MAX34407
General Description
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
The MAX34407 is a current and voltage monitor that
is specialized for determining power consumption. The
device has a wide dynamic range to allow it to accurately
measure power in systems that consume small to large
amounts of power. The device is configured and monitored with a standard I2C/SMBus serial interface. The
unidirectional current sensor offers precision high-side
operation with a low full-scale sense voltage. The device
automatically collects the current-sense and voltage
samples. The samples are then multiplied to obtain a
power value and the power values are then accumulated.
Upon a command from the host, the device transfers the
accumulated power samples as well as the accumulation
count to a set of registers that the host can access. This
transfer occurs without missing a sample and allows the
host to retrieve the data not in real time, but at any time
interval.
Applications
●● Tablets
●● Ultra Notebooks
●● Smartphones
Ordering Information appears at end of data sheet.
19-7431; Rev 1; 7/17
Features and Benefits
●● Enables Code Optimization to Minimize Power
Consumption in Portable Platforms
• Four Power Monitors with Wide 66dB Dynamic
Range
• Measures Both Current and Voltage
• Low Power Consumption
• Slow Mode for Reduced Power Consumption
• Power-Down Mode
●● Minimizes Processor Overhead with Autonomous
Operation
• Per Channel 48-Bit Power Accumulators Capture
17 Minutes of Data at 1024 Samples per Second
• Per Channel 12-Bit Voltage Registers
●● High-Integration Solution Minimizes Parts Count,
PCB Space, and BOM Cost
• Wide Current Common-Mode Range of 2.5V to 15V
• Low Full-Scale, Current-Sense Voltage of 100mV
• I2C/SMBus Interface
• Temperature Range: -40°C to +85°C
• Small, 2.285mm x 2.185mm Footprint WLP Package
with 16 Bumps at 0.5mm Pitch
●● Ease of Development
• Evaluation Kit with Advanced GUI Available
(MAX34407EVKIT#)
• Windows Driver Available
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Typical Application Circuit and Block Diagram
2.7V TO 3.6V
AUTOMATIC
SEQUENCING
CHANNEL 4
CURRENT
FLOW
CHANNEL 2
MUX
IN-
CHANNEL 1
POWER
CONTROL
VREF
CHANNEL 3
IN+
RSENSE
OSCILLATOR
ADC
(12 BIT)
CURRENT
(16 BIT)
VOLTAGE
(12 BIT)
MAX34407
GND
POWER
RESULT
(28 BIT)
POWER
ACCUMULATOR
(48 BIT)
X1/X16
VDD
1.6V TO 3.6V
VIO
REGISTERS
SCL
SMBUS
INTERFACE
DIGITAL
CONTROL
INTERFACE
SDA
PDN
SLOW
ADDR
RADDR
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Maxim Integrated │ 2
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Absolute Maximum Ratings
IN+ and IN- to GND................................................-0.3V to +16V
Differential Input Voltage, IN+ to IN-....................................±16V
VDD or VIO to GND..................................................-0.3V to +4V
SDA or SCL to GND.................................................-0.3V to +4V
All Other Pins...............-0.3V to VIO + 0.3V (not to exceed +4V)
Operating Temperature Range............................ -40°C to +85°C
Storage Temperature Range............................. -55°C to +125°C
Soldering Temperature................................. See the IPC/JEDEC
J-STD-020A Specification
Package Thermal Characteristics (Note 1)
WLP
Junction-to-Ambient Thermal Resistance (θJA)...........49°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
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
