71M6541D Datasheet, PDF (17/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
processed with locally connected sensors, as shown in Figure 3. When using one local and one remote
sensor (Figure 5), the multiplexer sequence is also as shown in Figure 7.
For both multiplexer sequences shown in Figure 6 and Figure 7, the frame duration is 13 CK32 cycles
(where CK32 = 32768 Hz), therefore, the resulting sample rate is 32768 Hz / 13 = 2520.6 Hz.
Table 3 summarizes the various AFE input configurations.
Multiplexer Frame
MUX_DIV[3:0] = 3 Conversions
Settle
CK32
MUX STATE S
0
Fig. 2:
IA
Fig. 3:
IA
Fig. 5:
IA
1
2
S
0
VA
IB
VA
Not Used
VA
VB
CROSS
MUX_SYNC
11/5/2010
Figure 6: States in a Multiplexer Frame (MUX_DIV[3:0] = 3)
Multiplexer Frame
MUX_DIV = 4 Conversions
Settle
CK32
MUX STATE S
0
Fig. 4:
IA
CROSS
1
2
VA
IB
3
S
0
VB
MUX_SYNC
11/5/2010
Figure 7: States in a Multiplexer Frame (MUX_DIV[3:0] = 4)
Table 3: ADC Input Configuration
Pin
ADC
Channel
Required
Setting
Comment
IAP ADC0
Differential mode must be selected with DIFFA_E = 1 (I/O
IAN
ADC1
DIFFA_E = 1
RAM 0x210C[4]). The ADC results are stored in CE RAM
location ADC0 (CE RAM 0x0), and ADC1 (CE RAM 0x1) is not
disturbed.
IBP ADC2
IBN ADC3
DIFFB_E = 1
or
RMT_E = 1
For locally connected sensors (Figure 2 and Figure 4), the
differential input must be enabled by setting DIFFB_E (I/O
RAM 0x210C[5].
For the remote connected sensor (Figure 3 and Figure 5)
with a remote shunt sensor, RMT_E (I/O RAM 0x2709[3])
must be set.
In both cases, the ADC results are stored in RAM location
ADC2 (CE RAM 0x2), and ADC3 (CE RAM 0x3) is not
disturbed.
VA ADC10
--
Single-ended mode only. The ADC result is stored in RAM
location ADC10 (CE RAM 0xA).
VB ADC9
--
Single-ended mode only (71M6542F only). The ADC result
is stored in RAM location ADC9 (CE RAM 0x9).