MIC2582R-LBQS - Micrel, Inc.

March 2001 1 MIC2582/83

MIC2582/83 Micrel

MIC2582/83

Single Channel Hot Swap Controller

Preliminary Information

General Description

The MIC2582 and MIC2582/83 are single channel positive

voltage hot-swap controllers designed to provide for the safe

insertion of boards into live system backplanes. Using few

external components, the parts act in conjunction with an

external N-Channel MOSFET device, for which the gate drive

is controlled to provide inrush current-limiting and output

voltage slew rate control. The MIC2582/3 are rated for

operation from supply voltages from 2.3V to 13.2V, but can

withstand transient voltages as high as 20V without damage.

Overcurrent fault protection is provided along with a program-

mable over-current threshold. Active current regulation dur-

ing start-up ensures that inrush current never exceeds the

programmed threshold. The MIC2582/3 provide a circuit

breaker function that latches the output MOSFET off if the

current limit threshold is exceeded for a programmed period

of time. Dual-level fault detection allows very fast response

to short-circuit faults while preventing lower level overcurrent

transients from causing “nuisance tripping” of the circuit

breaker. A FAULT# signal is provided indicating overcurrent

or undervoltage fault conditions.

Typical Application

VCC SENSE

SENSE

GATE

0.1µF

/PWRGD

/POR

DIS

VIN

2.3V - 13.2V

CFILTER

FILTER

CPOR

MIC2583

POR

GND

/FAULT

10‰

VOUT

0.1µFCL

100µF

MIC2582/83 Typical Circuit

Features

•Provides safe insertion and removal from live

backplanes

•2.3V to 13V supply voltage operation

•Surge voltage protection up to 20V

•Undervoltage Lockout protection

•Programmable inrush current-limiting

•Current regulation limits inrush current regardless of

load capacitance

•Dual-level overcurrent fault sensing eliminates false

tripping

•Fast response to short circuit conditions (< 1 µs)

•Power-On Reset and Power-Good status outputs

(MIC2582/83)

•Programmable output undervoltage detection

•Electronic circuit breaker

•FAULT# status output

•Auto-restart function (MIC2582/83R)

Applications

•RAID systems

•PC Board Hot-Swap insertion and removal

•Hot-Swap CompactPCI Cards

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

MIC2582/83 Micrel

MIC2582/83 2 March 2001

Ordering Information

Part Number Circuit Breaker Threshold Circuit Breaker Package

MIC2582-xBM x = J, 50mV Latched off 8 pin SOIC

x = K, 100mV

x = L, 150mV

x = M, 200mV

x = N, Off

MIC2582/83-xBQS x = J, 50mV Latched off 16 pin QSOP

x = K, 100mV

x = L, 150mV

x = M, 200mV

x = N, Off

MIC2582/83R-xBQS x = J, 50mV Auto-retry 16 pin QSOP

x = K, 100mV

x = L, 150mV

x = M, 200mV

x = N, Off

Pin Configuration

1/POR

CPOR

GND

8 VCC

SENSE

GATE

8-Pin SOIC

1/POR

/PWRGD

CPOR

CFILTER

GND

16 VCC

SENSE

GATE

DIS

/FAULT

16-Pin QSOP

March 2001 3 MIC2582/83

MIC2582/83 Micrel

Pin Description

Pin Name SOIC QSOP Pin Function

FAULT# NA 11 Circuit Breaker Fault Output. Open-Drain, Active-Low. Asserted when the

circuit breaker is tripped.

ON 2 3 ON input. With this pin high, the device is enabled, a start-up sequence is

initiated, and the GATE pin starts ramping up towards its final operating

voltage. The ON input is compared to a VTH reference with 25mV of

hysteresis.

Toggling ON is also used to reset the circuit breaker. ON must be low for

20µs in order to initiate a start-up sequence. This pin should not be taken

higher than VCC + 0.3V, or 8V, whichever is less.

