MC74 Datasheet, PDF (3/12 Pages) ON Semiconductor – Serial Digital Temperature Sensor

MC74
DC ELECTRICAL CHARACTERISTICS (VDD = 3.3 V or 5.0V ^(5), –40°C ≤ TA ≤ 125°C, unless otherwise noted.)
Symbol
Characteristic
Min
Typ
Max
Unit
Power Supply
VPOR
Power–On Reset Threshold
(VDD Falling Edge or Rising Edge)
V
1.2
—
2.2
IDD
IDD–STANDBY
Operating Current
(VDD = 5.5V, Serial Port Inactive) ⁽¹⁾
Standby Supply Current
(VDD = 3.3 V, Serial Port Inactive) ⁽⁴⁾
mA
—
200
350
mA
—
5.0
10
Temperature–to–Bits Converter
TERR
CR
Temperature Accuracy MC74A
+25°C ≤ TA ≤ +85°C
0°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ 0°C
Conversion Rate ⁽²⁾
°C
–2.0
—
+2.0
–3.0
—
+3.0
—
±2.0
—
4.0
8.0
—
sa/sec
Serial Port Interface
VIH
VIL
VOL
Logic Input High
Logic Input Low
SDA Output Low
IOL = 3 mA ⁽³⁾
IOL = 6 mA ⁽³⁾
0.8 x VDD
—
—
V
—
—
0.2 x VDD
V
V
—
—
0.4
—
—
0.6
CIN
Input Capacitance SDA, SCL
—
5.0
—
pF
ILEAK
I/O Leakage
–1.0
0.1
1.0
mA
1. Operating current is an average value integrated over multiple conversion cycles. Transient current may exceed this specification.
2. Maximum guaranteed conversion time after Power–On RESET (POR to DATA_RDY) is 250 msec.
3. Output current should be minimized for best temperature accuracy. Power dissipation within the MC74 will cause self–heating and
temperature drift error.
4. SDA and SCL must be connected to VDD or GND.
5. VDD = 3.3V for MC74A5–33SNTR. VDD = 5.0V for MC74A5–50T. All part types of the MC74 will operate properly over the wider power supply
range of 2.7V to 5.5V. Each part type is tested and specified for rated accuracy at its nominal supply voltage. As VDD varies from the nominal
value, accuracy will degrade 1°C/V of VDD change.
SERIAL PORT AC TIMING (VDD = 3.3 V or 5.0V, –40°C ≤ (TA = TJ) ≤ 125°C; CL = 80 pF unless otherwise noted.)
Symbol
Characteristic
Min
Typ
fSMB
SMBus Clock Frequency
10
—
tLOW
Low Clock Period (10% to 10%)
4.7
—
tHIGH
High Clock Period (90% to 90%)
4.0
—
tR
SMBus Rise Time (10% to 90%)
—
—
tF
SMBus Fall Time (90% to 10%)
—
—
tSU(START)
Start Condition Setup Time (90% SCL to 10% SDA)
(for Repeated Start Condition)
4.0
—
tH(START)
tSU–DATA
tH–DATA
tSU(STOP)
tIDLE
tPOR
Start Condition Hold Time
Data in Setup Time
Data in Hold Time
Stop Condition Setup Time
Bus Free Time Prior to New Transition
Power–On Reset Delay (VDD ≥ VPOR (Rising Edge))
4.0
—
1,000
—
1,250
—
4.0
—
4.7
—
—
500
Max
100
—
—
1,000
300
—
—
—
—
—
—
—
Unit
kHz
msec
msec
nsec
nsec
msec
msec
nsec
nsec
msec
msec
msec
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