LM2984C Datasheet, PDF (6/14 Pages) National Semiconductor (TI) – LM2984C Microprocessor Power Supply System

Block Diagram
Pin Description
Pin No
1
2
3
4
5
6
7
8
9
10
11
Pin Name
V_IN
R_t
C_t
mP_mon
C_mon
Ground
Reset
ON OFF
V_standby
V_buffer
V_OUT
Comments
Positive supply input voltage
Sets internal timing currents
Sets power-up reset delay timing
Microcomputer monitor input
Sets mC monitor timing
Regulator ground
Reset error flag output
Enables disables high current regulators
Standby regulator output (7 5 mA)
Buffer regulator output (100 mA)
Main regulator output (500 mA)
TL H 8821 – 2
External Components
Component Typical Value Component Range
Comments
C_IN
R_t
C_t
C_tc
R_tc
C_mon
R_rst
C_stby
C_buf
C_OUT
1 mF
130k
0 33 mF
0 01 mF
10k
0 47 mF
10k
10 mF
10 mF
10 mF
0 47 mF– 10 mF
24k–1 2M
0 033 mF–3 3 mF
0 001 mF–0 1 mF
1k – 100k
0 047 mF–4 7 mF
5k – 100k
10 mF–no bound
10 mF–no bound
10 mF–no bound
Required if device is located far from power supply filter
Sets internal timing currents
Sets power-up reset delay
Establishes time constant of AC coupled computer monitor
Establishes time constant of AC coupled computer monitor (See
applications section )
Sets time window for computer monitor Also determines period and pulse
width of computer malfunction reset (See applications section )
Load for open collector reset output Determined by computer reset input
requirements
A 10 mF is required for stability but larger values can be used to maintain
regulation during transient conditions
A 10 mF is required for stability but larger values can be used to maintain
regulation during transient conditions
A 10 mF is required for stability but larger values can be used to maintain
regulation during transient conditions
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