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MAX6879ETE+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24
General Description
The MAX6877/MAX6878/MAX6879 multivoltage power
trackers/sequencers/supervisors monitor up to three
system voltages and provide proper power-up and
power-down control for systems requiring voltage track-
ing or sequencing. These devices ensure controlled
voltage tracking within a specified range or sequencing
in the proper order as system power supplies are
enabled. The MAX6877/MAX6878/MAX6879 generate
all required voltages and timing to control up to three
external n-channel pass FETs for the OUT1/OUT2/
OUT3 supply voltages (see the Selector Guide for dif-
ferent features of each device).
The MAX6877/MAX6878/MAX6879 feature adjustable
undervoltage thresholds for each input supply. When all
the voltages are above these adjustable thresholds, the
devices turn on the external n-channel MOSFETs to
either sequence or track the voltages to the system.
During voltage-tracking mode, the voltage at the GATE
of each MOSFET is increased to slowly bring up all
supplies at a controlled slew rate. The MAX6877/
MAX6878/MAX6879 feature an autoretry or latch-off
mode with capacitor-adjusted timing.
These devices also provide a controlled power-down
(tracking mode) when the system shuts off in an orderly
manner. When an unexpected fault occurs, the outputs
are all pulled down simultaneously with an internal
100Ω pulldown to help discharge capactive loads at
the MOSFET’s source. The MAX6877/MAX6878/
MAX6879 feature independent internal charge pumps
to fully enhance the external FETs for low-voltage drop
at highpass current. The MAX6877 and MAX6878 also
feature a power-good output with a selectable timeout
period that can be used for system reset.
The MAX6877/MAX6878/MAX6879 are available in
small 4mm x 4mm 24-pin and 16-pin thin QFN pack-
ages and are fully specified over the -40°C to +85°C
extended operating temperature range.
Applications
Multivoltage Systems
Networking Systems
Telecom
Storage Equipment
Servers/Workstations
Features
♦ Pin-Selectable Tracking or Sequencing Control
for Up to Three Supply Voltages
♦ Capacitor-Adjustable Power-Up/Down Tracking
Slew Rate
♦ Capacitor-Adjustable Power-Up Sequencing Delay
♦ Internal Charge Pumps to Enhance External
n-Channel FETs
♦ Capacitor-Adjustable Timeout Period Power-Good
Output (MAX6877/MAX6878)
♦ Adjustable Undervoltage Lockout or
Logic-Enable Input
♦ Internal 100Ω Pulldown for Each Output to
Discharge Capacitive Load Quickly
♦ 0.5V to 5.5V Nominal IN_/OUT_ Range
♦ 2.7V to 5.5V Operating Voltage Range
♦ Immune to Short Voltage Transients
♦ Small 4mm x 4mm 24-Pin or 16-Pin Thin QFN
Packages
MAX6877/MAX6878/MAX6879
Dual-/Triple-Voltage, Power-Supply
Trackers/Sequencers/Supervisors
________________________________________________________________ Maxim Integrated Products 1
23
24
22
21
8
7
9
ABP
SET2
SET1
EN/UV
10
V
CC
GATE3
FAULT
PG/RST
OUT2
MARGIN
12
IN3
456
1718 16 14 13
IN2
IN1
TIMEOUT
*EXPOSED PADDLE CONNECTED TO GND.
SLEW
DELAY
GND
EP*
+
MAX6877
SET3
OUT3
3
15
GATE1
20
11
LTCH/RTR
OUT1
19
12
TRK/SEQ
GATE2
4mm x 4mm THIN QFN
TOP VIEW
Pin Configurations
Ordering Information
19-3771; Rev 1; 10/05
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information continued at end of data sheet.
+Denotes lead-free package.
EVALUATION KIT
AVAILABLE
Selector Guide appears at end of data sheet.
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX6877ETG+
-40°C to +85°C 24 Thin QFN
T2444-4
Pin Configurations continued at end of data sheet.