POR# 1 1 Power-On Reset Output. Open-Drain, Active-Low. Asserted during start-up

until a time period tPOR after the power-good threshold is reached. tPOR is

determined by capacitor CPOR. Also asserted during undervoltage lockout

fault conditions.

CPOR 3 4 Power-on Reset Timer. A capacitor connected between this pin and ground

sets the Power-On Reset interval, tPOR, and start-up delay tDELAY. When

VCC rises above the UVLO, the capacitor connected to CPOR begins to

charge. When the voltage at CPOR crosses 0.3V, a start cycle is initiated if

ON is asserted. CPOR is reset to zero volts.

When the voltage at FB rises above VFBTH, CPOR begins to charge again.

When the voltage at CPOR rises above VPORDLY, the timer resets, pulls

CPOR to ground, and POR# is de-asserted. If CPOR = 0, then tDELAY is set to

20µs.

SENSE 7 15 Circuit Breaker Sense Input. A resistor between this pin and VCC sets the

current-limit threshold. When the current-limit threshold of 50mV is ex-

ceeded for tOCSLOW (internally set at 5µs for the MIC2582), the circuit

breaker is tripped and the GATE pin is immediately pulled low. If the voltage

across the sense resistor exceeds VTHSLOW due to fast high amplitude faults

such as short-circuits, then the GATE pin is immediately brought low (no

delay).

VTHSLOW is available for value of 50mV, 100mV, 200mV, or Off. Whenever

the voltage across the sense resistor exceeds the current-limit threshold, the

GATE voltage is adjusted to ensure a constant load current. To disable the

circuit breaker, the SENSE and VCC pins can be tied together.

GATE 6 14 Gate Drive Output. Connects to the gate of an N-Channel MOSFET. An

internal clamp ensures that no more than 8V is applied between the GATE

and Source. When the circuit breaker trips or when undervoltage lockout

occurs the GATE pin is immediately brought low.

FB 5 12 Power-Good Threshold Input. This input is internally compared to a 1.24V

reference with 30mV of hysteresis. Whenever this input goes below 1.24V,

POR# is asserted. A 5µs filter on this pin prevents negative-going glitches

from causing nuisance activation of this pin. If this input momentarily goes

below 1.24V, then POR# is activated for one timing cycle, tPOR.

VCC 8 16 Positive Supply Input. 2.3V - 13.2V. The GATE pin is held low by an internal

undervoltage lockout circuit until VCC exceeds a threshold of 2.1V. If VCC

exceeds 13.2V, an internal shunt regulator protects the chip from transient

voltages up to 20V at the VCC and SENSE pins.

CFILTER NA 5 Current-limit Response Timer. A capacitor connected to this pin defines the

period of time tOCSLOW in which an overcurrent event must last to signal a

fault condition and trip the circuit breaker. If no capacitor is connected to this

pin, then tOCSLOW is set to 5µs.

During auto-retry, the MIC2582/83R exhibits a preset duty cycle of 10%.

The value of CFILTER will set the interval between auto-retry attempts.

See Applications section.

MIC2582/83 Micrel

MIC2582/83 4 March 2001

Pin Name SOIC QSOP Pin Function

PWRGD NA 2 Power-good Output. Open Drain. When the voltage at the FB pin is lower

than 1.24V, PWRGD output is held low. When the voltage at the FB pin is

higher than 1.24V, then PWRGD is de-asserted. A pull-up resistor con-

nected to this pin and to VCC will pull the output up to VCC.

DIS NA 13 Discharge output. When the MIC2582/83 is turned off, a 500Ω resistor

connected to this output allows the discharging of external load capacitance

to ground.

