1
5 Bit Programmable Synchronous Buck
Converter with Dual LDOs Controller
NIKO-SEM
N1164
AUG-03-2001
GENERAL DESCRIPTION
The N1164 is a 5 bit TTL-compatible input,
digital-to-analog (DAC) programmable, syn-
chronous buck converter with dual LDOs
controller designed specifically to power the
Pentium
II as well as the next generation of
P6 family or other high performance core
logic in desktop personal computer and file
servers CPU applications.
The N1164 switching section provides pro-
grammability of output voltage from 1.3V to
2.05V in 50mV steps and 2.0V to 3.5V in 100
mV increments and the linear sections use
external N-Channel power MOSFETs to
provide fixed output voltages of 1.5V for GTL
bus and 2.5V for clock.
The N1164 monitors all the output voltages.
A signal Power-Good signal is issued when
the core is within
15% of the DAC setting.
Additional features are built-in over-voltage,
over-current protections for the core output
and logic compatible shutdown.
FEATURES
Synchronous operation with high efficiency
TTL-compatible 5 bit DAC, output voltage
selection from 1.3V to 3.5V programmable
High current totem pole output, up to 2 A
for direct driving of the external N-Channel
power MOSFETs.
200 KHz fixed frequency internal oscillator
Fast transient response
Provides 2 regulated voltages, 1.5V and
2.5V for linear section
Power-Good output voltage monitor
Over-Voltage and Over-Current protection
Logic level enable input
High performance and low cost solution
APPLICATIONS
Powering Pentium
II, III or Deschutes,
K6 and other advanced processor
High power DC to DC controller with triple
output supplies
TYPICAL APPLICATION
N1164, Motherboard Power Regulation for Computers
5V
3.3V
12V
ENABLE
VID 0~4
POWER-GOOD
+
+
+
+
+
+
VCORE
N1164
LINEAR
SECTION
SWITCHING
SECTION
1.5V
GTC BUS
2.5V
CLOCK
2
5 Bit Programmable Synchronous Buck
Converter with Dual LDOs Controller
NIKO-SEM
N1164
AUG-03-2001
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND
- 0.3V to 7V
Operating Temperature
Range, T
A
0 to 70 C
BST to GND
-0.3V to 15V
Operating Junction
Temperature Range, T
J
0 to 125 C
Thermal Resistance
Junction to Case,
JC
25 C/W
Storage Temperature
Range, T
STG
-65 to 150 C
Thermal Resistance
Junction to Ambient,
JA
80 C/W
Lead Temperature, T
LEAD
(Soldering, 10 Seconds)
300 C
ELECTRICAL SPECIFICATIONS
<Unless specified: V
CC
= 4.75V ~ 5.25V, GND = PGND = 0V, VOSENSE = V
O
, 0mV < (CS
+
- CS
-
) < 60mV, LDOV = 11.4V ~ 12.6V, T
A
= 25
C>
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
SWITCHING SECTION
Supply Voltage
V
CC
4.5
7
V
Supply Current
V
CC
= 5.0V
8
15
mA
Output Voltage
I
O
= 2A
See Table 1.
Load Regulation
I
O
= 0.3A to 15A
1
%
Line Regulation
All VID Codes
0.5
%
Gain (A
OL
) V
OSENSE
to V
O
35
dB
Current Limit Voltage
55
70
85
mV
Oscillator Frequency
175 200 225
KHz
Oscillator Max Duty Cycle
90
95
%
Peak DH Sink/Source Current
BSTH - DH = 4.5V, DH - PGNDH = 2V
1 A
Peak DL Sink/Source Current
BSTL - DL = 4.5V, DL - PGNDL = 2V
1 A
OVP Threshold Voltage
120
%
OVP Source Current
V
OVP
= 3.0V
10
mA
Power-Good Threshold Voltage
85
115
%
Dead Time
100 200
nS
LINEAR SECTIONS
Quiescent Current
LDOV = 12V
5
mA
Output Voltage (LDO1)
2.45 2.500 2.55
V
Output Voltage (LDO2)
1.47 1.500 1.53
V
Load Regulation
I
O
= 0 to 8A
1
%
Line Regulation
1
%
Output Impedance
1
K
3
5 Bit Programmable Synchronous Buck
Converter with Dual LDOs Controller
NIKO-SEM
N1164
AUG-03-2001
PIN CONFIGURATIONS
PIN DEFINITIONS
Pin #
Pin Name
Pin Function Description
1
AGND
Small signal analog and digital ground
2
GATE1
Gate drive output LDO1
3
LDOS1
Sense input for LDO1
4
LDOS2
Sense input for LDO2
5 V
CC
Input
voltage
6
OVP
High signal out if V
O
>set point +20%
7 PWRGOOD
*
Open collector logic output, high if V
O
within 10% of set point
8
CS-
Current sense input (Negative)
9
CS+
Current sense input (Positive)
10
PGNDL
Power ground for high side switch
11
DH
High side driver output
12
PGNDL
Power ground for low side switch
13
DL
Low side driver output
14
BSTL
Supply for low side driver
15
BSTH
Supply for high side driver
16
EN
*
Logic low shuts down the converter; high or open for normal operation.