MAX6877/MAX6878/MAX6879
Dual-/Triple-Voltage, Power-Supply
Trackers/Sequencers/Supervisors
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
, IN1, IN2, or IN3 = +2.7V to +5.5V, EN/UV = MARGIN = ABP, T
A
= -40°C to +85°C, unless otherwise specified. Typical values
are at T
A
= +25°C, unless otherwise noted.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
IN1, IN2, IN3, V
CC
....................................................-0.3V to +6V
ABP
.....................................-0.3V to the highest of V
IN1
- V
IN3
or V
CC
SET1, SET2, SET3 ....................................................-0.3V to +6V
GATE1, GATE2, GATE3 .........................................-0.3V to +12V
OUT1, OUT2, OUT3 .................................................-0.3V to +6V
LTCH/RTR, TRK/SEQ, MARGIN ...............................-0.3V to +6V
FAULT, PG/RST, EN/UV ...........................................-0.3V to +6V
DELAY, SLEW, TIMEOUT .........................................-0.3V to +6V
OUT_ Current....................................................................±50mA
GND Current.....................................................................±50mA
Input/Output Current (all pins except
OUT_ and GND) ...........................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin 4mm x 4mm Thin QFN
(derate 16.9mW/°C above +70°C).............................1349mW
24-Pin 4mm x 4mm Thin QFN
(derate 20.8mW/°C above +70°C).............................1667mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Maximum Junction Temperature .....................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Voltage on ABP (the highest of V
CC
or IN_)
to ensure that PG/RST and FAULT are valid
and GATE_ = 0V
1.4
Operating Voltage Range V
CC
Voltage on ABP (the highest of V
CC
or IN_)
to ensure the device is fully operational
2.7 5.5
V
Supply Current I
CC
V
C C
= 5.5V , IN 1 = IN 2 = IN 3 = 3.3V , no l oad
1.1 1.8 mA
SET_ falling, T
A
= +25
o
C
0.4925
0.5
0.5075
SET_ Threshold Range V
TH
SET_ falling, T
A
= -40
o
C to +85
o
C
0.4875
0.5
0.5125
V
SET_ Threshold Hysteresis
V
TH_HYS
SET_ rising 0.5 %
SET_ Input Current I
SET
SET_ = 0.5V
-100 +100
nA
V
EN_R
Input rising
1.286
EN/UV Input Voltage
V
EN_F
Input falling
1.22 1.25 1.28
V
EN/UV Input Current I
EN
-5 +5 µA
EN/UV Input Pulse Width t
EN
EN/UV falling, 100mV overdrive 7 µs
DELAY, TIMEOUT Output Current
I
D
(Notes 2, 3)
2.12
2.5
2.88
µA
DELAY, TIMEOUT Threshold
Voltage
V
C C
= 3.3V
1.25
V
SLEW Output Current (Note 4) I
S
22.5
25
27.5
µA
Track/Sequence Slew-Rate
Timebase Accuracy
SR C
SLEW
= 200pF (Note 4) -15
+15
%
Timebase/C
SLEW
Ratio 100pF < C
SLEW
< 1nF (Note 4)
104
kΩ
S l ew - Rate Accur acy d ur i ng P ow er -
U p and P ow er - D ow n
C
SLEW
= 200pF, ABP = 5.5V (Note 4) -50
+50
%
Power-Good Threshold V
TH_PG
V
OUT_
falling
91.5 92.5 93.5
%
(All voltages referenced to GND, unless otherwise noted.)
MAX6877/MAX6878/MAX6879
Dual-/Triple-Voltage, Power-Supply
Trackers/Sequencers/Supervisors
_______________________________________________________________________________________ 3
Note 1: Specifications guaranteed for the stated global conditions. 100% production tested at T
A
= +25°C and T
A
= +85°C.
Specifications at T
A
= -40°C to +85°C are guaranteed by design. These devices meet the parameters specified when at
least one of V
CC
, IN1/IN2/IN3 is between 2.7V to 5.5V, while the remaining IN1/IN2/IN3 are between 0 and 5.5V.
