19-3479; Rev 0; 10/04
KIT
ATION
EVALU
E
BL
AVAILA
EEPROM-Programmable, Quad,
Power-Supply Tracker/Sequencer Circuit
General Description
Features
♦
Tracking/Sequencing for Up to Four Supply
Voltages (With One MAX6876 Device) and
Tracking for Up to 16 Supply Voltages (Using
Four MAX6876 Devices)
♦
EEPROM-Configurable Tracking/Sequencing
Control
♦
Bus Voltage Independent Operation (MAX6876 Is
Powered from the Tracked Supply Voltages or
Always-On Supply)
♦
EEPROM-Selectable Undervoltage/Overvoltage-
Lockout Thresholds for Each Input Supply
♦
EEPROM-Selectable Power-Up/Down Slew Rate
♦
Programmable Power-Good Output Thresholds
and Timing
♦
Global Adjustable Undervoltage Lockout or Logic
ENABLE Input
♦
Independent Internal Charge Pumps to Enhance
External n-Channel FETs (V
GATE_SOURCE
= 5V)
♦
Post Power-Up Selectable Overcurrent Detection
♦
0.5V to 5.5V IN_ Threshold Range
♦
±1.5% Threshold Accuracy
♦
I
2
C/SMBus™-Compatible Serial Interface
♦
Small 6mm x 6mm, 36-Pin Thin QFN Package
MAX6876
The MAX6876 EEPROM-configurable, multivoltage
power tracker/supervisor monitors four system voltages
and ensures proper power-up and power-down condi-
tions for systems requiring voltage tracking and/or
sequencing. The MAX6876 provides a highly config-
urable solution as key thresholds and timing parame-
ters are programmed through an I
2
C interface and
these values are stored in internal EEPROM. The
MAX6876 also provides supervisory functions and an
overcurrent detection circuit.
The MAX6876 features programmable undervoltage and
overvoltage thresholds for each input supply. When all
voltages are within specifications, the device turns on the
external n-channel MOSFETs to either sequence or track
the voltages to the system. All of the voltages can be
sequenced or tracked or powered up with a combination
of the two options. During tracking, the voltage at the
GATE of each MOSFET is increased to slowly turn on
each supply. The voltages at the source of each MOSFET
are compared to each other to ensure that the voltage dif-
ferential between each monitored supply does not
exceed 250mV (typ). Tracking is dynamically adjusted to
force all outputs to track within a ±125mV window from a
reference ramp; if, for any reason, any supply fails to
track within ±250mV from the reference ramp, a
FAULT
output is asserted, the power-up mode is terminated, and
all outputs are powered off. Power-up mode is also termi-
nated if the controlled voltages fail to complete the ramp-
up within a programmable
FAULT
timeout. The MAX6876
features latch-off and autoretry modes to power on again
after a fault condition has been detected.
Other features of the MAX6876 include a reset circuit, a
manual reset input (MR), and a margin disable input
(MARGIN). The device also features outputs for indicat-
ing a power-good condition (PG_) and an overcurrent
condition (OC), and a bus-removal (REM) output.
The MAX6876 is available in a small 6mm x 6mm, 36-
pin thin QFN package and is fully specified over the
extended -40°C to +85°C temperature range.
Ordering Information
PART
MAX6876ETX
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
36 Thin QFN
PKG
CODE
T3666-3
Pin Configuration
GATE1
OUT1
TOP VIEW
IN1
IN2
GATE2
OUT2
IN3
GATE3
OUT3
36 35 34 33 32 31 30 29 28
V
CC
GND
ABP
TRKEN
SYNCH
HOLD
OC
REM
FAULT
1
2
3
4
5
6
7
8
9
27
26
25
24
23
22
21
20
19
Applications
Multivoltage Systems
Networking Systems
Telecom
Storage Equipment
Servers/Workstations
MAX6876
EP*
IN4
GATE4
OUT4
REFIN
N.C.
PG4
PG3
PG2
PG1
10 11 12 13 14 15 16 17 18
ENABLE
MARGIN
RESET
N.C.
