ADM1085 Analog Devices, ADM1085 Datasheet

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ADM1085

Manufacturer Part Number
ADM1085
Description
Voltage Sequencer with Active High, Open-Drain Enable Output
Manufacturer
Analog Devices
Datasheet

Specifications of ADM1085

# Supplies Monitored
1
Volt Monitoring Accuracy
7%
# Output Drivers
1
Fet Drive/enable Output
Enable
Sequencing
Up
Package
6 ld SC70

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FEATURES
Provide programmable time delays between enable
Can be cascaded with power modules for multiple
Power supply monitoring from 0.6 V
Output stages
Capacitor-adjustable time delays
High voltage (up to 22 V) enable and V
Low power consumption (15 μA)
Specified over –40°C to +125°C temperature range
6-lead SC70 package
APPLICATIONS
Desktop/notebook computers, servers
Low power portable equipment
Routers
Base stations
Line cards
Graphics cards
GENERAL DESCRIPTION
The ADM1085/ADM1086/ADM1087/ADM1088 are simple
sequencing circuits that provide a time delay between the
enabling of voltage regulators and/or dc-dc converters at power-
up in multiple supply systems. When the output voltage of the
first power module reaches a preset threshold, a time delay is
initiated before an enable signal allows subsequent regulators to
power up. Any number of these devices can be cascaded with
regulators to allow sequencing of multiple power supplies.
Threshold levels can be set with a pair of external resistors in a
voltage divider configuration. With appropriate resistor values,
the threshold can be adjusted to monitor voltages as low as 0.6 V.
The ADM1086 and ADM1088 have push-pull output stages,
with active high (ENOUT) and active low ( ENOUT ) logic
outputs, respectively. The ADM1085 has an active-high
(ENOUT) logic output; the ADM1087 has an active-low
( ENOUT ) output. Both the ADM1085 and ADM1087 have
open-drain output stages that can be pulled up to voltage levels
as high as 22 V through an external resistor. This level-shifting
property ensures compatibility with enable input logic levels of
different regulators and converters.
Rev. A
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 owners.
signals
supply sequencing
(ADM1085/ADM1087)
Push-pull output (ADM1086/ADM1088)
High voltage (up to 22 V) open-drain output
IN
inputs
ADM1085/ADM1086/ADM1087/ADM1088
Simple Sequencers
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
All four models have a dedicated enable input pin that allows
the output signal to the regulator to be controlled externally.
This is an active high input (ENIN) for the ADM1085 and
ADM1086, and an active low input ( ENIN ) for the ADM1087
and ADM1088.
The Simple Sequencers are specified over the extended
−40°C to +125°C temperature range. With low current
consumption of 15 μA (typical) and 6-lead SC70 packaging,
the parts are suitable for low-power portable applications.
Table 1. Selection Table
Part No.
ADM1085
ADM1086
ADM1087
ADM1088
V
V
IN
IN
ADM1085/ADM1086
ADM1087/ADM1088
0.6V
0.6V
FUNCTIONAL BLOCK DIAGRAMS
Enable Input
ENIN
ENIN
ENIN
ENIN
GND
GND
©2006 Analog Devices, Inc. All rights reserved.
ADJUSTABLE
ADJUSTABLE
CAPACITOR
CAPACITOR
DELAY
DELAY
Figure 1.
®
CEXT
CEXT
V
V
CC
CC
in 6-Lead SC70
ENOUT
Open-drain
Push-pull
ENIN
ENIN
Output Stage
www.analog.com
ENOUT
Open-drain
Push-pull
ENOUT
ENOUT

Related parts for ADM1085

ADM1085 Summary of contents

Page 1

... IN All four models have a dedicated enable input pin that allows the output signal to the regulator to be controlled externally. This is an active high input (ENIN) for the ADM1085 and ADM1086, and an active low input ( ENIN ) for the ADM1087 and ADM1088. The Simple Sequencers are specified over the extended − ...

Page 2

... ADM1085/ADM1086/ADM1087/ADM1088 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Functional Block Diagrams............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 4 ESD Caution.................................................................................. 4 Pin Configuration and Function Descriptions............................. 5 Typical Performance Characteristics ............................................. 6 Circuit Information .......................................................................... 9 Timing Characteristics and Truth Tables.................................. 9 REVISION HISTORY 4/06—Rev Rev. A Added Lead-Free Models ..................................................Universal Update Outline Dimensions ...

Page 3

... Leakage Current IN CEXT Charge Current Threshold Temperature Coefficient ENIN/ENIN to ENOUT/ENOUT Propagation Delay ENIN/ENIN Voltage Low ENIN/ENIN Voltage High ENIN/ENIN Leakage Current ENOUT/ENOUT Voltage Low ENOUT/ENOUT Voltage High (ADM1086/ADM1088) ENOUT/ENOUT Open-Drain Output Leakage Current (ADM1085/ADM1087) ADM1085/ADM1086/ADM1087/ADM1088 Min Typ Max Unit 2.25 3 μ ...

Page 4

... T = 25°C, unless otherwise noted. A Table 3. Parameter CEXT ENIN, ENIN ENOUT, ENOUT (ADM1085, ADM1087) ENOUT, ENOUT (ADM1086, ADM1088) Operating Temperature Range Storage Temperature Range θ Thermal Impedance, SC70 JA Lead Temperature Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) ESD CAUTION ESD (electrostatic discharge) sensitive device ...

