lm2638m National Semiconductor Corporation, lm2638m Datasheet - Page 2

• Manufacturer Part Number: lm2638m
• Description: Motherboard Power Supply Solution With A 5-bit Programmable Switching Controller And Two Linear Regulator Controllers
• Manufacturer: National Semiconductor Corporation

www.national.com
I
I
I
I
R
SWITCHING SECTION
V
I
f
D
D
R
R
R
V
V
V
V
GA
BW
V
V
t
D
t
t
EN
CC
Q_VCC
Q_VDD
VID
OSC
SS
PWGD
PWBAD
DACOUT
CC_TH1
CC_TH2
DAC_IH
DAC_IL
RAMP_L
RAMP_H
DS_CP
MAX
MIN
SNS1
DS_SRC
DS_SINK
STEP_SS
Symbol
Absolute Maximum Ratings
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Electrical Characteristics
plain type apply for T
V
V
Junction Temperature
Power Dissipation (Note 2)
EA
CC
DD
EN Pin Internal Pull-up Current
Operating V
V
V
CP Pin Resistance
5-Bit DAC Output Voltage
VID Pins Internal Pull-up
Current
Oscillator Frequency
Maximum Duty Cycle
Minimum Duty Cycle
SNS1 Pin Resistance to
Ground
Gate Driver Resistance When
Sourcing Current
Gate Driver Resistance When
Sinking Current
V
Threshold
V
DAC Input High Voltage
DAC Input Low Voltage
Error Amplifier DC Gain
Error Amplifier Unity Gain
Bandwidth
Ramp Signal Valley Voltage
Ramp Signal Peak Voltage
Soft Start Time
Duty Cycle Step Change during
Soft Start
PWGD Response Time
PWGD Response Time
CC
DD
CC
CC
Shutdown Current
Shutdown Current
Power-On-Reset
Shutdown Threshold
A
= T
Parameter
CC
J
Current
= +25˚C. Limits appearing in boldface type apply over the 0˚C to +70˚C range.
V
CC
(Note 1)
= 5V, V
EN = 5V, VID = 10111
EN = 0V, VID Pins Floating
EN = 0V, VID Pins Floating
High Side FET
Low Side FET
(Note 3)
RT = 100 k
RT = 25 k
SNS1 Rises from 0V to Rated
Output Voltage
SNS1 Falls from Rated Output
Voltage to 0V
150˚C
1.6W
17V
7V
DD
Conditions
= 12V unless otherwise specified. Typicals and limits appearing in
2
Operating Ratings
Storage Temperature
ESD Susceptibility
Soldering Time, Temperature (10 sec.)
V
Junction Temperature Range
CC
N −1.5%
Min
204
8.5
3.0
3.5
60
60
2
2
1000
4096
1.25
3.25
12.5
Typ
100
100
245
1.5
1.5
4.0
3.6
8.4
3.4
90
10
90
10
76
(Note 1)
N
6
4
0
6
5
N +1.5%
−65˚C to +150˚C
Max
140
140
286
7.5
4.3
1.3
4.75V to 5.25V
13
15
10
0˚C to +125˚C
3
300˚C
Cycles
3 kV
Units
Clock
MHz
kHz
mA
mA
k
dB
µA
µA
µA
µs
µs
%
%
%
V
V
V
V
V
V
V