MR
SDA
SCL
A0
A1
SMBus is a trademark of Intel Corp.
*EXPOSED PADDLE
6mm x 6mm
THIN QFN
________________________________________________________________
Maxim Integrated Products
1
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.
EEPROM-Programmable, Quad,
Power-Supply Tracker/Sequencer Circuit
MAX6876
ABSOLUTE MAXIMUM RATINGS
(All voltages are referenced to GND, unless otherwise noted.)
GATE_.............................................................-0.3V to (IN_ + 6V)
IN1–IN4, V
CC
............................................................-0.3V to +6V
OUT1–OUT4, SYNCH, ABP,
REFIN...............................-0.3V to Max (IN1–IN4, V
CC
) + 0.3V
ENABLE, TRKEN,
HOLD, FAULT, MR, MARGIN......-0.3V
to +6V
RESET,
PG1–PG4,
OC,
REM....................................-0.3V to +6V
SDA, SCL, A0, A1.....................................................-0.3V to +6V
Input/Output Current (all pins except OUT_ and GND) ...±20mA
OUT_, GND Current..........................................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
36-Pin, 6mm x 6mm Thin QFN
(derate 26.3mW/°C above +70°C) ..............................2105mW
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
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.
ELECTRICAL CHARACTERISTICS
(V
CC
, IN1–IN4 = +2.7V to +5.5V; ENABLE =
MARGIN
=
MR
= ABP = TRKEN; T
A
= -40°C to +85°C, unless otherwise specified.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
(Note 2)
SYMBOL
V
CC
CONDITIONS
GATE_ = PG_ =
RESET
= 0
Voltage on ABP (from V
CC
or IN1–IN4) to
ensure the device is fully operational
Minimum voltage on ABP (from V
CC
or
IN1–IN4) to ensure the device is EEPROM
configured
V
CC
= 5.5V, IN1–IN4 = 3.3V, no load
Supply Current
I
CC
Configuration registers or memory access,
no load
IN1–IN4 (in 20mV increments)
IN1–IN4 (in 10mV increments)
0.5V < IN_ < 5.5V, IN_
T
A
= 0°C to +85°C falling for UV, rising for
OV
2V < IN_ < 5.5V, IN_
falling for UV, rising for
OV (20mV increments)
Threshold Accuracy
T
A
= -40°C to
+85°C
1V < IN_ < 2V, IN_
falling for UV, rising for
OV (20mV increments)
1V < IN_ < 3.05V, IN_
falling for UV, rising for
OV (10mV increments)
0.5V < IN_ < 1V, IN_
falling for UV, rising for
OV (10mV increments)
Threshold Hysteresis
RESET
Threshold Tempco
V
TH_HYS
∆V
TH/C
1.00
0.50
-1.5
1.8
2.5
MIN
1.4
2.7
5.5
V
TYP
MAX
UNITS
Undervoltage Lockout
V
UVLO
2.5
3
4
5.50
3.05
+1.5
V
mA
IN_ Threshold Range
V
TH
V
%
-2.5
+2.5
%
-50
+50
mV
-2.5
+2.5
%
-25
0.5
50
+25
mV
%V
TH
ppm/°C
2
_______________________________________________________________________________________
EEPROM-Programmable, Quad,
Power-Supply Tracker/Sequencer Circuit
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
, IN1–IN4 = +2.7V to +5.5V; ENABLE =
MARGIN
=
MR
= ABP = TRKEN; T
A
= -40°C to +85°C, unless otherwise specified.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Tracking-Differential-Voltage Hold