Page 5

... PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 ENIN, ENIN Enable Input. Controls the status of the enable output. Active high for ADM1085/ADM1086. Active low for ADM1087/ADM1088. 2 GND Ground Input for the Monitored Voltage Signal. Can be biased via a voltage divider resistor network to customize the IN effective input threshold ...

Page 6

... ADM1085/ADM1086/ADM1087/ADM1088 TYPICAL PERFORMANCE CHARACTERISTICS 700 680 660 640 V RISING TRIP 620 600 580 560 V FALLING TRIP 540 520 500 –40 –25 – TEMPERATURE (°C) Figure 3. V Threshold vs. Temperature IN 12.0 11.5 11.0 10.5 10 –40°C A 9.5 9.0 8.5 8.0 2.1 2.4 2.7 3.0 V (V) CC Figure 4. Supply Current vs. Supply Voltage 20 18 ...

Page 7

... Falling Propagation Delay vs. Temperature CC 500 450 400 350 300 250 200 150 100 50 0 2.1 2.4 2.7 3.0 SUPPLY VOLTAGE (V) Figure 11. Output Fall Time vs. Supply Voltage ADM1085/ADM1086/ADM1087/ADM1088 200 180 160 140 120 100 3.3 3.6 0 Figure 12. ENIN/ ENIN Leakage Current vs. ENIN/ ENIN Voltage 200 180 160 ...

Page 8

... ADM1085/ADM1086/ADM1087/ADM1088 300 280 260 240 220 200 180 160 140 120 100 –40 –25 – TEMPERATURE (°C) Figure 15. CEXT Charge Current vs. Temperature 100 –40 –25 – TEMPERATURE (°C) to ENOUT/ ENOUT Propagation Delay (CEXT Floating) vs. ...

Page 9

... CIRCUIT INFORMATION TIMING CHARACTERISTICS AND TRUTH TABLES The enable outputs of the ADM1085/ADM1086/ADM1087/ ADM1088 are related to the V and enable inputs by a simple IN AND function. The enable output is asserted only if the enable input is asserted and the voltage above V IN the time delay elapsed. Table 5 and Table 6 show the enable ...

Page 10

... ADM1085/ADM1086/ADM1087/ADM1088 OPEN-DRAIN AND PUSH-PULL OUTPUTS The ADM1085 and ADM1087 have open-drain output stages that require an external pull-up resistor to provide a logic high voltage level. The geometry of the NMOS transistor enables the output to be pulled up to voltage levels as high (≤22V) CC ADM1085/ADM1087 Figure 21 ...

Page 11

... Separate capacitors on the CEXT pins determine the time delays between enabling of the 3.3 V, 2.5 V, 1.8 V, and 1.2 V supplies. Because the dc-to-dc converters and ADM1085s are connected in a cascade, and the output of any converter is dependent on that of the previous one, an external controller can disable all four supplies simultaneously by disabling the first dc-to-dc converter in the chain ...

Page 12

... ADM1085/ADM1086/ADM1087/ADM1088 12V IN EN OUT DC/DC 3.3V 3. ENOUT IN ADM1086 ENIN CEXT ENABLE CONTROL 12V 3.3V 2.5V 1.8V 1.2V 12V IN SD OUT ADP3334 3.3V 3. ENOUT IN ADM1087 ENIN CEXT Figure 25. Typical ADM1087 Application Circuit Using ADP3334 Voltage Regulators IN EN OUT EN DC/DC 2.5V 3. ENOUT IN ADM1086 ENIN CEXT EN1 EN2 EN3 Figure 24 ...

Page 13

... POWER 9V 5V ADP3333 DISPLAY POWER Rev Page 3. OUT SD ADP3333 3.3V 3. ENOUT IN ADM1085 ENIN CEXT SD ENABLE Figure 28. Enabling a Pair of Regulators from a Single ADM1085 5V POWER_GOOD EN MICROCOMPUTER 3.3V V ENOUT EN IN ADM1086 ENIN CEXT Figure 29. Power Good Delay IN OUT ADP3333 2.5V 12V IN OUT ADP3333 1.8V 5V NORTH ...

Page 14

... V and can detect if a supply is present. Therefore, a simple sequencer can monitor two supplies and assert what can be interpreted as a power good signal when both supplies are present. The outputs of two ADM1085s can be wire-AND’ together to make a quad- supply power good indicator. 3.3V 3.3V ...

Page 15

... ADM1086AKS-REEL7 −40°C to +125°C 1 ADM1086AKSZ-REEL7 −40°C to +125°C ADM1087AKS-REEL7 −40°C to +125°C ADM1087AKSZ-REEL7 1 −40°C to +125°C ADM1088AKS-REEL7 −40°C to +125°C 1 ADM1088AKSZ-REEL7 −40°C to +125°C EVAL-ADM1087EB Pb-free part. ADM1085/ADM1086/ADM1087/ADM1088 2.20 2.00 1.80 2.40 1. 1.25 2.10 1.80 1. PIN 1 0.65 BSC 1.30 BSC 1 ...

Page 16

... ADM1085/ADM1086/ADM1087/ADM1088 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04591-0-4/06(A) T Rev Page ...

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