17
VOSENSE
Top end of internal feedback chain
18 VID4
*
Programming input (MSB)
19 VID3
*
Programming
input
20 VID2
*
Programming
input
21 VID1
*
Programming
input
22 VID0
*
Programming input (LSB)
23
LDOV
+12V for LDO section
24
GATE2
Gate drive output LDO2
*
: All logic level inputs and outputs are open collector TTL compatible.
4
5 Bit Programmable Synchronous Buck
Converter with Dual LDOs Controller
NIKO-SEM
N1164
AUG-03-2001
OUTPUT VOLTAGE
<Unless specified: V
CC
= 4.75V ~ 5.25V, GND = PGND = 0V, VOSENSE = V
O
, 0mV < (CS
+
- CS
-
) < 60mV, LDOV = 11.4V ~ 12.6V, T
A
= 25
C>
-
Table 1
-
VID
4 3 2 1 0
Min.
(V)
Typ.
(V)
Max.
(V)
0 1 1 1 1
1.274
1.300
1.326
0 1 1 1 0
1.323
1.350
1.377
0 1 1 0 1
1.372
1.400
1.428
0 1 1 0 0
1.421
1.450
1.479
0 1 0 1 1
1.470
1.500
1.530
0 1 0 1 0
1.527
1.550
1.573
0 1 0 0 1
1.576
1.600
1.624
0 1 0 0 0
1.625
1.650
1.675
0 0 1 1 1
1.675
1.700
1.726
0 0 1 1 0
1.724
1.750
1.776
0 0 1 0 1
1.773
1.800
1.827
0 0 1 0 0
1.822
1.850
1.878
0 0 0 1 1
1.871
1.900
1.929
0 0 0 1 0
1.921
1.950
1.979
0 0 0 0 1
1.970
2.000
2.030
0 0 0 0 0
2.019
2.050
2.081
1 1 1 1 1
1.940
2.000
2.060
1 1 1 1 0
2.058
2.100
2.142
1 1 1 0 1
2.156
2.200
2.244
1 1 1 0 0
2.254
2.300
2.346
1 1 0 1 1
2.352
2.400
2.448
1 1 0 1 0
2.450
2.500
2.550
1 1 0 0 1
2.548
2.600
2.652
1 1 0 0 0
2.646
2.700
2.754
1 0 1 1 1
2.744
2.800
2.856
1 0 1 1 0
2.842
2.900
2.958
1 0 1 0 1
2.940
3.000
3.060
1 0 1 0 0
3.038
3.100
3.162
1 0 0 1 1
3.136
3.200
3.264
1 0 0 1 0
3.234
3.300
3.366
1 0 0 0 1
3.332
3.400
3.468
1 0 0 0 0
3.430
3.500
3.570
Note: I
O
= 2.0A in Application Circuit
5
5 Bit Programmable Synchronous Buck
Converter with Dual LDOs Controller
NIKO-SEM
N1164
AUG-03-2001
1.3V (VID=01111) - Turn On Overshoot - 2.0V (VID=11111)
2.05V (VID=00000) - Turn On Overshoot - 3.5V (VID=10000)
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