Ramp (Note 3)
Tracking-Differential-Voltage
Hysteresis
Tracking-Differential
FAULT
Voltage (Note 3)
V
TRK_F
V
OUT_
> V
TH_PL
V
OUT_
< V
TH_PG
00
FAULT
Timeout Period (Note 4)
Register
t
FAULTUP
,
contents
t
FAULTDOWN
(Table 16)
t
FG
R
IN1-4
R
OUT1-4
t
PO
t
D-GATE
t
POK
For IN_ voltages < the highest IN_ supply
OUT_ pulldown disabled
V
ABP
≥
V
UVLO
IN_ falling/rising, 100mV overdrive
OUT_ rising, 100mV overdrive
OUT_ falling, 100mV overdrive
000
001
GATE,
RESET,
Autoretry Timeout
Period (Notes 5, 6)
t
RESET,
t
AUTO,
t
GATE
Register
contents
(Table 16)
010
011
100
101
110
111
00
OC
Timeout Period
t
OC
Register
contents
(Table 16)
01
10
11
00
Register
contents
(Table 16)
01
10
11
Register
contents
(Table 16),
OUT_ falling
00
01
10
11
T
A
= 0°C to +85°C
T
A
= -40°C to 0°C
T
A
= 0°C to +85°C
T
A
= -40°C to 0°C
T
A
= 0°C to +85°C
T
A
= -40°C to 0°C
T
A
= 0°C to +85°C
T
A
= -40°C to 0°C
10
20
40
80
160
320
1280
10
40
80
160
560
480
280
240
140
120
70
60
96.25
93.75
91.25
88.75
6
3
25
25
12.5
25
50
100
200
400
1600
12.5
50
100
200
800
800
400
400
200
200
100
100
97.5
95
92.5
90
15
30
60
120
240
480
1920
15
60
120
240
1040
1120
520
560
260
280
130
140
98.75
96.25
93.75
91.25
%
ms
ms
55
70
01
10
11
FAULT
to GATE Delay
IN1–IN4 Input Impedance
OUT1–OUT4 Input Impedance
Power-On Delay
IN_ to GATE_ Delay
OUT_ to PG_ Delay
200
20
40
80
160
SYMBOL
V
TRK
CONDITIONS
V
OUT_
> V
TH_PL
V
OUT_
< V
TH_PG
MIN
95
TYP
125
25
250
25
50
100
200
2
90
100
145
130
3
300
30
60
120
240
µs
kΩ
kΩ
ms
µs
ms
µs
µs
ms
MAX
155
UNITS
mV
mV
mV
MAX6876
Track/Sequence Slew Rate Rising
or Falling
TRK
SLEW
V/s
IN_ to OUT_ Overcurrent
Threshold
V
TH_OC
_______________________________________________________________________________________
3
EEPROM-Programmable, Quad,
Power-Supply Tracker/Sequencer Circuit
MAX6876
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
, IN1–IN4 = +2.7V to +5.5V; ENABLE =
MARGIN
=
MR
= ABP = TRKEN; T
A
= -40°C to +85°C, unless otherwise specified.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
IN_ to OUT_ Power-Good
Threshold
V
TH_PG and
V
TH_OC
Hysteresis
Power Low Threshold
Power Low Hysteresis
OUT_ to GND Pulldown
Impedance (When Enabled)
REM Output Low
V
OL_REM
SYMBOL
Register
contents
(Table 16),
OUT_ rising
CONDITIONS
00
01
10
11
MIN
93.75
91.25
88.75
86.25
125
TYP
95
92.5
90
87.5
0.5
OUT_ falling
142
10
ABP
≥
2.5V
ABP
≥
2.5V, I
SINK
= 4mA
ABP
≥
4.0V, I
SINK
= 15mA
ABP
≥
1.4V, I
SINK
= 50µA (PG_,
RESET
only)
V
OL
ABP
≥
2.5V, I
SINK
= 1mA
ABP
≥
4.0V, I
SINK
= 4mA
ABP
≥
1.4V, I
SINK
= 50µA
GATE1–GATE4 Output Low
V
GOL
ABP
≥
2.5V, I
SINK
= 1mA
ABP
≥
4.0V, I
SINK
= 4mA
PG1–PG4,
HOLD, FAULT, OC
,
RESET,
REM Output Open-Drain
Leakage Current
GATE_ Output-Voltage High
GATE_ Pullup Current
GATE_ Pulldown Current
MARGIN, FAULT, HOLD, MR,
ENABLE Input Voltage
MR
Input Pulse Width
