Download ADM1200-2ARJ - Analog Devices, Inc.

Simple Tracker TM
ADM1200
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
Ability to Track Down Supplies (ADM1200-1)
Emergency Shutdown Feature (ADM1200-2)
Packaged in tiny 6-Lead SOT-23 Package
APPLICATIONS
Multi-Voltage Supply Rail Tracker
Telecoms and Datacom s Systems
Multi voltage Network Processors , FPGAs, ASICs, DSPs
PC/Server Applications
Functional Block Diagram
Q1
VIN
VOUT
2.7V - 16.5V
VCC
UP/DOWN
(ADM1200-1)
UP/STOP
(ADM1200-2)
CSLEW
UP / DOWN
DETECTOR
SLEW RATE
CONTROL
VOUT
ADM1200
GND
The ADM1200 is a cascadable Simple Tracker TM device which
ensures that voltage rails track within ~100mV of each other in
multi supply systems. Any number of these devices can be
cascaded to form a multi supply tracking solution.
Applications Diagram
Q1
3.3VIN
3.3VOUT
Vcc
ADM1200
Vcc
GATE
UP/DOWN
The Slew Rate of the ramp is adjustable via an external capacitor
on the CSLEW pin and can be programmed from 100V/s to
1000V/s. When multiple devices are cascaded the CSLEW pin of
each subsequent device should be tied to the output rail(VOUTFB)
of the previous device to ensure that supply will track up and
down with the previous supply.
GATE
FET
DRIVER
LOGIC
CSLEW
GENERAL DESCRIPTION
The ADM1200 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.
VFET
CHARGE
PUMP
20nF
UP/DOWN
V OUT
C SLEW
GND
C SLEW
Q2
2.5VIN
2.5VOUT
V cc
ADM1200
The ADM1200 is offered in two variants. The ADM1200-1
features an UP/DOWNb pin and the ADM1200-2 features an
Up/STOPb pin. For both devices a high level on the this input
will initiate tracking power up sequence. A low on the
UP/DOWNb pin of the ADM1200-1 will initiate a tracking
down of the supply rails, while a low on the UP/STOPb pin of
the ADM1200-2 will initiate an emergency fast shutdown of all
supply rails simultaneously.
Vcc
GATE
20nF
UP/DOWN
VOUT
C SLEW
GND
Q3
1.5VIN
1.5VOUT
V cc
ADM1200
Vcc
The ADM1200 is packaged in a tiny 6-pin SOT-23 package.
GATE
20nF
UP/DOWN
VOUT
C SLEW
GND
Rev. PrH
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.
www.analog.com
Tel: 781.329.4700
Fax: 781.326.8703
2003 Analog Devices, Inc. All rights reserved.
©©2005
Preliminary Technical Data
ADM1200—SPECIFICATIONS
Table 1. VCC = Full Operating Range, TA = -40°C to +85°C, unless otherwise noted.
Parameter
Min
VCC Pin
Operating Voltage Range Vcc
Undervoltage Lockout, VUVLO
UVLO Hysteresis
Switched Voltage Range
Quiesent Current
Up/Downb Pin
Input Threshold
Input Threshold Hysteresis
Input Current
CSLEW Pin
Slew up Current
Slew down Current
Tracking Gain
Minimum Tracking Voltage
Maximum Tracking voltage
Slew Rate
VOUTFB Pin
Input Current
Voltage Range
GATE Pin
Gate Pullup Current
Gate Pulldown Current
Gate Pulldown Current
GATE Voltage, VGATE
2.7
2.4
Typ
2.525
25
0.65
0.65
0.58
0.6
60
Units
16.5
2.65
V
V
mV
V
mA
16.5
1.0
0.62
100
V
mV
nA
100
1000
µA
µA
V/V
V
V
V/s
-10
0
10
Vcc
µA
V
10
12
10
µA
µA
mA
V
V
V
-100
-10
10
1
0.1
Vcc – 0.3
5
6
5
12
12
2
6.5
8
6.5
NOTES:
1
Asserted when voltage on PFI pin exceeds threshold
Absolute Maximum Ratings
Table 2. ADM1200 Absolute Maximum Ratings
Parameter
VCC Pin
UP/DOWNb, UP/STOPb
CSLEW Pin
Gate Pin
VOUTFB Pin
Power Dissipation
Storage Temperature
Operating Temperature Range
Lead Temperature Range
(Soldering 10 sec)
Junction Temperature
Max
Rating
20V
20V
20V
Vcc + 11V
20V
TBD
–65°C to +125°C
–40°C to +85°C
300°C
150°C
Rev. PrH | Page 2 of 6
Conditions
Vcc Rising
Rising
VSLEW/VOUTFB
Vslew – Vout > 100mV
Vout – Vslew > 100mV
ADM1200-2 only –vgate = 3.0V
VGATE – VCC; VCC = 2.7V
VGATE – VCC; VCC = 5.0V
VGATE – VCC; VCC = 16.5V
Preliminary Technical Data
ADM1200
ENABLING A SINGLE SUPPLY
Q1
3.3VIN
The ADM1200 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.
ADM1200
Vcc
GATE
UP/DOWN
20nF
UP/DOWN
V OUT
C SLEW
An internal charge pump ensures that the ADM1200 is capable
of fully enhancing an external FET via the GATE pin, turning
on the output. An external capacitor may be required on the
GATE node for stability.
