lm27212 National Semiconductor Corporation, lm27212 Datasheet - Page 7

• Manufacturer Part Number: lm27212
• Description: Two-phase Current-mode Hysteretic Buck Controller
• Manufacturer: National Semiconductor Corporation

DAC and References
Error Comparator
Current Limit
Time Delays
t
Electrical Characteristics
type apply over a junction temperature range of -5˚C to +110˚C. Unless otherwise specified, VDD = 5V, SGND = DGND =
SRCK1 = 0V. (Note 5) (Continued)
CPU_PWRGD
Symbol
t
BOOT
I
SS3
Dynamic Output Swing Slew
Rate Control Current
(charging)
VID Pins Input Logic
Low-to-High Transition
Threshold
VID Pins Input Logic
High-to-Low Transition
Threshold
DAC Accuracy Measured at
VREF Pin.
V1R7 Accuracy
VSTP Offset
VBOOT Offset
VSLP Offset
VREF Driving Capability
VDAC Driving Capability
V1R7 Driving Capability
Error Comparator Input Bias
Current (Sourcing)
Error Comparator Input Offset
Voltage
Hysteresis Current
Error Comparator Propagation
Delay
Current Limit Comparator
Input Bias Current
Current Limit Comparator
Input Offset Voltage
Current Limit Setting Current
VBOOT Voltage Holdup Time From assertion of XPOK to assertion of
Power Good Mask For Initial
VID Voltage Settling During
Start Up
Parameter
Specifications with standard typeface are for T
-5˚C
DAC codes from 0.844V to 1.708V.
DAC codes from 0.700V to 0.828V.
-5˚C
DAC codes from 0.844V to 1.708V.
DAC codes from 0.700V to 0.828V.
17kΩ from V1R7 to GND.
VSTP = 1.398V, Measured at VREF pin.
VBOOT = 1.00V, Measured at VREF pin.
VSLP = 0.748V, Measured at VREF pin.
source
sink
source
sink
source
CMP1 = CMP2 = 1.436V.
CMPREF = 1.436V.
Rhys = 17kΩ
Rhys = 170kΩ
20mV overdrive
ILIMREF = 1.436V.
Rhys = 17kΩ, ILIMREF
Rhys = 17kΩ, ILIMREF
Rhys = 170kΩ, ILIMREF
CLK_EN#.
From assertion of CLK_EN# to assertion of
PGOOD.
<
<
Tj
Tj
<
<
85˚C
110˚C
Conditions
7
<
>
<
ILIMx
ILIMx
ILIMx
J
= 25˚C, and those in bold face
0.315
1.674
Min
-1.0
-1.3
-1.3
-1.5
-4.5
-4.5
-4.5
255
255
90
12
82
10
-2
-2
9
3
1.708
11.7
14.3
Typ
335
580
294
250
1.5
1.4
21
98
10
70
21
30
18
5
1.742
Max
0.63
+1.0
+1.3
+1.3
+1.5
+4.5
+4.5
+4.5
415
115
345
38
+2
35
+2
30
9
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Units
mV
mV
mV
mA
mA
mA
mA
mV
mV
ms
µA
µA
µA
µA
µA
µA
µA
µA
µA
ns
µs
%
%
%
%
V
V
V