(VDD = 2.7V to 3.6V, VIO = 1.6V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
VDD Operating Range
VDD Average Supply Current
(Note 2)
Common-Mode Voltage Range
(Note 3)
IDD
MAX
UNITS
3.6
V
PDN = VIO and SLOW = GND
300
450
µA
PDN = VIO and SLOW = VIO
2.4
4
µA
PDN = GND
0.7
1.6
IIO
0.2
VCM
2.5
PDN = GND or SLOW = VIO
IN+ Average Input Bias Current
(Note 3)
TYP
2.7
VIO Operating Range
VIO Average Supply Current
(Note 2)
MIN
3.1
VCM = 1.5V and VSENSE = 0mV
PDN = VIO and SLOW = GND
4.8
SLOW = GND
Per Channel Power Calculation
Rate
SLOW = GND
SLOW = VIO
Current Sample Resolution
VSENSE < 4mV
µA
V
1
µA
15
V
1
VCM = 2.5V and VSENSE = 0mV
PDN = VIO and SLOW = GND
Per Channel Current and Voltage
Sample Rate
2
3.6
µA
1024
sps
8
sps
1024
sps
8
sps
16
Bits
Voltage Sample Resolution
12
Bits
Current-Sense Full Scale
100
mV
16
V
SLOW = VIO
Voltage-Sense Full Scale
Power-Measurement Accumulation
Accuracy (1 Sigma Error Range
with > 1000 Accumulations)
(Note 4)
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VSENSE = 97mV
±0.8
VSENSE = 10mV
±1
VSENSE = 1mV
±1.5
VSENSE = 100µV
±8
VSENSE = 50µV
±15
%
Maxim Integrated │ 3
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Electrical Characteristics (continued)
(VDD = 2.7V to 3.6V, VIO = 1.6V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
Input Bandwidth
TYP
MAX
200
Input Logic-High
SCL/SDA/PDN/SLOW
VIH
Input Logic-Low
SCL/SDA/PDN/SLOW
VIL
SDA Output Logic-Low
VOL
UNITS
kHz
0.75 x
VIO
V
0.25 x
VIO
IOL = 4mA
V
0.4
V
SDA Output Leakage
±1
µA
SCL, SDA Leakage
±5
µA
SLOW, PDN Leakage
±1
µA
Measured from VDD > 2.7V
and VIO > 1.6V and PDN
deasserted to SMBus port active
Power-Up Time
650
µs
Note 2: SMBus not active.
Note 3: Common-mode voltage applies to the IN+ and IN- pins.
Note 4: Not production tested; bench characterization data.
AC Electrical Characteristics: I2C/SMBus Interface
(VIO = 1.6V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIO = 3.3, TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
400
kHz
SCL Clock Frequency
fSCL
10
Bus Free Time Between STOP and
START Conditions
tBUF
1.3
µs
tHD:STA
0.6
µs
Low Period of SCL
tLOW
1.3
µs
High Period of SCL
tHIGH
0.6
µs
Receive
0
ns
Transmit
Hold Time (Repeated) START
Condition
Data Hold Time
tHD:DAT
300
ns
Data Set-Up Time
tSU:DAT
100
ns
Start Set-Up Time
tSU:STA
0.6
µs
SDA and SCL Rise Time
tR
300
ns
SDA and SCL Fall Time
tF
300
ns
Stop Set-Up Time
tSU:STO
Noise Spike Reject
tSP
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0.6
µs
30
ns
Maxim Integrated │ 4
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
I2C/SMBus Timing
SDA
tBUF
tF
tLOW
tSP
tHD:STA
SCL
STOP
tHD:STA
tHIGH
tR
tHD:STA
tSU:DAT
tHD:DAT
START
tSU:STO
REPEATED
START
NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN).
Typical Operating Characteristics
(VDD = VIO = 3.3V, TA = +25°C, VCM = 5V, VSENSE = 1mV.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. TEMPERATURE
2.5
200
2.0
150
100
1.5
2.50
2.75
3.00
3.25
VDD (V)
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3.50
3.75
1.0
FAST IDD (µA)
250
4.0
3.0
250
2.5
200
2.0
150
100
-50
-30
-10
10
30
TEMPERATURE (ºC)
50
70
90
POWER MEASUREMENT ERROR
vs. SUPPLY VOLTAGE toc03
5.00%
3.5
300
SLOW IDD (µA)
3.0
toc02
350
3.5
300
FAST IDD (µA)
4.0
4.00%
ERROR
350
SLOW IDD (µA)
toc01
3.00%
2.00%
1.5
1.00%
1.0
0.00%
2.0
2.5
3.0
3.5
4.0
VDD (V)
Maxim Integrated │ 5
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Typical Operating Characteristics (continued)
(VDD = VIO = 3.3V, TA = +25°C, VCM = 5V, VSENSE = 1mV.)
