Datasheet ADM1201 Datasheet (Analog Devices)

© 2005

Preliminary Technical Data

FEATURES

Enables Power Supply Tracking of multiple supplies
Up/Down Tracking limits Supply Differences to ~100mV
Capacitor Adjustable Slew Rate
On Board Charge Pump Fully enhances FET
Emergency Shutdown Feature
In-Built Power Fail Detector Circuitry
Packaged in tiny 8-Lead TSOT Package

APPLICATIONS

Multi-Voltage Supply Rail Tracker
Telecoms and Datacoms Systems
Multi voltage Network Processors
Multivoltage FPGAs, ASICs, DSPs
PC/Server Applications

GENERAL DESCRIPTION

The ADM1201 is a cascadable Simple Tracker
ensures that voltage rails track up and ramp within ~100mV of
each other in multi supply systems. Any number of these
devices can be cascaded to form a multi supply tracking
solution. The ADM1201 requires 2.7V to 16.5V on its Vcc pin
to operate. An on-board charge pump generates a high voltage
GATE drive to fully enhance FETs in the power path.

The Slew Rate of the ramp up and ramp down is adjustable via
an external capacitor on the C

pin and can be programmed

SLEW

from 100V/s to 1000V/s. When multiple devices are cascaded
the C

pin of each subsequent device should be tied to the

SLEW

output rail of the previous device to ensure that supply will
track up and down with the previous supply.

TM

device which

Simple Tracker

with Emergency Shutdown

Functional Block Diagram

V

IN

C

SLEW

Applications Diagram

5VIN

POWER ON/OFF

EMERGENCY

SHUTDOWN

3.3VIN

UP/DOWN

STOP

C

SLEW

2.7V - 16V

UP / DOWN
DETECTOR

V

CC

SLEWRATE

CONTROL

POWER FAIL

DETECTOR

GND

CHARGE

PUMP

LOGIC

ADM1201

ADM1201

V

cc

UP/DOWN
STOP
C

SLEW

DRIVER

GND

TM

ADM1201

Q

1

V

FET

GATE

FET

V

OUTFB

PFI

Q

1

GATE

20nF

V

OUT

PFI

Q2

V

R

1

R

2

5VOUT

R

1

R

2

3.3VOUT

OUT

The ADM1201 features an Up/Downb pin for external control
of the Up and Down tracking. A low-to-high transition on the
this input will initiate tracking power up sequence., while a
high-to-low will initiate a tracking down of the supply rails. A
STOPb pin is also available- a high-to-low on this pin will
initiate an emergency fast shutdown of the supply..

Power Fail Detector circuitry is also present. A resistor divider
on the PFI input will dictate what level the ADM1201 registers a
power fail on that supply. When a power fail is detected the
internal Power Fail Comparator will pull the STOPb pin down
which will shut down the output immediately. STOPb pins of
multiple ADM1201 devices may be tied together so that a fault
on any supply rail will cause all devices to go into emergency
shutdown.

The ADM1201 is available in a tiny 8-pin TSOT package.

Rev. PrG

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.

ADM1201

V

2.8VIN

cc

UP/DOWN
STOP

C

SLEW

GND

GATE

V

OUT

PFI

20nF

Q3

ADM1201

V

cc

UP/DOWN
STOP

C

SLEW

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]

www.analog.com

GND

GATE

V

OUT

PFI

20nF

Fax: [phone]© 2003 Analog Devices, Inc. All rights reserved.

R

3

R

4

2.8VOUT

R

5

R

6

Preliminary Technical Data

ADM1201—SPECIFICATIONS

Table 1. V

Parameter Min Typ Max Units Conditions

VCC Pin

Operating Voltage Range Vcc 2.7 16.5 V
Undervoltage Lockout, V
UVLO Hysteresis 25 mV
Switched Voltage Range 0.65 16.5
Quiesent Current 0.65 1.0

Up/Downb Pin
Input Threshold 0.58 0.6 0.62
Input Threshold Hysteresis 60 mV
Input Current
Stopb Pin
Input Threshold 0.58 0.6 0.62
Input Threshold Hysteresis 60 mV
Internal Pull Up -5
Output Low Voltage 0.4 V Note 1, Iload = 300uA
Power Fail Detector, PFI Pin
PFI Detector Threshold
PFI Detector Hysterisis
PFI Input Current