Note 2: A current I
D
= 2.5µA ±15% is generated internally and is used to set the DELAY and TIMEOUT periods and used as a refer-
ence for t
DELAY
and t
TIMEOUT
.
Note 3: The total DELAY is t
DELAY
= 200ms + (500kΩ x C
DELAY
). Leave DELAY unconnected for 200µs delay. The total TIMEOUT is
t
TIMEOUT
= 200µs + (500kΩ x C
TIMEOUT
). Leave TIMEOUT unconnected for 200µs timeout.
Note 4: A current I
S
= 25µA ±10% is generated internally and used as a reference for t
FAULT
, t
RETRY
, and slew rate.
Note 5: During power-up, only the condition OUT_ < ramp - V
TRK
is checked in order to stop the ramp. However, both conditions
OUT_ < ramp - V
TRK_F
and OUT_ > ramp + V
TRK_F
cause a fault. During power-down, only the condition OUT > ramp +
V
TRK
is checked in order to stop the ramp. However, both conditions OUT_ < ramp - V
TRK_F
and OUT_ > ramp + V
TRK_F
cause a fault (see Figure 10). Therefore, if OUT1, OUT2, and OUT3 (during power-up tracking and power-down) differ by
more than 2 x V
TRK_F
, a fault condition is asserted.
Note 6: A 100Ω pulldown to GND activated by a fault condition. See the Internal Pulldown section.
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
, IN1, IN2, or IN3 = +2.7V to +5.5V, EN/UV = MARGIN = ABP, T
A
= -40°C to +85°C, unless otherwise specified. Typical values
are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Power-Good Threshold Hysteresis V
HYS_PG
V
OUT_
rising 0.5 %
GATE_ Output High V
GOH
I
SOURCE
= 0.5µA
IN_ +
4.2
IN_ +
5.0
IN_ +
5.8
V
GATE_ Pullup Current I
GUP
During power-up and power-down,
V
GATE_
= 1V
2.5 4 µA
I
GD
During power-up and power-down,
V
GATE_
= 5V
2.5 4 µA
When disabled, V
GATE_
= 5V, V
IN_
≥ 2.7V 9.5
GATE_ Pulldown Current
I
GDS
When disabled, V
GATE_
= 5V, V
IN_
≥ 4V 20
mA
SET_ to GATE_ Delay t
D-GATE
SET falling, 25mV overdrive 6 µs
V
IN_
≥ 2.7V, I
SINK
= 1mA, output asserted 0.3
FAULT, PG/RST Output Low V
OL
V
IN_
≥ 4.0V, I
SINK
= 4mA, output asserted 0.4
V
Tracking Differential Voltage Stop
Ramp
V
TRK
Differential between each of the OUT_ and
the ramp voltage during power-up and
power-down, Figure 10 (Note 5)
75
125
180 mV
Tracking Differential Fault Voltage
V
TRK_F
Differential between each of the OUT_ and
the ramp voltage, Figure 10 (Note 5)
200 250
310 mV
Tracking Differential Voltage
Hysteresis
20 %
Power-Low Threshold V
TH_PL
OUT_ falling
125 142
170 mV
Power-Low Hysteresis
V
TH_PLHYS
OUT_ rising 10 mV
OUT to GND Pulldown Impedance
V
ABP
> 2.7V (Note 6)
100
Ω
MARGIN, TRK/SEQ, LTCH/RTR
Pullup Current
I
IN
71013µA
V
IL
0.8
MARGIN, TRK/SEQ, LTCH/RTR
Input Voltage
V
IH
2.0
V
MARGIN, TRK/SEQ, LTCH/RTR
Glitch Rejection
100
ns
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24

MAX6879ETE+T

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Buy MAX6879ETE+T
Manufacturer:
Maxim Integrated
Description:
Supervisory Circuits Dual Power-Sup Sequencer
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