POWER MEASUREMENT ERROR
vs. COMMON-MODE VOLTAGE
4.00%
4.00%
3.00%
3.00%
30%
toc05
5.00%
PERCENT OF POPULATION
vs. POWER MEASUREMENT ERROR
toc06
25%
PERCENT OF POPULATION
5.00%
POWER MEASUREMENT ERROR
vs. TEMPERATURE
toc04
ERROR
ERROR
20%
2.00%
15%
2.00%
10%
1.00%
0.00%
1.00%
-50
-30
-10 10 30 50
TEMPERATURE (ºC)
70
0.00%
90
5%
2
6
10
14
0%
18
COMMON MODE (V)
POWER MEASUREMENT ERROR
POWER MEASUREMENT ERROR
vs. VSENSE VOLTAGE
toc07
80%
700
70%
600
60%
30%
20%
10%
0.00001
0.0001
0.001
0.01
VSENSE VOLTAGE (V)
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0.1
0%
VOL (mV)
40%
toc08
500
ERROR
50%
VOL
vs. IOL
SDA PIN
400
300
200
100
0
0
5
10 15 20 25 30 35 40 45 50
IOL (mA)
Maxim Integrated │ 6
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Pin Configuration
TOP VIEW
MAX34407
1
2
3
4
IN2+
IN1-
IN1+
VDD
IN2-
VIO
PDN
GND
IN3-
ADDR
SLOW
SCL
IN3+
IN4-
IN4+
SDA
+
A
B
C
D
16 WLP
Pin Description
PIN
NAME
A1
IN2+
External-Sense Resistor Power-Side Connection for Current-Sense Amplifier 2. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
A2
IN1-
External-Sense Resistor Load-Side Connection for Current-Sense Amplifier 1. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
A3
IN1+
External-Sense Resistor Power-Side Connection for Current-Sense Amplifier 1. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
A4
VDD
Supply Voltage for Current-Sense Amplifiers. +2.7V to +3.6V supply. This pin should be
decoupled to GND with a 100nF ceramic capacitor. Power can be applied to VDD either before
or after or in the absence of VIO.
B1
IN2-
External-Sense Resistor Load-Side Connection for Current-Sense Amplifier 2. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
B2
VIO
Supply Voltage for Digital Interface. +1.6V to +3.6V supply. This pin should be decoupled to
GND with a 100nF ceramic capacitor. Power can be applied to VIO either before or after or in the
absence of VDD.
B3
PDN
Power-Down Mode Input. When this pin is tied low, the device is completely powered down
including the I2C/SMBus interface.
B4
GND
Ground Connection
C1
IN3-
External-Sense Resistor Load-Side Connection for Current-Sense Amplifier 3. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
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FUNCTION
Maxim Integrated │ 7
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Pin Description (continued)
PIN
NAME
FUNCTION
I2C/SMBus-Compatible Address Select Input. A resistor tied to GND from this pin selects the
C2
ADDR
C3
SLOW
Slow Accumulate Mode Input. When this pin is tied high, the power accumulation is slowed to
reduce overall device power consumption.
C4
SCL
I2C/SMBus-Compatible Clock Input. SCL does not load the SMBus when either VDD or VIO is
not present.
D1
IN3+
External-Sense Resistor Power-Side Connection for Current-Sense Amplifier 3. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
D2
IN4-
External-Sense Resistor Load-Side Connection for Current-Sense Amplifier 4. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
D3
IN4+
External-Sense Resistor Power-Side Connection for Current-Sense Amplifier 4. Voltages can
be applied to these pins in the absence of power being applied to VDD or VIO. Unused currentsense inputs should be tied together and left unconnected.
D4
SDA
I2C/SMBus-Compatible Data Input/Output. Output is open drain. SDA does not load the SMBus
when either VDD or VIO is not present.
SMBus slave address. See the Addressing section for more details.
Note: For information on how wafer-level packages
(WLPs) are marked, see the Package Top Marking section.
Detailed Description
The MAX34407 automatically sequences through the
channels to collect samples from the common-mode voltage and the current-sense amplifiers. The 16-bit current
value and the 12-bit voltage value are then multiplied
to create a 28-bit power value that is then written to the
power accumulator.
The MAX34407 contains a 48-bit power accumulator for
each channel. This accumulator is updated 1024 times
per second to allow the device to operate for at least 17
minutes without the host retrieving the results. When the
host is ready to pull the latest accumulation data, it first
sends the UPDATE command that causes the MAX34407
to load the latest accumulation data and accumulation
count into the internal MAX34407 registers so the host
can read them at any time. This type of operation allows
the host to control the accumulation period. The only constraint is that the host should access the data before the
accumulators can overflow. If the accumulators overflow,
they do not roll over.
