LTC2978C View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC2978C' PDF : 64 Pages View PDF
LTC2978
Pin Functions
PIN NAME
VSENSEM6
VSENSEP7
VSENSEM7
VOUT_EN0
VOUT_EN1
VOUT_EN2
VOUT_EN3
VOUT_EN4
VOUT_EN5
VOUT_EN6
VOUT_EN7
VIN_EN
DNC
VIN_SNS
VPWR
VDD33
VDD33
VDD25
WP
PWRGD
SHARE_CLK
WDI/RESETB
FAULTB00
FAULTB01
FAULTB10
FAULTB11
SDA
SCL
ALERTB
CONTROL0
CONTROL1
ASEL0
ASEL1
REFP
REFM
VSENSEP0
VSENSEM0
VDACM0
VDACP0
VDACP1
PIN NUMBER PIN TYPE DESCRIPTION
1*
In
DC/DC Converter Differential (–) Output Voltage-6 Sensing Pin
2*
In
DC/DC Converter Differential (+) Output Voltage or Current-7 Sensing Pin
3*
In
DC/DC Converter Differential (–) Output Voltage or Current-7 Sensing Pin
4
Out
DC/DC Converter Enable-0 Pin. Output High Voltage Optionally Pulled Up to 12V by 5µA
5
Out
DC/DC Converter Enable-1 Pin. Output High Voltage Optionally Pulled Up to 12V by 5µA
6
Out
DC/DC Converter Enable-2 Pin. Output High Voltage Optionally Pulled Up to 12V by 5µA
7
Out
DC/DC Converter Enable-3 Pin. Output High Voltage Optionally Pulled Up to 12V by 5µA
8
Out
DC/DC Converter Open-Drain Pull-Down Output-4
9
Out
DC/DC Converter Open-Drain Pull-Down Output-5
10
Out
DC/DC Converter Open-Drain Pull-Down Output-6
11
Out
DC/DC Converter Open-Drain Pull-Down Output-7
12
0ut
DC/DC Converter VIN ENABLE Pin. Output High Voltage Optionally Pulled Up to 12V by 5µA
13
Do Not Connect Do Not Connect to This Pin
14
In
VIN SENSE Input. This Voltage is Compared Against the VIN On and Off Voltage Thresholds in Order to
Determine When to Enable and Disable, Respectively, the Downstream DC/DC Converters.
15
In
VPWR Serves as the Unregulated Power Supply Input to the Chip (4.5V to 15V). If a 4.5V to 15V Supply
Voltage is Unavailable, Short VPWR to VDD33 and Power the Chip Directly from a 3.3V Supply. Bypass to
GND with 0.1µF Capacitor.
16
In/Out If Shorted to VPWR, it Serves as 3.13V to 3.47V Supply Input Pin. Otherwise, it is a 3.3V Internally
Regulated Voltage Output (Use 0.1µF Decoupling Capacitor to GND).
17
In
Input for Internal 2.5V Sub-Regulator. Short This Pin to Pin 16
18
In/Out 2.5V Internally Regulated Voltage Output. Bypass to GND with a 0.1µF Capacitor.
19
In
Digital Input. Write-Protect Input Pin, Active High
20
Out
Power Good Open-Drain Output. Indicates When Outputs are Power Good. Can be Used as System
Power-On Reset. The Latency of This Signal May Be as Long as the ADC Latency. See Note 6.
21
In/Out Bidirectional Clock Sharing Pin. Connect a 5.49k Pull-Up Resistor to VDD33.
22
In
Watchdog Timer Interrupt and Chip Reset Input. Connect a 10k Pull-Up Resistor to VDD33. Rising Edge
Resets Watchdog Counter. Holding This Pin Low for More Than tRESETB Resets the Chip.
23
In/Out Open-Drain Output and Digital Input. Active Low Bidirectional Fault Indicator-00. Connect a 10k Pull-Up
Resistor to VDD33.
24
In/Out Open-Drain Output and Digital Input. Active Low Bidirectional Fault Indicator-01. Connect a 10k Pull-Up
Resistor to VDD33.
25
In/Out Open-Drain Output and Digital Input. Active Low Bidirectional Fault Indicator-10. Connect a 10k Pull-Up
Resistor to VDD33.
26
In/Out Open-Drain Output and Digital Input. Active Low Bidirectional Fault Indicator-11. Connect a 10k Pull-Up
Resistor to VDD33.
27
In/Out PMBus Bidirectional Serial Data Pin
28
In
PMBus Serial Clock Input Pin (400kHz Maximum)
29
Out
Open-Drain Output. Generates an Interrupt Request in a Fault/Warning Situation
30
In
Control Pin 0 Input
31
In
Control Pin 1 Input
32
In
Ternary Address Select Pin 0 Input. Connect to VDD33, GND or Float to Encode 1 of 3 Logic States.
33
In
Ternary Address Select Pin 1 Input. Connect to VDD33, GND or Float to Encode 1 of 3 Logic States.
34
Out
Reference Voltage Output. Needs 0.1µF Decoupling Capacitor to REFM.
35
Out
Reference Return Pin. Needs 0.1µF Decoupling Capacitor to REFP.
36*
In
DC/DC Converter Differential (+) Output Voltage-0 Sensing Pin
37*
In
DC/DC Converter Differential (–) Output Voltage-0 Sensing Pin
38*
Out
DAC0 Return. Connect to Channel 0 DC/DC Converter’s GND Sense or Return to GND
39
Out
DAC0 Output
40
Out
DAC1 Output
14
For more information www.linear.com/LTC2978
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