Cherry Semiconductor CS5157HGDR16, CS5157HGD16 Datasheet

Features

■ Dual N-Channel Design

■ Excess of 1MHz Operation

■ 100ns Transient Response

■ 5-Bit DAC

■ Backward Compatible with

Adjustable CS5120/5121

■ 30ns Gate Rise/Fall Times

■ 1% DAC Accuracy

■ 5V & 12V Operation

■ Remote Sense

■ Programmable Soft Start

■ Lossless Short Circuit

Protection

■ V

CC

Monitor

■ 25ns FET Nonoverlap Time

■ V

2

TM

Control Topology

■ Current Sharing

■ Overvoltage Protection

Package Options

CPU 5-Bit Synchronous Buck Controller

CS5157H

Description

Application Diagram

V

ID0

V

ID1

V

ID2

V

ID3

SS

V

ID4

C

OFF

V

FFB

V

FB

COMP
LGnd
V

CC1

V

GATE(L)

PGnd
V

GATE(H)

V

CC2

16 Lead SO Narrow

1

0.33µF

V

ID0

V

ID1

V

ID2

V

ID3

V

ID0

V

ID1

V

ID2

V

ID3

V

CC1

SS

CS5157H

C

OFF

LGnd

V

FB

V

FFB

COMP

IRL3103

IRL3103

0.1µF

12V 5V

2µH

1.3V to 3.5V @ 13A

V

CC2

V

GATE(H)

V

GATE(L)

PGnd

1200µF/10V x 3
AlEl

3.3k

0.1µF

1200µF/10V x 5
AlEl

100pF

330pF

V

ID4

V

ID4

Pentium is a registered trademark of Intel Corporation.

A Company

®

V2is a trademark of Switch Power, Inc.

Rev. 1/27/99

CS5157H

The CS5157H is a 5-bit synchronous
dual N-Channel buck controller. It
is designed to provide unprece­dented transient response for
today’s demanding high-density,
high-speed logic. The regulator
operates using a proprietary control
method, which allows a 100ns
response time to load transients.
The CS5157H is designed to operate
over a 4.25-20V range (V

CC

) using

12V to power the IC and 5V or

12Vas the main supply for conver­sion.

The CS5157H is specifically
designed to power Pentium

®

II pro­cessors and other high performance
core logic. It includes the following
features: on board, 5-bit DAC, short
circuit protection, 1.0% output tol­erance, VCCmonitor, and pro­grammable soft start capability. The
CS5157H is available in 16 pin sur­face mount.

Switching Power Supply for core logic - Pentium

®

II processor

Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: [phone] Fax: [phone]

Email: [e-mail]

Web Site: www.cherry-semi.com

1

2

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

CS5157H

Electrical Characteristics:

0°C < TA< +70°C; 0°C < TJ< +125°C; 8V < V

CC1

< 14V; 5V < V

CC2

< 20V; DAC Code: V

ID4

= V

ID2

=

V

ID1

= V

ID0

= 1; V

ID3

= 0; CV

GATE(L)

and CV

GATE(H)

= 1nF; C

OFF

= 330pF; CSS= 0.1µF, unless otherwise specified.

Absolute Maximum Ratings

Pin Name Max Operating Voltage Max Current

V

CC1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25mA DC/1.5A peak

V

CC2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20mA DC/1.5A peak

SS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-100µA

COMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200µA

VFB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.2µA

C

OFF

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.2µA

V

FFB

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.2µA

V

ID0

- V

ID4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-50µA

V

GATE(H)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100mA DC/1.5A peak

V

GATE(L)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16V/-0.3V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100mA DC/1.5A peak

LGnd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25mA

PGnd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100mA DC/1.5A peak

Operating Junction Temperature, TJ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0° to 150°C

Lead Temperature Soldering

Reflow (SMD styles only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 sec. max above 183°C, 230°C peak

Storage Temperature Range, TS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-65° to 150°C

ESD Susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV

■ Error Amplifier

V

FB

Bias Current VFB= 0V 0.3 1.0 µA

Open Loop Gain 1.25V < V

COMP

< 4V; Note 1 50 60 dB
Unity Gain Bandwidth Note 1 500 3000 kHz
COMP SINK Current V

COMP

= 1.5V; VFB= 3V; VSS> 2V 0.4 2.5 8.0 mA

COMP SOURCE Current V

COMP

= 1.2V; VFB= 2.7V; VSS= 5V 30 50 80 µA

COMP CLAMP Current V

COMP

= 0V; VFB= 2.7V 0.4 1.0 1.6 mA
COMP High Voltage VFB= 2.7V; VSS= 5V 4.0 4.3 5.0 V
COMP Low Voltage VFB=3V 160 600 mV
PSRR 8V < V

CC1

< 14V @ 1kHz; Note 1 60 85 dB

■ V

CC1

Monitor

Start Threshold Output switching 3.75 3.90 4.05 V
Stop Threshold Output not switching 3.70 3.85 4.00 V
Hysteresis Start-Stop 50 mV