12-bit ADC, the device takes two current samples; one
with the current sense amplifier in a high-gain mode and
another with the amplifier in a low-gain mode. The highgain setting is 16 times the low-gain setting. Based on
the two current-sense ADC results, the device determines
which result provides the best accuracy and fills the 16-bit
current sample accordingly.
SMBus Operation
The MAX34407 uses the SMBus command/response
format as described in the System Management Bus
Specification Version 2.0. The structure of the data flow
between the host and the slave is shown below for several
different types of transactions. Data is sent MSB first. The
fixed slave address of the MAX34407 is determined on
device power-up by sampling the resistor tied to the ADDR
pin. See the Addressing section for details. On device
power-up, the device defaults to the CONTROL command
code (01h). If the host sends an invalid command code,
the device does not acknowledge (NACK) the command
code. If the host attempts to read the device with an invalid
command code, all ones (FFh) are returned in the data
byte.
The MAX34407 contains a 12-bit ADC. During each sample time, a 12-bit voltage sample is resolved and a 16-bit
current sample. To create a 16-bit current value from the
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Maxim Integrated │ 8
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Table 1. Read Byte Format
1
7
1
1
8
1
1
7
1
1
8
1
1
S
Slave
Address
W
A
Command
Code
A
SR
Slave
Address
R
A
Data Byte
NA
P
Table 2. Write Byte Format
1
7
1
1
8
1
8
1
1
S
Slave
Address
W
A
Command
Code
A
Data Byte
A
P
Table 3. Send Byte Format
1
7
1
1
8
1
1
S
Slave
Address
W
A
Command
Code
A
P
Table 4. Block Read Format
1
7
1
1
8
1
1
7
1
1
8
1
S
Slave
Address
W
A
Command
Code
A
SR
Slave
Address
R
A
Byte Count
A
8
…
Data Byte
1 (MSB)
1
8
1
1
A
Data Byte
N (LSB)
NA
P
…
…
Key:
S = Start
SR = Repeated Start
P = Stop
W = Write Bit (0)
R = Read Bit (1)
A = Acknowledge (0)
NA = Not Acknowledge (1)
Shaded Block = Slave Transaction
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Maxim Integrated │ 9
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Addressing
The MAX34407 responds to receiving its fixed slave
address by asserting an ACK on the bus. The fixed slave
address of the MAX34407 is determined on device power-
up by sampling the resistor tied to the ADDR pin when VDD
rises to a valid range. See Table 5 for more details. The
device does not respond to a general call address, only
when it receives its fixed slave address.
Table 5. SMBus Slave Address Select
RADDR (±1%) (kΩ)
SLAVE ADDRESS
RADDR (±1%) (Ω)
SLAVE ADDRESS
20.5
0011 110 (3Ch)
1.74k
0010 110 (2Ch)
11.0
0011 100 (38h)
931
0010 100 (28h)
5.90
0011 010 (34h)
442
0010 010 (24h)
3.16
0011 000 (30h)
Tie to GND
0010 000 (20h)
Table 6. Command Codes
COMMAND
CODE
NAME
TYPE
NUMBER
OF BYTES
POR
(Note 5)
00h
UPDATE
Request Accumulator Update
Send Byte
0
—
01h
CONTROL
Device Configuration and Status
R/W Byte
1
00h
02h
ACC_COUNT
03h
PWR_ACC_1
Accumulator Counter
Block Read
3
Note 6
Power Accumulator for Channel 1
Block Read
6
Note 6
04h
05h
PWR_ACC_2
Power Accumulator for Channel 2
Block Read
6
Note 6
PWR_ACC_3
Power Accumulator for Channel 3
Block Read
6
Note 6
06h
PWR_ACC_4
Power Accumulator for Channel 4
Block Read
6
Note 6
07h
VOLTAGE_1
Voltage for Channel 1
Block Read
2
Note 6
08h
VOLTAGE_2
Voltage for Channel 2
Block Read
2
Note 6
DETAILED DESCRIPTION
09h
VOLTAGE_3
Voltage for Channel 3
Block Read
2
Note 6
0Ah
VOLTAGE_4
Voltage for Channel 4
Block Read
2
Note 6
0Fh
DID
Device ID and Revision
Read Byte
1
Note 7
Note 5: The acronym POR means power-on reset. This is the default value when power is applied to the device.