FAULT, HOLD, MARGIN, MR,
ENABLE Glitch Rejection
Digital Input to Logic Delay,
FAULT, HOLD, MARGIN, MR,
ENABLE
MARGIN, MR
Digital Input to ABP
Pullup Resistance
I
LKG
Output deasserted
-1
100
0.3
0.4
0.3
0.3
0.4
0.3
0.3
0.8
+1
µA
V
V
165
MAX
96.25
93.75
91.25
88.75
%
mV
mV
Ω
V
UNITS
V
TH_PG
%
V
OUT_HYS
V
TH_PL
V
TH_PL_HYS
Output Low PG1–PG4,
HOLD,
FAULT, OC, RESET
(Note 2)
V
GOH
I
GATEUP
I
GATE_
= 0.5µA
During power-up/down, V
GATE_
= 1V
IN_ +
4.4
2.5
2.5
IN_ + 5
4.5
4.5
IN_ +
5.8
V
µA
µA
I
GATEDOWN
During power-up/down, V
GATE_
= 4V
V
IL
V
IH
t
MR
0.3 x
ABP
V
0.6 x
ABP
2
100
µs
ns
t
D
1
µs
R
P
70
100
130
kΩ
4
_______________________________________________________________________________________
EEPROM-Programmable, Quad,
Power-Supply Tracker/Sequencer Circuit
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
, IN1–IN4 = +2.7V to +5.5V; ENABLE =
MARGIN
=
MR
= ABP = TRKEN; T
A
= -40°C to +85°C, unless otherwise specified.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
TRKEN Input Delay
TRKEN Reference Voltage Range
TRKEN Input Current
Reference Input Voltage Range
Reference Input Resistance
SYMBOL
t
EN
V
TRKEN
I
TRKEN
V
REFIN
R
REFIN
V
REFIN
= 1.25V
Input rising
Input falling
V
TRKEN
= 1.25V
CONDITIONS
TRKEN falling, 100mV overdrive
1.245
1.225
-100
1.225
1.25
500
0.3 x
ABP
0.6 x
ABP
1
I
SINK
= 3mA
10
400
1.3
0.6
1.3
0.6
0.6
0.6
0.1
50
100
0
300
300
C
BUS
= 400pF
20 +
0.1 x
C
BUS
50
11
300
0.9
0.4
1
MIN
TYP
2
1.285
1.25
1.320
1.275
+100
1.275
MAX
UNITS
µs
V
nA
V
kΩ
MAX6876
SERIAL INTERFACE LOGIC (SDA, SCL, A0, A1)
Logic-Input Low Voltage
Logic-Input High Voltage
Input Leakage Current
Output-Voltage Low
Output Leakage Current
Input/Output Capacitance
Serial Clock Frequency
Clock Low Period
Clock High Period
Bus Free Time
START Setup Time
START Hold Time
STOP Setup Time
Clock Low to Valid Output
Data Out Hold Time
Data In Setup Time
Data In Hold Time
SCL/SDA Rise Time
SCL/SDA Fall Time
Transmit SDA Fall Time
SCL/SDA Noise Suppression Time
Byte Write Cycle Time
V
IL
V
IH
I
ILKG
V
OL
I
OLKG
C
I/O
f
SCL
t
LOW
t
HIGH
t
BUF
t
SU:STA
t
HD:STA
t
SU:STO
t
AA
t
DH
t
SU:DAT
t
HD:DAT
t
R
t
F
t
F
t
I
t
WR
V
V
µA
V
µA
pF
kHz
µs
µs
µs
µs
µs
µs
µs
ns
ns
ns
ns
ns
ns
ns
ms
SERIAL INTERFACE TIMING (SDA, SCL)
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 are guaranteed by design.
Note 2:
The internal supply voltage, measurable on ABP, is equal to the maximum of IN1–IN4 and V
CC
supplies.
Note 3:
Differential between each of the OUT_ and the SYNCH ramp voltage during power-up/down measured as V
OUT_
- 2 x
V
SYNCH
.
Note 4:
FAULT
timeout starts to count at the beginning of each sequence of power-up/down and clears when the programmed
OUT_ voltages track successfully.
_______________________________________________________________________________________
5
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