GND
C SLEW
Q2
2.5VIN
2.5VOUT
V cc
Power up can be externally initiated by driving the
UP/DOWNb (ADM1200-1) or UP/STOPb (ADM1200–2)
logic pin high. A low on this pin will initiate a power down.
ADM1200
Vcc
GATE
20nF
UP/DOWN
VOUT
C SLEW
The VOUTFB pin monitors the output voltage.
GND
A single ADM1200 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, CSLEW, will dictate the
slew rate of the GATE voltage at startup. An internal current
10µA source charges CSLEW and the GATE voltage is ramped at
the same rate.
Q3
1.5VIN
1.5VOUT
V cc
ADM1200
Vcc
GATE
20nF
UP/DOWN
VOUT
C SLEW
Q1
3.3VIN
3.3VOUT
Vcc
GND
3.3VOUT
Figure 2. ADM1200 Solution for Tracking 3 Supplies
ADM1200-1
A low-to-high transition on the UP/DOWNb or UP/STOPb pin
will initiate turn-on of the supplies. The ADM1200 will begin to
source current into the CSLEW capacitor. The voltages on all
GATE pins will begin to rise, or “track” up, at the same rate, as
set by the value of CSLEW. All supply voltages will remain within
100mV of the CSLEW voltage until they level off at their full
potentials.
V cc
GATE
POWER ON/OFF
1nF
UP/STOP
VOUTFB
C SLEW
CSLEW
GND
Figure 1. ADM1200 Switching on a Single Supply
A high-to-low on the UP/DOWNb pin of the ADM1200-1 will
initiate a tracking down of the supply rails. The voltages will
attempt to stay with ~100mV of each other assuming the load
current will be sufficient to discharge the capacitors at the
required rate. (See Figure 3.)
MULTI-SUPPLY TRACKING
The primary function of the ADM1200 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 ADM1200 device driving a FET.
The UP/DOWNb (ADM1200-1) or UP/STOPb (ADM1200-2)
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.
A high-to-low on the UP/STOPb pin of the ADM1200-2 will
initiate an emergency fast shutdown of all supply rails
simultaneously. (See Figure 4.) Note that while the pass FETs
will be turned off immediately the actual discharge rate of each
supply rail will depend on the load.
In figure 2, the ADM1200 is configured to control the ramp of
the largest supply first. The output of the first device is
connected to the slew pin on the second device to allow the rate
of the first supply to control the rate of the second and so on.
Rev. PrH | Page 3 of 6
ADM1200
Preliminary Technical Data
UP/DO WN
SLEW RATE CONTROL
Voltage tracking is achieved by controlling the slew rate of a
rising or falling supply 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. The gate
responds to maintain ~100mV between the VOUTFB pin and
the SLEW
pin.
3.3V
2.5V
1.5V
OUTP UT
V OLTAGE S
Figure 3. ADM1200-1 Power-Up and Power-Down Waveforms
UP/STOP
3.3V
2.5V
1.5V
OUTP UT
V OLTAGE S
Figure 6. Tracking up Waveforms
Figure 4. ADM1200-2 Power-Up and Power-Down Waveforms
Rev. PrH| Page 4 of 6
Preliminary Technical Data
ADM1200
PIN CONFIGURATIONS
UP / DOWN
1
6
VCC
UP / STOP
1
2
5 GATE
GND
2
TOP VIEW
(Not to Scale)
VOUTFB
3
VCC
ADM1200-2ARJ
ADM1200-1ARJ
GND
6
5 GATE
TOP VIEW
(Not to Scale)
4 CSLEW
VOUTFB
3
4 CSLEW
PIN FUNCTIONAL DESCRIPTIONS
Pin No.
1
Name
UP/DOWNb or UP/STOPb
2
3
4
GND
VOUTFB
CSLEW
5
6
GATE
VCC
Description
Logic Pin. Drive high to initiate track up off all ADM1200 controlled rails. Drive low to
initiate track down of output (ADM1200-1) or a fast shutdown of output (ADM1200-2).
Chip Ground Pin.
Monitors the Source of the external FET
Connect to an external capacitor to control the slew rate of the output at turn on (and
turn-off for ADM1200-1).
Drives the GATE node of the external FET
Chip Power Supply, 2.7V to 16.5V.
Rev. PrH | Page 5 of 6
ADM1200
Preliminary Technical Data
OUTLINE DIMENSIONS
0.122 (3.10)
0.106 (2.70)
0.071 (1.80)
0.059 (1.50)
6
5
4
1
2
3
0.118 (3.00)
0.098 (2.50)
PIN 1
0.037 (0.95) BSC
0.075 (1.90)
BSC
0.051 (1.30)
0.035 (0.90)
0.057 (1.45)
0.035 (0.90)
0.059 (0.15)
0.000 (0.00)
0.020 (0.50) SEATING
0.010 (0.25) PLANE
10°
0.009 (0.23) 0°
0.003 (0.08)
0.022 (0.55)
0.014 (0.35)
Figure 5. 6-Lead SOT-23 Package (RJ-6)—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
ADM1200-1ARJ
ADM1200-2ARJ
Variant
UP/DOWNb logic input
UP/STOPb logic input
Temperature Package
–40°C to +85°C
–40°C to +85°C
2005
003 Analog Devices, Inc. All rights reserved. Trademarks and registered
trademarks are the
Printed in the U.S.A.
property
of
their
respective
companies.
PR05128-0-2/05(PrH)
Rev. PrH | Page 6 of 6
Package Description
SOT-23
SOT-23
Package Outline
RJ-6
RJ-6