Note 6: These registers are set to all zeros upon POR.
Note 7: The device ID is factory set and varies based on the die revision.
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Maxim Integrated │ 10
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Update (00h)—Send Byte
at least 500µs before reading any command. Each time
the device receives this command, it transfers the all of
the data in the power accumulators and the accumulator
counter to a set of registers that can be read with the
SMBus interface, and it resets all of the counters. See
Figure 1 for more details.
The UPDATE send byte command does not contain any
data. The UPDATE command must be sent to the device
before reading any of the other commands, and it must
be sent after writing to the CONTROL command. After
sending the UPDATE command, the host should wait
UPDATE
COMMAND TRANSFERS AND
RESETS ALL ACCUMULATORS
SMBus COMMANDS
UPDATE(00h)
INTERNAL REAL-TIME COUNTERS
ACCUMULATOR COUNTER (24 BITS)
ACC_COUNT(02h)
POWER ACCUMULATOR FOR CHANNEL 1 (48 BITS)
PWR_ACC_1(03h)
POWER ACCUMULATOR FOR CHANNEL 2 (48 BITS)
PWR_ACC_2(04h)
POWER ACCUMULATOR FOR CHANNEL 3 (48 BITS)
PWR_ACC_3(05h)
POWER ACCUMULATOR FOR CHANNEL 4 (48 BITS)
PWR_ACC_4(05h)
OVERFLOW ON ANY
ACCUMULATOR
SETS THE OVF BIT
OR
CONTROL(01h)
Figure 1. MAX34407 Register Structure
Table 7. Control (01h)—R/W Byte
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
NAME:
0
0
SMM
PARK_EN
PARK1
PARK0
SLOW
OVF
POR:
0
0
0
0
0
0
0
0
Note: Bit positions 6 and 7 must be written to 0 for proper device operation.
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Maxim Integrated │ 11
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Bit 5: SMM (Single Measure Mode)
When this bit is set, the device performs only one measure and accumulation cycle for the four input channels (normal
scan mode) or four samples of one channel in channel park mode in response to an UPDATE command. The data can
be read by issuing another UPDATE command that moves the previous UPDATE data into the SMBus read registers and
starts another measurement cycle. Data should be read between UPDATE commands. UPDATE commands should be
no less than 500µs apart for reliable measurements. The power accumulators remain at 48 bits even though the single
calculated power is a 28-bit value. After the SMM bit is changed, the UPDATE command should be sent to reset the
accumulators and perform the selected scan operation.
0 = Single-measure mode is disabled.
1 = Single-measure mode is enabled.
Bit 4: PARK_EN
This bit enables the channel park feature. If this bit is set, only one channel is enabled, and the device samples the
selected channel four times faster than the normal round robin rate. The channel to monitor is selected with the PARK0
and PARK1 bits. After the PARK_EN bit is changed, the UPDATE command should be sent to clear out the accumulators
and start a new accumulation period. When the channel park feature is enabled, the minimum time before the power
accumulators can overflow reduces by a factor of four since the selected channel is being updated four times faster. Also,
the power accumulators for the disabled channels do not contain any meaningful data.
0 = Round-robin sampling of all four channels.
1 = One channel is selected (with the PARK0/1 bits).
Bits 3 to 2: PARK1 to PARK0
If the PARK_EN (Park Enable) bit is set, then these bits select which channel is to be monitored at the exclusion of the
other channels.
PARK1
PARK0
SELECTED CHANNEL
0
0
Channel 1
0
1
Channel 2
1
0
Channel 3
1
1
Channel 4
Bit 1: SLOW
This bit is logically OR’ed with the SLOW input pin. If either this bit is set or the SLOW pin is high, then the power accumulation calculation rate is slowed in order to lower the power consumption of the device.
Bit 0: OVF
This status bit is set to a one if any of the power accumulators or the accumulator counter overflows. When the accumulators
or counter overflow, they do not roll over. This status bit can be cleared by writing a 0. If any of the power accumulators or the
accumulator counter are still full, then this bit immediately sets again. Accumulators and the counter that have overflowed
can be cleared by sending the UPDATE command.
