Rainbow Electronics MAX1386 - Manual (Page 28)

MAX1385/MAX1386
Dual RF LDMOS Bias Controllers
with I
2 C/SPI Interface
28 ______________________________________________________________________________________
IH1 and IH2 (Read/Write)
Write to Channel 1 and Channel 2 High-Current-
Threshold registers by sending the appropriate write
command byte followed by data bits D15–D0 (see
Table 5). Bits D15–D12 are don’t care. Read channel 1
and channel 2 high-current thresholds by sending the
appropriate read command byte. Channel 1 and
Channel 2 Current-Threshold registers are compared to
ADC readings at PGAOUT1 and PGAOUT2. Use the
following equation to find the required threshold code
for a specified threshold current:
where I DRAIN is the current threshold in amperes,
R SENSE is the sense resistor, Av
PGA
is the voltage gain
of the PGA, V REFADC is the ADC reference voltage, and
I THRESH is the resulting threshold register value
in decimal.
IL1 and IL2 (Read/Write)
Write to Channel 1 and Channel 2 Low-Current-
Threshold registers by sending the appropriate write
command byte followed by data bits D15–D0 (see
Table 6). Bits D15–D12 are don’t care. Read channel 1
and channel 2 low-current thresholds by sending the
appropriate read command byte. Channel 1 and
Channel 2 Low-Current Threshold registers are com-
pared to ADC readings at PGAOUT1 and PGAOUT2.
I I R Av
V
THRESH DRAIN SENSE PGA
REFADC
= Ч Ч Ч
4096
FLAG REGISTER
READ
FLAG REGISTER
READ
TIME
TIME
MEASUREMENT VALUE
(TEMPERATURE OR CURRENT)
HIGH THRESHOLD
LOW THRESHOLD
ALARM OUTPUT
OUTPUT-
COMPARATOR MODE
(ACTIVE LOW)
OUTPUT-
INTERRUPT MODE
(ACTIVE LOW)
Figure 10. Hysteresis-Threshold-Mode Timing Diagram
D15 D14 D13 D12
D11
(MSB)
D10 D9 D8 D7 D6 D5 D4 D3 D2 D1
D0
(LSB)
POR X X X X 0 1 1 1 1 1 1 1 1 1 1 1
Bit Value
(°C)
X X X X -256 +128 +64 +32 +16 +8 +4 +2 +1 +0.5 +0.25 +0.125
Table 3. TH1 and TH2 (Read/Write)
X = Don’t care.