■ DAC

Input Threshold V

ID0

, V

ID1

, V

ID2

, V

ID3

, V

ID4

1.00 1.25 2.40 V

Input Pull Up Resistance V

ID0

, V

ID1

, V

ID2

, V

ID3

, V

ID4

25 50 100 kΩ
Pull Up Voltage 4.85 5.00 5.15 V
Accuracy (all codes except 11111) Measure VFB= V

COMP

, 25°C ≤ TJ≤ 125°C 1.0 %

V

ID4VID3VID2VID1VID0

0 1 1 1 1 1.2870 1.3000 1.3130 V
0 1 1 1 0 1.3365 1.3500 1.3635 V
0 1 1 0 1 1.3860 1.4000 1.4140 V
0 1 1 0 0 1.4355 1.4500 1.4645 V
0 1 0 1 1 1.4850 1.5000 1.5150 V

0 1 0 1 0 1.5345 1.5500 1.5655 V
0 1 0 0 1 1.5840 1.6000 1.6160 V

0 1 0 0 0 1.6335 1.6500 1.6665 V
0 0 1 1 1 1.6830 1.7000 1.7170 V

CS5157H

3

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Electrical Characteristics:

0°C < TA< +70°C; 0°C < TJ< +125°C; 8V < V

CC1

< 14V; 5V < V

CC2

< 20V; DAC Code: V

ID4

= V

ID2

=

V

ID1

= V

ID0

= 1; V

ID3

= 0; CV

GATE(L)

and CV

GATE(H)

= 1nF; C

OFF

= 330pF; CSS= 0.1µF, unless otherwise specified.

■ DAC: continued

V

ID4VID3VID2VID1VID0

0 0 1 1 0 1.7325 1.7500 1.7675 V
0 0 1 0 1 1.7820 1.8000 1.8180 V
0 0 1 0 0 1.8315 1.8500 1.8685 V
0 0 0 1 1 1.8810 1.9000 1.9190 V
0 0 0 1 0 1.9305 1.9500 1.9695 V
0 0 0 0 1 1.9800 2.0000 2.0200 V
0 0 0 0 0 2.0295 2.0500 2.0705 V
1 1 1 1 1 1.2191 1.2440 1.2689 V
1 1 1 1 0 2.0790 2.1000 2.1210 V
1 1 1 0 1 2.1780 2.2000 2.2220 V
1 1 1 0 0 2.2770 2.3000 2.3230 V
1 1 0 1 1 2.3760 2.4000 2.4240 V
1 1 0 1 0 2.4750 2.5000 2.5250 V
1 1 0 0 1 2.5740 2.6000 2.6260 V
1 1 0 0 0 2.6730 2.7000 2.7270 V
1 0 1 1 1 2.7720 2.8000 2.8280 V
1 0 1 1 0 2.8710 2.9000 2.9290 V
1 0 1 0 1 2.9700 3.0000 3.0300 V
1 0 1 0 0 3.0690 3.1000 3.1310 V
1 0 0 1 1 3.1680 3.2000 3.2320 V
1 0 0 1 0 3.2670 3.3000 3.3330 V
1 0 0 0 1 3.3660 3.4000 3.4340 V
1 0 0 0 0 3.4650 3.5000 3.5350 V

■ V

GATE(H)

and V

GATE(L)

Out SOURCE Sat at 100mA Measure V

CC1

– V

GATE(L),;VCC2

– V

GATE(H)

1.2 2.0 V

Out SINK Sat at 100mA Measure V

GATE(H)

– V

PGnd

; 1.0 1.5 V

V

GATE(L)

– V

PGnd

Out Rise Time 1V < V

GATE(H)

< 9V; 1V < V

GATE(L)

< 9V 30 50 ns

V

CC1

= V

CC2

= 12V

Out Fall Time 9V > V

GATE(H)

> 1V; 9V > V

GATE(L)

> 1V 30 50 ns

V

CC1

= V

CC2

= 12V

Delay V

GATE(H)

to V

GATE(L)

V

GATE(H)

falling to 2V; V

CC1

= V

CC2

= 8V 25 50 ns

V

GATE(L)

rising to 2V

Delay V

GATE(L)

to V

GATE(H)

V

GATE(L)

falling to 2V; V

CC1

= V

CC2

= 8V 25 50 ns

V

GATE(H)

rising to 2V

V

GATE(H)

, V

GATE(L)

Resistance Resistor to LGnd (Note 1) 20 50 100 kΩ

V

GATE(H)

, V

GATE(L)

Schottky LGnd to V

GATE(H)

@ 10mA 600 800 mV

LGnd to V

GATE(L)

@ 10mA

■ Soft Start (SS)

Charge Time 1.6 3.3 5.0 ms
Pulse Period 25 100 200 ms
Duty Cycle (Charge Time/Pulse Period) × 100 1.0 3.3 6.0 %
COMP Clamp Voltage VFB= 0V; VSS= 0 0.50 0.95 1.10 V
V

FFB

SS Fault Disable V

GATE(H)

= Low; V

GATE(L)

= Low 0.9 1.0 1.1 V

High Threshold 2.5 3.0 V

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

4

CS5157H

Package Pin Description

PACKAGE PIN # PIN SYMBOL FUNCTION

Electrical Characteristics:

0°C < TA< +70°C; 0°C < TJ< +125°C; 8V < V

CC1

< 14V; 5V < V

CC2

< 20V; DAC Code: V

ID4

= V

ID2

=

V

ID1

= V

ID0

= 1; V

ID3

= 0; CV

GATE(L)

and CV

GATE(H)

= 1nF; C

OFF

= 330pF; CSS= 0.1µF, unless otherwise specified.