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Maxim Integrated │ 12
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Table 8. Accumulator Counter (02h)—Block Read
BIT 23
BIT 22
BIT 21
BIT 20
BIT 19
BIT 18
BIT 17
BIT 16
NAME:
CNT23
CNT22
CNT21
CNT20
CNT19
CNT18
CNT17
CNT16
POR:
0
0
0
0
0
0
0
0
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
NAME:
CNT15
CNT14
CNT13
CNT12
CNT11
CNT10
CNT9
CNT8
POR:
0
0
0
0
0
0
0
0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
NAME:
CNT7
CNT6
CNT5
CNT4
CNT3
CNT2
CNT1
CNT0
POR:
0
0
0
0
0
0
0
0
Bits 23 to 0: CNT23 to CNT0
These bits report the number of times the accumulators have been updated. Send the UPDATE command before reading this register. By dividing the total accumulated power reported in each power accumulator by this count, the average
power can be determined. The accumulator counter does not roll over. If the accumulator counter overflows, the OVF bit
in the CONTROL command is set and remains set until the UPDATE command is sent.
Table 9. Power Accumulator for Channel 1 (03h)—Block Read
Power Accumulator for Channel 2 (04h)—Block Read
Power Accumulator for Channel 3 (05h)—Block Read
Power Accumulator for Channel 4 (06h)—Block Read
BIT 47
BIT 46
BIT 45
BIT 44
BIT 43
BIT 42
BIT 41
BIT 40
NAME:
ACC47
ACC46
ACC45
ACC44
ACC43
ACC42
ACC41
ACC40
POR:
0
0
0
0
0
0
0
0
BIT 39
BIT 38
BIT 37
BIT 36
BIT 35
BIT 34
BIT 33
BIT 32
NAME:
ACC39
ACC38
ACC37
ACC36
ACC35
ACC34
ACC33
ACC32
POR:
0
0
0
0
0
0
0
0
BIT 31
BIT 30
BIT 29
BIT 28
BIT 27
BIT 26
BIT 25
BIT 24
NAME:
ACC31
ACC30
ACC29
ACC28
ACC27
ACC26
ACC25
ACC24
POR:
0
0
0
0
0
0
0
0
BIT 23
BIT 22
BIT 21
BIT 20
BIT 19
BIT 18
BIT 17
BIT 16
NAME:
ACC23
ACC22
ACC21
ACC20
ACC19
ACC18
ACC17
ACC16
POR:
NAME:
POR:
0
0
0
0
0
0
0
0
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
ACC15
ACC14
ACC13
ACC12
ACC11
ACC10
ACC9
ACC8
0
0
0
0
0
0
0
0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
NAME:
ACC7
ACC6
ACC5
ACC4
ACC3
ACC2
ACC1
ACC0
POR:
0
0
0
0
0
0
0
0
www.maximintegrated.com
Maxim Integrated │ 13
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Bits 47 to 0: ACC47 to ACC0
These bits report the total power accumulated by each channel. Send the UPDATE command before reading these registers. The power accumulators do not roll over. If any of the power accumulator overflows, the OVF bit in the CONTROL
command is set and remains set until the UPDATE command is sent.
Table 10. Voltage for Channel 1 (07h)—Block Read
Voltage for Channel 2 (08h)—Block Read
Voltage for Channel 3 (09h)—Block Read
Voltage for Channel 4 (0Ah)—Block Read
NAME:
POR:
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
V11
V10
V9
V8
V7
V6
V5
V4
0
0
0
0
0
0
0
0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
NAME:
V3
V2
V1
V0
N/A
N/A
N/A
N/A
POR:
0
0
0
0
0
0
0
0
Note: Bit positions marked as N/A are not assigned and have no meaning. These bits can be either 0 or 1 when read.
Bits 15 to 4: V11 to V0
These bits report the last measured common-mode voltage for each channel. The LSB bit weighting is 3.9mV (16V full
scale/4096). The UPDATE command must be sent before reading the channel voltages. The host should wait 500µs after
sending the UPDATE command before reading the VOLTAGE commands.
Table 11. Device ID & Revision Register (0Fh)—Read Byte
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
NAME:
ID4
ID3
ID2
ID1
ID0
REV2
REV1
REV0
POR:
0
0
1
0
1
Factory set
Bits 7 to 3: ID4 to ID0
These bits report the device identification (ID). The ID is fixed at 05h.
Bits 2 to 0: REV2 to REV0
These bits report the device revision. The device revision is factory set.
