuration, 2AUJ Model Table 4. Pin Function Descriptions Pin No.
PAGE 6
ADM1171 Data Sheet 2.65 0.45 2.63 0.40 2.61 0.35 0.30 0.25 0.20 0.15 2.57 2.53 2.51 0.05 2.47 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) VCC FALLING 2.55 2.49 0 VCC RISING 2.59 0.10 0 VCC = 5V 2.45 –50 –25 0 25 50 75 100 125 150 16 18 125 150 TEMPERATURE (°C) 05125-046 UVLO THRESHOLD (V) 0.50 05125-023 SUPPLY CURRENT (mA) TYPICAL PERFORMANCE CHARACTERISTICS Figure 7. UVLO Threshold vs. Temperature Figure 4. Supply Current vs. Supply Voltage (GATE off) 0.
PAGE 7
ADM1171 0 9 –1 8 –2 7 –3 6 5 4 –4 –5 –6 3 –7 2 –8 1 –9 0 0 2 8 6 4 12 10 14 16 18 SUPPLY VOLTAGE (V) VCC = 5V –10 –50 –25 0 25 75 50 100 125 150 TEMPERATURE (°C) Figure 10. Delta GATE Voltage vs. Supply Voltage 05125-038 ITIMERUP (µA) 10 05125-014 DELTA GATE VOLTAGE (V) Data Sheet Figure 13. ITIMERUP (in Initial Cycle) vs.
PAGE 8
ADM1171 Data Sheet 3.0 1.38 VCC = 5V TA = 25°C 2.8 1.36 TIMER HIGH THRESHOLD (V) 2.6 2.2 2.0 1.8 1.6 1.4 1.34 1.32 1.30 1.28 1.26 0 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) 1.22 –50 05125-034 1.0 25 50 100 75 125 150 Figure 19. TIMER High Threshold vs. Temperature 0.24 3.0 TA = 25°C VCC = 5V 2.8 0.23 TIMER LOW THRESHOLD (V) 2.6 2.4 2.2 2.0 1.8 1.6 1.4 0.22 0.21 0.20 0.19 0.18 0.17 1.2 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 0.16 05125-037 1.
PAGE 9
Data Sheet ADM1171 1.45 80 TA = 25°C 70 1.35 60 tOFF(ONLOW) (µs) HIGH THRESHOLD 1.30 LOW THRESHOLD 1.25 1.20 VCC = 15V 50 40 30 1.10 10 0 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) 0 –50 –25 0 25 50 75 100 125 150 16 18 TEMPERATURE (°C) 05125-048 VCC = 3V 20 1.05 Figure 25. tOFF(ONLOW) vs. Temperature Figure 22. ON (ON-CLR) Pin Threshold vs. Supply Voltage 50 1.45 VCC = 5V 49 1.40 48 HIGH THRESHOLD 1.35 47 1.30 VCB (mV) LOW THRESHOLD 1.25 1.20 46 45 44 43 1.
PAGE 10
Data Sheet 12 –10.4 10 –10.5 SOFT START CURRENT (µA) GATE CURRENT (mA) ADM1171 8 6 4 VCC = 3V –10.6 –10.7 –10.8 VCC = 5V VCC = 12V 2 –10.9 0 –11.0 –50 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) –25 0 25 50 75 100 125 150 TEMPERATURE (°C) Figure 28. GATE Current (down) vs. Supply Voltage 05125-018 0 05125-008 VCC = 15V Figure 31. Soft Start Current vs.
PAGE 11
Data Sheet ADM1171 2.0 0.10 VCC = 12V 1.5 0.06 1.0 GAIN ACCURACY (%) 0.04 0.02 0 –0.02 –0.04 0.5 0 –0.5 –1.0 –0.06 –0.10 –50 0 50 100 TEMPERATURE (°C) 150 Figure 34. CSOUT Total Output Error vs. Temperature –2.0 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) Figure 35. CSOUT Gain Accuracy vs. Temperature Rev. A | Page 11 of 16 150 05125-052 –1.5 –0.08 05125-051 TOTAL OUTPUT ERROR (%) 0.
PAGE 12
ADM1171 Data Sheet THEORY OF OPERATION Many systems require the insertion or removal of circuit boards to live backplanes. During this event, the supply bypass and holdup capacitors can require substantial transient currents from the backplane power supply as they charge. These currents can cause permanent damage to connector pins or undesirable glitches and resets to the system.
PAGE 13
Data Sheet ADM1171 gate voltage of the external FET. This minimizes the bus supply voltage drop caused by the fault and protects neighboring cards. When the initial cycle ends, a start-up cycle activates and the GATE pin is pulled high; the TIMER pin continues to pull down. As the voltage across the sense resistor approaches the current limit, a timer activates. This timer resets again if the sense voltage returns below this level.
PAGE 14
ADM1171 Data Sheet threshold. The device can be reset by toggling the ON-CLR pin or by manually pulling the TIMER pin low. On theADM1171-1, the TIMER pin activates the 2 μA pull-down once the 1.3 V threshold is reached, and continues to pull down until it reaches the 0.2 V threshold. At this point, the 100 μA pull-down is activated and the GATE pin is enabled. The device keeps retrying in the manner as shown in Figure 38.
PAGE 15
Data Sheet ADM1171 OUTLINE DIMENSIONS 2.90 BSC 8 7 6 5 1 2 3 4 1.60 BSC 2.80 BSC PIN 1 INDICATOR 0.65 BSC 1.95 BSC *0.90 0.87 0.84 *1.00 MAX 0.10 MAX 0.38 0.22 0.20 0.08 SEATING PLANE 8° 4° 0° 0.60 0.45 0.30 *COMPLIANT TO JEDEC STANDARDS MO-193-BA WITH THE EXCEPTION OF PACKAGE HEIGHT AND THICKNESS. Figure 40.