■ PWM Comparator

Transient Response V

FFB

= 0 to 5V to V

GATE(H)

= 9V to 1V; 100 125 ns

V

CC1

= V

CC2

= 12V

V

FFB

Bias Current V

FFB

= 0V 0.3 µA

■ Supply Current

I

CC1

No Switching 8.5 13.5 mA

I

CC2

No Switching 1.6 3.0 mA

Operating I

CC1

VFB= COMP = V

FFB

813mA

Operating I

CC2

VFB= COMP = V

FFB

25mA

■ C

OFF

Normal Charge Time V

FFB

= 1.5V; VSS= 5V 1.0 1.6 2.2 µs

Extension Charge Time VSS= V

FFB

= 0 5.0 8.0 11.0 µs

Discharge Current C

OFF

to 5V; V

FB

>1V 5.0 mA

■ Time Out Timer

Time Out Time VFB= V

COMP

; V

FFB

= 2V; 10 30 65 µs

Record V

GATE(H)

Pulse High Duration

Fault Mode Duty Cycle V

FFB

= 0V 35 50 70 %

Note 1: Guaranteed by design, not 100% tested in production.

16L SO Narrow

1,2,3,4,6 V

ID0

– V

ID4

Voltage ID DAC input pins. These pins are internally pulled up to 5V
providing logic ones if left open. V

ID4

selects the DAC range. When V

ID4

is High (logic one), the DAC range is 2.10V to 3.50V with 100mV incre­ments. When V

ID4

is Low (logic zero), the DAC range is 1.30V to 2.05V

with 50mV increments. V

ID0

- V

ID4

select the desired DAC output volt­age. Leaving all 5 DAC input pins open results in a DAC output voltage
of 1.2440V, allowing for adjustable output voltage, using a traditional
resistor divider.

5 SS Soft Start Pin. A capacitor from this pin to LGnd in conjunction with

internal 60µA current source provides soft start function for the con­troller. This pin disables fault detect function during Soft Start. When a
fault is detected, the soft start capacitor is slowly discharged by internal
2µA current source setting the time out before trying to restart the IC.
Charge/discharge current ratio of 30 sets the duty cycle for the IC when
the regulator output is shorted.

7C

OFF

A capacitor from this pin to ground sets the time duration for the on
board one shot, which is used for the constant off time architecture.

8V

FFB

Fast feedback connection to the PWM comparator. This pin is connected
to the regulator output. The inner feedback loop terminates on time.

9V

CC2

Boosted power for the high side gate driver.

10 V

GATE(H)

High FET driver pin capable of 1.5A peak switching current. Internal cir­cuit prevents V

GATE(H)

and V

GATE(L)

from being in high state simultane-

ously.

5

CS5157H

Block Diagram

Package Pin Description: continued

PACKAGE PIN # PIN SYMBOL FUNCTION

16L SO Narrow

11 PGnd High current ground for the IC. The MOSFET drivers are referenced to

this pin. Input capacitor ground and the source of lower FET should be
tied to this pin.

12 V

GATE(L)

Low FET driver pin capable of 1.5A peak switching current.

13 V

CC1

Input power for the IC and low side gate driver.

14 LGnd Signal ground for the IC. All control circuits are referenced to this pin.

15 COMP Error amplifier compensation pin. A capacitor to ground should be

provided externally to compensate the amplifier.

16 V

FB

Error amplifier DC feedback input. This is the master voltage feedback
which sets the output voltage. This pin can be connected directly to the
output or a remote sense trace.

Q

V

ID1

V

CC1

SS

COMP

V

FB

V

ID0

LGnd

V

FFB

V

CC2

V

GATE(H)

PGnd

V

GATE(L)

V

ID2

V

ID3

-

+

5 BIT

DAC

C

OFF

Slow Feedback

Maximum

On-Time

Timeout

V

CC1

R

Q

S

C

OFF

One Shot

PWM
COMP

SS High
Comparator

FAULT

Latch

2.5V

Error
Amplifier

Fast Feedback

-

+

V

CC1

Monitor

Comparator

V

ID4

-

+

-

+

-

+

-

+

V

FFB

Low

Comparator

PWM
Comparator

SS Low
Comparator

R

Q

S

Q

R

Q

S

2µA

5V

60µA

Normal

Off-Time

Timeout

Extended

Off-Time

Timeout

Time Out

Timer

(30µs)

Edge Triggered

Off-Time
Timeout

3.90V

3.85V
FAULT

FAULT

GATE(H) = ON

GATE(H) = OFF

PGnd

PWM
Latch

1V

0.7V