LP3971SQ-B410EV National Semiconductor, LP3971SQ-B410EV Datasheet - Page 26

• Manufacturer Part Number: LP3971SQ-B410EV
• Description: BOARD EVALUATION LP3971SQ-B410
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LP3971SQ-B410EV

• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 9, Non-Isolated
• Voltage - Input: 2.7 ~ 5.5V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: LP3971
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Not Compliant

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Designation
Reset Value
SYSTEM CONTROL REGISTER 1 (SCR1) 8H'07
Note: ** denotes EPROM programmable registers for default value.
SYSTEM CONTROL REGISTER 1 (SCR1) 8H'07 DEFINITIONS
Bit
Bit
5:4
1
0
7
6
3
2
1
0
Bit
Access
Access
R/W
R/W
R/W
R/W
R/W
R/W
—
R
R
FPWM3
FPWM2
FPWM1
BPSEN
SENDL
WUPT
WUPS
Name
ECEN
Name
BPSEN
—
7
0
Bypass System enable safety Lock. Prevents activation of PWR_EN when SYS_EN is low.
0 = PWR_EN “AND” with SYS_EN signal
1 = PWR_EN independent of SYS_EN
Reserved
Delay time for High Voltage Power Domains LDO2, LDO3, LDO4, Buck2, and Buck3 after
activation of SYS_EN. V
Buck 3 PWM/PFM Mode Select
0 - Auto Switch between PFM and PWM operation
1 - PWM Mode Only will not switch to PFM
Buck 2 PWM/PFM Mode Select
0 - Auto Switch between PFM and PWM operation
1 - PWM Mode Only will not switch to PFM
Buck 1 PWM/PFM Mode Select
0 - Auto Switch between PFM and PWM operation
1 - PWM Mode Only will not switch to PFM
External Clock Select
0 = Internal Oscillator clock for Buck Converters
1 = External 13 MHz Oscillator clock for Buck Converters
TEST_JIG Pin Wake Up Status
0 = No wake up event
1 = Wake up event
SPARE Pin Wake Up Status
0 = No wake up event
1 = Wake up event
Reserved
Data Code
6
1
2h'2
2h'0
2h'1
2h'3
1**
5
SENDL**
CC
_LDO1 has no delay.
26
0**
Delay mS
4
0.0
0.5
1.0
1.4
FPWM3
Description
Description
3
0
Notes
Default
FPWM2
2
0
FPWM1
1
0
ECEN
0
0