GND 4 7,8 Ground connection

NC NA 6,9,10 No Connection

March 2001 5 MIC2582/83

MIC2582/83 Micrel

Absolute Maximum Ratings

All voltages are referred to GND (Note 1)

Supply Voltage (VCC) ..................................... –0.3V to 20V

POR#, FAULT# , PWRGD pins...................... –0.3V to 15V

SENSE pin ............................................–0.3V to VCC+0.3V

ON pin .........-0.3V to Vcc+0.3V OR 8V, whichever is lower

GATE pin........................................................ –0.3V to 20V

FB input pins .................................................... –0.3V to 6V

Junction Temperature ............................................... 125°C

ESD Rating, Note 3

Operating Ratings (Note 2)

Supply Voltage (VCC) .................................... 2.3V to 13.2V

Thermal Resistance Rθ(J-A) (8-pin SOIC)..............163°C/W

Thermal Resistance Rθ(J-A) (16-pin SOIC)....... 112.4°C/W

Operating Temperature Range ..................–40°C to +85°C

Electrical Characteristics

VCC = 5.0V, TA = 25°C unless otherwise noted. Bold values indicate –40°C ≤ TA ≤ +85°C.

Symbol Parameter Condition Min Typ Max Units

VCC Supply voltage Temp = –20°C to +85°C 2.3 13.2 V

Temp = –40°C to +85°C2.7 13.2 V

ICC Supply current VON = 2V 1.6 2.5 mA

VTRIP Circuit breaker trip voltage VTRIP = VCC – VSENSE VTRIPSLOW 37 43 50 mV

VTRIPFAST 85 91 105 mV

VGS External Gate Drive |VCC – VGATE|V

CC > 3V 5.5 6.3 8 V

VCC = 2.3V 2.7 3.8 5 V

IGATEON GATE pin pull-up current Start cycle, VGATE = 0V

VCC =13.2V 10 16 24 µA

VCC = 2.3V 9 14 19 µA

IGATEOFF GATE pin sink current FAULT# = 0, VGATE>1V VCC = 13.2V 100 mA

VCC = 2.3V 50 mA

Turn off 110 µA

ITIMER Current-limit timer current VCC – VSENSE > VTRIPSLOW 4.5 6.5 8.5 µA

VCC – VSENSE < VTRIPSLOW –8.5 –6.5 –4.5 µA

IPOR Power-On Reset timer current Timer On 12 14 16 µA

Timer Off 0.5 1.45 mA

VTH POR Delay and CFILTER timer VPOR rising

threshold VCFILTER rising 1.19 1.24 1.29 V

VUV Undervoltage Lockout threshold VCC rising 2.1 2.2 2.3 V

VCC falling 1.9 2.05 2.2 V

VUVHYS UV Lockout hysteresis 175 mV

VONTH ON pin threshold voltage ON rising 1.19 1.23 1.29 V

ON falling 1.16 1.21 1.26 V

ION ON pin input current VON = VCC –0.5 µA

VONHYS ON pin hysteresis 25 mV

VDELAYTH Under-voltage start-up timer VPOR rising .28 .33 .38 V

threshold

VAUTO Auto-restart threshold voltage upper threshold 1.24 V

lower threshold 0.33 V

MIC2582/83 Micrel

MIC2582/83 6 March 2001

Symbol Parameter Condition Min Typ Max Unit

IAUTO Auto-restart current charge current 12 µA

discharge current 1.2 µA

VFBTH Power-Good threshold voltage FB rising 1.19 1.24 1.29 V

FB falling 1.16 1.21 1.26 V

VFBHYS FB hysteresis 30 mV

VOL FAULT# , POR# , PWRGD output IOUT = 1mA 0.4 V

voltage

RDIS Output discharge resistance 500 1000 Ω

AC Parameters

tOCFAST Fast overcurrent SENSE to GATE VCC = 5V 1 µs

low trip time VCC - VSENSE = 100mV

CGATE = 10nF

Figure 1

tOCSLOW Slow overcurrent SENSE to GATE VCC = 5V 5 µs

low trip time CTIM = 0, VIN - VSENSE = 50mV

Figure 1

tONDLY ON delay filter 20 µs

tFBDLY FB delay filter 20 µs

Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. Devices are ESD sensitive. Handling precautions recommended.