C

Pin

SLEW

Slew up Current
Slew down Current
Tracking Gain 1 V/V V
Minimum Tracking Voltage 0.1 V
Maximum Tracking voltage Vcc – 0.3 V
Slew Rate

V

Pin

OUTFB

Input Current
Voltage Range 0 Vcc V

GATE Pin

Gate Pullup Current 12
Gate Pulldown Current 12
Gate Pulldown Current 2
GATE Voltage, V
6 8 12 V V
5 6.5 10 V V

NOTES:

1

Activated when voltage on PFI pin exceeds threshold

= Full Operating Range, TA = -40°C to +85°C, unless otherwise noted.

CC

2.4 2.525 2.65 V Vcc Rising

UVLO

5 6.5 10 V V

GATE

-100 100 nA

0.58 0.6 0.62 V
20 mV

-100 100 nA

-10
10

100 1000 V/s

-10 10

V

mA

V

V

µA

µA
µA

µA

µA
µA

mA

Rising

Rising

SLEW/VOUTFB

Vslew – Vout > 100mV
Vout – Vslew > 100mV
ADM1202-2 only –vgate = 3.0V

– VCC; VCC = 2.7V

GATE

– VCC; VCC = 5.0V

GATE

– VCC; VCC = 16.5V

GATE

Rev. PrG | Page 2 of 6

Preliminary Technical Data ADM1201

ENABLING A SINGLE SUPPLY

The ADM1201 requires a supply voltage of 2.7V to 16.5V on its
Vcc pin for operation. The device may be powered from the
input supply rail that is being switched or from an auxiliary
supply.

An internal charge pump ensures that the ADM1201 is capable
of fully enhancing an external FET via the GATE pin. An
external capacitor may be required on the GATE node for
stability.

Power up can be externally initiated by driving the
UP/DOWNb logic pin high. A low on this pin will initiate a
power down. The V

pin monitors the output voltage.

OUTFB

A single ADM1201 device may be used where a single supply
rail is required to switch on at a controlled slew rate (see Figure

1). The value of the slew rate capacitor, C

, will dictate the

SLEW

slew rate of the GATE voltage at startup. An internal current
source charges C

and the GATE voltage is ramped at the

SLEW

same rate.

Q

3.3VIN

1

3.3VOUT

ADM1201

V

POWER ON/OFF

EMERGENCY

SHUTDOWN

cc

UP/DOWN
STOP
C

SLEW

GND

GATE

V

OUTFB

PFI

20nF

R

1

R

2

Figure 1. ADM1201 Switching on a Single Supply

MULTI-SUPPLY TRACKING

The primary function of the ADM1201 is to provide a voltage
tracking solution for multiple supply rails. The implementation
in Figure 2 will provide this function. Each voltage rail has its
own ADM1201 device driving a FET.

Q

5VIN

1

5VOUT

ADM1201

V

POWER ON/OFF

EMERGENCY

SHUTDOWN

3.3VIN

cc

UP/DOWN
STOP
C

SLEW

GND

V

OUTFB

GATE

PFI

20nF

R

1

R

2

Q2

3.3VOUT

ADM1201

V

2.8VIN

cc

UP/DOWN

STOP

C

SLEW

GND

V

OUTFB

GATE

PFI

20nF

R

3

R

4

Q3

2.8VOUT

ADM1201

V

cc

UP/DOWN
STOP

C

SLEW

GND

GATE

V

OUTFB

20nF

PFI

R

5

R

6

Figure 2. ADM1201 Solution for Tracking 3 Supplies

A low-to-high transition on the UP/DOWNb pin will initiate
turn-on of the supplies. The ADM1201 will begin to source
current into the C

capacitor. The voltages on all GATE pins

SLEW

will begin to rise, or “track” up, at the same rate, as set by the
value of C
the C

SLEW

. All supply voltages will remain within 100mV of

SLEW

voltage until they level off at their full potentials.

A high-to-low on the UP/DOWNb pin of the ADM1201 will
initiate a tracking down of the supply rails, while a high-to-low
on the STOPb pin of the ADM1201 will initiate an emergency
fast shutdown of all supply rails simultaneously.

