SINK AND SOURCE DC/DC CONTROLLER FOR
TERMINATION POWER SUPPLY APPLICATIONS
SC1110
PRELIMINARY - October 9, 2000
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
The SC1110 is a low-cost, full featured, synchronous
voltage-mode controller designed to generate termina-
tion voltage in double data rate (DDR) memory sys-
tems and other applications where wide data bus need
to be actively terminated. Synchronous control of the
MOSFET half bridge allows power flowing bi-
directionally. The termination voltage can be tightly
regulated to track the chipset voltage, i.e. to be exactly
50% of that at all times.
•= Generates termination voltages for active termina-
tion schemes
•= 1% set point accuracy
•= For ±7A output current, transient regulation is bet-
ter than ±80mV
•= VREFIN pin available
•= Buffered VREFOUT for system usage
•= RDSON sensing for over current protection in hiccup
mode
•= Soft start and logic input enabling
•= 250kHz switching for best transient and efficiency
performance
The SC1110 is ideal for low cost implementation of ter-
mination voltage supplies. SC1110 features include
temperature compensated voltage reference, triangle
wave oscillator and current sense comparator circuitry,
and allows the use of inexpensive N-channel power
switches.
•= Gate drive capable for 0.5A sourcing and sinking
APPLICATIONS
•= For DDR memory systems
•= For active termination schemes in high speed logic
systems
The SC1110 operates at a fixed 250kHz, providing an
optimum compromise between efficiency, transient
performance, external component size, and cost.
ORDERING INFORMATION
DEVICE(1)
SC1110CSTR
Note:
PACKAGE
TEMP. RANGE (TJ)
SO-14
0 - 125°C
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
TYPICAL APPLICATION CIRCUIT
REFOUT
+5Vcc
+
C1
R1
5k
R2
1.24k
R3
10
C10,11
2 x 560uF
C7
1.0
C8,9
Vin 2.5V
0.01
U1
R4
1k
2 x 10uF
C2
0.1
SC1110
C4
0.022
_
1
2
3
4
5
6
7
14
13
12
11
10
9
VCC
REFOUT
REFIN
SENSE
COMP
BSTL
SS/ENBL
PWRGD
SS/ENBL
OCSET
PWRGD
GND
R5
1k
C3
0.1
C5
0.047
R6
4.7k
C25
0.1
D1
MBRM120
PHASE
DL
BSTH
DH
R7
2.2
Q1
C6
1.0
L1
800 nH
Si9426DY
8
+
R8
2.2
Q2
Si9426DY
C12-14
3 x 560uF
C15-24
10 x 10uF
Vout = 1.25V @ 7A
_
C10-14: Sanyo, 4SP560M
C8,9,15-24: TDK, CC3216AX5R0J106K
L1: Panasonic, ETQP6F0R8L or Falco, QPIP1205-809-3
Q1,Q2 options: Si9426DY, FDS6890A, IRF7401
D1: ON Semi (Motorola)
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320