Timing Diagrams

GATE

(VCC – VSENSE)

VTRIPFAST

50mV

tOCSLOW tOCFAST

Figure 1. Current -Limit Rsponse

/POR

/PWRGD

1.5V

1.2V

POR

Figure 2. Power-on Reset Response

GATE

UVLO

DELAY

Figure 3. Power-on Start-up Delay Timing

March 2001 7 MIC2582/83

MIC2582/83 Micrel

Functional Description

Functional Overview

When ON is asserted high, the device is enabled and a start-

up sequence is initiated. The GATE begins to ramp up at a

rate determined by CGATE. When the FB pin exceeds the

internal 1.24V threshold reference, PWRGD# is de-asserted,

signaling an available output. Internal current regulation

ensures that the inrush current will not exceed the pro-

grammed threshold. A circuit breaker function will latch the

output MOSFET off if the current limit threshold is exceeded

for a period, tOCSLOW, determined by CFILTER (tOCSLOW = 5µs

with no CFILTER).

ON Pin (Maximum Voltage)

The ON pin for the MIC2582/3 has an absolute maximum

voltage rating of (VCC + 0.3V) or 8V, whichever is less. At

operating voltages of 2.3 - 7.5V, the ON pin may be con-

nected directly to the VCC pin through a pull-up resistor

(100kΩ suggested). But when operating at voltages between

7.5 and 13.2V, it is necessary to include a voltage divider from

the ON pin to ground. A 100kΩ resistor is also recommended

for the divider.

GATE Pin Rise Time

The internal output MOSFET is at the GATE pin. The GATE

pin rise time must be limited when operating the MIC2582/3

with a large output capacitance. Using the basic formula dv/

dt = I/C, the rise time may be computed for a given MOSFET

and CGATE. Here, I is the average GATE pin pull-up current,

and C is the total capacitance (CGATE + CGS). For applica-

tions using COUT = 500µF, a 100nF CGATE is recommended

to allow the output capacitor time to charge.

Supply Bypass (Protect VCC pin)

When operating above an input of 10V, a capacitor of 47µF

minimum value is needed to suppress voltage transients from

causing damage to the VCC pin. When operating below 10V,

a minimum value of 4.7µF may be used.

Voltage Divider at FB Pin

There are two important points to note here. First, consider-

ation should be taken to determine the desired output value

for MIC2582/3 turn on. For example, if the application is

operating at 12V, the desired turn on may be 11.5V. The two

FB resistors are selected to divide 11.5V accordingly, with

1.24V set at the FB pin. Second, the ratio of these two

resistors should be chosen to maintain relatively low power

consumption. A current level of approximately 100µA is

recommended.

MIC2582/83 Micrel

MIC2582/83 8 March 2001

Package Information

MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com

This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or

other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.

45°

0°–8°

0.244 (6.20)

0.228 (5.79)

0.197 (5.0)

0.189 (4.8) SEATING

PLANE

0.026 (0.65)

MAX)

0.010 (0.25)

0.007 (0.18)

0.064 (1.63)

0.045 (1.14)

0.0098 (0.249)

0.0040 (0.102)

0.020 (0.51)

0.013 (0.33)

0.157 (3.99)

0.150 (3.81)

0.050 (1.27)

TYP

PIN 1

DIMENSIONS:

INCHES (MM)

0.050 (1.27)

0.016 (0.40)

45°

0.2284 (5.801)

0.2240 (5.690)

SEATING

PLANE

0.009 (0.2286)

REF 0.012 (0.30)

0.008 (0.20)

0.157 (3.99)

0.150 (3.81)

0.050 (1.27)

0.016 (0.40)

0.0688 (1.748)

0.0532 (1.351)

0.196 (4.98)

0.189 (4.80)

0.025 (0.635)

BSC

PIN 1

DIMENSIONS:

INCHES (MM)

0.0098 (0.249)

0.0040 (0.102) 0.0098 (0.249)

0.0075 (0.190) 8°

0°

8-Pin SOP (M)

16-pin QSOP (QS)