The UP/DOWNb pins of all devices can be driven by a single
logic input which will initiate a system power-up going high or
power-down going low.

The C

pins of all subsequent devices should be tied to the

SLEW

supply that the controlled needs to be tracked with. If multiple
parts are configured as in Figure 2 then the C

capacitor on

SLEW

the first ADM1201 will set the slew rates for all devices.

Rev. PrG | Page 3 of 6

Figure 3 show power-up and power-down waveforms for the
ADM1201.

ADM1201 Preliminary Technical Data

A

UP/DOWN

STOP

OUTPUT

VOLTAGES

3.3V

2.5V

1.5V

3.3V

2.5V

1.5V

Figure 3. ADM1201 Power-Up and Power-Down Waveforms

(Condition 1) and a voltage is detected on the output
(Condition 2) when Power Fail Circuitry is enabled. The output
of the PFI block is internally connected to the STOPb pin. So if
a power fail condition on the output is detected after startup,
the STOPb will be pulled low internally, initiating an emergency
shutdown of the supply rail. When multiple ADM1201 devices
are cascades all STOPb pins may be wired together so that a
power fail on any output after start-up will initiate a system­wide emergency shutdown of all supply rails.

POWER FAIL DETECTOR

Figure 4 below shows the internal circuitry that enables the
Power Fail Detector. When the ADM1201 powers up initially
the Power Fail Detector is disabled. Two conditions must be
met before the Power Fail Detector is enabled:

1. The voltage on the slew rate capacitor, C

at or above V

. This ensures that the PFI Detector is

CC

, must be

SLEW

only enabled once the supply rail has been turned on.

2. The voltage on the PFI pin must be greater than 0.4V.

This ensures that some voltage greater than zero is
present on the output (and that a fault is not pulling
the output down).

When the GATE is ramped up and the output is turned on

DM1201 Truth Table

UP/DOWNb STOPb GATE

(Input) ( I/O) (Output)

00OFF
01OFF
10*OFF
11ON

* A high-to-low on STOPb will initiate an emergency
(fast) gate shutdown of all ADM1201 devices with STO Pb
pins connected.

Figure 5. ADM1201 Power-Up and Power-Down Truth Table

Absolute Maximum Ratings

Table 2. ADM1201 Absolute Maximum Ratings

Parameter
VIN Pin 20V
PFI Pin 20V
Logic Pins Up/Downb, Stopb 20V
C

Pin 20V

SLEW

Gate Pin Vcc +11V
V

Pin 20V

OUT

Power Dissipation TBD
Storage Temperature –65°C to +125°C
Operating Temperature Range –40°C to +85°C
Lead Temperature Range

(Soldering 10 sec)
Junction Temperature 150°C

Rating

300°C

Rev. PrG | Page 4 of 6

Preliminary Technical Data ADM1201

PIN CONFIGURATION

V

UP / DO WN

1

ADM1201AUJ

8

CC

GND

STOP

V

OUTFB

2

TOP VIEW

(Not to Scale)

3

4

7

6

5

PFI

GATE

C

SLEW

PIN FUNCTIONAL DESCRIPTIONS

Pin No. Name Description

1 UP/DOWNb Logic Pin. Drive high to initiate Power Up; Drive low to initiate Power Down.
2 GND Chip Ground Pin
3 STOPb Logic Pin. Drive low trigger an emergency shutdown of all supply.
4 VOUTFB Monitors the Source of the external FET
5 CSLEW

6 GATE Drives the GATE node of the external FET
7 PFI

8 VCC Chip Power Supply, 2.7V to 16.5V.

Connect to an external capacitor to control the slew rate of the of the GATE at turn on
(and turn-off for ADM1201-1).

Power Fail Detector Input Pin. A power fail fault is registered at a voltage of 0.6V on this
pin. An external resistor divider sets the output voltage that trips a power fail fault.

Rev. PrG | Page 5 of 6

ADM1201 Preliminary Technical Data

2005

PR05129-0-2/05(PrG)

OUTLINE DIMENSIONS

Figure XX. 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 3. Ordering Guide

Part Number Temperature Package Package Description Package Outline

ADM1201AUJ –40°C to +85°C TSOT UJ-8

003 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Printed in the U.S.A.

Rev. PrG | Page 6 of 6