Applications Information
Average Power Calculation Example
The average power can be derived in an external calculation as shown below if the current-sense resistor value is known:
Power accumulator (48 bit) = 0001CEFBD314h (7767577364 decimal)
Accumulator counter (24 bit) = 0005DEh (1502 decimal)
Current-sense resistor = 10mΩ
Step 1
Calculate the unscaled average power by dividing the power accumulator value with the accumulator count value:
0001CEFBD314h/0005DEh = 4EE921h (5171489 decimal)
Step 2
Calculate the ratio of the Step 1 result to the calculated power full-scale value which is a 28-bit value:
5171489/228 = 0.019265
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Maxim Integrated │ 14
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Step 3
Multiply the result from Step 2 by the correction factor listed in Table 12 that matches the current-sense resistor value:
0.019265 x 160 = 3.08W
Table 12. Correction Factors for Various Current-Sense Resistor Values
CURRENT-SENSE
RESISTOR VALUE
(mΩ)
FULL-SCALE
CURRENT
(A)
FULL-SCALE
VOLTAGE
(V)
POWER SCALE
CORRECTION
CALCULATION
POWER SCALE
CORRECTION FACTOR
(W)
100
1
16
1 x 16
16
50
2
16
2 x 16
32
40
2.5
16
2.5 x 16
40
25
4
16
4 x 16
64
20
5
16
5 x 16
80
15
6.667
16
6.667 x 16
106.667
10
10
16
10 x 16
160
5
20
16
20 x 16
320
4
25
16
25 x 16
400
2
50
16
50 x 16
800
1
100
16
100 x 16
1600
Kelvin Sense
For best performance, a Kelvin sense arrangement is recommended. See Figure 2. In a Kelvin sense arrangement,
the voltage sensing nodes across the sense element are placed so that they measure the true voltage drop across
the sense element and not any additional excess voltage drop that can occur in the copper PCB traces or the solder
mounting of the sense element. Routing the differential sense lines along the same path to the MAX34407 and keeping
the path short also improve the system performance.
Minimizing Trace Resistance
PCB trace resistance from the sense resistor (RSENSE) to the IN+ inputs can affect the MAX34407 power-measurement
accuracy. Every 1 ohm of PCB trace resistance will add about 25µV of error. It is recommended to place the sense resistors
as close as possible to the MAX34407 and not to use minimum width PCB traces.
CURRENT PATH
KELVIN CONNECTIONS
COPPER
TRACE
COPPER
TRACE
SENSE RESISTOR OUTLINE
ROUTE SENSE LINES ALONG
THE SAME PATH
IN+
IN-
Figure 2. Kelvin Sense Connection Layout Example
www.maximintegrated.com
Maxim Integrated │ 15
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Package Top Marking
TOP SIDE
+
3 4 4 0 7
Y Y WW$ $
# # # @@
O = If shown above, designates the location of Pin One/Ball A1 laser mark or mold tool mark.
+ = If shown above, indicates the part is Pb-free and designates location of Pin One/Ball A1 Pb-free laser mark.
# = If shown above, indicates the part is RoHS compliant and designates location of Pin One/Ball A1 RoHS laser mark.
$$ = Will be substituted with the product revision code from the reliability database
### = Will be substituted with the last 3 numeric characters from the lot number
@@ = Will be substituted with the first two alpha characters after the numeric characters from the lot number
* = Will be substituted with the factory code - second letter from the left of the lot number
1. Date Code
: yy = Last two digits of year of assembly
ww = Week of assembly
2. Plus sign(+), located near pin one(or ball pad A1), indicates that this part is Pb free.
Ordering Information
PART
Package Information
TEMP RANGE
PIN-PACKAGE
MAX34407EWE+
-40°C to +85°C
16 WLP
MAX34407EWE+T
-40°C to +85°C
16 WLP
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
www.maximintegrated.com
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
16 WLP
W16N2+1
21-0893
Refer to Application
Note 1891
Maxim Integrated │ 16
MAX34407
SMBus 4-Channel Wide Dynamic Range
Power Accumulator
Revision History
REVISION
NUMBER
REVISION
DATE
0
11/14
Initial release
—
1
7/17
Added Package Top Marking section
16
DESCRIPTION
PAGES
CHANGED
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2017 Maxim Integrated Products, Inc. │ 17
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